From the S Class Wiki

Male reproductive system- This is a set of organs of the male body, which performs a reproductive function and is responsible for sexual reproduction. It consists of interconnected external genital and internal accessory organs, and is also associated with the endocrine, nervous, cardiovascular system of the body.

The functions of the male reproductive system

The male reproductive system performs several functions:

• production of male sex hormones (testosterone, androstenedione, androstenediol, etc.);
• the production of sperm, consisting of sperm and seminal plasma;
• transportation and ejaculation of sperm;
• having intercourse;
• reaching orgasm.

Also, indirectly, the male reproductive system affects the entire body, ensures the normal functioning of other organs and systems, and slows down the aging process. In particular, it is closely related to the endocrine system, which also produces hormones, the urinary system, with which the male reproductive system has elements in common.

External genital organs

The male reproductive system includes 2 external genital organs, which are responsible for sexual intercourse and orgasm.

The penis is the male external genital organ, which is responsible for physiological copulation and the excretion of urine from the body. The male penis consists of a base, a trunk, and a head. The top of the penis is covered with skin, which, in an unexcited state, covers the entire penis with the glans. In a state of erection, the penis increases in size, exposing the head due to the movable foreskin.

The shaft of the penis consists of several parts: one spongy body and two corpus cavernosum, formed mainly by collagen fibers. The head of the penis has a widened and narrowed part. The urethra runs along the entire penis and extends outward on the head. Sperm and urine are excreted through it. The penis is innervated by the dorsal nerve and supplied with blood through the dorsal arteries. The outflow of blood from the penis occurs through the veins.

The scrotum is an outgrowth of the anterior abdominal wall, a natural sac-like formation located between the penis and the anus of a man. Inside the scrotum are the testicles. From above, it has a skin. The scrotum is divided in half by a septum. Due to the specific structure, the temperature inside the scrotum is below normal human body temperature and is approx. 34.4 ° C.

Internal organs of the male reproductive system

As with women, the bulk of the male reproductive system is within. These are also adnexal organs that perform the main part of the reproductive function.

The testicles are a paired organ of the male reproductive system, which is located inside the scrotum. The testicles, or paired male gonads, are asymmetric and vary somewhat in size, so they are not compressed when walking or sitting. Usually the right testicle is slightly higher than the left. The epididymis and the spermatic cord are attached to the back of the testicle, from above they are surrounded by a whitish fibrous membrane. In the testes, hormones, sperm are formed, and they also perform an endocrine function.

Prostate - the prostate gland, which is responsible for the secretory function, is involved in erection and sperm transfer. It also prevents infection from entering the upper urinary tract and back to the testicles. The prostate is located behind the rectum and in front of the pubic joint. Consists mainly of prostatic glands with connective tissue. The prostate produces sperm, a constituent of sperm that gives it odor and is involved in cellular metabolism. Also, the prostate produces hormones and prostate juice. The prostate is interconnected with other organs of the male reproductive system, the adrenal glands, the pituitary gland and the thyroid gland.

The epididymis is a paired organ located on the posterior surface of a man's testicle. One of the processes of spermatogenesis, maturation, takes place in the appendages. Here sperm accumulates and is stored until the moment of eruption. Sperm cells grow and mature in the appendages for about 14 days, after which they can perform their direct function - to fertilize a female egg.

The seminal vesicles are a paired organ to which the seminal ducts fit. Together with the seminal ducts, the seminal vesicles form the ejaculatory ducts. The seminal vesicles carry the secretion of the seminal vesicles and perform a secretory function to nourish the sperm.

The vas deferens is a paired organ with an active muscular membrane, responsible for the transport of sperm. Consists of 4 parts.

Ejaculatory ducts - Drain semen into the urethra for ejaculation.

The urethra is an integral part of the male reproductive system and the genitourinary system. It runs along the penis and is brought out on the head through the slit. Has a length of approximately 20 cm.

Cooper's or bulbourethral glands - perform an exocrine function. Located in the muscle tissue of the perineum, they consist of lobular parts. The size of each gland does not exceed a pea. They produce a viscous mucous secretion, which gives the sperm a peculiar taste and contributes to the unhindered transport of sperm through the urethra. This secretion contains alkaline enzymes that neutralize urine residues in the urethra.

Formation and development

The organs of the male reproductive system begin to form in the prenatal period. The internal genital organs are laid already at 3-4 weeks of embryo development, the external organs begin to form at 6-7 weeks. From the 7th week, the gonad begins to form testicles, from the 9th week, the body of the embryo already produces a small amount of testosterone. From 8 to 29 weeks, the penis and scrotum take their natural shape, the testicles descend into the scrotum until the 40th week.

From birth to 7 years of age, the peripubertal period lasts, during which intensive development does not occur. From 8 to 16 years, the period of active development of the male reproductive system lasts. In puberty, the external and internal genital organs increase in size, and the intensive production of male hormones begins. In the development of the male reproductive function and the regulation of the system, cerebral neurotransmitters, endogenous opiates, hypothalamic and pituitary hormones, and steroid sex hormones also play an important role. The complex interconnection of the genitourinary, endocrine and central nervous systems by the end of puberty forms the male reproductive system and function.

The male reproductive system works quite stably. Males do not have any monthly cycle with a surge in hormone production. The decline of reproductive function also occurs more smoothly in a man, andropause is less noticeable and is not so painful.

