What is the male reproductive system made of. Reproductive function of men. Trauma and surgery

The human reproductive system is a functional self-regulating system that flexibly adapts to changes in the state of the external environment and the body itself.

However, when studying the functioning of the female reproductive system, one should always remember that it is characterized by constant variability, the cyclical nature of ongoing processes, and its balance is unusually mobile. Moreover, in a woman's body, not only the state of the organs of the hypothalamic-pituitary-ovarian axis and target organs changes cyclically, but also the function of the endocrine glands, autonomic regulation, water-salt exchange and others. In general, almost all organ systems of a woman undergo more or less profound changes in connection with the menstrual cycle.

In the process of evolutionary development, two types of the ovarian cycle of mammals have been formed. In reflex ovulating animals, after the reproductive system is ready for ovulation, follicle rupture occurs in response to mating. In this process, the main role is played by nervous system. In spontaneously ovulating animals, ovulation occurs regardless of sexual activity, and the time of release of the egg is determined by sequential processes in the reproductive system. The most important in this case are the hormonal mechanisms of regulation with less involvement of the central nervous system (CNS). Spontaneous ovulation characteristic of primates and humans.

An important role in the regulation of the reproductive system is also played by organs that are not directly related to the five described hierarchical levels, primarily the endocrine glands.

Men's reproductive system

The human male reproductive system is a collection of organs of the male reproductive system. The male reproductive organs are divided into internal and external. The internal ones include the sex glands - the testicles (with their appendages), in which spermatozoa develop and the sex hormone testosterone is produced, the vas deferens, seminal vesicles, the prostate gland, and the bulbourethral glands. The external genitalia include the scrotum and the penis. The male urethra, in addition to excreting urine, serves to pass the semen that enters it from the ejaculatory ducts.

The boy's gonads - the testicles, shortly before his birth, descend from the child's abdominal cavity, where they develop, into a skin sac called the scrotum. The scrotum is part of the abdominal cavity and is connected to it by the inguinal canal. After descending through the inguinal canal into the scrotum of the testicles, the inguinal canal is usually overgrown with connective tissue. Descent of the testicles into the scrotum is necessary for normal sperm formation, as it requires a temperature several degrees Celsius lower than the normal temperature. human body. If the testicles remain in the human abdominal cavity, then the formation of full-fledged spermatozoa will not occur in them.

Each testicle contains about a thousand convoluted seminiferous tubules in which spermatozoa are produced. They are produced by the epitheliospermatogenic layer of the convoluted seminiferous tubules, which contains spermatogenic cells located on various stages differentiation (stem cells, spermatogonia, spermatocytes, spermatids and spermatozoa), as well as supporting cells (sustentocytes).

The formation of mature sperm occurs in waves along the tubules. The seminiferous tubules themselves, through thin connecting tubes, are connected to the epididymis, also called epididymis, having the appearance of a highly convoluted tube, reaching a length of up to 6 meters in an adult male. In the epididymis there is an accumulation of mature sperm.

External male genitalia (penis and scrotum)

From each epididymis (epididymis) the vas deferens leaves. It passes from the scrotum through the inguinal canal into the abdominal cavity. Then it goes around the bladder and passes into the lower part of the abdominal cavity and flows into the urethra.

The urethra, also called urethra, is a tube coming from the bladder and having an exit outside, from the human body. In the male body, the urethra runs through the penis. In the penis, the urethra is surrounded by three so-called cavernous bodies. Sometimes they are also subdivided into two proper cavernous bodies and one spongy body, located below, in the furrow between the two cavernous bodies. In its thickness passes the urethra.

Cavernous bodies are a tissue that has a spongy structure, that is, consisting of a large number of small cells. With sexual arousal, an erection occurs, which is necessary for the function of copulation - the cells are filled with blood due to the expansion of the arteries that supply blood to the cavernous bodies.

During sexual intercourse, spermatozoa, suspended in 2-5 ml of seminal fluid, enter the woman's vagina. The seminal fluid contains glucose and fructose, which serve to nourish the spermatozoa, as well as some other components, including mucous substances, which facilitate the passage of sperm through the excretory channels in the human body.

Seminal fluid is formed in the body of a man as a result of consistent work of three different glands. Not far from the confluence of the vas deferens into the urethra, the secret of a pair of so-called seminal vesicles pours into the vas deferens.

Further, the secret of the prostate gland, also called prostate, which is located around urethra at its exit from the bladder. The secret of the prostate is excreted into the urethra through two groups of short narrow ducts that flow into the urethra.

Further, a pair of glands, called cooper glands or bulbourethral glands. They are located at the base of the cavernous bodies located in the penis.

The secretions secreted by the seminal vesicles and cooper glands are alkaline, while the secretions of the prostate are a watery liquid. milky having a characteristic odour.

female reproductive system

The human female reproductive system consists of two main parts: the internal and external genital organs. The external genitalia are collectively referred to as the vulva.

ovaries- a paired organ located in the lower part of the abdominal cavity and held in it by ligaments. In shape, the ovaries, reaching a length of up to 3 cm, resemble an almond seed. During ovulation, the mature egg is released directly into the abdominal cavity, passing through one of the fallopian tubes.

Fallopian tubes otherwise called oviducts. They have a funnel-shaped extension at the end through which a mature ovum (egg) enters the tube. The epithelial lining of the fallopian tubes has cilia, the beating of which creates the movement of fluid flow. This fluid flow sends an egg ready for fertilization into the fallopian tube. The fallopian tubes open at their other end into the upper parts of the uterus, into which the egg is sent through the fallopian tubes. Fertilization of the egg takes place in the fallopian tube. Fertilized ova (eggs) enter the uterus, where they normal development fetus up to delivery.

Uterus- muscular pear-shaped organ. It is located in the middle of the abdominal cavity behind the bladder. The uterus has thick muscular walls. The inner surface of the uterine cavity is lined with a mucous membrane penetrated by a dense network of blood vessels. The uterine cavity connects to the vaginal canal, which passes through a thick muscular ring that protrudes into the vagina. It is called the cervix. Normally, a fertilized egg travels from the Fallopian tubes to the uterus and attaches to the muscular wall of the uterus, developing into a fetus. In the uterus, the normal development of the fetus takes place until childbirth. The length of the uterus in a woman of reproductive age is on average 7-8 cm, width - 4 cm, thickness - 2-3 cm. nulliparous women ranges from 40 to 50 g, and in those who have given birth it reaches 80 g. Such changes occur due to hypertrophy of the muscular membrane during pregnancy. The volume of the uterine cavity is ≈ 5 - 6 cm³.

Vagina- This is a thick muscular tube that comes from the uterus and has an outlet outside the woman's body. The vagina is the recipient of the male copulatory organ during sexual intercourse, the recipient of the seed during intercourse, and is also the birth canal through which the fetus exits after the completion of its intrauterine development in the uterus.

Large labia- it's two skin folds containing inside adipose tissue and venous plexuses running from the lower edge of the abdomen down and back. In an adult woman, they are covered with hair. The large labia perform the function of protecting the woman's vagina from the ingress of microbes and foreign bodies into it.

The labia majora are richly supplied sebaceous glands and border the opening of the urethra (urethra) and the vestibule of the vagina, behind which they grow together. In the lower third of the labia majora are the so-called bartholin glands.

Small labia

The labia minora are located between large labia, and are usually hidden between them. They are two thin skin folds of pink color, not covered with hair. At the front (upper) point of their connection is a sensitive organ, which, as a rule, is the size of a pea, capable of erection. This organ is called the clitoris.

Clitoris in most women it is closed by folds of skin bordering it. This organ develops from the same germ cells as the male penis, therefore it contains cavernous tissue, which fills with blood during sexual arousal, as a result of which the woman's clitoris also increases in size. This phenomenon is similar to male erection also called erection.

A very large number of nerve endings contained in clitoris, as well as in labia minora react to irritation of an erotic nature, so stimulation (stroking and similar actions) of the clitoris can lead to sexual arousal of a woman.

Some African peoples have a custom of the so-called female circumcision when the girls removed clitoris or even labia minora. This leads to a decrease sexual activity women in adulthood, and according to some sources is considered one of the possible causes of the development female infertility in adulthood. In the developed countries of the world, this custom is considered barbaric and is prohibited by law.

Behind (below) the clitoris is the external opening of the urethra (urethra). In women, it serves only to remove urine from the bladder.

Above the clitoris itself in the lower abdomen is a small thickening of adipose tissue, which in adult women is covered with hair. It bears the name venus tubercle.

The hymen is a thin membrane, a fold of mucous membrane, consisting of elastic and collagen fibers. With a hole covering the entrance to the vagina between the internal and external genital organs. During the first sexual intercourse, it is usually destroyed, after childbirth it is practically not preserved.

upper respiratory tract.

