What is the structure and function of the male reproductive system. Explore common penis conditions, tests, and treatments.

The Male Reproductive System: An Overview

The male reproductive system is a complex and vital part of the human body, responsible for sexual function, fertility, and the elimination of waste. At the core of this system is the penis, the male sex organ that plays a crucial role in both sexual activity and urination.

Anatomy of the Penis

The penis is composed of several key structures:

• Glans (head) of the penis: The glans is the tip of the penis, covered in a moist, pink tissue called mucosa in uncircumcised men. In circumcised men, the mucosa transforms into dry skin.
• Corpus cavernosum: Two columns of tissue running along the sides of the penis that fill with blood during an erection, causing the penis to harden.
• Corpus spongiosum: A column of sponge-like tissue running along the front of the penis, ending at the glans. It also fills with blood during an erection, keeping the urethra open.
• Urethra: The tube that runs through the corpus spongiosum, allowing urine and semen to exit the body.

The Erection Process

An erection is the result of changes in blood flow to the penis. When a man becomes sexually aroused, nerves cause the blood vessels in the penis to expand, allowing more blood to flow in and less to flow out. This increased blood flow hardens the tissue in the corpus cavernosum, resulting in an erect penis.

Common Penis Conditions

The male reproductive system can be affected by a variety of conditions, including:

• Erectile Dysfunction: The inability to achieve or maintain an erection sufficient for satisfactory sexual intercourse.
• Priapism: An abnormal erection that does not go away even after stimulation has stopped, which can lead to serious problems.
• Hypospadias: A birth defect where the urethra opening is on the underside of the penis rather than the tip.
• Phimosis and Paraphimosis: Conditions where the foreskin cannot be retracted or returned to its normal position.
• Balanitis and Balanoposthitis: Inflammation of the glans penis, often due to infection.
• Chordee: An abnormal curvature of the penis, present from birth.
• Peyronie’s Disease: An abnormal curvature of the penis shaft, often caused by injury or other medical conditions.
• Urethritis: Inflammation or infection of the urethra, frequently caused by sexually transmitted infections.
• Micropenis: An abnormally small penis, present from birth due to a hormone imbalance.
• Penis Warts: Warts caused by the human papillomavirus (HPV), which are highly contagious.
• Penis Cancer: A rare form of cancer in the United States, with circumcision reducing the risk.

Diagnostic Tests and Treatments

There are several diagnostic tests and treatment options available for conditions affecting the male reproductive system:

• Diagnostic Tests: Urethral swabs, urinalysis, nocturnal penis tumescence testing, urine cultures, and polymerase chain reaction (PCR) tests can help diagnose various penis conditions.
• Treatments: Medications such as phosphodiesterase inhibitors (e.g., Viagra) can enhance blood flow to the penis, while antibiotics can treat bacterial infections. Surgery may be necessary for conditions like hypospadias or penis cancer.

The Importance of Regular Check-ups

Regular check-ups and prompt attention to any issues or concerns related to the male reproductive system are crucial for maintaining overall health and well-being. By understanding the anatomy, functions, and potential conditions of the penis, men can take proactive steps to address any problems and maintain optimal sexual and urinary function.

Conclusion

The male reproductive system, with the penis at its core, is a complex and essential part of the human body. By understanding the anatomy, functions, and common conditions affecting this system, men can take steps to maintain their sexual and urinary health, and seek timely medical attention when necessary.

Diagram, Function, Conditions, and More

Human Anatomy

Written by Matthew Hoffman, MD

• Image Source
• Penis Conditions
• Penis Tests
• Penis Treatments

© 2014 WebMD, LLC. All rights reserved.

The penis is the male sex organ, reaching its full size during puberty. In addition to its sexual function, the penis acts as a conduit for urine to leave the body.

The penis is made of several parts:
• Glans (head) of the penis: In uncircumcised men, the glans is covered with pink, moist tissue called mucosa. Covering the glans is the foreskin (prepuce). In circumcised men, the foreskin is surgically removed and the mucosa on the glans transforms into dry skin.
• Corpus cavernosum: Two columns of tissue running along the sides of the penis. Blood fills this tissue to cause an erection.
• Corpus spongiosum: A column of sponge-like tissue running along the front of the penis and ending at the glans penis; it fills with blood during an erection, keeping the urethra — which runs through it — open.
• The urethra runs through the corpus spongiosum, conducting urine out of the body.