Fading of the functions of the male reproductive system and andropause

The reproductive function of a man is not as closely related to age as it does in women. After 30, a man may experience a slight decrease in libido, usually associated not with the extinction of reproductive function, but with psychological problems, routine in family life, stress, and bad habits. After 40, testosterone levels decrease and a physiological decrease in libido begins. But some men retain the ability to produce viable sperm until old age. At a very old age, a man can conceive a child if he does not have serious illnesses, he leads a healthy lifestyle.

The main processes of extinction of the function of the male reproductive system occur in the testicles. However, even with testicular atrophy and a decrease in its mass, the male body continues to produce enough testosterone to maintain sexual function.

Most male health problems are associated with pathologies, which include

Basic concepts and key terms: REPRODUCTIVE SYSTEM. The female reproductive system. Male reproductive system. Remember! What is reproduction?

Interesting

The symbols of Mars and Venus are symbols of ancient astrology. The female sign of Venus is depicted as a circle with a cross pointing down. It is called "the mirror of Venus" and it symbolizes femininity, beauty and love. The male sign of Mars is depicted as a circle with an arrow pointing up and to the right. This symbol is called the "shield and spear of Mars". In biology, these symbols were introduced by Karl Linnaeus to denote the sex of plants.

What are the features of human reproduction?

Reproduction is a physiological function that allows a species to reproduce itself. Sexual reproduction is characteristic of humans, in which sex cells, or gametes, have a half set of chromosomes. These cells are formed by two types of sex glands - the ovaries and the testes. They are located in the body of individuals of different sexes. A person is dioecious with the phenomenon of sexual dimorphism.

Human reproduction is provided by the REPRODUCTIVE (SEXUAL) SYSTEM (from Lat. Reproductio - reproduction) - a set of genital organs that provide sexual reproduction. Distinguish between male and female reproductive systems.

All hereditary information about the human body is encoded in the DNA contained in the chromosomes. There are 46 of them in humans. Before reproduction, gametes are formed from the cells of the gonads, in which there are 23 chromosomes and half the set of hereditary information. Soon after fertilization and fusion of the nuclei of the germ cells, the full set of hereditary information is restored. This is why children have the characteristics of both parents.

Human reproduction becomes possible with the onset of sexual and physical maturity. But man is a biosocial species, therefore, the mental readiness of future parents, the social conditions of their life and social norms of behavior play an important role in its reproduction.

A person may experience early puberty, which is associated with acceleration (acceleration of the pace of individual development and growth of children and adolescents in comparison with previous generations).

Table 50. FEATURES OF HUMAN REPRODUCTION

organization	Peculiarity
Molecular	Hereditary information recorded in DNA is passed on to the next generation by carriers of heredity - chromosomes
Cellular	Male gametes - sperm and female gametes - eggs contain 23 chromosomes
Fabric	All 4 types of tissues are involved in the formation of the genitals.
Organ	The genitals, unlike the organs of other systems, differ in men and women.
Systemic	The female and male reproductive systems have external and internal genital organs
Organic	Male and female bodies differ in primary (the structure of the genitals) and secondary (features of the structure, functions and behavior that distinguish the male from the female) sexual characteristics

So, human reproduction is provided by the reproductive system and differs in male and female organisms.

What is the significance of the female reproductive system?

The reproductive system of a woman is formed by the external genital organs (labia and clitoris), internal genital organs (ovaries, fallopian tubes, uterus, vagina), mammary glands (paired organs in which a secret is formed for feeding babies).

The main genital organs in women are two ovaries. These are paired oval-shaped organs located at the funnel-shaped ends of the fallopian tubes. They contain immature eggs, which are formed in a woman's body even before she is born. The maturation of eggs in a woman's ovaries occurs from the end of puberty to the end of the reproductive period. Every month every woman ovulates - one of the eggs reaches full maturity and leaves the ovary. After release, the egg enters the fallopian tube, through which it moves to the uterus. If the egg is not fertilized, menstruation occurs. In addition to eggs, the ovaries contain secretory cells that secrete sex hormones (estradiol, progesterone).

The fallopian tubes are paired organs that connect the ovaries to the

by the lumen of the uterus. The total length of the fallopian tube is about 12 cm. By capturing a mature egg from the ovary, the fallopian tubes provide nutrition and transport to the uterus. In the fallopian tubes, fertilization also occurs with the formation of a zygote.

The uterus is a hollow unpaired muscular organ in which an embryo and a fetus develop from a zygote during pregnancy. It distinguishes between the body of the uterus, to which the fallopian tubes fit, and the cervix, which is the narrow end of this organ. The uterus passes into the vagina, through which sperm enter the female body.

So, the female reproductive system is a set of organs that ensure the formation of eggs, the secretion of female sex hormones, fertilization and intrauterine development.

What is the structure and function of the male reproductive system?

The male reproductive system is formed by the external genital organs (scrotum and penis), internal genital organs (testicles, epididymis, vas deferens, seminal vesicles, ejaculatory duct), and the prostate gland. Unlike the female, the male reproductive system is almost entirely outside. This structure is due to the fact that for the maturation of spermatozoons, a temperature below 36.6 ° C is required.

The main genitals of men are two testicles. These are paired organs located in the skin sac - the scrotum. The testicles are composed of convoluted seminiferous tubules in which sperm are formed. In addition, male sex hormones androgens, in particular testosterone, are synthesized in the cells of the testicles. Further, the sperm enter the epididymis, where they reach maturity and are stored until they are excreted. From each of the epididymis, the vas deferens begins, which connects to the duct of the seminal vesicles. These paired organs secrete fluid to provide nutrients to the sperm. The ducts of the epididymis and the ducts of the seminal vesicles merge into a common ejaculatory duct, which opens into the canal of the penis. The prostate gland (prostate) is located under the bladder around the urethra. It forms a secret that protects the male gametes and maintains their mobility.