The airways (airways) are part of the apparatus external respiration, a set of anatomical structures, which are breathing tubes, through which a mixture of respiratory gases is actively transported from the environment of the body to the lung parenchyma and vice versa - from the lung parenchyma to the environment. So the airways are involved in the performance of the ventilation function of the lungs in order to carry out external respiration.

The respiratory tract is divided into two sections: the upper airways (respiratory) tract and the lower airways (respiratory) tract.

The upper respiratory tract includes the nasal cavity, the nasal part of the pharynx and the oropharynx. The lower respiratory tract includes the larynx, trachea, and bronchial tree. The bronchial tree represents all the extrapulmonary and intrapulmonary branches of the bronchi to the terminal bronchioles. The bronchi and bronchioles supply and discharge respiratory gas mixtures to the lung parenchyma and from it to the upper respiratory tract. The lung parenchyma is a part of the external respiratory apparatus, consisting of pulmonary acini. The pulmonary acinus begins with the terminal (terminal) bronchiole, which branches into the inspiratory bronchioles. Respiratory bronchioles branch into alveolar ducts. The alveolar ducts terminate in the alveolar sacs. The terminal and respiratory bronchioles, as well as the alveolar ducts, make up the alveolar tree. The walls of all elements of the alveolar tree are composed of alveoli.
The airways and lung parenchyma are a probabilistic structure. Like most living structures, they have the property of scale invariance.
In the parenchyma of the lungs, which is not classified as the respiratory tract, a cyclic process of external respiration is carried out, part of which is diffusion gas exchange.
Space inside respiratory tract, the volume of the respiratory tract, is often called the anatomical dead space, harmful space due to the fact that there is no diffusion exchange of gases in it.
The airways perform important functions. They provide cleansing, moisturizing and warming of the inhaled mixture.

gases (inhaled air). The airways are one of the actuating mechanisms for regulating the flow of gas mixtures during breathing. This occurs due to expansion and narrowing of the glottis and bronchi, which are synchronous to the act of inhalation and exhalation, which changes the aerodynamic resistance to the flow of respiratory gas mixtures. Violation of prediction in the implementation of the respiratory function leads to a mismatch between the mechanisms of control of respiratory movements and control of the airway lumen. In this case, the expansion or narrowing of the bronchi may occur too early/late in relation to the respiratory movements and/or be excessive/insufficient. This can cause difficulty in inhaling or exhaling. An example of this is shortness of breath during attacks of bronchial asthma.

Lungs.

Lungs- respiratory organs in humans, all mammals, birds, reptiles, most amphibians, as well as some fish (lungfish, lobe-finned and multi-finned).

The lungs are also called respiratory organs in some invertebrates (in some mollusks, holothurians, arachnids). In the lungs, gas exchange takes place between the air in the lung parenchyma and the blood flowing through the pulmonary capillaries.

human lungs- paired respiratory organ. The lungs are laid in the chest cavity, adjacent to the right and left to the heart. They have the shape of a semi-cone, the base of which is located on the diaphragm, and the top protrudes 1-3 cm above the collarbone into the neck. The lungs have a convex costal surface (sometimes there are imprints from the ribs on the lungs), a concave diaphragmatic and median surface facing the median plane of the body. This surface is called mediastinal (mediastinal). All organs located in the middle between the lungs (heart, aorta and a number of other blood vessels, trachea and main bronchi, esophagus, thymus, nerves, The lymph nodes and ducts), make up the mediastinum ( mediastinum). On the mediastinal surface of both lungs there is a recess - the gates of the lungs. They include the bronchi, the pulmonary artery and two pulmonary veins. pulmonary artery branches parallel to the branching of the bronchi. On the mediastinal surface of the left lung there is a rather deep cardiac pit, and on the front edge is a cardiac notch. The main part of the heart is located here - to the left of the midline.

The right lung has 3 lobes and the left has 2 lobes. The skeleton of the lung is formed by tree-branching bronchi. Every lung is covered serosa- pulmonary pleura and lies in the pleural sac. The inner surface of the chest cavity is covered with parietal pleura. Outside, each of the pleurae has a layer of glandular cells that secrete pleural fluid into the pleural fissure (the space between the wall of the chest cavity and the lung). Each lobe of the lungs consists of segments - sections that resemble an irregular truncated cone facing the root of the lung, each of which is ventilated by a constant segmental bronchus and is supplied by the corresponding branch pulmonary artery. The bronchus and artery occupy the center of the segment, and the veins that drain blood from the segment are located in the connective tissue septa between adjacent segments. The right lung usually has 10 segments (3 in upper lobe, 2 in the middle and 5 in the lower), in the left lung - 8 segments (4 each in the upper and lower lobe). The lung tissue inside the segment consists of pyramidal lobules (lobules) 25 mm long, 15 mm wide, the base of which is facing the surface . The bronchus enters the top of the lobule, which by successive division forms 18-20 terminal bronchioles in it. Each of the latter ends with a structural and functional element of the lungs - the acinus. The acinus consists of 20-50 alveolar bronchioles, dividing into alveolar ducts; the walls of both are densely dotted with alveoli. Each alveolar passage passes into the terminal sections - 2 alveolar sacs. Alveoli are hemispherical protrusions and consist of connective tissue and elastic fibers, lined with a thin transparent epithelium and braided with a network of blood capillaries. In the alveoli, gas exchange takes place between the blood and atmospheric air. At the same time, oxygen and carbon dioxide pass in the process of diffusion from the blood erythrocyte to the alveoli, overcoming the total diffusion barrier from the epithelium of the alveoli, the basement membrane and the wall of the blood capillary, with a total thickness of up to 0.5 μm, in 0.3 s. The diameter of the alveoli is from 150 microns in an infant to 280 microns in an adult and 300-350 microns in the elderly. The number of alveoli in an adult is 600-700 million, in a newborn baby - from 30 to 100 million. The total area inner surface alveoli changes between exhalation and inhalation from 40 m² to 120 m² (for comparison, the area of ​​\u200b\u200bthe human skin is 1.5-2.3 m²). Thus, air is delivered to the alveoli through a tree-like structure - the tracheobronchial tree, starting from the trachea and further branching into main bronchi, lobar bronchi, segmental bronchi, lobular bronchi, terminal bronchioles, alveolar bronchioles and alveolar passages.

45. Gas exchange (biological), gas exchange between the body and the environment. From environment oxygen continuously enters the body, which is consumed by all cells, organs and tissues; the carbon dioxide formed in it and an insignificant amount of other gaseous products of metabolism are excreted from the body. G. is necessary for almost all organisms, without it it is impossible normal exchange matter and energy, and hence life itself.

a) Skeleton upper limb: on each side includes the bones of the shoulder girdle (scapula and collarbone) and the bones of the free upper limb (humerus, bones of the forearm and hand). Bones of the shoulder girdle: * The shoulder blade is a flat triangular bone located on the back of the chest in the upper lateral part of the body at the level of 2-7 ribs, connected to the spinal column and ribs with the help of muscles. In the scapula, two surfaces are distinguished (costal - anterior and dorsal - posterior), three edges and three corners. The shoulder blade connects to the clavicle. *Clavicle - C (English) - shaped curved long bone that connects to the sternum and ribs. Bones of the free upper limb: * Humerus - refers to long bones, it distinguishes between the middle part (diaphysis) and two ends (upper - proximal and lower - distal epiphyses). * The bones of the forearm - the ulna, the radius, are also long bones, in accordance with this, they distinguish between the diaphysis, proximal and distal epiphyses. *The composition of the hand includes small bones of the wrist, five long bones of the metacarpus and bones of the fingers of the hand. The bones of the wrist form a vault, concavity facing the palm. In a newborn, they are only outlined; gradually developing, they become clearly visible only by the age of seven, and the process of their ossification ends much later (at 10-13 years). By this time, the ossification of the phalanges of the fingers ends. Of particular importance is 1 finger in connection with the labor function. It has great mobility and is opposed to all other fingers.

b) Skeleton lower limb: on each side, the bones of the pelvic girdle (pelvic bones) and the bones of the free lower limb (femur, bones of the lower leg and foot) enter. The sacrum is connected to the pelvic bones. The bones of the pelvic girdle: * Pelvic bone consists of three bones - the ilium (occupies the upper position), ischial and pubic (located below). They have bodies that fuse with each other at the age of 14-16 years in the region of the acetabulum. They have round depressions where the heads of the femurs of the legs enter. Bones of the free lower limb: * Femur- the most massive and longest tubular among the long bones of the skeleton. * The bones of the lower leg, the composition includes the tibia and fibula, which are long bones. The first is larger than the second. * The bones of the foot are formed by the bones: tarsus (proximal part of the skeleton of the foot), metatarsus and phalanges of the toes. The human foot forms an arch that rests on the calcaneus and on the anterior ends of the metatarsal bones.

