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MALE REPRODUCTIVE SYSTEM. The male reproductive system consists of the: Testes which produce sperm and male hormones Ducts that carry sperm from testes to outside body Accessory glands that produce secretions Penis – copulation organ. Testes.
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MALE REPRODUCTIVE SYSTEM
The male reproductive system consists of the: • Testes which produce sperm and male hormones • Ducts that carry sperm from testes to outside body • Accessory glands that produce secretions • Penis – copulation organ
Testes • Testes are contained within the scrotal sac or scrotum and is literally outside body. • Within scrotum, the testis (singular) testes (plural) is covered with the layers forming the capsule. • the layer is called the tunica albuginea is composed of dense collagenous fibrous tissue. • The tunica albuginea thickens and protrudes into the testis to form the mediastinum testis. • Septa extend from this to divide the testis into lobules
Low magnification of testis showing many seminiferous tubules tortuous
Testes • Proliferating spermatogenic cells are active mitotically and produce spermatozoa by spermatogenesis • Spermatogenic supporting cells called Sertoli or sustentacular cells
Spermatogenesis • Germ cells comprise a stratified layer of epithelium 4-8 cells deep lining the seminiferous tubule. • As these cells differentiate, they move from the basal area toward the lumen of the seminiferous tubule. • This process of differentiation is called spermatogenesis and takes about 64 days. • The beginning cells are called spermatogia that are found next to the basal lamina. • These cells are diploid and are found in the testis prior to puberty.
Primary spermatocytes are located some distance away from the basal lamina • They are much larger and at this point are still diploid cells • They divide by meiosis to produce haploid secondary spermatocytes. • Although the nuclear division is complete, the cytoplasm remains connected. • Secondary spermatocytes division results in the formation of 4 spermatids which are usually still attached by cytoplasm division that is incomplete. • Spermatids lie close to the lumen. • Spermatids then differentiate forming head region and flagellum to form spermatozoa.(tadpole)(spermiogenesis) mitosis
Sertoli or sustentacular cells: • help to form a blood barrier preventing blood from entering seminiferous tubules. • Support, protection and nutrition of developing sperm • Phagocytosis of excess cytoplasm of sperm. • Release of spermatozoa into tubules • Secretion of testicular fluid • Production of androgen binding protein under control of FSH from adenohypophysis. • Sertoli cells are usually larger and often appear somewhat triangular in shape.
1. Spermatozoa 2. Spermatids 3. Spermatogonia 4. Sertoli cells
Interstitial Cells of Leydig • Interstitial cells are located within the connective tissue between the Seminiferous tubules. • The interstitial cells are endocrine in nature and produce the male hormone testosterone (androgen). Testis showing parts of three seminiferous tubules with interstitial cells between them
Epididymis • The epididymis is a long coiled tube that stores sperm prior to its entry into the ductus deferens (vas deferens). • The epididymis is a long tube 5-6 meters long (in some cases longer than this). • It is important for storage and maturation of sperm. • Histologically is can be distinguished by the stero-cilia lining.
Efferent ducts have irregular level of ciliated epithelium that moves sperm to the epididymus.
Prostate Gland • Prostate gland surrounds the urethra in the area where the vas deferens empties into the urethra. • It is an aggregate of many small tuboalveolar glands • Secretes a thin milky liquid which aids in providing a medium for sperm to swim in. • In prostatic cancer, large concentrations of acid phosphatase are found and can show up in blood.
Testis and epididymis Tunica albuginea testis Mediastinum testis epididymis
Seminiferous tubule Rete testis in the medistinum testis
Seminiferous tubule • Boundary tissue • Complex spermatogenic epi.
Spermatogonium • Primary spermatocytes • Secondary spermatocytes • Spermatids • Spermatozoons • Sustentacular cells (Sertoli cells) • Interstitial cells (Leydig cells)
Seminiferous tubule Tubuli recti Rete testis Mediastinum testis
Tubuli recti (straight tubule) Seminiferous tubule
Ductule efferents Ductus epididymis • Epididymis