So, the male reproductive system is a set of organs that ensure the formation of sperm, the secretion of male sex hormones and insemination.

ACTIVITY

Learning to cognize

Independent work with the table

Apply the comparison method and determine the signs of similarity and differences between the female and male reproductive systems.

	Female reproductive system	Male reproductive system
External organs
Internal organs
Location of major organs
The name of the cells that form
Hormones that form

Biology + Chemistry

The body of an adult contains about 2-3 g of zinc, almost 90% of its total amount is concentrated in muscles and bones. A significant amount of this trace element is found in the prostate gland and in seminal fluid, which indicates its importance for human reproductive health. Also, this trace element has a significant effect on the state of the immune system. Zinc activates the activity of T-lymphocytes, lymphocyte synthesis of cytokines that regulate the immune response and act as a growth factor for the immune system. How does zinc enter the human body? What foods contain zinc?

Biology + Mythology

In ancient Roman mythology, Cupid is a winged boy, a little god of lovers, a satellite of Venus. He is armed with a golden bow and arrows, which hit the human heart, causing people to feel a sense of love. Hence the expression "to be wounded by Cupid's arrow" - to fall in love. Try to find a physiological connection between sex hormones, heart and love. What is the role of the endocrine system in the regulation of human reproduction processes?

RESULT

	Questions for self-control
	1. What is the reproductive system? 2. What set of chromosomes do gametes contain? 3. What is the female reproductive system? 4. Name the female genital organs that form the eggs. 5. What is the male reproductive system? 6. Name the male genital organs that form sperm.
	7. Name the features of human reproduction. 8. What is the significance of the female reproductive system? 9. Describe the structure and function of the male reproductive system.
	What is the role of the endocrine system in the regulation of human reproduction processes?

This is tutorial material

An important factor in planning future offspring is not only the health of the woman, but also the correct functioning of the systems of the male body. The male reproductive system is a collection of organs responsible for procreation (reproduction).

Such a system is responsible for performing the following functions:

1. Production and transportation of male germ cells (sperm).
2. Delivery of sperm to the female reproductive system (during intercourse).
3. The production of hormones that are responsible for the proper functioning of the male reproductive system.

The physiology of the male reproductive system is closely related to the urinary system of the body.

Consider the structure and function of the male reproductive organs (with photo).

Modern anatomy gives a complete picture of the physiology of the structure of the human reproductive system. There are many video and photographic materials, many articles and medical manuals have been written that consider the functions and structure of the reproductive system.

Male puberty occurs not much later than puberty in women, and does not have such a pronounced indicator as female menstruation. Men usually reach full puberty by the age of 18, although full-fledged sperm are produced by the age of 13-14. Unlike the female body, male germ cells (gametes) continue to be produced throughout life after puberty. Of course, it should be noted that spermatogenesis in men of age occurs less intensively, the number and activity of cells produced may decrease. However, their ability to fertilize is preserved.

The male reproductive system consists of two types of organs of the reproductive system: external and internal.

• Outdoor:

1. Scrotum.
2. Penis (penis).

• Internal:

1. Prostate gland (prostate).
2. Seminal vesicles.
3. Testicles and their appendages.
4. The vas deferens.

Let's consider the structure of the male reproductive organs in more detail.

The musculocutaneous sac, inside which the testes with the appendages and the duct responsible for ejaculation are located, is called the scrotum. The anatomy of the structure of the scrotum is quite simple: it is divided by a septum into two chambers, each of which contains one of the two gonads. The main functions are to protect the testicles and maintain an optimal temperature for the process of sperm formation and development (spermatogenesis). By its structure, the scrotum consists of several layers, including skin, as well as muscle tissue that raises or lowers the testicles under certain influences (changes in ambient temperature, physiological processes - arousal, ejaculation).

The penis is the main organ responsible for urination and delivery of semen into a woman's body. The anatomy and physiology of the penis distinguishes three main structural divisions: the head, base, and the body itself. In the upper part there are two so-called cavernous bodies. They are parallel to each other and run from the base to the glans penis. Under the cavernous bodies is the spongy body, the urethra is located in it. All of them are covered with a dense membrane containing chambers (lacunae) that fill with blood during sexual arousal. It is the lacunae that contribute to the emergence of an erection. The function of external protection of bodies is performed by the skin, which is sufficiently elastic and capable of stretching. The endings of the corpus spongiosum and cavernous bodies are located in the head of the penis, which is covered with thin skin with many nerve endings.

The external genital organs, which represent the male reproductive system, continue to grow only during puberty.

The testicles (testicles) are the most important paired organs that affect the process of sperm formation. Testicular growth is quite slow and accelerates only during puberty. Each of the paired organs in their structure is divided into seminal lobules, in which the seminiferous tubules are located, which take part in spermatogenesis. These tubules make up about 70 percent of their volume. Passing through the membrane, the tubules enter the epididymis, in which the ability of sperm to fertilize is finally formed.

The epididymis is a narrow duct adjacent to the testicle and is responsible for the final maturation of spermatozoa, their accumulation and movement along the genital tract. The process of spermatogenesis is carried out in this part of the male reproductive system. The length of the duct itself is about 8 m, and the movement of spermatozoa to the place of their accumulation takes about 14 days. The anatomy of the epididymis consists of three main divisions: the tail, body, and head. The head is divided into lobules, which flow into the duct of the epididymis and pass into the duct of the vas deferens.