An erection results from changes in blood flow in the penis. When a man becomes sexually aroused, nerves cause penis blood vessels to expand. More blood flows in and less flows out of the penis, hardening the tissue in the corpus cavernosum.

• Erectile dysfunction: A man’s penis does not achieve sufficient hardness for satisfying intercourse. Atherosclerosis (damage to the arteries) is the most common cause of erectile dysfunction.
• Priapism: An abnormal erection that does not go away after several hours even though stimulation has stopped. Serious problems can result from this painful condition.
• Hypospadias: A birth defect in which the opening for urine is on the front (or underside), rather than the tip of the penis. Surgery can correct this condition.
• Phimosis (paraphimosis): The foreskin cannot be retracted or if retracted cannot be returned to its normal position over the penis head. In adult men, this can occur after penis infections.
• Balanitis: Inflammation of the glans penis, usually due to infection. Pain, tenderness, and redness of the penis head are symptoms.
• Balanoposthitis: Balanitis that also involves the foreskin (in an uncircumcised man).
• Chordee: An abnormal curvature of the end of the penis, present from birth. Severe cases may require surgical correction.
• Peyronie’s Disease: An abnormal curvature of the shaft of the penis may be caused by injury of the adult penis or other medical conditions.
• Urethritis: Inflammation or infection of the urethra, often causing pain with urination and penis discharge. Gonorrhea and chlamydia are common causes.
• Gonorrhea: The bacteria N. gonorrhea infects the penis during sex, causing urethritis. Most cases of gonorrhea in men cause symptoms of painful urination or discharge.
• Chlamydia: A bacteria that can infect the penis through sex, causing urethritis. Up to 40% of chlamydia cases in men cause no symptoms.
• Syphilis: A bacteria transmitted during sex. The initial symptom of syphilis is usually a painless ulcer (chancre) on the penis.
• Herpes: The viruses HSV-1 and HSV-2 can cause small blisters and ulcers on the penis that reoccur over time.
• Micropenis: An abnormally small penis, present from birth. A hormone imbalance is involved in many cases of micropenis.
• Penis warts: The human papillomavirus (HPV) can cause warts on the penis. HPV warts are highly contagious and spread during sexual contact.
• Cancer of the penis: Penis cancer is very rare in the U.S. Circumcision decreases the risk of penis cancer.

• Urethral swab: A swab of the inside of the penis is sent for culture. A urethral swab may diagnose urethritis or other infections.
• Urinalysis: A test of various chemicals present in urine. A urinalysis may detect infection, bleeding, or kidney problems.
• Nocturnal penis tumescence testing (erection testing): An elastic device worn on the penis at night can detect erections during sleep. This test can help identify the cause of erectile dysfunction.
• Urine culture: Culturing the urine in the lab can help diagnose a urinary tract infection that might affect the penis.
• Polymerase chain reaction (PCR): A urine test that can detect gonorrhea, chlamydia, or other organisms that affect the penis.

• Phosphodiesterase inhibitors: These medicines (such as sildenafil or Viagra) enhance the flow of blood to the penis, making erections harder.
• Antibiotics: Gonorrhea, chlamydia, syphilis, and other bacterial infections of the penis can be cured with antibiotics.
• Antiviral medicines: Taken daily, medicines to suppress HSV can prevent herpes outbreaks on the penis.
• Penis surgery: Surgery can correct hypospadias, and may be necessary for penis cancer.
• Testosterone: Low testosterone by itself rarely causes erectile dysfunction. Testosterone supplements may improve erectile dysfunction in some men.

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3A: Anatomy of the Male Reproductive System

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The male reproductive system includes external (penis, scrotum, epididymus, and testes) and internal (accessory) organs.

Learning Objectives

• Distinguish among the parts and functions of the male reproductive system

Key Points

• The functions of the male reproductive system include producing and transporting sperm, ejaculating sperm into the female reproductive tract, and producing and secreting male hormones.
• Most of the male reproductive system is located outside of the body. These external structures are the penis, scrotum, epididymis, and testes.
• The internal organs of the male reproductive system are called accessory organs. They include the vas deferens, seminal vesicles, prostate gland, and bulbourethral glands.