There are longitudinal and transverse arches of the foot. The longitudinal, springy arch of the foot is unique to humans, and its formation is associated with upright posture. The weight of the body is evenly distributed along the arch of the foot, which has great importance when carrying heavy loads. The vault acts like a spring, softening the shocks of the body when walking. The vaulted arrangement of the bones of the foot is supported by a large number of strong articular ligaments. With prolonged standing and sitting, carrying heavy loads, wearing narrow shoes, the ligaments are stretched, which leads to flattening of the foot, and then they say that flat feet have developed. Rickets can also contribute to the development of flat feet.

The spinal column is, as it were, the axis of the whole body; it connects to the ribs, to the bones of the pelvic girdle, and to the skull. There are cervical (7 vertebrae), thoracic (12 vertebrae), lumbar (5 vertebrae), sacral (5 vertebrae) and coccygeal (4-5 vertebrae) sections of the spine. The spinal column consists of 33-34 vertebrae connected to each other. The spinal column occupies about 40% of the body length and is its main core, support. A vertebra consists of the vertebral body, vertebral arch and processes. The vertebral body is located anterior to the other parts.

Above and below, the vertebral body has rough surfaces, which, through the intervertebral cartilages, connect the bodies of individual vertebrae into a flexible, but strong column. Behind the body is an arc, which, together with the posterior surface of the body, forms the vertebral foramen. The vertebral foramina form the spinal canal along the entire length of the spine, in which the spinal cord is placed. Muscles are attached to the processes of the vertebrae. Between the vertebrae are intervertebral discs from fibrous cartilage; they contribute to the mobility of the spinal column.

Disc height changes with age.

The process of ossification of the spinal column begins in the prenatal period and ends completely by the age of 21-23. In a newborn child, the spinal column is almost straight, the bends characteristic of an adult are only outlined and develop gradually. The first to appear is cervical lordosis (bending forward with a bulge) when the baby begins to hold the head (6-7 weeks). By six months, when the child begins to sit, a thoracic kyphosis (a curve directed backwards) develops. When the child begins to walk, lumbar lordosis is formed. With the formation of lumbar lordosis, the center of gravity moves backward, preventing the body from falling in a vertical position.

Curves of the spine are a specific feature of a person and arose in connection with vertical position body. Thanks to the bends, the spinal column is springy.

Shocks and shocks when walking, running, jumping are weakened and faded, which protects the brain from concussions. The movements between each pair of adjacent vertebrae have a small amplitude, while the entire set of segments of the spinal column has significant mobility. In the spinal column, movements are possible around the frontal axis (flexion by 160 degrees, extension by 145 degrees), around the sagittal axis (abduction and adduction with an amplitude of 165 degrees), around vertical axis(rotation to the sides up to 120 degrees) and, finally, springy movements due to changes in the curves of the spine.

As a person grows, bones grow in length and thickness. The growth of bones in thickness occurs due to cell division of the inner layer of the periosteum. In length, young bones grow due to the cartilage located between the body of the bone and its ends. The development of the skeleton in men ends by the age of 20-25, in women - at 18-21 years.

Muscle tissues determine all types of motor processes within the body, as well as the movement of the body and its parts in space. This is ensured by the special properties of muscle cells - excitability and contractility. All muscle tissue cells contain the thinnest contractile fibers - myofibrils, formed by linear protein molecules - actin and myosin. When they slide relative to each other, the length of the muscle cells changes.

There are three types muscle tissue: striated, smooth and cardiac (Fig. 12.1). Striated (skeletal) muscle tissue is built from many multinucleated fiber-like cells 1-12 cm long. The presence of myofibrils with light and dark areas that refract light differently (when viewed under a microscope) gives the cell a characteristic transverse striation, which determined the name of this type of fabric. All skeletal muscles, muscles of the tongue, walls are built from it. oral cavity, pharynx, larynx, upper esophagus, mimic, diaphragm. Features of striated muscle tissue: speed and arbitrariness (i.e., the dependence of contraction on the will, desire of a person), consumption of a large amount of energy and oxygen, fatigue.

Rice. 12.1. Types of muscle tissue: a - striated; 6 - cardiac; c - smooth.

Cardiac tissue consists of transversely striated mononuclear muscle cells, but has different properties. The cells are not arranged in a parallel bundle, like skeletal cells, but branch, forming a single network. Due to the many cellular contacts, the incoming nerve impulse is transmitted from one cell to another, providing simultaneous contraction and then relaxation of the heart muscle, which allows it to perform its pumping function.

Cells of smooth muscle tissue do not have transverse striation, they are fusiform, mononuclear, their length is about 0.1 mm. This type of tissue is involved in the formation of the walls of tube-shaped internal organs and vessels ( digestive tract, uterus, bladder, blood and lymph vessels). Features of smooth muscle tissue: involuntariness and low force of contractions, the ability to prolonged tonic contraction, less fatigue, a small need for energy and oxygen.

49. skeletal muscles human consists of several types of muscle fibers, differing from each other in structural and functional characteristics. Currently, there are four main types of muscle fibers.

Slow phasic fibers of the oxidative type. Fibers of this type are characterized great content myoglobin protein, which is able to bind O2 (similar in its properties to hemoglobin). Muscles that are predominantly composed of fibers of this type are called red because of their dark red color. They perform a very important function of maintaining a person's posture. Limit fatigue in fibers of this type and, consequently, muscles occurs very slowly, due to the presence of myoglobin and a large number of mitochondria. Recovery of function after fatigue occurs quickly.

Fast phasic fibers of the oxidative type. Muscles, which are predominantly composed of this type of fiber, perform rapid contractions without noticeable fatigue, which is explained by the large number of mitochondria in these fibers and the ability to form ATP through oxidative phosphorylation. As a rule, the number of fibers that make up the neuromotor unit in these muscles is less than in the previous group. The main purpose of this type of muscle fibers is to perform fast, energetic movements.

For muscle fibers of all these groups, the presence of one, in last resort, several end plates formed by one motor axon.

Skeletal muscles are an integral part of the human musculoskeletal system. In this case, the muscles perform the following functions:

Provide a certain posture of the human body;

Move the body in space;

Move individual parts of the body relative to each other;

They are a source of heat, performing a thermoregulatory function.

The structure of the nervous system

For ease of study, the unified nervous system is divided into central (brain and spinal cord) and peripheral (cranial and spinal nerves, their plexuses and nodes), as well as somatic and autonomic (or autonomous).

The somatic nervous system mainly carries out the connection of the organism with the external environment: the perception of stimuli, the regulation of movements of the striated muscles of the skeleton, etc.

Vegetative - regulates metabolism and the work of internal organs: heartbeat, peristaltic contraction of the intestine, secretion of various glands, etc. Both of them function in close interaction, however, the vegetative system has some independence (autonomy), managing many involuntary functions.

Spinal cord: left - general plan of the structure;

on the right - cross sections of different departments

The spinal cord is located in the spinal canal and looks like a white cord stretching from the occipital foramen to the lower back. The cross section shows that the spinal cord consists of white (outside) and gray (inside) matter. The gray matter consists of the bodies of nerve cells and has the shape of a butterfly on the transverse layer, from the straightened "wings" of which two anterior and two posterior horns depart. In the anterior horns are centrifugal neurons, from which the motor nerves depart. rear horns include nerve cells (intermediate neurons), to which the processes of sensory neurons that lie in thickenings of the posterior roots are suitable. Connecting with each other, the anterior and posterior roots form 31 pairs of mixed (motor and sensory) spinal nerves.

Each pair of nerves innervates a specific group of muscles and the corresponding area of ​​the skin.

White matter is made up of nerve cells nerve fibers), united in pathways that stretch along the spinal cord "connecting both its individual segments to each other, and the spinal cord to the brain. Some pathways are called ascending, or sensitive, transmitting excitation to the brain, others are descending, or motor, which conduct impulses from the brain to certain segments of the spinal cord.

The spinal cord performs two functions: reflex and conduction. The activity of the spinal cord is under the control of the brain.

The brain is located in cerebral region skulls. Its average weight is 1300–1400 g. After the birth of a person, brain growth continues up to 20 years. Consists of five departments; anterior (large hemispheres), intermediate, middle, posterior and medulla oblongata.

The hemispheres (the newest part in evolutionary terms) reach high development in humans, accounting for 80% of the mass of the brain.

The phylogenetically older part is the brain stem. The trunk includes the medulla oblongata, the medullary (varoli) bridge, the midbrain and the diencephalon. Numerous nuclei of gray matter lie in the white matter of the trunk. The nuclei of 12 pairs of cranial nerves also lie in the brainstem. The brain stem is covered by the cerebral hemispheres.

