Secondary sexual characteristics in girls. Secondary and primary sexual characteristics of men and women

A number of distinctive features of the structure and functions of the organs of the body, which determine the sex of the organism. Sexual characteristics are divided into biological and social (gender), so-called behavioral characteristics.

Separation

Sexual characteristics are divided into primary, secondary (biological) and tertiary (gender).

Primary and secondary signs are genetically determined, their structure is already laid down in a fertilized egg long before the birth of a child. Further development of sexual characteristics occurs with the participation of hormones.

Primary sexual characteristics

Primary sexual characteristics include those characteristics associated with the reproductive system and relate to the structure of the genital organs.

secondary sexual characteristics

Secondary sexual characteristics, a set of features or characteristics that distinguish one sex from another (with the exception of the gonads, are primary sexual characteristics).

Examples among people: in men - mustache, beard, Adam's apple; in women - a typical development of the mammary glands, the shape of the pelvis, a greater development of fatty tissue. For animals: the characteristic bright plumage of male birds, odorous glands, well-developed horns, fangs in male mammals. The adaptive value in animals lies in the fact that these signs serve to attract individuals of the opposite sex or to fight for their possession. Studies on castration and transplantation of the gonads have shown the relationship between the function of the gonads and the development of sexual characteristics in mammals, birds, amphibians and fish. These experiments allowed the Soviet researcher M. M. Zavadovsky to conditionally divide sexual characteristics into dependent (eusexual), which develop in connection with the activity of the gonads, and independent (pseudosexual), the development of which is carried out independently of the function of the gonads. Animals do not develop dependent sexual characteristics during castration. If by this moment they have already managed to develop, then gradually they lose their functional significance and sometimes completely disappear. As a result of castration of males and females, basically similar forms come out; if such an “asexual” individual is transplanted with a gonad or a sex hormone is injected, then characteristic dependent sexual characteristics of the corresponding sex develop. An example of such experiments is the development in a castrated hen, under the influence of the male sex gland, of a rooster's headdress (comb, beard, earrings), a rooster's voice, and male behavior. Independent sexual Ozaki, such as spurs or cock plumage, develop without the participation of sex hormones, it was possible to establish experiments with the removal of the gonads: these signs are also found in castrated roosters.

In addition to dependent and independent sexual characteristics, there is also a group of somosexual or tissue sex, which are inherent in only one sex, but do not depend on the function of the gonads; in the case of castration, sex differences in these characteristics are completely preserved. This group is characteristic of insects.

Tertiary sex characteristics

Tertiary sexual characteristics in higher living beings are psychological and socio-cultural differences in the behavior of the sexes. Especially in human society, tertiary sex characteristics are highly influenced by different cultures. So, for example, a kilt is a traditional male outfit in Scotland, while in many countries the skirt is considered an item of an exclusively female wardrobe. In modern society, there is a change in sexual (gender) roles - women become more independent, socially active.

anomalies

• Hermaphroditism is the presence in a dioecious organism of signs of both sexes, and these signs are fully developed, intermediate.
• Transgender - primary and secondary sexual characteristics do not coincide with the gender self-identification of the individual.

Sex characteristics in humans

Although the biological sex is laid down at the moment of fertilization of the egg by the sperm, in the early stages sexual characteristics are practically not noticeable. Only in the third month of intrauterine life, male or female genital organs are formed from the general structure. The original structure is noticeable even after birth.

During puberty, the final development of the genital organs and their reproductive functions occurs. At the same time, secondary sexual characteristics begin to appear. Usually, in girls, this process begins somewhat earlier than in boys, but it depends on factors such as heredity, climate and nutrition. The manifestation of sexual characteristics usually occurs in a certain order.

female sex characteristics

• Primary
  • Vulva
  • Clitoris
  • Vagina
  • Uterus
  • Fallopian tubes
  • ovaries
• Secondary
  • Breast
  • Female type pubic hair, perineal hair, inguinal folds, axillary hair
  • Hairiness on arms and legs
  • Menstruation
  • Wide pelvis, narrow shoulders. High percentage of body fat

• Growth of mammary glands
• Appearance of smooth pubic hair
• Pubic hair changes structure
• The appearance of underarm hair
• First menstruation (menarche)

Puberty occurs 4-6 years after the first menstruation

Male sexual characteristics

• Primary
  • Penis
  • testicles
  • Scrotum
  • vas deferens
  • Prostate
  • seminal vesicles
• "Secondary"
  • Hair: pubis, anus, armpits, abdomen, chest, beard, mustache
  • Body structure: narrow hips, broad shoulders. Small percentage of body fat
  • More strongly pronounced Adam's apple
  • Baldness

