The organs responsible for reproduction in men are called testicles. They produce sex cells - spermatozoa and hormones, for example, testosterone. The anatomical and histological structure of the testicles in men is complex, since these organs perform several functions at once. They carry out spermatogenesis - the formation and development of germ cells. Also, the testicles perform an endocrine function. They are located in a special skin bag - the scrotum. A special temperature is maintained there, which is somewhat lower than in other parts of the body.
The testicles are elliptical in shape and measure about 4cm long and 3cm wide. Normally, there may be a slight asymmetry of the gonads. Each testicle is divided by membrane septa into many lobules. They contain convoluted seminal canals that form the testicular plexus. Its efferent ducts enter the epididymis. There the main part of the sperm is formed - the head. Later - the channels enter the vas deferens, which goes to the bladder. Further, they expand and penetrate through another organ of the male reproductive system - the prostate. Before this, the channel is formed into the ejaculatory duct, which has an outlet in the areaurethra.
Histological structure of testicles in men
The male gonads are composed of the spermatic cord and interstitial tissue. Outside, they are covered with a protein shell. It is represented by dense connective tissue. The protein shell is fused with the organ. Laterally, it thickens, forming the mediastinum of the testis. At this point, the connective tissue is divided into many strands. They form lobules, inside which are convoluted tubules. They are represented by the following structural units:
- Sertoli cell - sustentocyte. Together with other elements, it participates in the formation of the blood-testicular barrier.
- Cells responsible for spermatogenesis.
- Myofibroblasts. Their other name is peritubular cells. The main function of myofibroblasts is to ensure the movement of seminal fluid through convoluted channels.
Besides this, there is interstitial tissue in the structure of the testis. It is about 15%. The interstitial tissue is represented by elements such as Leydig cells, macrophages, capillaries, etc. If the tortuous channels are responsible for the formation of germ cells, then the formation and production of male hormones occurs here.
Sertoli cell: structure
Sertoli cells have an elongated shape. Their size is about 20-40 microns. These are rather large structural units, which are otherwise called supporting cells. The cytoplasm of these elements contains many organelles. Among them:
- The core. It has an irregular, sometimes pear-shaped shape. Chromatin in the nucleus is unevenly distributed.
- Smooth and rough EPS. The first one is responsible for the production of steroid hormones, the second one provides protein synthesis.
- Golgi apparatus. Thanks to this organelle, the final synthesis, storage and excretion of products occurs.
- Lysosomes - involved in phagocytosis.
- Microfilaments. These organelles are involved in sperm maturation.
In addition, each Sertoli cell contains fatty inclusions. The base of the sustentocytes is located on the walls of the seminiferous tubules, and the apex is turned into their lumen.
Sertoli cells: functions
The Sertoli cell is one of the constituent parts that form the convoluted seminiferous tubules. It is of great importance, as it participates in the process of spermatogenesis and the synthesis of male hormones. The following functions of Sertoli cells are distinguished:
- Trophic. These elements provide immature sperm with oxygen and nutrients.
- Protective. Each cell has lysosomes in the cytoplasm - organelles involved in phagocytosis. They absorb and recycle decay products, such as dead spermatid fragments.
- Providing the blood-testicular barrier. This function is provided due to close intercellular contacts. The barrier is necessary to separate the male sex cells from the blood and the substances contained in it. In addition, it prevents the penetration of sperm antigens into the plasma. Due to this, it decreasesrisk of developing autoimmune inflammation.
- Endocrine function. Sertoli cells are involved in the formation of sex hormones.
Sustentocytes are necessary for the formation and maintenance of a special environment in which spermatozoa favorably develop. It is known that the ionic composition of Sertoli cells differs from blood plasma. The sodium concentration in them is lower, and the potassium content, on the contrary, is increased. In addition, many biologically active substances are synthesized in Sertoli cells. Among them are prostaglandins, cytokines, follistatin, growth and division factors, opioids, etc.
Functions and structure of Leydig cells
Leydig cells are part of the interstitial tissue of the testis. Their size is about 20 µm. There are over 200106 Leydig cells in the male gonads. The structural features of these elements are a large oval-shaped nucleus and a foamy cytoplasm. It contains vacuoles containing the protein lipofuscin. It is formed during the breakdown of fats at the time of the synthesis of steroid hormones. In addition, in the cytoplasm there are 1 or 2 nucleoli containing RNA and protein. The main function of Leydig cells is the production of testosterone. In addition, they are involved in the synthesis of activin. This substance stimulates the production of FSH in the brain.
What is Sertoli Cell Syndrome?
One of the rare diseases of the male reproductive system is Sertoli cell syndrome. Infertility is considered the main manifestation of this pathology. The disease refers to congenital anomalies of development, since with itthere is aplasia (significant reduction or absence) of the germinal tissue of the testicles. As a result of this violation, the seminiferous tubules do not develop. The only element that is not damaged is the Sertoli cell. Another name for this pathology is del Castillo syndrome. Some Sertoli cells still undergo degeneration, however, most of them are normal. Despite this, the tubular epithelium is atrophied. Spermatozoa in this pathology are not formed.
Leydig cell dysfunction
When Leydig cells are damaged, their main function, the synthesis of testosterone, is disrupted. As a result, symptoms such as:
- Decreased muscle mass.
- Absence of secondary sexual characteristics (male pattern hair, voice timbre).
- Libido disorder.
- Lower bone density.