The prostate gland is located in the immediate vicinity of the bladder and is palpable only through the rectum. The dimensions of the gland of a healthy man are set within certain limits: width from 3 to 5 cm, length from 2 to 4 cm, thickness from 1.5 to 2.5 cm.In case of size deviations from the norm, it is necessary to urgently carry out diagnostics to make an accurate diagnosis and prescribing the correct treatment. The gland is divided into two lobes, connected by an isthmus. The urethra and the ejaculatory ducts pass through it.

The main function of the prostate is the production of testosterone, a hormone that directly affects the fertilization of the egg. In addition to the secretory function of the prostate, the motor function can be distinguished: muscle tissue is involved in the release of prostate secretions during ejaculation, and is also responsible for the retention of urine. Thanks to the secretion produced, the penetration of infections of the urethra into the upper tract of the man's urinary system is blocked. With age, there is an increased risk of developing various diseases of the prostate gland, affecting its physiology. As a result, the male reproductive function decreases.

The seminal vesicles are another organ of the male reproductive system, paired in structure, located above the prostate gland, between the walls of the rectum and the bladder. The main function of the vesicles is the production of an important active substance (secretion) that is part of the semen. The secret nourishes the sperm, increasing their resistance to the negative effects of the external environment. It is a source of energy for gametes. The ducts of the seminal vesicles join the ducts responsible for ejaculation, and at the end form the ejaculatory duct. Violations of the physiology or diseases of the seminal vesicles can cause problems of conception, as well as complete infertility of a man.

Disruption of the reproductive system

According to statistics, women are much more likely to undergo preventive examinations and tests to identify problems of the reproductive system. Men, for the most part, prefer to go to doctors only in case of exacerbations of diseases or obvious violations of the physiology of the functioning of the genital organs. At the same time, the reproductive health of men and women is one of the most important indicators of reproduction. During pregnancy planning, couples often face problems of conception caused by malfunctioning of the male genitourinary system.

The main reasons for violations:

• Infectious diseases.
• Malfunction of the prostate gland.
• Colds and inflammations.

Sexual dysfunction as a consequence of the disease is quite obvious. However, there are other reasons as well. First of all, it is necessary to say about the wrong way of life: the intake of psychoactive substances, which causes a psychedelic effect (for example, hallucinogenic mushrooms), other drugs and alcohol. In addition, the cause can be congenital anomalies in the structure of organs, manifested anatomically.

Let us dwell on the most common diseases affecting the reproductive system.

First of all, it should be said about such a disease as prostatitis. This is the most common cause of fertility problems in men. Currently, every fourth man suffers from prostate inflammation to some extent. As a rule, men aged 40 and older are at risk. However, younger men are also susceptible to the disease. The influence of the work of the gland on the physiology of the reproductive system is very high. In order to improve its functioning, it is necessary to undergo a complete examination, according to the results of which treatment will be prescribed. Taking medications on your own without consulting a doctor can increase the risk of complications.

Another disease that affects the physiology of the reproductive system is vesiculitis. This pathology is characterized by inflammation of the seminal vesicles. Men with chronic prostatitis are at high risk of developing this disease. The main symptom of the disease: pain during ejaculation, in the perineum and groin, as well as general weakness. With advanced forms, treatment is carried out surgically; if diagnosed in the early stages, treatment with antibacterial drugs is possible.

As a prevention of diseases of the reproductive system, it is necessary to adhere to the basic rules:

1. High quality and varied food.
2. Complex physical activity.
3. Preventive examinations of narrow specialists.
4. Regular sex life.
5. Exclusion of casual sexual intercourse.

Also, do not forget about the rules of personal hygiene and adherence to sleep and wakefulness. If any symptoms of diseases of the reproductive system appear (itching, redness, pain, cracks in the skin or swelling), it is necessary to urgently consult a doctor for a diagnosis and an accurate diagnosis. It is important to remember that letting any disease take its course or self-medication can threaten with even greater disturbances in physiological processes. The advanced stages of some diseases can be cured only by surgery, and some diseases of the reproductive system become chronic and increase the risk of developing complications such as infertility or impaired potency.

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

However, when studying the functioning of the female reproductive system, one should always remember that it is characterized by constant variability, cyclical 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 metabolism, etc. 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 mammalian ovarian cycle have formed. In reflexively ovulating animals, after the reproductive system is ready for ovulation, follicular rupture occurs in response to mating. The nervous system plays the main role in this process. In spontaneously ovulating animals, ovulation occurs regardless of sexual activity, and the time for the release of an egg is determined by sequential processes in the reproductive system. The most important in this case are hormonal mechanisms of regulation with less involvement of the central nervous system (CNS). Spontaneous ovulation is common in primates and humans.

Organs that are not directly related to the five described hierarchical levels, primarily the endocrine glands, also play an important role in the regulation of the reproductive system.

Male reproductive system

The male reproductive system of a person is a collection of organs of the male reproductive system. The male genitals are divided into internal and external. The internal ones include the gonads - the testes (with their appendages), in which sperm develop and the sex hormone testosterone is produced, the vas deferens, seminal vesicles, prostate gland, bulbourethral glands. The external genitals include the scrotum and penis. The male urethra, in addition to excreting urine, serves for the passage of semen entering it from the ejaculatory ducts.