Key Terms

• semen: Contains spermatozoa, proteolytic and other enzymes, and
  fructose that promotes spermatozoa survival. It also provides a medium for sperm
  motility.
• spermatogenesis: The process of sperm production within the seminiferous tubules in the testes.
• testosterone: Steroid hormone produced primarily in the male testes and responsible for the development of male secondary sex characteristics.

The organs of the male reproductive system are specialized for three primary functions:

1. To produce, maintain, transport, and nourish sperm (the male reproductive cells), and protective fluid ( semen ).
2. To discharge sperm within the female reproductive tract.
3. To produce and secrete male sex hormones.

External Male Sex Organs

Most of the male reproductive system is located outside of the man’s body. These external structures are the penis, scrotum, epididymis, and testes.

Male Reproductive System: Lateral view of male reproductive system with organs labeled.

The penis is the male organ for sexual intercourse and urination. Semen and urine leave the penis through the urethra. The scrotum is a loose, pouch-like sack of skin that hangs behind the penis, containing the testes.

The scrotum has a protective function, including the maintenance of optimal temperatures for sperm survival and function. For sperm development, the testes must maintain a temperature slightly cooler than normal body temperature. Special muscles in the wall of the scrotum contract and relax in order to move the testes near the body.

The epididymus is located at the back of the testis and connects it to the vas deferens. Its function is to store and carry sperm. The testis is the location for testosterone production. The coiled collection of tubes within the testes are the seminiferous tubules. Within these tubules, spermatogenesis takes place.

Accessory Sex Organs

The internal organs of the male reproductive system are called accessory organs. They include the vas deferens, seminal vesicles, prostate gland, and bulbourethral (Cowper’s) glands.

• Vas deferens: Transports mature sperm to the urethra in preparation for ejaculation.
• Seminal vesicles: Sac-like pouches that attach to the vas deferens near the base of the bladder. The vesicles produce molecules such as fructose that serve as energy sources for sperm. The seminal vesicle fluid makes up most of the volume of a man’s ejaculate.
• Prostate gland: A walnut-sized structure located below the urinary bladder in front of the rectum. It contributes additional fluid to the ejaculate that serves as nourishment for sperm.
• Bulbourethral (Cowper’s) glands: Pea-sized structures located on the sides of the urethra just below the prostate gland. These glands produce a clear, slippery fluid that empties directly into the urethra. Fluid produced by these glands lubricates the urethra and neutralizes acidity associated with residual urine.

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Anatomy and function of the male reproductive system

In men and women, the genital organs are located both inside the pelvic cavity and outside it. Most of the male reproductive system is located outside. Such a device in wildlife is a demonstration of its strength and superiority. Perhaps this is why many, if not most, men are embarrassed to see a doctor if they have problems in their intimate life.

This article is not to be used for diagnosis, treatment, and is not a substitute for seeing a doctor.

The reproductive system of a man is extremely important, like the rest of the body’s systems that ensure normal life. Therefore, an untimely appeal to a specialist or, even worse, ignoring the warning signs, creates much bigger problems than they were originally.

The male reproductive system has three main tasks:

1. Formation of spermatozoa in the testes (seniferous tubules). In the process of one ejaculation, 30-500 million spermatozoa come out.
2. Evacuation of seminal fluid from the male genital organs and its delivery to the female.
3. Synthesis of the main androgen (a group of steroid sex hormones in men) – testosterone.