The medulla oblongata is a continuation of the spinal cord and repeats its structure: furrows also lie on the anterior and posterior surfaces. It consists of white matter (conducting bundles), where clusters of gray matter are scattered - nuclei, from which cranial nerves originate. From above and from the sides, almost the entire medulla oblongata is covered with the cerebral hemispheres and the cerebellum. In the gray matter of the medulla oblongata lie vital centers that regulate cardiac activity, breathing, swallowing, carrying out protective reflexes (sneezing, coughing, vomiting, tearing), secretion of saliva, gastric and pancreatic juice, etc. Damage to the medulla oblongata can be the cause of death due to the cessation heart activity and respiration.

The hindbrain includes the pons and cerebellum. The substance of the pons contains the nuclei of the trigeminal, abducens, facial and auditory nerves.

Cerebellum - its surface is covered with gray matter, under it is white matter, in which there are nuclei - accumulations of white matter. The main function of the cerebellum is the coordination of movements, which determines their clarity, smoothness and maintaining the balance of the body, as well as maintaining muscle tone. The activity of the cerebellum is controlled by the cerebral cortex.

The midbrain is located in front of the pons and is represented by the quadrigemina and the legs of the brain. In the legs of the brain, pathways continue from the medulla oblongata and the pons to the cerebral hemispheres.

The midbrain plays an important role in the regulation of tone and in the implementation of reflexes, due to which standing and walking are possible.

The diencephalon occupies the highest position in the trunk. It consists of visual tubercles (thalamus) and hypothalamus (hypothalamus). The visual cusps regulate the rhythm of cortical activity and are involved in the formation of conditioned reflexes, emotions, etc.

The hypothalamic region is connected with all parts of the central nervous system and with the endocrine glands. It is a regulator of metabolism and body temperature, constancy internal environment organism and functions of the digestive, cardiovascular, urogenital systems and endocrine glands.

forebrain in humans, it consists of highly developed hemispheres and the middle part connecting them. Right and left hemisphere separated from each other by a deep gap, at the bottom of which lies the corpus callosum. The surface of the cerebral hemispheres is formed by gray matter - the cortex, under which is white matter with subcortical nuclei. The total surface of the cerebral cortex is 2000–2500 cm2, its thickness is 2.5–3 mm. It has from 12 to 18 billion neurons arranged in six layers. More than 2/3 of the surface of the cortex is hidden in deep furrows between convex gyri. Three main sulci - central, lateral and parietal-occipital - divide each hemisphere into four lobes: frontal, parietal, occipital and temporal.

Large hemispheres of the brain

bottom surface hemispheres and the brain stem is called the base of the brain.

To understand how the cerebral cortex functions, you need to remember that the human body has a large number of various receptors that can capture the most minor changes in the external and internal environment.

Receptors located in the skin respond to changes in the external environment. Muscles and tendons contain receptors that signal to the brain about the degree of muscle tension and joint movements. There are receptors that respond to changes in the chemical and gas composition of the blood, osmotic pressure, temperature, etc. In the receptor, irritation is converted into nerve impulses. Through sensitive nerve pathways, impulses are conducted to the corresponding sensitive areas of the cerebral cortex, where a specific sensation is formed - visual, olfactory, etc.

functional system, consisting of a receptor, a sensitive pathway and a cortical area where it is projected this species sensitivity, IP Pavlov called the analyzer.

Analysis and synthesis of the information received is carried out in a strictly defined area - the zone of the cortex of pain

The most important areas of the cortex are motor, sensory, visual, auditory, olfactory.

The motor zone is located in the anterior central gyrus in front of the central sulcus of the frontal lobe, the zone of skin-muscular sensitivity is located behind the central sulcus, in the posterior central gyrus of the parietal lobe. The visual zone is concentrated in the occipital zone, the auditory zone is in the superior temporal gyrus. temporal lobe, olfactory and gustatory - in the anterior part of the temporal lobe.

The activity of the analyzers reflects the external material world in our consciousness. This enables mammals to adapt to conditions by changing behavior. A person, knowing natural phenomena, the laws of nature and creating tools of labor, actively changes the external environment, adapting it to his needs.

The cerebral cortex performs the function of a higher analyzer of signals from all receptors of the body and the synthesis of responses into a biologically expedient act. It is the highest organ for coordinating reflex activity and the organ for acquiring temporary connections - conditioned reflexes. The cortex performs an associative function and is the material basis of human psychological activity - memory, thinking, emotions, speech and behavior regulation.

Conducting pathways of the brain connect its parts to each other, as well as to spinal cord(ascending and descending nerve pathways) so that the entire central nervous system functions as one.

53. Higher nervous activity is a complex form of life activity that ensures individual behavioral adaptation of humans and higher animals to changing environmental conditions. The concept of higher nervous activity was introduced by the great Russian physiologist I.P. Pavlov in connection with the discovery of the conditioned reflex as a new, hitherto unknown form of nervous activity.

I.P. Pavlov contrasted the concept of "higher" nervous activity with the concept of "lower" nervous activity, aimed mainly at maintaining the body's homeostasis in the process of its life. Wherein nerve elements, which carry out interaction within the body, are united by nerve connections already by the time of birth. And vice versa, nerve connections, which provide higher nervous activity, are realized in the process of the organism's vital activity in the form life experience. Therefore, lower nervous activity can be defined as an innate form, and higher nervous activity as acquired in the individual life of a person or animal.

The origins of the opposition between higher and lower forms of nervous activity go back to the ideas of the ancient Greek thinker Socrates about the existence of a “lower form of the soul” in animals, which differs from the human soul, which has “mental power”. Long centuries of ideas about the "soul" of man and his unknowability mental activity remained inseparable in the minds of people. Only in the 19th century in the works of the domestic scientist, the founder of modern physiology I.M. Sechenov revealed the reflex nature of brain activity. In the book Reflexes of the Brain, published in 1863, he was the first to attempt an objective study of mental processes. Ideas I.M. Sechenov was brilliantly developed by I.P. Pavlov. Based on the method of conditioned reflexes developed by him, he showed the ways and possibilities of experimental study of the cerebral cortex, which plays a key role in the complex processes of mental activity. The main processes that dynamically replace each other in the central nervous system are the processes of excitation and inhibition. Depending on their ratio, strength and localization, the control influences of the cortex are built. The functional unit of higher nervous activity is the conditioned reflex.

In humans, the cerebral cortex plays the role of "manager and distributor" of all vital functions (IP Pavlov). This is due to the fact that in the course of phylogenetic development, the process of corticalization of functions occurs. It is expressed in the increasing subordination of the body's somatic and vegetative functions to the regulatory influences of the cerebral cortex. In the case of the death of nerve cells in a significant part of the cerebral cortex, a person turns out to be unviable and quickly dies with a noticeable violation of the homeostasis of the most important autonomic functions.

The doctrine of higher nervous activity is one of the greatest achievements of modern natural science: it marked the beginning of a new era in the development of physiology; is of great importance for medicine, since the results obtained in the experiment served as the starting point physiological analysis and pathogenetic treatment(for example, sleep) of certain diseases of the human central nervous system; for psychology, pedagogy, cybernetics, bionics, scientific organization of labor and many other branches of human practical activity

54. A biological signal is any substance that is distinguishable from other substances present in the same environment. Like electrical signals, a biological signal must be separated from noise and transformed in such a way that it can be perceived and evaluated. Such signals are the structural components of bacteria, fungi and viruses; specific antigens; end products of microbial metabolism; unique nucleotide sequences of DNA and RNA; surface polysaccharides, enzymes, toxins and other proteins.

detection systems. To capture the signal and separate it from the noise, a detection system is needed. Such a system is the eye of a researcher conducting microscopy and a gas-liquid chromatograph. It is clear that different systems differ sharply from each other in their sensitivity. However, the detection system must be not only sensitive, but also specific, i.e. distinguish weak signals from noise. In clinical microbiology, immunofluorescence, colorimetry, photometry, chemiluminescent oligonucleotide probes, nephelometry, and assessment of the cytopathic effect of the virus in cell culture are widely used.

Signal amplification. Gain allows you to capture even weak signals. The most common method of signal amplification in microbiology is cultivation, as a result of which each bacterium forms a separate colony on solid nutrient media, and a suspension of identical bacteria in liquid media. For cultivation, it is only necessary to create microorganisms suitable conditions to grow, but it takes a long time. Significantly less time is required for PCR and ligation chain reaction, allowing to identify DNA and RNA, electron amplification (for example, in gas-liquid chromatography), ELISA, concentration and separation of antigens or antibodies by immunosorption and immunoaffinity chromatography, gel filtration and ultracentrifugation. Research laboratories have many methods for detecting and amplifying biological signals, but not all of them have proven their suitability for clinical microbiology.

55. Endocrine glands, or endocrine organs, are called glands that do not have excretory ducts. They produce special substances - hormones that enter directly into the blood.