The boy's sex glands - the testicles, shortly before his birth, descend from the child's abdominal cavity, where they develop, into a skin sac called the scrotum. The scrotal cavity 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 this requires a temperature several degrees Celsius lower than the normal temperature of the human body. If the testicles remain in the abdominal cavity of a person, then the formation of full-fledged spermatozoa in them will not occur.

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

The formation of mature spermatozoa occurs in waves along the tubules. The seminiferous tubules themselves are connected through thin connecting tubes 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. The accumulation of mature sperm occurs in the epididymis.

External male genital organs (penis and scrotum)

Each epididymis (epididymis) has a vas deferens. It runs 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 that goes from the bladder and has an exit to the outside, from the human body. In a man's body, the urethra runs through the intra-penis (penis). In the penis, the urethra is surrounded by three so-called cavernous bodies. Sometimes they are also divided into two cavernous body and one spongy body located below, in a furrow between two cavernous bodies. The urethra passes through its thickness.

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

Semen is formed in a man's body as a result of the sequential work of three different glands. Not far from the confluence of the vas deferens into the urethra, the secretion of a pair of so-called seminal vesicles pours out into the vas deferens.

Next, the secretion of the prostate gland, also called prostate, which is located around the urethra at its exit from the bladder. The secretion of the prostate is excreted into the urethra through two groups of short, narrow ducts that drain 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's glands are alkaline, and the secretions of the prostate are a milky watery liquid with a characteristic odor.

Female reproductive system

The female reproductive system of a person consists of two main parts: the internal and external genital organs. The external genitals are collectively called 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 3 cm, resemble an almond seed. During ovulation, a 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 egg (egg) enters the tube. The epithelial lining of the fallopian tubes has cilia, the beating of which creates a movement of fluid flow. This flow of fluid directs the egg into the fallopian tube, ready for fertilization. The other end of the fallopian tubes opens into the upper part of the uterus, into which the egg is guided through the fallopian tubes. The fertilization of the egg takes place in the fallopian tube. Fertilized eggs (eggs) enter the uterus, where the normal development of the fetus proceeds until delivery.

Uterus- muscular pear-shaped organ. It is located in the middle of the abdomen at the back of the bladder. The uterus has thick muscle walls. The inner surface of the uterine cavity is lined with a mucous membrane permeated with a dense network of blood vessels. The uterine cavity connects to the vaginal canal, which passes through a thick muscle ring that protrudes into the vagina. It is called the cervix. Normally, a fertilized egg enters the uterus from the Fallopian tubes and attaches to the muscular wall of the uterus, developing into a fetus. In the uterus, the normal development of the fetus proceeds 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.The mass of the uterus in nulliparous women ranges from 40 to 50 g, and in those who have given birth it reaches 80 g. for hypertrophy of the muscularis during pregnancy. The volume of the uterine cavity is ≈ 5 - 6 cm³.

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

Large labia- These are two skin folds containing fatty tissue and venous plexus inside, extending from the lower edge of the abdomen down and back. In an adult woman, they are covered with hair. The labia majora serves to protect the woman's vagina from the ingress of microbes and foreign bodies into it.

The labia majora are abundantly supplied with sebaceous glands and border the opening of the urethra (urethra) and the vestibule of the vagina, behind which they grow together. The so-called Bartholin glands are located in the lower third of the labia majora.

Small labia

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

Clitoris in most women, it is closed by the skin folds bordering it. This organ develops from the same germ cells as the male penis, so it contains cavernous tissue, which fills with blood during sexual arousal, as a result of which the woman's clitoris also grows 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, therefore, stimulation (stroking and the like) of the clitoris can lead to a woman's sexual arousal.

Some African peoples have a custom of the so-called female circumcision when the girls are removed clitoris or even small labia... This leads to a decrease in the sexual activity of women in adulthood, and according to some sources it is considered one of the possible reasons for the development of 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 only serves to drain urine from the bladder.

Above the clitoris itself, in the lower abdomen, there 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 made of elastic and collagen fibers. With a hole covering the opening of the vagina between the internal and external genitals. During the first intercourse, it usually collapses, after childbirth it practically does not persist.

Upper respiratory tract.

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

The airways are divided into two sections: the upper airways (airways) and the lower airways (airways).

The upper respiratory tract includes the nasal cavity, nasal pharynx, and 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. Bronchi and bronchioles supply and remove respiratory gas mixtures to the lung parenchyma and from it to the upper respiratory tract. The lung parenchyma is a part of the external respiration apparatus, consisting of pulmonary acini. Pulmonary acinus begins with the terminal (terminal) bronchiole, which branches out to the respiratory bronchioles. Respiratory bronchioles branch out by the alveolar passages. Alveolar passages end with alveolar sacs. Terminal and respiratory bronchioles, as well as alveolar passages make up the alveolar tree. The walls of all elements of the alveolar tree are composed of alveoli.
The airway 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 referred to as the respiratory tract, a cyclical process of external respiration is carried out, part of which is the diffusion exchange of gases.
The space inside the airways, the volume of the airways, is often called the anatomical dead space, a harmful space due to the fact that there is no diffusion exchange of gases in it.
The airways have important functions. They provide cleansing, moisturizing and warming of the inhaled mixture.

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

Lungs.

Lungs- the organs of air respiration in humans, all mammals, birds, reptiles, most amphibians, as well as in some fish (lungs, cross-finned and polypinous).