The order of development in puberty:

• Beginning of testicular growth
• Appearance of pubic hair
• Minor voice change
• first ejaculation
• More coarse pubic hair
• Period of fastest growth
• The appearance of hair on the legs and in the armpits
• breaking voice
• The appearance of facial hair
• Hair on other parts of the body
• Head hair loss

Secondary sexual characteristics are formed during puberty. Their appearance is associated with an increase in the level of certain blood hormones (in men - testosterone and its metabolites). Secondary sexual characteristics characterize the maturity of the organism and its gender.

The appearance of secondary signs of sex

In children before adolescence, sex differences are determined by genetics and gonads. The male chromosome set is normal - 46 XY. This genetics corresponds to the laying in the prenatal period and the further development of the gonads of the testicles and, accordingly, the external genital organs according to the male type.

In childhood (up to 8-9 years on average), there are no other significant physical differences between boys and girls. Then the period of puberty begins, that is. In the debut, the secretion of gonadotropin-releasing hormone of the hypothalamus sharply increases. This biologically active substance acts on the pituitary gland. As a result, in this part of the endocrine system, the production of gonadotropins increases, which in turn stimulate the gonads.

List of signs

Morphological differences between men and women are especially pronounced in young and middle-aged adults. Some of the secondary sex characteristics are obvious, while others may be less noticeable. The list of differences includes the characteristics of hairline, skin, skeletal structure, etc.

List of male secondary sexual characteristics:

• Enlargement of the testicles in volume.(cm. ).
• Penis growth.(cm. )
• Pigmentation of the skin of the scrotum.
• . spermatogenesis.
• sexual behavior. The ability to experience sexual arousal.
• High growth. Body length depends on many factors (heredity, living conditions, diseases in childhood and adolescence, etc.). In men, growth is generally higher, since, other things being equal, growth zones close later (due to later puberty). According to the latest data, men in Russia have an average height of 178 cm (which is 12 cm more than women).
• Large body weight. Weight is determined by both proportions and developed muscles and high bone mineral density. In a young adult normosthenic male 170 cm tall, the average normal weight is about 70 kg (against 64 kg in women of the same height).
• High mineral density of the skeleton. In men, bone mass accounts for about 15% of the total weight (against 10-12% in women). The density peak (at the age of 30) is more pronounced in men, and the decrease in bone density and strength is much slower than in women.
• High percentage of muscle tissue. On average, in men at a young and middle age, the mass of muscles is more than 40-45% of the weight (against 30-35% in women). Muscles are well developed initially and respond better to physical activity.
• Low percentage of adipose tissue. In men under 60 years of age, the mass of fat is normally less than 22-25% of the total weight. On average, men have a mass of fat 2 times less than women with the same weight. It is easier for the representatives of the stronger sex to lose weight. Weight loss is possible without significant restriction of calorie content of food.
• abdominal obesity(). This type of overweight is characterized by the deposition of fat inside the abdominal cavity. Abdominal obesity is often accompanied (dyslipidemia, diabetes mellitus, gout).
• Shorter torso and relatively long limbs. This is especially noticeable when measuring height in a sitting position. In men, this height is 5 cm less (with the same body length). Basically, the differences appear due to the proportions of the skeleton and the features of the deposition of fatty tissue in the ischial region.
• For men, relatively broad shoulders and narrow pelvis. The body can be schematically depicted as an inverted pyramid.
• Wide chest. On average, in young men, the girth of the chest is 10% larger. In men, the chest is longer, that is, it occupies a larger part of the body than the stomach.
• Narrow pelvis. The pelvis is narrower (by an average of 5 cm), deeper, the iliac bones are not turned outward, the pelvic cavity is less voluminous, and the dimensions of the inlet and outlet are much narrower. The pelvic bones themselves are thicker and inactive. Such a pelvis provides reliable support to the internal organs. A narrow pelvis allows men to achieve greater speed in running.
• male skull characterized by relatively large size, pronounced superciliary arches, occipital protuberances, massive lower jaw.
• For men, relatively large pneumatization of the skull bones. The bones with air spaces (sinuses) are massive, and the sinuses themselves are more voluminous. Pneumatization of the skull bones provides additional protection and thermal insulation.
• Larger teeth with characteristic odontoscopic features. The researchers also established the fact of a gender difference in the size of the alveolar arch and the bony palate.
• The shape of the larynx with a developed protrusion(prominentia laryngea). The growth of cartilage forms the so-called Adam's apple, that is, "Adam's apple".
• Lower voice tone. Articulation depends on the thickness of the ligaments and the size of the glottis. Voice mutation in young men occurs quite early and accompanies the growth of the larynx.
• Growth of terminal hair on the face and body in a male pattern. Androgen-dependent hair growth zones include the skin of the face (chin, skin above the upper lip, sideburns), neck, chest, back, abdomen, shoulders (read).
• Growth of armpit and pubic hair in a male pattern(rhombus facing one vertex to the navel).
• . Characteristic baldness of the parietal and frontal areas associated with the action of male sex hormones on the hair follicles.
• In men not pronounced lumbar lordosis(less curvature of the spine).
• Male posture- representatives of the stronger sex stand straight or lean back a little. This feature is formed due to differences in the musculoskeletal system.
• Abdominal (diaphragmatic) type of breathing. In boys and girls of the first year of life, the diaphragmatic type of breathing predominates, then diaphragmatic-thoracic is more often observed. From the age of 8-10 years, gender differences appear. In boys, diaphragmatic breathing is established, in girls - chest breathing.
• Relatively large adrenal mass(compared to women's) with a relatively smaller mass of all other endocrine glands. - organs that help to resist stress, extreme loads and are responsible for behavioral reactions (aggression, struggle, protection).
• skin in men differs in greater thickness (dermis by 15-20%, and the stratum corneum of the epidermis - by 40-50%), darker color, greater activity of the sebaceous and sweat glands.