Hormones are organic substances of various chemical nature: peptide and protein (protein hormones include insulin, somatotropin, prolactin, etc.), amino acid derivatives (adrenaline, norepinephrine, thyroxine, triiodothyronine), steroid (hormones of the gonads and adrenal cortex). Hormones have high biological activity (therefore, they are produced in extremely small doses), specificity of action, distant effect, i.e., they affect organs and tissues located far from the place where hormones are formed. Entering the bloodstream, they are carried throughout the body and carry out humoral regulation functions of organs and tissues, changing their activity, stimulating or inhibiting their work. The action of hormones is based on the stimulation or inhibition of the catalytic function of certain enzymes, as well as in

56. Sensory system - a set of peripheral and central structures of the nervous system responsible for the perception of signals of various modalities from the environment or internal environment. The sensory system consists of receptors, neural pathways, and parts of the brain responsible for processing the received signals. The best known sensory systems are vision, hearing, touch, taste and smell. The sensory system can sense physical properties such as temperature, taste, sound, or pressure.

Analyzers are also called sensor systems. The concept of "analyzer" was introduced by the Russian physiologist I.P. Pavlov. Analyzers (sensory systems) are a set of formations that perceive, transmit and analyze information from the environment and internal environment of the body.

57. Organ of hearing. general information The human hearing organ is a paired organ designed to perceive sound signals, which, in turn, affects the quality of orientation in the environment. The ear is the human hearing organ Sound signals are perceived using a sound analyzer, the main structural unit of which is phonoreceptors. Conducts information in the form of signals to the auditory nerve, which is part of the vestibulocochlear nerve. Final destination receiving signals and the place of their processing - the cortical region auditory analyzer, located in the cerebral cortex, in its temporal lobe. More detailed information about the structure of the organ of hearing is presented below.

The structure of the organ of hearing The organ of hearing in humans is the ear, in which there are three sections: The outer ear, represented by the auricle, the external auditory canal and the tympanic membrane. The auricle consists of elastic cartilage covered with skin and has a complex shape. In most cases, it is motionless, its functions are minimal (compared to animals). The length of the external auditory meatus is from 27 to 35 mm, the diameter is about 6-8 mm. Its main task is to conduct sound vibrations to the eardrum. Finally, the tympanic membrane, formed by connective tissue, is the outer wall tympanic cavity and separates the middle ear from the outer; The middle ear is located in the tympanic cavity, a depression in the temporal bone. The tympanic cavity contains three auditory ossicles known as the malleus, anvil, and stirrup. In addition, the middle ear has Eustachian tube connecting the middle ear cavity with the nasopharynx. Interacting with each other, the auditory ossicles direct sound vibrations to the inner ear; The inner ear is a membranous labyrinth located in the temporal bone. Internally, the ear is divided into the vestibule, the three semicircular canals, and the cochlea. Only the cochlea belongs directly to the organ of hearing, while the other two elements of the inner ear are part of the organ of balance. The snail has the appearance of a thin cone, twisted in the form of a spiral. Along its entire length, with the help of two membranes, it is divided into three channels - the scala vestibule (upper), the cochlear duct (middle) and the scala tympani (lower). At the same time, the lower and upper channels are filled with a special fluid - perilymph, and the cochlear duct is filled with endolymph. The main membrane of the cochlea contains the organ of Corti - an apparatus that perceives sounds; The organ of Corti is represented by several rows of hair cells that act as receptors. In addition to the receptor cells of Corti, the organ contains an integumentary membrane hanging over the hair cells. It is in the organ of Corti that the vibrations of the fluids filling the ear are converted into a nerve impulse. Schematically, this process is as follows: sound vibrations are transmitted from the fluid that fills the cochlea to the stirrup, due to which the membrane with the hair cells located on it begins to vibrate. During oscillations, they touch the integumentary membrane, which leads them to a state of excitation, and this, in turn, entails the formation of a nerve impulse. Each hair cell is connected to a sensory neuron, the totality of which forms the auditory nerve.

human reproduction

Human reproduction (human reproduction), a physiological function necessary for the preservation of man as a biological species. The process of reproduction in humans begins with conception (fertilization), i.e. from the moment of penetration of the male reproductive cell (sperm) into the female reproductive cell (egg, or ovum). The fusion of the nuclei of these two cells is the beginning of the formation of a new individual. The human fetus develops in a woman's uterus during pregnancy, which lasts 265–270 days. At the end of this period, the uterus begins to spontaneously rhythmically contract, the contractions become stronger and more frequent; the amniotic sac (fetal bladder) ruptures and, finally, a mature fetus is "expelled" through the vagina - a child is born. Soon the placenta (afterbirth) departs. The whole process, starting with contractions of the uterus and ending with the expulsion of the fetus and placenta, is called childbirth.

In more than 98% of cases, at conception, only one egg is fertilized, which leads to the development of one fetus. In 1.5% of cases, twins (twins) develop. About one in 7,500 pregnancies results in triplets.

Only biologically mature individuals have the ability to reproduce. During puberty (puberty), a physiological restructuring of the body occurs, manifested in physical and chemical changes that mark the onset of biological maturity. In a girl during this period, fat deposits around the pelvis and hips increase, the mammary glands grow and round, hair growth of the external genitalia and armpits develops. Shortly after the appearance of these, the so-called. secondary, sexual characteristics, the menstrual cycle is established.

In boys, in the process of puberty, the physique changes noticeably; the amount of fat on the abdomen and hips decreases, the shoulders become wider, the timbre of the voice decreases, hair appears on the body and face. Spermatogenesis (the formation of sperm) in boys begins somewhat later than menstruation in girls.

Reproductive system of women

reproductive organs. The female internal reproductive organs include the ovaries, fallopian tubes, uterus, and vagina.

The ovaries - two glandular organs weighing 2-3.5 g each - are located behind the uterus on both sides of it. In a newborn girl, each ovary contains an estimated 700,000 immature eggs. All of them are enclosed in small round transparent bags - follicles. The latter alternately ripen, increasing in size. The mature follicle, also called the graafian vesicle, ruptures to release the egg. This process is called ovulation. The egg then enters the fallopian tube. Usually, during the entire reproductive period of life, approximately 400 fertile eggs are released from the ovaries. Ovulation occurs monthly (around the middle menstrual cycle). The bursting follicle plunges into the thickness of the ovary, overgrows with scar connective tissue and turns into a temporary endocrine gland - the so-called. corpus luteum that produces the hormone progesterone.

The fallopian tubes, like the ovaries, are paired formations. Each of them stretches from the ovary and connects to the uterus (from two different sides). The length of the pipes is approximately 8 cm; they are slightly bent. The lumen of the tubes passes into the uterine cavity. The walls of the tubes contain inner and outer layers of smooth muscle fibers, which are constantly contracting rhythmically, which provides undulating movements of the tubes. From the inside, the walls of the tubes are lined with a thin membrane containing ciliated (ciliated) cells. As soon as the egg enters the tube, these cells, along with muscle contractions of the walls, ensure its movement into the uterine cavity.

The uterus is a hollow muscular organ located in the pelvic region of the abdominal cavity. Its dimensions are approximately 8 cm. Pipes enter it from above, and from below its cavity communicates with the vagina. The main part of the uterus is called the body. The non-pregnant uterus has only a slit-like cavity. The lower part of the uterus, the cervix, about 2.5 cm long, protrudes into the vagina, where its cavity, called the cervical canal, opens. When a fertilized egg enters the uterus, it sinks into its wall, where it develops throughout pregnancy.

The vagina is a hollow cylindrical formation 7–9 cm long. It is connected to the cervix along its circumference and goes to the external genital organs. Its main functions are the outflow of menstrual blood to the outside, the reception of the male genital organ and male seed during copulation and providing a passage for the fetus to be born. In virgins, the external entrance to the vagina is partially closed by a crescent-shaped fold of tissue, the hymen. This fold usually leaves enough room for menstrual blood to drain; after the first copulation, the opening of the vagina expands.

Milk glands. Full (mature) milk in women usually appears approximately 4–5 days after birth. When a baby suckles, there is an additional powerful reflex stimulus for the glands to produce milk (lactation).

The menstrual cycle is established shortly after the onset of puberty under the influence of hormones produced by the endocrine glands. In the early stages of puberty, pituitary hormones initiate ovarian activity, triggering a complex of processes that take place in the female body from puberty to menopause, i.e. for approximately 35 years. The pituitary gland cyclically secretes three hormones that are involved in the process of reproduction. The first - follicle-stimulating hormone - determines the development and maturation of the follicle; the second - luteinizing hormone - stimulates the synthesis of sex hormones in the follicles and initiates ovulation; the third - prolactin - prepares the mammary glands for lactation.

Under the influence of the first two hormones, the follicle grows, its cells divide, and a large fluid-filled cavity is formed in it, in which the oocyte is located. The growth and activity of follicular cells are accompanied by their secretion of estrogens, or female sex hormones. These hormones can be found both in the follicular fluid and in the blood. The term estrogen comes from the Greek oistros (fury) and is used to refer to a group of compounds that can cause oestrus (oestrus) in animals. Estrogens are present not only in the human body, but also in other mammals.