The respiratory organs in some invertebrates (in some mollusks, sea cucumbers, arachnids) are also called lungs. In the lungs, gas exchange is carried out 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 half-cone, the base of which is located on the diaphragm, and the apex protrudes 1-3 cm above the clavicle into the neck. The lungs have a convex costal surface (sometimes there are prints 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, lymph nodes and ducts) make up the mediastinum ( mediastinum). On the mediastinal surface of both lungs there is a depression - the gate of the lungs. They include the bronchi, the pulmonary artery, and two pulmonary veins exit. The pulmonary artery branches parallel to the branching of the bronchi. A fairly deep heart pit is located on the mediastinal surface of the left lung, and a heart notch is located on the anterior edge. The main part of the heart is located right here - to the left of the midline.

The right lung has 3, and the left has 2 lobes. The skeleton of the lung is formed by treelike branching bronchi. Each lung is covered with a serous membrane - pulmonary pleura and lies in the pleural sac. The inner surface of the chest cavity is covered with parietal pleura. Outside, each of the pleura 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 - areas that resemble an irregular truncated cone facing the root of the lung, each of which is ventilated with a permanent segmental bronchus and is supplied with the corresponding branch of the 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 the adjacent segments. In the right lung there are usually 10 segments (3 in the upper lobe, 2 in the middle and 5 in the lower), in the left lung - 8 segments (4 each in the upper and lower lobes). The lung tissue inside the segment consists of a pyramidal shape of lobules (lobules) with a length of 25 mm, 15 mm wide, the base of which faces the surface. The bronchus enters the apex 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 - an acinus. The acinus consists of 20-50 alveolar bronchioles, dividing into alveolar passages; the walls of both are densely covered with alveoli. Each alveolar passage passes into the end sections - 2 alveolar sacs. Alveoli are hemispherical protrusions and consist of connective tissue and elastic fibers, lined with thin transparent epithelium and braided by a network of blood capillaries. Gas exchange takes place in the alveoli between blood and atmospheric air. In this case, oxygen and carbon dioxide pass through the diffusion process from the 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 Thus, air is delivered to the alveoli through a treelike structure - the tracheobronchial tree, starting from the trachea and further branching into the main bronchi, lobar bronchi, segmental bronchi, lobular bronchi, terminal bronchioles, alveolar bronchioles and alveolar passages.

45. Gas exchange (biological), the exchange of gases between the body and the environment. Oxygen is continuously supplied to the body from the environment, which is consumed by all cells, organs and tissues; the body releases carbon dioxide formed in it and a small amount of other gaseous metabolic products. G. is necessary for almost all organisms, without it normal metabolism and energy, and hence life itself, is impossible.

a) Skeleton of the upper limb: on each side are the bones of the shoulder girdle (scapula and clavicle) and the bones of the free upper limb (humerus, bones of the forearm and hand). The bones of the shoulder girdle: * The scapular triangular bone is located on the posterior side 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 angles. The scapula connects to the collarbone. * Clavicle - C (English) - a figuratively curved long bone that connects to the sternum and ribs. Bones of the free upper limb: * The humerus - refers to the long bones, it distinguishes between the middle part (diaphysis) and two ends (upper - proximal and lower - distal epiphyses). * Bones of the forearm - ulna, radius, also to the long bones, in accordance with this, they distinguish between the diaphysis, proximal and distal epiphyses. * The hand consists of the small bones of the wrist, the five long bones of the metacarpus, and the bones of the fingers. The bones of the wrist form a vault facing the palm of the hand. In a newborn, they are only outlined; developing gradually, 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. 1 finger is of particular importance in connection with the labor function. He has great mobility and is opposed to all other fingers.

b) Skeleton of the lower limb: on each side are the bones of the pelvic girdle (pelvic bones) and the bones of the free lower limb (femur, bones of the lower leg and foot). The sacrum is connected to the pelvic bones. The bones of the pelvic girdle: * The pelvic bone consists of three bones - the ilium (it occupies the top position), the ischium and the pubic bone (located below). They have bodies that grow together at the age of 14-16 in the acetabulum. They have round depressions, where the heads of the femur bones of the legs enter. Bones of the free lower limb: * The femur is the most massive and longest tubular among the long bones of the skeleton. * Shin bones, which include the tibia and fibula, which are long bones. The first is more massive than the second. * The bones of the foot are formed by the bones: the tarsus (proximal part of the skeleton of the foot), metatarsus and phalanges of the toes. The human foot forms a vault, which rests on the calcaneus and on the front ends of the metatarsal bones.

There are longitudinal and transverse arches of the foot. The longitudinal, springy arch of the foot is inherent only in humans, and its formation is associated with upright posture. The weight of the body is evenly distributed along the arch of the foot, which is of great importance when carrying heavy loads. The arch acts like a spring, softening the body's tremors when walking. The vaulted arrangement of the foot bones is supported by a large number of strong articular ligaments. With prolonged standing and sitting, carrying large weights, wearing narrow shoes, the ligaments stretch, 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 vertebral 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. Distinguish between cervical (7 vertebrae), thoracic (12 vertebrae), lumbar (5 vertebrae), sacral (5 vertebrae) and coccygeal (4-5 vertebrae) parts of the spine. The vertebral column consists of 33-34 vertebrae connected to each other. The vertebral column occupies about 40% of the body length and is its main core, support. The vertebra consists of the vertebral body, vertebral arch and processes. The vertebral body is located anterior to other parts.

Above and below, the vertebral body has rough surfaces, which, by means of intervertebral cartilages, connect the bodies of individual vertebrae into a flexible, strong column. An arc is located posterior to the body, which, together with the posterior surface of the body, forms the vertebral foramen. The vertebral foramen form the vertebral canal along the entire length of the spine, in which the spinal cord is located. Muscles are attached to the processes of the vertebrae. Intervertebral discs made of fibrous cartilage are located between the vertebrae; they contribute to the mobility of the spinal column.