Structure and functions of the external male genitalia

The group of male external reproductive organs includes:

• Penis (penis) – an organ involved in sexual contact, spewing seminal fluid. The place of attachment of the phallus to the pubis is the root. The body of the penis and the head are covered by the foreskin (skin fold), which normally should easily and painlessly move away, exposing the head. In the foreskin there are multiple glands that produce smegma (sebaceous lubricant). Internally, the penis consists of two cavernous (cavernous) and one spongy (spongiform) bodies. It is to the cavernous bodies that a man owes the appearance of an erection, in which the bodies are filled with blood and “swell”, increasing the size of the penis. In the spongy body is the urethra (urethra), which blocks the path for the passage of urine during intercourse and ejaculation.
• Testicles (testicles) – olive-shaped paired organs of different sizes produce testosterone and spermatozoa. They are located in the sac (scrotum), which acts as a “climate control”. For healthy spermatogenesis (sperm production), the testicles must be maintained at a constant temperature below general body temperature. This provides the scrotum and the external location of the testicles. Otherwise, spermatogenesis will be impaired, which will negatively affect fertility (the ability to conceive).
• The epididymis is an oblong narrow paired organ, part of the vas deferens. In the epididymis, spermatozoa accumulate and mature for further advancement into the vas deferens. Spermatozoa accumulate in a thickening formed in the tail. In the scrotum, the appendage is adjacent to the testicle, forming a pocket. Normally, it is easily palpable through the scrotum.

Male internal genitalia

The main internal male organ is the exocrine androgen-dependent prostate gland, nut-shaped, located in the center of the pelvis near the bladder. The function of the gland is to control urination, erection, ejaculation, ensure the viability of spermatozoa and transport them.

Isolate the secretory and barrier function of the prostate. The gland produces its own secret, which enters the sperm during ejaculation. The secret contains enzymes, acids, immunoglobulins and other trace elements. The secret also contains immunity factors that allow the prostate to perform a barrier function, which consists in preventing the penetration of pathogenic microflora from the urethra into the urinary tract and preventing the spread of microorganisms from the urethra to the vas deferens. The presence of zinc ions in secret protects the male genital tract from infection. The work of the gland is controlled by pituitary and steroid hormones, estrogens.

Male internal genital organs also include:

• Deferent ducts — their task is to transport ejaculate to the urethra, which can also be attributed to the reproductive system. The ducts originate from the appendages of the testicles.
• Seminal vesicles – produce a fluid that is part of the semen. The secret of the bubbles, containing a large amount of fructose, is “responsible” for the vital energy of spermatozoa.
• Bulbourethral glands – tiny pea-sized Cooper glands located near the prostate, secrete into the urethra. The secret of the glands lubricates the walls of the urethra, neutralizes the acidity of urine.

Hormones that regulate the function of the male reproductive system

The function of the reproductive system in men is regulated by three main hormones:

• Luteinizing (LH).
• Follicle stimulating (FSH).
• Testosterone.

LH and FSH are pituitary hormones. Testosterone is synthesized under the influence of LH, spermatozoa are formed under the influence of LH. Testosterone is responsible for the timely appearance of secondary sexual characteristics, seminal fluid production, muscle building, physical strength and endurance, libido, voice pitch.

Function of hormones in the male reproductive system

Read more about hormones in men in this material – note. altravita-ivf.ru

Sperm formation

Spermatogenesis (production of seminal fluid) is carried out under the influence and control of hormonal substances. It starts from the moment of puberty (11-15 years), therefore, until this age, spermatozoa are not produced in the boy’s body. When testosterone reaches the age-appropriate level in a teenager, this leads to the activation of stem cells in the testicles (spermogonia). Spermogonium is converted into spermatocytes containing a double chromosome set. Spermatocytes divide, forming, in turn, secondary spermatocytes, which contain one chromosome set each.

The spermatocytes are then transformed into spermatid cells, which undergo spermiogenesis (the final stage of spermatogenesis). Spermatid cells turn into spermatozoa, which mature in the epididymis. After maturation, the sperm are ready to fertilize the egg.

The speed of movement of spermatozoa is 20 cm / h with a length of only 0.05 mm.

Menopause in men: myth or reality?

Menopause or menopause is the cessation of the activity of the female sex glands (ovaries), as a result of which menstruation completely stops. The reason for this is the cessation or a significant decrease in the production of estrogen by the ovaries. Men never stop producing testosterone, and any man can theoretically become a father in old age. Exceptions are severe diseases or congenital anomalies that affect spermatogenesis and erectile function. With age (from 35-45 years old), testosterone production begins to decline, and fertility also decreases accordingly. Having passed the analysis for testosterone, men have the opportunity to assess the state of their health.