Luteinizing hormone stimulates the rupture of the follicle and the release of the egg. After that, the cells of the follicle undergo significant changes, and a new structure develops from them - the corpus luteum. Under the action of luteinizing hormone, it, in turn, produces the hormone progesterone. Progesterone inhibits the secretory activity of the pituitary gland and changes the state of the mucous membrane (endometrium) of the uterus, preparing it to receive a fertilized egg, which must be introduced (implanted) into the uterine wall for subsequent development. As a result, the wall of the uterus thickens significantly, its mucosa, containing a lot of glycogen and rich in blood vessels, creates favorable conditions for the development of the embryo. The coordinated action of estrogens and progesterone ensures the formation of the environment necessary for the survival of the embryo and the preservation of pregnancy.

The pituitary gland stimulates the activity of the ovaries approximately every four weeks (ovulatory cycle). If fertilization does not occur, most of the mucous along with the blood is rejected and enters the vagina through the cervix. Such cyclical bleeding is called menstruation. For most women, bleeding occurs approximately every 27 to 30 days and lasts 3 to 5 days. The entire cycle ending with the shedding of the lining of the uterus is called the menstrual cycle. It is regularly repeated throughout the reproductive period of a woman's life. The first periods after puberty may be irregular, and in many cases they are not preceded by ovulation. Menstrual cycles without ovulation, often found in young girls, are called anovulatory.

Menstruation is not at all the release of "spoiled" blood. In fact, the discharge contains very small amounts of blood mixed with mucus and uterine lining tissue. The amount of blood lost during menstruation is different for different women, but on average does not exceed 5-8 tablespoons. Sometimes minor bleeding occurs in the middle of the cycle, which is often accompanied by mild abdominal pain, characteristic of ovulation. Such pains are called mittelschmerz (German "median pains"). Pain experienced during menstruation is called dysmenorrhea. Usually dysmenorrhea occurs at the very beginning of menstruation and lasts 1-2 days.

Pregnancy. The release of the egg from the follicle in most cases occurs approximately in the middle of the menstrual cycle, i.e. 10-15 days after the first day of the previous menstruation. Within 4 days, the egg moves through the fallopian tube. Conception, i.e. fertilization of the egg by the sperm takes place in the upper part of the tube. This is where the development of a fertilized egg begins. Then it gradually descends through the tube into the uterine cavity, where it is free for 3-4 days, and then penetrates into the wall of the uterus, and the embryo and structures such as the placenta, umbilical cord, etc. develop from it.

Pregnancy is accompanied by many physical and physiological changes in the body. Menstruation stops, the size and mass of the uterus increase sharply, the mammary glands swell, in which preparations for lactation are underway. During pregnancy, the volume of circulating blood exceeds the initial one by 50%, which significantly increases the work of the heart. In general, the period of pregnancy is a heavy physical load.

Pregnancy ends with the expulsion of the fetus through the vagina. After childbirth, after about 6 weeks, the size of the uterus returns to its original size.

Menopause. The term "menopause" is derived from the Greek words meno ("monthly") and pausis ("cessation"). Thus, menopause means the cessation of menstruation. The entire period of extinction of sexual functions, including menopause, is called menopause.

Menstruation also stops after the surgical removal of both ovaries, performed in certain diseases. Exposure of the ovaries to ionizing radiation can also lead to the cessation of their activity and menopause.

Approximately 90% of women stop menstruating between the ages of 45 and 50. This can happen suddenly or gradually over many months, when periods become irregular, the intervals between them increase, the bleeding periods themselves gradually shorten and the amount of blood lost decreases. Sometimes menopause occurs in women under the age of 40. Equally rare are women with regular menstruation at 55 years of age. Any bleeding from the vagina that occurs after menopause requires immediate medical attention.

Menopausal symptoms. During the period of cessation of menstruation or immediately before it, many women develop a complex set of symptoms that together make up the so-called. menopausal syndrome. It consists of various combinations of the following symptoms: "hot flashes" (sudden redness or sensation of heat in the neck and head), headaches, dizziness, irritability, mental instability and joint pain. Most women complain only of "hot flashes", which can occur several times a day and are usually more severe at night. Approximately 15% of women do not feel anything, noting only the cessation of menstruation, and maintain excellent health.

Many women misunderstand what to expect from menopause and menopause. They are worried about the possibility of loss of sexual attractiveness or the sudden cessation of sexual activity. Some are afraid of mental disorders or general withering. These fears are based predominantly on hearsay rather than medical facts.

Reproductive system of men

The function of reproduction in men is reduced to the production of a sufficient number of spermatozoa with normal mobility and the ability to fertilize mature eggs. The male reproductive organs include the testicles (testes) with their ducts, the penis, and an accessory organ, the prostate gland.

Testicles (testicles, testicles) - paired glands of an oval shape; each of them weighs 10–14 g and is suspended in the scrotum on the spermatic cord. The testicle consists of a large number of seminiferous tubules, which, merging, form the epididymis - the epididymis. This is an oblong body adjacent to the top of each testicle. The testicles secrete male sex hormones, androgens, and produce sperm containing male germ cells - spermatozoa.

Spermatozoa are small, very mobile cells, consisting of a head carrying a nucleus, a neck, a body, and a flagellum, or tail. They develop from special cells in thin convoluted seminiferous tubules. Maturing spermatozoa (the so-called spermatocytes) move from these tubules into larger ducts that flow into spiral tubules (efferent or excretory tubules). From them, spermatocytes enter the epididymis, where their transformation into spermatozoa is completed. The epididymis contains a duct that opens into the vas deferens of the testis, and that, connecting with the seminal vesicle, forms the ejaculatory (ejaculatory) duct of the prostate gland. At the moment of orgasm, spermatozoa, together with the fluid produced by the cells of the prostate gland, vas deferens, seminal vesicle and mucous glands, are ejected from the seminal vesicle into the ejaculatory duct and further into the urethra of the penis. Normally, the volume of the ejaculate (semen) is 2.5-3 ml, and each milliliter contains more than 100 million spermatozoa.

Fertilization. Once in the vagina, the spermatozoa, with the help of tail movements, and also due to the contraction of the walls of the vagina, move into the fallopian tubes in about 6 hours. The chaotic movement of millions of spermatozoa in the tubes creates the possibility of their contact with the egg, and if one of them penetrates it, the nuclei of the two cells merge and fertilization is completed.

Infertility

Infertility, or the inability to reproduce, can be due to many reasons. Only in rare cases is it due to the absence of eggs or sperm.

female infertility. A woman's ability to conceive is directly related to age, general health, stage of the menstrual cycle, as well as psychological mood and lack of nervous tension. Physiological causes of infertility in women include the absence of ovulation, the unavailability of the uterine endometrium, infections of the genital tract, narrowing or obstruction of the fallopian tubes, and congenital anomalies of the reproductive organs. Other pathological conditions can lead to infertility if left untreated, including various chronic diseases, nutritional disorders, anemia, and endocrine disorders.

diagnostic tests. Finding out the cause of infertility requires a complete medical examination and diagnostic laboratory tests. The patency of the fallopian tubes is checked by blowing them. To assess the condition of the endometrium, a biopsy is performed (removal of a small piece of tissue) followed by microscopic examination. The function of the reproductive organs can be judged by the analysis of the level of hormones in the blood.

male infertility. If a semen sample contains more than 25% abnormal sperm, fertilization rarely occurs. Normally, 3 hours after ejaculation, about 80% of spermatozoa retain sufficient mobility, and after 24 hours, only a few of them show sluggish movements. Approximately 10% of men suffer from infertility due to insufficient sperm. These men usually have one or more of the following defects: a small number of spermatozoa, a large number of their abnormal forms, a decrease or complete absence sperm motility, small ejaculate volume. The cause of infertility (sterility) may be inflammation of the testicles caused by mumps (mumps). If the testicles have not yet descended into the scrotum at the onset of puberty, the cells that produce sperm can be irreversibly damaged. The outflow of seminal fluid and the movement of spermatozoa is prevented by obstruction of the seminal vesicles. Finally, fertility (the ability to reproduce) may be reduced as a result of infectious diseases or endocrine disorders.

diagnostic tests. In semen samples, determine total number spermatozoa, the number of normal forms and their mobility, as well as the volume of the ejaculate. For microscopic examination of the testicular tissue and the condition of the cells of the tubules, a biopsy is performed. The secretion of hormones can be judged by determining their concentration in the urine.

Psychological (functional) infertility. Emotional factors also affect fertility. It is believed that the state of anxiety may be accompanied by a spasm of the tubes, which prevents the passage of the egg and sperm. Overcoming feelings of tension and anxiety in women in many cases creates the conditions for successful conception.

