Male genital gland : morphology , anatomy and physiology
Endocrinology / / August 12, 2017
Diseases of male genital glands
Profiles embryology, anatomy and physiology
male gonads are formed from the mesoderm.The first beginnings of sexual glands clearly detected in 3-4-millimeter embryo as a thickening of the epithelium in the inner legs of the somites.At 5-millimeter embryo at the end of the first month of embryonic development as a result of thickening of mesodermal (coelomic) epithelium on the medial surface of the chalk formed Wolffian sex rollers.
first signs of differentiation of male sex glands have been reported in the embryo of about 7 weeks.This is reflected in the appearance of anastomosing cords of cells that later develop through the formation of luminal seminiferous tubules.Epithelial cells located in the connective tissue between their strands formed interstitial cells.
gonaduct develop from cells pronephros, Wolffian duct and urogenital sinus.Combining them with the gonads occurs again.
Lowering the testicles into the scrotum ends the 8th month of fetal development.
scheme lowering the testicles
and - egg located in the lumbar region between the transverse fascia and abdominal, vaginal process formed
b - egg nearer to the pelvis
in - testicle descended to the bottom of the scrotum, behind the processus vaginalis of the peritoneum, the last part has not yet been obliterated
g - obliteration of the processus vaginalis testis above
It is associated with various moments.You can consider it established that a very important role in lowering the testicles belongs to a shortening of ligaments hubernaculum testis.Considerable importance is attached to the increased production of gonadotropins in the last months of pregnancy.
Testicles are in the form of an ellipsoid, and are located in the scrotum.The size of an adult male testis - 4-4.5 cm of eggs -. 20-30, the distinction is made between two surfaces - lateral and medial two edge - front and back (it is associated with an appendage), and two end - upper and lower.
Outside testicles are covered with serous cover (tunica vaginalis propria), under which there is albuginea (tunica albuginea testis).Between them there are always a small amount of clear liquid.Under the tunica is the glandular tissue of the testicle.Between them is a layer of loose connective tissue (tunica vascularis testis).
along the rear edge of testicular albuginea forms a triangular shape porous thickening - mediastinum testis.From his fan-like divergent thin connective tissue septa, septula testis, who share gland parenchyma 200-400 lobules conical shape.Slices contain convoluted tubules, tubuli seminiferi contorti, connecting with each other, they form a straight tubules - tubuli seminiferi recti, recent moves to form a network, rete testis, located deep in the mediastinum.From the network go 12-15 efferent tubules, ductuli efferente testis.These canals flow into the appendage (epididymus), which then enters the ductus defferens.
vas deferens as a part of the spermatic cord in the inguinal canal rises from the inner hole of which he is medially under the peritoneum over the edge of the pelvis, moving backwards and downwards, and the ureter crosses under the bottom of the bladder coming to the seminal vesicles.Close proximity to the prostate gland vas deferens connects with ductus excretorius seminal vesicle.From this place he called ductus ejacula-torius, which opens to the seed mound in the prostatic urethra.
seminiferous epithelium of the convoluted tubules contain only.Between the tubules are interstitial connective tissue containing Leydig cells.
En shell convoluted tubules lined by germinal epithelium, from which sperm develop.Straight tubules are lined with low cuboidal or flattened, and the efferent - ciliated cylindrical and cubic epithelium.
Blood supply to the testicle and the epididymis is carried out on a.spermatica interna and a.deferentialis, which anastomose with each other.Shell eggs are supplied with blood by a.spermatica interna and a.pudenda externa.venous outflow occurs through acinar plexus, which empties into the v.spermatica interna.The latter flows into the left renal vein to the right - in the inferior vena cava.
The egg is very rich in lymphatic vessels, of which the lymph is removed through the lymphatic trunks;the past as part of the spermatic cord reach oryushnoi cavity and terminate in the lumbar lymph nodes.It is now believed that the lymph capillaries and vessels testicles are directly involved in the outflow of thyroid hormones.
testicular nerves sympathetic plexus formed around a.testicularis - plexus testicularis and about a.deferentialis - plexus deferentialis.Sensory nerve fibers are also part of this plexus.
Figure 1. Cross-section of the tubule:
Testicles have generative and endocrine functions.The first is to develop and maintain the kind of sperm, the second is to develop a specific hormone that promotes the appearance of secondary sexual characteristics, normal sex drive.
Sperm cells are located in the lumen of the tubules have a length of about 60 Y and consist of head, neck and tail.The duration of education of mature spermatozoa on the average 19-20 days.When ejaculation erupting secret accessory sex glands and the prostate gland, which is mixed with sperm.The ejaculate contains 200-360 million. Sperm.
testicular endocrine function is concentrated in the intermediate Leydig cells.This position is contested by some authors, but the work of recent years have confirmed the undoubted part of Leydig cells in the production of testosterone.In the body there is a constant conversion of testosterone into androsterone, which is excreted in the urine (see. Fig. 2).
In addition, in the tubules of the testis is formed poorly-studied hormone, called inhibin.This substance unknown chemical nature, a non-androgenic activity, but capable of acting on the pituitary gland, reducing the production of FSH.Some consider him the estrogen produced by Sertoli cells, but the issue needs further study.
physiological significance of the male sex hormone is the formation of male sex organs and ensuring their normal function.It affects the appearance and preservation of libido and potentio, the development of secondary sexual characteristics and normal functioning of many organs and tissues.One of the main functions of the testes themselves - spermatogenesis is also closely linked with hormonal their function.
data about the role of the male sex hormone are based both on the clinical observations in patients with a congenital deficiency of testicular function after traumatic or surgical castration, and in experimental studies of castrated animals.