Reducing the production of male sex hormones occurs under the influence of various factors: endocrine diseases, obesity, chronic diseases, STDs, stress, constant overheating of the testicles in saunas, baths, frequent hypothermia, depression, trauma, accidents (electric shock, accidents) and so Further. The impact of adverse factors leads not only to a decrease in testosterone production, but also to erectile and ejaculatory dysfunction.

Anatomical structure of the male genital organs

Genitourinary system

The term “genitourinary” explains that this system consists of two components: urinary and genital. The combination of these two subsystems into one indicates a close relationship between the organs of this system, and in the male body this relationship is more closely manifested than in the female, since the male urethra (urethra) performs a dual function: urine excretion and ejaculation. Therefore, the urologist deals with the pathology of the male genitourinary system and the female urinary system.

The urinary system includes: kidneys, ureters, bladder, urethra. Kidneys In their shape, the kidneys resemble beans (or beans). The average size of the kidneys in an adult is 10 x 6 cm. The right kidney is usually located slightly lower than the left, since it is located under the liver. The kidneys are surrounded by fatty tissue, which, along with the surrounding muscles and ligaments, hold them in place. This explains why in thin people, as well as due to sudden weight loss, a disease such as nephroptosis can occur – omission of the kidney.

Kidneys consist of two layers. Superficial – cortical, and deeper – cerebral. On the section of the kidney, you can see the medulla is a system of tubules (tubules). The function of the tubules is to collect and divert urine into the pelvis. The pelvis is a combined collector of all tubules of the kidney. It opens into the gate of the kidney, in which, in addition to the pelvis, there is also an artery and a vein.

The basic unit of the kidney is the nephron. This is such a glomerulus, it consists of the very initial “cup-shaped” end of the tubule, which is entangled with capillaries, through which blood continuously circulates. Due to blood pressure and the membrane properties of the capillary walls, plasma is filtered from the blood into the glomerulus – that is, the liquid part of the blood without erythrocytes, leukocytes and other blood cells, which, normally, do not pass through the membrane, as well as some substances (sugar, protein, etc. ) But in certain diseases, these blood components are filtered through the glomerular membrane and are found in the urine.

So, the main function of the kidneys is to “filter” the blood. The kidneys are the main organ that cleanses the blood of all toxins and metabolic products. When they become ill, this filtering function is disturbed, which leads to accumulation in the blood and poisoning of the body with its own metabolic products. It is worth noting that some drugs and their metabolic products are excreted from the body through the kidneys.

Ureters

The ureters are a downward extension of the pelvis and are a tube about 30 cm long. The lumen of the ureter is 5-6 mm. But this width is not constant and the lumen of the ureter narrows in three places – the so-called physiological narrowing. The significance of these narrowings lies in the fact that small kidney stones can get stuck in them. The ureters empty into the bladder.

Bladder

The bladder is an extensible reservoir, the wall of which contains a muscular layer and is lined with a mucous membrane from the inside. The ureters flow into the bladder. The average bladder capacity is 300 to 600 ml.

Urethra (urethra)

The urethra is a hollow tube that carries urine out of the bladder. The urethra in men and women is different: in men it is long and narrow (30 cm long, about 8 mm wide), while in women it is short and wide (3-4 cm long, 1-1.5 cm wide). These structural features of the urethra in women are the main reason that they often develop inflammatory diseases of the bladder – cystitis, since the infection easily enters the bladder through the short female urethra. The lumen of the urethra is covered with a mucous membrane. Inflammation of this membrane – urethritis – occurs as a result of infection, both non-specific (conditionally pathogenic) and specific (gonorrhea, chlamydia, trichomoniasis, etc.).

Reproductive system. Male reproductive organs

Male internal genital organs

• Deferent ducts
• spermatic cord
• Seminal vesicles
• Prostate
• Bulbourethral gland

Male external genitalia

• Male urethra
• Scrotum
• Testicles
• Peritoneum of the pelvic cavity

Prostate (prostate gland)

The prostate is located directly under the bladder at its neck and covers the urethra, i. e. the urethra passes through it. This is the so-called prostatic urethra. Both the ducts of the prostate and the ducts of the seminal vesicles open into it. The prostate is a glandular organ, meaning most of its tissue is glandular. In shape and size, the prostate resembles a chestnut.