Treatment and research. Great progress has been made in the treatment of infertility. Modern methods of hormone therapy can stimulate spermatogenesis in men and ovulation in women. With the help of special instruments, it is possible to examine the pelvic organs for diagnostic purposes without surgical intervention, and new microsurgical methods make it possible to restore the patency of the pipes and ducts.

Fertilization in vitro (in vitro fertilization). An outstanding event in the field of infertility was the birth in 1978 of the first child that developed from an egg fertilized outside the mother's body, i.e. extracorporeally. This "test-tube" child was the daughter of Leslie and Gilbert Brown, born in Oldham (UK). Her birth completed years of research work by two British scientists, gynecologist P. Steptoe and physiologist R. Edwards. Due to the pathology of the fallopian tubes, the woman could not become pregnant for 9 years. To get around this obstacle, eggs taken from her ovary were placed in a test tube, where they were fertilized by adding her husband's sperm and then incubated under special conditions. When the fertilized eggs began to divide, one of them was transferred to the mother's uterus, where implantation took place and the natural development of the embryo continued. The baby born by caesarean section was normal in all respects. After that, in vitro fertilization (literally "in glass") became widespread. Currently, such assistance to infertile couples is provided in many clinics in various countries, and as a result, thousands of "test-tube" children have already appeared.

Freezing embryos. Recently, a modified method has been proposed, which has given rise to a number of ethical and legal problems: freezing of fertilized eggs for later use. This technique, developed mainly in Australia, allows a woman to avoid repeated egg retrieval procedures if the first implantation attempt fails. It also makes it possible to implant the embryo into the uterus at the right time in a woman's menstrual cycle. Embryo freezing (at the most initial stages development) with its subsequent thawing also allows you to achieve a successful pregnancy and childbirth.

Transfer of the egg. In the first half of the 1980s, another promising method of combating infertility was developed, called egg transfer, or in vivo fertilization - literally "in a living" (organism). This method involves the artificial insemination of a woman who has agreed to become a donor with the sperm of the future father. A few days later, the fertilized egg, which is a tiny fetus (embryo), is gently washed out of the donor's uterus and placed in the uterus of the expectant mother, who carries the fetus and gives birth. In January 1984, the first child was born in the United States, which developed after the transfer of the egg.

Egg transfer is a non-surgical procedure; it can be done in the doctor's office without anesthesia. This method can help women who do not produce eggs or have genetic disorders. It can also be used for blocked fallopian tubes, if the woman does not want to undergo repeated procedures, often required for in vitro fertilization. However, a child born this way does not inherit the genes of its mother.

Bibliography

Bayer K., Sheinberg L. Healthy lifestyle. M., 1997

For the preparation of this work, materials from the site http://bio.freehostia.com were used.

All living beings reproduce. Reproduction - the process by which organisms create more organisms like them - is one of the things that distinguishes living things from non-living things.

In humans, the male and female reproductive systems work together to make a baby. In the human reproductive process, two types of germ cells or gametes are involved.

A male gamete, or sperm, and a female gamete, an egg or ovum, meet in a woman's reproductive system to create a child. The male and female reproductive systems are essential for reproduction.

People pass on some characteristics of themselves to the next generation through their genes, special carriers of human traits.

Parents of genes pass on to their offspring what makes children like others in theirs, but they also make each child unique. These genes come from the father's sperm and mother's eggs, which are produced by the male and female reproductive systems.

Understanding the male reproductive system, what it does, and the issues that can affect it can help you better understand your child's reproductive health.

About the male reproductive system

Most species have two sexes: male and female. Each gender has its own unique reproductive system. They differ in shape and structure, but both are specifically designed to produce, feed, and transport either eggs or sperm.

Unlike the female, whose reproductive organs are located entirely inside the pelvis, the male has reproductive organs, or sex organs, that are both inside and outside the pelvis. The male genitalia include:

• testicles;
• the duct system, which consists of the epididymis and the vas deferens;
• accessory glands, which include the seminal vesicles and the prostate gland;
• penis.

In a pubescent guy, the two testicles (or testicles) produce and store millions of tiny sperm cells. The testicles are oval and about 2 inches (5 centimeters) long and 1 inch (3 centimeters) in diameter.

Testicles are also part of endocrine system as they produce hormones including testosterone. Testosterone is a major part of puberty in boys, and as a guy makes his way through puberty, his testicles produce more and more.

Testosterone is the hormone that causes boys to produce deeper voices, bigger muscles, body and facial hair, and stimulates sperm production.

Along with the testicles are the epididymis and the vas deferens, which make up the ductal system of the male reproductive organs.

Seed oozing is a muscular tube that runs up along the testicles and transports a spermatic fluid called semen. The epididymis is a set of coiled tubes (one for each testicle) that connects to the seed of the seed.

The epididymis and testicles hang in a pouch-like shape behind the pelvis, called the scrotum. This bag of skin helps regulate the temperature of the testicles, which must be cooler than body temperature in order to obtain sperm.

The scrotum changes size to support correct temperature. When the body is cold, the scrotum contracts and becomes stiffer to retain body heat.

As it heats up, the scrotum becomes larger and more flexible to get rid of additional heat. It happens without the guy thinking it through. The brain and nervous system give the scrotum a cue to resize.

Accessory glands, including the seminal vesicles and the prostate gland, provide fluids that lubricate the duct system and nourish the sperm. The seminal vesicles are sac-like structures attached to the vas deferens towards the bladder.

The prostate gland, which produces some of the semen, surrounds the ejaculatory ducts at the base of the urethra, just below the bladder.

The urethra is the duct that carries semen out of the body through the penis. The urethra is also part of the urinary system because it is also the channel through which urine passes as it leaves the bladder and exits the body.

The penis actually consists of two parts: the shaft and the glans. The shaft is the main part of the penis, and the glans is the tip (sometimes called the glans).

At the end of the head is a small slit or opening through which seeds and urine exit the body through the urethra. The inside of the penis is made up of spongy tissue that can expand and contract.

All boys are born with a foreskin, a fold of skin at the end of the penis that covers the glans. Some boys are circumcised, which means that a doctor or clergyman cuts off the foreskin.

Circumcision is usually done during the first few days of a boy's life. Although circumcision is not a medical necessity, parents who choose to circumcise their sons often do so on the basis of religious beliefs, concerns about hygiene or cultural or social reasons.

Boys who have circumcised penises and those who don't are no different: all penises work and feel the same, whether or not it has been removed. foreskin.

What does the male reproductive system do

The male reproductive organs work together to produce and release sperm into the female's reproductive system during intercourse. The male reproductive system also produces sex hormones that help a boy develop into a sexually mature person during puberty.

When a boy is born, he has all parts of his reproductive system in place, but for now puberty cannot be played. When puberty begins, usually between the ages of 9 and 15, the pituitary gland — which is located near the brain — releases hormones that stimulate the testicles to produce testosterone.

The production of testosterone leads to many physical changes. Although the timing of these changes is different for each guy, the stages of puberty usually follow a predetermined sequence:

• During the first stage of male puberty, the scrotum and testicles grow.
• Then the penis becomes longer, and the seminal vesicles and prostate gland grow.
• Hair begins to grow in the pubic area and then on the face and armpits. At this time, the boy's voice also intensifies.
• Boys also have a growth spurt during puberty as they reach their adult height and weight.

Sperm

Men who have reached puberty produce millions of sperm cells every day. Each sperm is extremely small: only 1/600 of an inch (0.05 millimeter). Sperm develops in the testicles in a system of tiny tubes called seminiferous tubules.

At birth, these tubules contain simple, round cells, but during puberty, testosterone and other hormones cause these cells to transform into sperm.

Cells divide and change until they have a head and a short tail like tadpoles. The head contains the genetic material (genes).

The sperm use their tails to push themselves towards the epididymis where they complete their development. It takes about 4-6 weeks for sperm to pass through the epididymis.

The sperm then passes to the vas deferens or the spermatozoon. The seminal vesicles and prostate produce a whitish fluid called seminal fluid, which mixes with semen to form semen when a male is sexually stimulated.

The penis, which usually hangs, becomes heavy when a man is sexually aroused. The tissues in the penis fill with blood and become hard and erect (erection). The stiffness of the penis makes it easier to insert into a woman's vagina during intercourse.

When the penis is stimulated, the muscles around the reproductive organs contract and force semen to pass through the duct system and urethra. The semen is pushed out of the man's body through the urethra, a process called ejaculation. Every time a guy ejaculates, he can contain up to 500 million sperm.

When a female ejaculates during intercourse, sperm is deposited in the female's vagina. From the vagina, semen makes its way through the cervix and travels through the uterus with the help of uterine contractions.

If a mature egg is in one of the female fallopian tubes, a single sperm can enter, as well as fertilization or conception. This fertilized egg is now called a zygote and contains 46 chromosomes - half of the egg and half of the sperm.

The genetic material from a man and a woman is combined in such a way that a new person can be created. The zygote divides again and again as it grows in the female womb, maturing over the course of pregnancy into an embryo, fetus, and finally a newborn baby.