Lack of secondary sexual characteristics in men

Secondary sexual characteristics appear during puberty. The timing of this period in the life of each person is individual.

Delayed puberty is said to be when a boy does not have any secondary sexual characteristics by the age of 14.

Such adolescents are shown to be examined by a pediatrician, endocrinologist, urologist and andrologist. In addition, medical assistance may be required for those young men who, 4.5 years after the onset of puberty, have not reached the 5th (final) stage of sexual development, that is, full maturity.

Endocrinologist Tsvetkova I. G.

Signs characterizing changes in the structure and function of various organs that determine gender and maturity. It should be distinguished from the primary sexual characteristics that identify the genitals. Secondary sexual characteristics depend on the primary ones, develop under the influence of sex hormones and appear during puberty. These include features of the development of the musculoskeletal system, body proportions, subcutaneous fat and hairline, the degree of development of the mammary glands, voice timbre, behavioral features, and many others ( cm. puberty.).
Under the influence of female sex hormones, girls rapidly increase in height and body weight, and the limbs grow faster than the torso, the shape of the skeleton changes, especially the pelvis, as well as the figure due to the deposition of fat, mainly in the buttocks, abdomen and hips, body shapes are rounded, the skin becomes thinner and softer. The growth of the mammary glands begins, the areola protrudes. Subsequently, the mammary glands increase, adipose tissue is deposited in them, they take the form of a mature mammary gland. Pubic hair appears, then in the armpits, their growth on the head intensifies. The growth of pubic hair in girls begins earlier than in boys, and is characterized by a distribution characteristic of women in the form of a triangle with a top directed downwards and a sharply defined upper border above the pubis. The sweat glands, especially the glands of the armpits, begin to secrete sweat with an odor inherent in the female sex. The secretion of the sebaceous glands increases, as a result of which, in the second half of puberty, the formation of juvenile acne sometimes occurs. In most girls, after 2-3 years from the onset of the onset of secondary sexual characteristics, at the age of 12-13 years, menstruation begins ( cm. Menarche) is the main sign of puberty, indicating the body's ability to become pregnant. However, the general maturity of the body occurs after a few years, during which the further development of secondary sexual characteristics and the formation of reproductive function take place, preparing the girl's body to perform the function of motherhood In boys, the appearance of secondary sexual characteristics characterized by more intense growth of the body, an increase in muscle mass, increased growth of the penis and testicles (which is sometimes accompanied by a slight soreness). The shape of the larynx changes, the voice becomes rougher, lower, pigmentation of the skin of the scrotum, vegetation on the pubis and in the armpits appear, mustaches and beards begin to break through, an Adam's apple ("Adam's apple") appears. Many young men during this period have swelling of the mammary glands and increased sensitivity of the nipples. At the age of 14-15, young men often experience sexual arousal, and at night - spontaneous eruption of the seed (pollution). , further development of secondary sexual characteristics and maturity, which occurs by the age of 23-25.