The main function of the prostate is the production of a special clear liquid – prostatic secretion (prostate juice), which is part of the semen. The composition of sperm is quite complex. Sperm is a mixture of secretions from a number of glands. In particular, in addition to spermatozoa, semen contains secretions of the prostate gland, seminal vesicles and glands of Littre and Cooper.

The secretions of the prostate gland attached to the seed have an alkaline reaction and an opalescent appearance, contain lycitine grains, prostatic bodies, epithelial, granular cells and spermine, which gives the seed a translucent milky appearance and a specific smell. The discharge of the seminal vesicles is odorless, sticky, colorless, consists of epithelial cells, single leukocytes and formations similar to sago grains.

The secrets of the prostate and seminal vesicles liquefy the thick semen, ensure the viability of the spermatozoa and give them the necessary mobility.

Sperm has the appearance of a cloudy, gelatinous, stretchy liquid, and the white color is due to the presence of spermatozoa in it. The secretion of the testicles consists of spermatozoa and phosphate crystals.

Seminal vesicles

Seminal vesicles are peculiar convoluted sacs along the posterolateral surface of the bladder. The main function of the seminal vesicles is a reservoir of seminal fluid. In the seminal vesicles, the seminal fluid also undergoes some changes in order to become a full-fledged sperm. During sexual intercourse, during ejaculation, seminal fluid is ejected from the seminal vesicles through the ducts into the urethra, and, mixing with the juice of the prostate and the secret of other glands, is ejected through the external opening of the urethra.

The vas deferens

The vas deferens are thin tubes that lead from the testicles and empty into the seminal vesicles. Through them, the seminal fluid from the testicles enters the seminal vesicles.

Testicles

The testicles are a paired organ. They are located in the scrotum. In them, the formation and maturation of spermatozoa occurs. In addition, the testicles are the main organ in which the main male sex hormone, testosterone, is produced. It should be noted such an interesting fact that usually the left testicle is located slightly lower than the right one.

As already noted, the main function of the testicles is the production of spermatozoa. Spermatozoa are produced in them by special cells – Sertolli cells. In addition to these cells, there are also Leydig cells in the testicles, these are hormone-active cells that produce testosterone.

Each testis consists of lobules filled with convoluted seminiferous tubules. On top of each testicle is an appendage that passes into the vas deferens. The functions of the testis are under the control of the anterior pituitary gland. It is worth noting the fact that such an arrangement of the testicles – the main, from the point of view of reproduction, genital organs – is associated with a special temperature regime, which is necessary for the maturation of spermatozoa in them. Those. for normal maturation of spermatozoa, a temperature of several degrees below body temperature is required. Therefore, such an important organ, from the point of view of storing and transmitting the genetic information of a species, is located in a not very reliable place – outside. However, many animals have a muscle that, in case of danger, raises the testicle and draws it into the abdominal cavity. In humans, it is underdeveloped.

Each testicle is covered with membranes in its half of the scrotum. There are seven in total. Sometimes, in case of accumulation between the layers of the testicles, dropsy (hydrocele) occurs.

Penis

The male penis is used for sexual intercourse and enables fertilization, and also in the thickness of his spongy body passes the urethra, through which urine or semen is excreted. Those. the penis has a dual function: urination and procreation. The penis has a complex structure. In the upper part of it there are two cavernous bodies, and under them – a spongy body. The cavernous bodies are covered with a connective tissue protein membrane.

Cavernous bodies got their name for their special cellular structure, which looks like a cave. Such a structure is necessary to ensure an erection and sexual intercourse. Studies show that an erection occurs as a result of the expansion of the arteries that bring blood to the penis, the spasm of the veins through which this blood departs from the penis, and the relaxation of the cells of the cavernous bodies of the penis. Arteries, veins and cells of the corpora cavernosa are composed of smooth muscles. These muscles are affected by the so-called neurotransmitters – substances that are released during stimulation of the nerves that control the erection process.

After appropriate sexual stimulation, these substances lead to relaxation (relaxation) of the smooth muscles of the cavernous bodies of the penis, expansion of their arterial cells, which is manifested by a powerful increase in blood flow to the penis.