Male Reproductive System PDF

MALE REPRODUCTIVE SYSTEM MALE REPRODUCTIVE SYSTEM  MALE REPRODUCTIVE SYSTEM Divides into three parts: The testis: located outside the major body cavity and housed in the scrotum. The excretory duct system: which transport the sperm from the testis. Epididymis Ductus...

MALE REPRODUCTIVE SYSTEM MALE REPRODUCTIVE SYSTEM  MALE REPRODUCTIVE SYSTEM Divides into three parts: The testis: located outside the major body cavity and housed in the scrotum. The excretory duct system: which transport the sperm from the testis. Epididymis Ductus (vas) deferens Ejaculatory duct Accessory glands: Produce and modify the contents of the semen. Seminal vesicle. Prostate. Bulbo-urethral glands (Cowper’s glands)  TESTIS They are paired ovoid organs. Produce male gametes (spermatozoa) & testosterone. Formed of: ▪ Stroma ▪ Parenchyma Stroma Capsule: Testes are surrounded by a thick capsule of: Tunica vaginalis: The most outer layer(serosa).. Tunica albuginea: Thick white fibrous connective tissue capsule. Septa: Connective tissue that extend from capsule and divided the testis into lobules. TESTIS HISTOLOGY  PARENCHYMA The testis has about 300 lobules, within these lobules the testis tissues is divided into: ❑Seminiferous tubule: Which produce spermatozoa (Spermatogenesis). ❑ Interstitial tissue: Leydig cells produce testosterone  SEMINIFEROUS TUBULES Each testis lobules contain 1-4 seminiferous tubules. ❑Tubules are enclosed by a thick basal lamina surrounded by 3-4 layers of smooth muscle cells or myoid cells. ❑Tubules internally are lined by seminiferous epithelium, that has two types cells. A- Spermatogenic cells (Spermatogonia or Germ cells): Develop into sperm. Include the different maturational stages of spermatozoa B- Sertoli cells (irregular shape) Support, nutrition, hormone receptors. TESTIS, LOW POWER, SEMINIFEROUS TUBULES  SERTOLI CELL Cell trunk extends from basement membrane to lumen, irregular in shape with oval or triangle nucleus and cytoplasmic processes. All germ cells are surrounded by Sertoli processes Functions: Supports and nourishes germ cells. Main endocrine target cell in the seminiferous tubule Receptors for Testosterone & FSH They aid in concentrating the testosterone by secreting androgen-binding protein under the influence of FSH. Secret inhibin B hormone that suppresses the release of FSH.  SERTOLI CELLS Functions (cont): Blood-testis barrier (Sertoli-Sertoli tight junctions) Blocks entrance of extraneous proteins, etc., into seminiferous tubules between Sertoli cells (must go through Sertoli cell). Special fluid inside tubule (high K+) made by Sertoli cell. Possible protection of germ cells from immune system. (Sperm first arise at puberty, when immune system already set. Sperm surface antigens may be seen as foreign) They help in the movement of spermatozoa by secreting fluids. They phagocytose apoptotic cells, foreign bodies, etc. SEMINIFEROUS TUBULE SECONDARY SPERMATOCYTE, DIVISION FIGURES PRIMARY SPERMATOCYTES, SPERMATIDS, SERTOLI CELLS  SPERMATOGENIC CELLS (SPERMATOGONIA) Sperm contains: head, neck & tail 60 nm long actively motile The head contains the nucleus that carries the genetic material. It takes 48 days for maturity Spermatogenesis is regulated by FSH  LEYDIG CELL Present in Interstitial tissue. Round to polygonal with large central round nucleus and eosinophilic cytoplasm. The cytoplasm contain lipid droplets(for hormone synthesize). Produce androgenic steroid hormones, mainly testosterone. Testosterone secretion is regulated by pituitary LH A well-developed smooth endoplasmic reticulum (SER) is the site of most enzymes of testosterone biosynthesis. LEYDIG CELLS IN THE INTERSTITIAL TISSUE, TESTIS  THE EXCRETORY GENITAL DUCTS Rete testis: Network of tubules located in the mediastinum of the testis. Efferent ducts: Passageway from testis to epididymis. There are 15-30 efferent ducts. Epididymis: Single long coiled duct (~6 m long), has three parts; head, body and tail. Line by pseudostratified columnar epithelium with stereocilia(non motile cilia). Function: Maturation and storage of sperm. Sperm are stored in the tail of the epididymis (for ejaculation). EPIDIDYMIS HISTOLOGY  THE VAS DEFERENS(DUCTUS DEFERENS) Straight tube that continues from the tail of the epididymis to the prostatic urethra. Line by pseudostratified columnar epithelium with stereocilia. Has the greatest muscle-to-lumen ratio of any hollow organ. Function: Ductus deferens conducts sperm from epididymal tail.  ACCESSORY GENITAL GLANDS The Seminal Vesicles Pair of convoluted tubular gland sit behind the urinary bladder. Their mucous membrane forming complex folds. Line by secretory pseudostratified columnar epithelium. Function: Secrete 60% of semen contains fructose, also proteins, prostaglandins, and mucus.  PROSTATE GLAND Single gland present at the base of urinary bladder surrounding the urethra, formed of: Stroma: Formed of dense fibromuscular C.T. Parenchyma Contains 30-50 tubulo-alveolar glands. Secretory alveoli of prostate are irregular and has papillary projection. Lumen of the gland mucosa contains cuboidal, columnar or pseudostratified columnar epithelium.  PROSTATE GLAND Secretory cells are slightly acidophilic and often have granules. Prostate secretion contains citric acid, fibrinolysin, AP and a number of other enzymes and lipids. Characteristics feature of prostate is presentation of corpora amylacea in the alveoli (rounded eosinophilic bodies). Semen passes through prostatic and penile urethra. At 50yrs old prostate become enlarged due to benign nodular hyperplasia changes, 50 -60% of males will have asymptomatic condition. PROSTATE  PENIS It consists of 3 cylindrical masses of erectile tissue: 1- Two corpora cavernosa dorsally. 2- One corpus spongiosum surrounding the urethra ventrally. The erectile tissue is composed of C. T. fibers and smooth muscle cells, separating blood spaces. It is surrounded externally by skin.