(Source: Sexological Dictionary)

The totality of physiological and psychosomatic features, which is formed during puberty ( e.g., armpit, pubic hair, voice mutation; facial hair, wet dreams in young men; development of the mammary glands and the appearance of menstruation in girls, etc.). cf.: primary sexual characteristics.

(Source: Dictionary of Sexual Terms)

See what "Secondary Sexual Characteristics" is in other dictionaries:

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Secondary sexual characteristics, signs that characterize changes in the structure and function of various organs that determine both puberty and gender. It should be distinguished from the primary sexual characteristics that identify the genitals. Secondary sexual characteristics depend on the primary ones, develop under the influence of sex hormones and appear during puberty. These include features of the development of the musculoskeletal system, body proportions, subcutaneous fat and hairline, the degree of development of the mammary glands, voice timbre, behavioral features, and many others.

Under the influence of female sex hormones, girls rapidly increase in height and body weight, and the limbs grow faster than the torso; the shape of the skeleton changes, especially the pelvis, as well as the figure due to the deposition of fat, mainly in the buttocks, abdomen and hips; body shapes are rounded, the skin becomes thinner and softer. The growth of the mammary glands begins, the areola protrudes. Subsequently, the mammary glands increase, adipose tissue is deposited in them, they take the form of a mature mammary gland. Pubic hair appears, then in the armpits, their growth on the head intensifies. The growth of pubic hair in girls begins earlier than in boys, and is characterized by a distribution characteristic of women in the form of a triangle with a top directed downwards and a sharply defined upper border above the pubis. The sweat glands, especially the glands of the armpits, begin to secrete sweat with an odor inherent in the female sex. The secretion of the sebaceous glands increases, as a result of which, in the second half of puberty, the formation of juvenile acne sometimes occurs. In most girls, after 2-3 years from the onset of the appearance of secondary sexual characteristics, at the age of 12-13 years, menstruation begins (see Menarche) - the main sign of puberty, indicating the body's ability to become pregnant. However, the general maturity of the body occurs after a few years, during which there is a further development of secondary sexual characteristics and the formation of the reproductive function, preparing the body of the girl to perform the function of motherhood.

In boys, the appearance of secondary sexual characteristics is characterized by more intense body growth, an increase in muscle mass, increased growth of the penis and testicles (sometimes accompanied by a slight soreness). The shape of the larynx changes, the voice becomes rougher, lower, pigmentation of the skin of the scrotum, vegetation on the pubis and in the armpits appear, mustaches and beards begin to break through, an Adam's apple ("Adam's apple") appears. Many young men during this period have swelling of the mammary glands and increased sensitivity of the nipples. At the age of 14 - 15, young men often have sexual arousal, and at night - spontaneous eruption of the seed (pollutation). The seminiferous tubules of immature boys are filled with spermatogonia, and only with the beginning of the functioning of the sex glands capable of producing mature spermatozoa, the young man's body enters the time of puberty, further development of secondary sexual characteristics and maturity, which occurs by 23-25 ​​years.

By and large, secondary sexual characteristics include all the features of the body that depend on gender. Secondary sexual characteristics begin to appear even in the prepubertal period. If up to 6-7 years old girls and boys can be confused, especially if they are dressed in clothes that do not indicate gender, then by 7-8 years old the appearance of girls and boys is noticeably different.

First changes

Closer to 11-13 years of age, pubic hair begins to grow in both sexes. If in girls it is a characteristic triangle with a top directed downwards, then in boys the hair grows more intensively, there is no clear boundary, there is often a “path” of hair from the pubis to the navel. In addition, in boys, intensive hair growth begins on the legs, in the armpits, at the age of 16-18, in some young men, hair appears on the chest.

Readiness for the birth of children

Around the same period, the first vellus hair on the face appears in young men - and mustaches, although for some, facial hair begins to grow only at 17-18 years old. One of the characteristic sexual characteristics inherent in the male sex is a change in the larynx, the "Adam's apple" or increases in size, the timbre of the voice changes, the voice becomes rougher. It is commonly said that the voice "breaks".

The structure of the skeleton in men and women is also significantly different, especially in the pelvis. These differences are clearly visible even in infants, but they become most distinct by the age of 13-15. In girls, it is less deep, but wider. This is related to the function of procreation. And in young men, the pelvis is narrower and deeper.

The absence of secondary sexual characteristics indicates diseases of the endocrine system or other disorders.