Fig.2 The conversion of testosterone into androsterone
use of drugs with androgenic activity for therapeutic purposes in patients with insufficient function of the testes or the syndrome of anorchia and castrated animals confirms the correctness of these ideas about the physiological significance of the male sex hormone.
Testosterone, enhancing protein anabolism, stimulates bone growth.Large doses of this preparation, facilitating earlier epiphyseal cartilage ossification, leading to premature stop of growth of long bones.
When testicular failure observed increased growth of bone with late ossification of cartilage, resulting in the fold eunuchoid body proportions.Often such patients epiphyseal cartilage neokostenevshimi remain for a long time.
In the literature there are indications of excessive deposition of fat in the animals after castration.Clinical observations show that the lack of testicular function may be marked as increased and reduced fat deposition.
male sex hormone influences the formation of skeletal muscles.Established that androgens stimulate erythropoiesis.
Testosterone increases protein anabolism, reduces urinary excretion of nitrogen and creatinine.Castration also increases their isolation.
testicles in men are the main but not the only source of androgens.A certain role in the production of adrenal cortex plays.So for tumors and congenital adrenal hyperplasia is observed in boys early appearance of secondary sexual characteristics.
sperm production begins at puberty (13-17 years) and often occurs continuously until old age.However, the majority of men in the age of spermatogenic function and fertility gradually regress.
- Menopause (Menopause) and diseases of menopause in women
- Pathology of menopause (menopause).Climacteric neurosis
- diagnosis and treatment of climacteric neurosis
- menstrual cycle Hormonal
- menstrual irregularities
- The use of estrogen for the treatment of climacteric neurosis
- The use of androgens in the treatment of climacteric neurosis
- morphology of adrenal
- MACROGENITOSOMIA PRAECOX.Diagnosis and differential diagnosis
occurs after 50-60 years of age should be considered as failure of the testes age physiological process that occurs along with other signs of aging.First, there is a slight reduction in the diameter of the convoluted tubule basement membrane thickening, weakening of spermatogenesis.After 50 years there is a gradual decrease in the level of androgens at a constant content of estrogen.
testicles gradually continue to decrease in volume, becoming less sensitive to pressure, the scrotum and the penis becomes flaccid, spermatogenesis is gradually fading and usually disappears completely between 80 and 90 years.
In this period there is partial regression of secondary sexual characteristics;hair above the pubis lose waviness and begin to fall;less beard and mustache grow rapidly.There is insufficient data to answer the question of whether age-lowering androgenic activity in the testis of aging period lead to the development of a depressive state, irritability, impatience, memory impairment, sleep or these states are age pathology not related to a decrease in testicular androgen activity.
function of the endocrine glands are under the influence of regulating the central nervous system.On the other hand, infringement of endocrine function has a significant impact on the work of the higher parts of the central nervous system.
testicular function is closely related to the function of other endocrine glands: pituitary, adrenal, thyroid and thymus.The greatest influence on testicular function has a correlation with the anterior pituitary gland, which produces hormones FSH and lyuteostimuliruyuschy.The first affects spermatogenesis, the second - on the development of intermediate cells and for production of hormones.
central regulation of gonadotropin production is carried out the influence of hypothalamic neurosecretory cells.Near experimental studies found that in hiasma optici are centers that stimulate the production of luteinizing hormone and follicle-inhibiting products.The suprachiasmatic
areas are centers that regulate cyclic allocation of luteinizing hormone and in the eminentia mediana - centers providing secretion of luteinizing hormone.
The oral part of the hypothalamus has a stimulating effect on sexual development, and caudal - braking.On the other hand, the hormones produced by the testicles, circulate in the blood and have an inhibitory effect on certain centers of the hypothalamus, and gonadotropin-releasing function of the anterior pituitary.
degenerative processes in the sexual glands occur in cases of poisoning, infectious diseases, especially chronic.
Degenerative changes in the seminiferous epithelium with destruction and desquamation of individual cells, with the cessation of spermatogenesis are accompanied by proliferation of interstitial tissue.The predominance of the interstitial tissue of epithelial characteristic of the sexual glands of men who are exposed to chronic alcohol poisoning and vitamin starvation.All
deleterious effects leading to a state of degeneration and atrophy of spermatogenic epithelium, with increasing duration and intensity of exposure can eventually lead to atrophy and degeneration, cause the death of the entire gland.Note that the ionizing radiation is also adversely affect the testes.The male sex gland, subjected to moderate impact, suffering primarily germinal part.In these cases, the amount of interstitial tissue increases not only with respect to (interstitial tissue is preserved intact), but may increase absolutely, undergoing hyperplasia.The gonads, subjected to the influence of ionizing radiation, can consistently monitor all phases of the degeneration of the seminiferous epithelium with its subsequent restoration.Interstitial tissue thereby increasing the mass that is determined by the multiplication of its cells.In cases where the ionizing radiation is produced in small doses, these changes are reversible and as recovery of spermatogenesis occurs regression of interstitial tissue.
Given the obvious relationship of the hypothalamus to the pituitary gland, the brain appendage and the hypothalamic region is considered as a single hypothalamic-pituitary system, which carries out the regulation of the reproductive glands.