Boys can sometimes have problems with their reproductive system, including:

Traumatic trauma

Even minor injury testicles can cause severe pain, bruising, or swelling. Most testicular injuries occur when the testicles are struck or crushed, usually during sports or other injury.

Testicular torsion when one of the testicles twists around, cutting off its blood supply, is also a medical emergency that is thankfully not common. Surgery is needed to unwind the cord and save the testicle.

Varicocele

This is a varicose vein (abnormally swollen vein) in the network of veins that run from the testicles. Varicoceles often develop while a boy is going through puberty.

A varicocele is not usually harmful, but it can damage the testicle or reduce sperm production. Take your son to see your doctor if he is concerned about changes in his testicles.

testicular cancer

It is one of the most common types of cancer in men under 40 years of age. This happens when cells in the testicle divide abnormally and form a tumor.

Testicular cancer can spread to other parts of the body, but if it is found early, the rate of cure is excellent. Adolescent boys should be encouraged to learn how to perform testicular self-examinations.

Epididymitis

This is an inflammation of the epididymis, the coiled tubes that connect the testes to the testes. It is usually caused by an infection such as sexually transmitted chlamydia and results in pain and swelling near one of the testicles.

Dropsy

A hydrocele is when fluid collects in the membranes surrounding the testicles. Hydrocells can cause swelling in the scrotum around the testicle, but are usually painless. In some cases, surgery may be required to correct the condition.

Inguinal hernia

When part of the intestine penetrates through an abnormal opening or weakening of the abdominal wall and into the groin or scrotum, it is known as an inguinal hernia. A hernia may look like a bulge or swelling in the groin area. She is treated with surgery.

Disorders affecting the penis include:

• Inflammation of the penis. Symptoms of penile inflammation include redness, itching, swelling, and pain. Balanitis is when the glans (head of the penis) become inflamed. Posthit is an inflammation of the foreskin, usually due to a yeast or bacterial infection.
• Hypospadias. In this disorder, the urethra opens to bottom side penis, not at the tip.
• Phimosis. This is tightness of the foreskin and is common in newborns and young boys. It usually gets better without treatment. If this interferes with urination, circumcision (removal of the foreskin) may be recommended.
• Paraphimosis. This can develop when the foreskin of a boy's uncircumcised penis is retracted (ripped off to expose the glans) and trapped so that it cannot be returned to an unprofitable position. As a result, blood flow to the head of the penis may be affected and the boy may have pain and swelling. The doctor may use a lubricant to make a small incision so that the foreskin can be pulled forward. If that doesn't work, circumcision is recommended.
• Ambiguous genitals. In most boys born with this disorder, the penis may be very small or non-existent, but testicular tissue is present. In a small number of cases, a child may have both testicles and ovarian tissue.
• Micropenis. This is a disorder in which the penis, although normally formed, is significantly below average size as defined by standard measurements.

If your son has symptoms, problems with his reproductive system, talk to your doctor - many problems with the male reproductive system can be treated. The doctor is also a good resource for your son if he has questions about growth and sexual development.

The male reproductive organs are considered less complex than the female ones. However, they are by no means limited to externally visible genitalia. Inside the male body, there is a complex system of tubules and ducts connected to the reproductive organs.

The epididymis is the epididymis of the testis. It is a highly convoluted canal and is part of the vas deferens. The appendage is lined with connective tissue adjacent to the testis and located on the upper part of the testicle. In this channel, spermatozoa mature and acquire the ability to be fertilized.

Another part of the sperm storage and transport system is a long curved canal - the vas deferens. The seminal vesicles are connected to it: two formations located behind the bladder. They produce part of the seminal fluid, which is necessary for the movement and nutrition of spermatozoa.

important organ for men's health - the prostate gland. The size of a chestnut, it is located below the bladder. It forms 60% of the seminal fluid necessary for the transport of spermatozoa.

It would seem that for fertilization, that is, for the ultimate goal, only one sperm is needed. But mother nature has programmed it so that every day male body produces millions of germ cells. From the testicle, they enter the epididymis, an organ that stores and provides mature spermatozoa. nutrients. The complete process of sperm maturation, from the germ cell in the seminiferous tubule to the mature form in the vas deferens, takes approximately 74 days. Normally, in order to become a father, a man must have at least 60-70 million spermatozoa in his semen.

The representatives of the stronger sex who have had this disease in the post-puberty period need to be especially attentive to their men's health and carefully check the possibility of having children. Mumps damages the sperm progenitor cells in the testicles. In most cases, only one testicle is affected, however some men develop complete infertility.

Varicocele

Varicocele is the presence of varicose veins in the testicles. The development of this pathology leads to a violation of blood flow in this area. An increase in blood supply leads to an increase in temperature in the testicle. This causes a decrease in testosterone levels, which in turn disrupts sperm production.

Cryptorchidism (undescended testicle)

While the boy is in the womb, his testicles are located inside the abdominal cavity. Shortly before birth, they descend into the scrotum. If the descent of the testicle does not occur before birth, this condition in the newborn is called cryptorchidism. Usually, during the first 6 months of life, the testicles descend into the scrotum on their own. However, it must be remembered that unresolved and untreated cryptorchidism can lead to impaired fertility and other pathological conditions.

testicular cancer

If you are having difficulty conceiving, you should definitely get tested for possible testicular cancer. A malignant tumor, developing in this organ, can destroy normal testicular tissue, which will lead to infertility.

Not so long ago, the negative impact of diabetes on the quality of spermatozoa was proven. In addition, hormonal imbalance due to overweight in type II diabetes also leads to problems in childbearing.

Trauma and surgery

Severe mechanical damage to the testicles disrupts the production of germ cells, which leads to the development of infertility. In addition, an injury sustained during sports or as a result of an accident can cause a rupture of the blood vessels supplying the testicles with blood. Unfortunately, surgery to correct an undescended testicle or an inguinal hernia can lead to impaired sperm production.

Anatomical anomalies

In some individuals, the fluid released during sexual intercourse does not contain spermatozoa at all. This phenomenon may be the result of an obstruction or a violation anatomical structure epididymis, which prevents germ cells from mixing with seminal fluid to form sperm.

Overheat

Heating has a damaging effect on the physiological production of spermatozoa. Too long stay hot tub can lead to an increase in testicular temperature and temporarily disrupt sperm production.

Severe stress, fatigue, or alcohol use

Overwork , anxiety and excessive alcohol consumption reduce sexual desire . But although until recently most cases of impotence were explained psychological reasons however, newer oral drugs may improve treatment outcomes.

Wrong image life

You can not discount the individual behavioral patterns, which can also affect fertility. For example, the negative impact overweight, eating unhealthy and unbalanced foods in combination with in a sedentary manner life.

The reproductive function of a man depends on underwear and living and working conditions!

The male ability to leave offspring in science has a term - fertility or reproduction. As it turned out, male reproduction is closely related to underwear that he is wearing. Male reproduction depends directly on the underwear and living conditions of a man. How does underwear affect male reproduction? Everything is very simple. Scientists have conducted studies that have shown that for normal spermatogenesis (the formation of spermatozoa, male germ cells of reproduction), the temperature of the testicles and scrotum should be 3-4 degrees lower than the normal body temperature of a man. That is why the male reproductive organs are located at some distance from the body, so that they are cool and active.

Reproductive function of a man

There is another important feature - if a man freezes so that the testicles do not freeze and lose their reproductive function, the testicles are pressed closer to the body. If it is very hot, on the contrary, the testicles descend away from the body. Nature took care of our men.

Remember! Overheating of the genital organs adversely affects the reproductive function of men.

Living and working conditions are important! Certain conditions life and work of men can, in which overheating of the testicles occurs, can lead to some diseases of the reproductive system. For example, living and working conditions associated with constant exposure to high temperatures or forced sitting position more than three consecutive hours (drivers, office workers, etc.). A heated car seat is detrimental to men on long journeys.

Men's underwear should maintain a normal temperature of the genitals. Mistresses and loving wives need to pay more attention to their man's wardrobe, especially underwear. Refuse tight-fitting swimming trunks, thongs are especially harmful, which strongly tighten the genitals, preventing them from freely regulating their temperature for the normal functioning of the reproductive function.

Underwear for men

What should be underwear for men?

The best underwear for a man is loose, spacious boxer shorts. They should be made of cotton or silk, without any unnecessary artificial impurities. Also, scientists recommend sleeping naked, it is useful. like this simple advice it is possible to preserve male reproductive function and produce healthy offspring. After all, children are the true meaning of life. Let's save and increase the family - the cell of society! :)

ATTENTION! IMPORTANT! The information is provided for informational purposes only and should not be used as a guide to self-medication. Self-medication can be dangerous for your health! Please, before use, consult your doctor! The need for the appointment, methods and doses of the use of the agent (or method) are determined solely by the attending physician!