The height of the discs 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 curves characteristic of an adult are only outlined and develop gradually. The first to appear is cervical lordosis (a forward bend) when the baby starts to hold the head (6-7 weeks). By the age of six months, when the baby begins to sit, thoracic kyphosis (a bulge directed backward) forms. When the child begins to walk, lumbar lordosis develops. With the formation of lumbar lordosis, the center of gravity moves posteriorly, preventing the body from falling in an upright position.

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

Impacts and shocks when walking, running, jumping are weakened and attenuated, which protects the brain from concussions. Movement between each pair of adjacent vertebrae has 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 the vertical axis (rotation to the sides up to 120 degrees) and and finally, springy movements due to changes in the curvature of the spine.

As a person grows, bones grow in length and thickness. The growth of bones in thickness occurs due to the division of cells in the inner layer of the periosteum. Young bones grow in length due to 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 the age of 18-21.

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

There are three types of muscle tissue: striated, smooth and cardiac (Fig. 12.1). Transverse striated (skeletal) muscle tissue is built of many multinucleated fiber-like cells 1-12 cm long.The presence of myofibrils with light and dark areas that refract light in different ways (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 of the oral cavity, pharynx, larynx, upper part of the esophagus, mimic muscles, diaphragm are built from it. Features of striated muscle tissue: speed and arbitrariness (that is, the dependence of contraction on the will, desire of a person), consumption of a large amount of energy and oxygen, rapid fatigability.

Rice. 12.1. Types of muscle tissue: a - striated; 6 - heart; 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. Thanks to the many cell 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 a pumping function.

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

49. Human skeletal musculature consists of muscle fibers of several types, 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 by a high content of myoglobin protein, which is able to bind O2 (similar in 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. Ultimate fatigue in fibers of this type and, therefore, in muscles occurs very slowly, which is due to the presence of myoglobin and a large number of mitochondria. Recovery of function after fatigue occurs quickly.

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

The muscle fibers of all of these groups are characterized by the presence of one, in extreme cases, several end plates formed by one motor axon.

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

Provide a specific posture for 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 subdivided into central (brain and spinal cord) and peripheral (cranial and spinal nerves, their plexuses and nodes), as well as somatic and autonomic (or autonomic).

The somatic nervous system carries out mainly the connection of the body with the external environment: the perception of stimuli, the regulation of the movements of the striated musculature 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), controlling 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 vertebral 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 spread "wings" of which two front and two rear horns extend. The anterior horns contain centrifugal neurons, from which motor nerves branch off. The dorsal horns include nerve cells (intermediate neurons), which are approached by the processes of sensory neurons that lie in the thickenings of the dorsal roots. 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 muscle group and a corresponding area of ​​the skin.

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

The spinal cord has two functions: reflex and conductive. The spinal cord is controlled by the brain.

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

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

The phylogenetically more ancient part is the brain stem. The trunk includes the medulla oblongata, cerebral (varolium) pons, midbrain and diencephalon. The white matter of the trunk contains numerous nuclei of gray matter. The nuclei of 12 pairs of cranial nerves also lie in the brain stem. The brain stem is covered by the cerebral hemispheres.

The medulla oblongata is an extension of the spinal cord and repeats its structure: grooves also lie on the front and back surfaces. It consists of white matter (conductive bundles), where clusters of gray matter are scattered - the nuclei from which the 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 termination cardiac activity and respiration.

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

Cerebellum - its surface is covered with gray matter, under it there is a 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. Controls the activity of the cerebellar cortex.

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

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

The diencephalon occupies the highest position in the trunk. Consists of the optic hillocks (thalamus) and the hypothalamus region (hypothalamus). The visual hillocks regulate the rhythm of cortical activity and are involved in the formation of conditioned reflexes, emotions, etc.

The sub-tuberous 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, the constancy of the internal environment of the body and the functions of the digestive, cardiovascular, genitourinary systems, as well as the endocrine glands.

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

Large hemispheres of the brain

The lower surface of the hemispheres and the brainstem 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 detect the smallest changes in the external and internal environment.

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

The functional system, consisting of a receptor, a sensitive pathway and a zone of the cortex, where this type of sensitivity is projected, I.P. Pavlov called an analyzer.

The analysis and synthesis of the information received is carried out in a strictly defined area - the area of ​​the cortex of a large

The most important zones 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 musculocutaneous 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 - in the superior temporal gyrus of the temporal lobe, the olfactory and gustatory zone - in the anterior temporal lobe.

The activity of analyzers reflects the external material world in our consciousness. This enables mammals to adapt to their environment by changing behavior. A person, cognizing 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 in the body and 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 bark performs an associative function and is the material basis of human psychological activity - memory, thinking, emotions, speech and regulation of behavior.

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

53. Higher nervous activity is a complex form of life that provides 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, previously 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 homeostasis of the organism in the process of its vital activity. In this case, the nerve elements that interact within the body are united by nerve connections by the time of birth. And, conversely, the nerve connections that provide higher nervous activity are realized in the process of vital activity of the organism in the form of life experience. Therefore, the lower nervous activity can be defined as a congenital form, and the higher nervous activity - as acquired in the individual life of a person or animal.

