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

spermatogenesis

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 epididymis Tunica albuginea Mediastinum testis Testis and 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)

Tubuli recti Seminiferous tubule Mediastinum testis Rete testis

Tubuli recti (straight tubule) Seminiferous tubule

Rete testis in the mediastinum testis

Epididymis Ductule efferents Ductus epididymis

Ductule efferents

Ductus epididymis