The origins of the opposition between the 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 and possesses “mental power”. For many centuries, the idea of ​​the "soul" of a person and the unknowability of his mental activity remained inseparable in the minds of people. Only in the 19th century. in the works of the Russian scientist, the founder of modern physiology I.M. Sechenov, the reflex nature of the activity of the brain was revealed. In his book Reflexes of the Brain, published in 1863, he was the first to attempt an objective study of mental processes. The ideas of I.M. Sechenov was brilliantly developed by I.P. Pavlov. On the basis of 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 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. Controlling influences of the cortex are built depending on their ratio, strength and localization. The functional unit of higher nervous activity is a 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, a process of corticalization of functions occurs. It is expressed in the increasing subordination of the somatic and autonomic functions of the body 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 for physiological analysis and pathogenetic treatment (for example, sleep) of some diseases of the human central nervous system; for psychology, pedagogy, cybernetics, bionics, scientific organization of labor and many other branches of human practice

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

Detection systems. To capture the signal and extract it from the noise, a detection system is needed. Such a system is both the eye of the researcher conducting the microscopy and the 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, that is, to separate weak signals from noise. In clinical microbiology, immunofluorescence, colorimetry, photometry, chemiluminescent oligonucleotide probes, nephelometry and evaluation of the cytopathic effect of the virus in cell culture are widely used.

Strengthening the signal. Amplification allows you to catch even weak signals. The most common way to amplify a signal in microbiology is cultivation, as a result of which each bacterium forms a separate colony on solid nutrient media, and a suspension of the same bacteria in liquid media. For cultivation, it is only necessary to create suitable conditions for the growth of microorganisms, but it takes a long time. PCR and ligase chain reaction, which make it possible to identify DNA and RNA, electronic amplification (for example, in gas-liquid chromatography), ELISA, concentration and separation of antigens or antibodies by immunosorption and immunoaffinity chromatography, gel filtration and ultracentrifugation, require much less time. In the arsenal of research laboratories there are 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 go 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 of hormone formation. Entering the blood, they are carried throughout the body and carry out humoral regulation of the functions of organs and tissues, changing their activity, exciting 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 surrounding or internal environment. The sensory system consists of receptors, neural pathways and parts of the brain responsible for processing received signals. The most famous sensory systems are sight, hearing, touch, taste and smell. Through the sensory system, physical properties such as temperature, taste, sound or pressure can be sensed.

Analyzers are also called sensor systems. The notion "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 surrounding and internal environment of the body.

57. The 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. Ear - the human hearing organ Sound signals are perceived using a sound analyzer, the main structural unit of which is phonoreceptors. The auditory nerve, which is part of the vestibular cochlear nerve, carries information in the form of signals. The final point of receiving signals and the place of their processing is the cortical section of the auditory analyzer, located in the cerebral cortex, in its temporal lobe. More detailed information on 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 three sections are distinguished: The external ear, represented by the auricle, the external auditory canal and the tympanic membrane. The auricle is composed 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 canal 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 the connective tissue, is the outer wall of the 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. In the tympanic cavity there are three ossicles known as the malleus, incus, and stapes. In addition, the middle ear contains the Eustachian tube, which connects the middle ear cavity to 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. The inner ear is divided into the vestibule, three semicircular canals, and the cochlea. Only the cochlea is directly related to the organ of hearing, while the other two elements of the inner ear are part of the organ of balance. The snail looks like a thin cone, twisted in the form of a spiral. Along its entire length, it is divided by two membranes into three channels - the vestibule staircase (upper), the cochlear duct (middle) and the tympanic staircase (lower). In this case, the lower and upper canals are filled with a special liquid - 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 overhanging 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 looks like this: sound vibrations are transmitted from the fluid filling the cochlea to the stapes, 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 excitement, 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.

The human reproductive system is a system of organs that make it possible to reproduce offspring. In men and women, the structure of the reproductive system is completely different.

Organs that make up the reproductive system and their functions

The composition of the organs and the tasks of the reproductive system

The organs of the male reproductive system include the following organs: testes, vas deferens, prostate (prostate), seminal vesicles, bulbourethral glands, urethra and penis. Unlike women, in men, the reproductive system is directly related to the urinary system. Therefore, a common name for both systems is often used - the genitourinary system.

The organs of a woman's reproductive system include: ovaries, fallopian tubes, uterus, vagina, vulva. Unlike men, in women, the urinary and reproductive systems are not directly related. However, during pregnancy, due to the special location of the uterus, there is direct pressure on the bladder.

The job of the male reproductive system is to produce sperm, or male reproductive cells, and transport them to female eggs for fertilization.

The tasks of the female reproductive system are somewhat broader than those of men. These include not only egg production. Sexual intercourse and fertilization take place inside a woman's genitals. They also carry out the task of carrying an unborn child for 9 months and provide labor. Also, the tasks of the female reproductive system include stimulating the production of breast milk throughout the entire period of lactation (breastfeeding).

Another important task of the reproductive system in both sexes is the synthesis of hormones that determine the work of the whole organism, including mood and behavior.

Prevention and treatment of the reproductive system

To improve the functioning of the entire reproductive system with already existing deviations, peptide preparations are excellent. NPTSRiZ company... To do this, you can use individual drugs or choose according to indications complex application of NPTsRiZ products... At the initial stages, synthesized bioregulators are used Cytogens, and for long-term treatment - Cytomax .

For women:

For men:

In addition to peptide bioregulators, the catalog contains other peptide products and geroprotectors for the male and female reproductive system. Only an integrated approach to maintaining your health gives long-term positive results. To do this, you should use ready-made schemes complex application of NPTsRiZ products.