Male Reproductive System

Male Reproductive System

General Description Testes dual-function

Genital ducts: epididymis ductus deferens ejaculatory ducts urethra

Accessory glands: prostate seminal vesicles bulbourethral glands

Penis colpulative organ

Testis Located in the scrotum Ovoid Covered by testicular capsule: tunica vaginalis and tunica albuginea

Seminifero us tubule

Testis Seminiferous tubules

Testis

Seminiferous tubules

Germinal or seminiferous epithelium Supporting or Sertoli cells Spermatogenic cells Basement membrane

Tunica propria (myoid cell)

Testis

Seminiferous tubules Spermatogenic cells Since puberty   

Being arranged in 4-8 layers Replicating and migrating as mature Successive generations from the periphery to the lumen     

Spermatogonia Primary spermatocytes Secondary spermatocytes Spermatids Spermatozoa

Seminiferous tubules Spermatogenesis: the phenomenon that the spermatogenic cells divide from start to finish and reducing spermatozoa. From spermatogonia to spermatozoa: 1. Spermatocytogenesis: from spermatogonia to primary spermatocyte 2. Meiosis: from primary spermatocyte to spermatid 3. Spermiogenesis: from spermatid to spermatozoa

Testis

Seminiferous tubules Spermatogonium Adjacent to the basement membrane Round or ellipsoid, small (10-12 µ m)

Testis

Seminiferous tubules Spermatogonium

Type A: Ad, deeply-stained nucleus, prominent nuclear vacuole Ap, flattened nucleus, finely-granulated and pale-stained chromatin Type B: large clumps of densely-stained chromatin, central nucleolus

Testis

Seminiferous tubules Proliferation and differentiation of Spermatogonium (stem cell)

Testis

Seminiferous tubules Primary spermatocyte

argest (>16 µ m), coarse clumps or thin threads of chromati 16 µ m or more in diameter

Testis

Seminiferous tubules Primary spermatocyte

46 chromosomes (46, XY) and 4n DNA (tetraploid) First meiosis Long prophase (up to 22 days) Frequently visible

Testis

Seminiferous tubules Secondary spermatocyte

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Lying nearer the lumen, smaller Spherical nuclei, pale-staining granular chromatin Haploid number of chromosomes (22 + X or Y) and 2n amount of DNA Short-lived and dividing quickly, difficult to observe

Testis

Seminiferous tubules Secondary spermatocyte

By second meiotic division, chromosomes split without prior duplication of DNA, halves of each chromosome Pass into 2 daughter cells, resulting in haploid spermatids

Testis

Seminiferous tubules Spermatid

Close to the lumen

Spherical or polygonal

6 µ m in diameter

Testis

Seminiferous tubules Spermatid

Testis

Seminiferous tubules Spermiogenesis and Spermatozoa

The process by which spermatids are transformed into spermatozo 1. Condensation and elongation of the nucleus main component of the head 2. Formation of the acrosome cup-like head cap containing hydrolytic enzymes important for fertilization 3. Formation of flagellum and mitochondrial sheath generating movement 4. Discharge of excess cytoplasm

Testis

Seminiferous tubules Spermiogenesis and Spermatozoa

Testis

Spermatozoa

60 µ m

Testis

Seminiferous tubules Spermatozoa in Smear of the Semen

Testis

Seminiferous tubules Sustentacular Cells

Testis

Seminiferous tubules Sustentacular Cells 

Numerous lateral processes

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Abundant organelles

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Tight (occluding) junction  Basal compartment  Adluminal compartment

Testis

Seminiferous tubules Functions of Sustentacular Cells

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Support, protection, and nutritional regulation of the developing spermatozoa   

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Secretion:  

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Physical support of the ramification Mediating exchange of nutrients and metabolites Protecting sperm cells from immunological attack Secreting a fluid for sperm transport Secreting ABP (androgen binding protein) and inhibin

Phagocytosis of residual bodies Blood-testis barrier  

Excluding germ cells from immune system Protecting the seminiferous epithelium against autoimmune reaction

Testis

Interstitial tissue Interstitial cells

Testis

Interstitial tissue Ultrastructure of Interstitial cells

Testis

Interstitial tissue Function of Interstitial Cells 

Secreting androgen which is essential for  Proliferation and differentiation of germs  The proper maintenance of the genital ducts and accessory glands  Development and maintenance of male second sex characteristics  Adolecent change of voice  Growth of moustache

Controlled by ICSH secreted by gonadotrophic cells in the anterior pituitary

Testis

Intratesticular Genital Ducts

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Tubulus rectus Rete testis

Testis

Intratesticular Genital Ducts Tubuli recti (straight tubules)and Rete testis

Genital Ducts • Epididymis • Ductus deferens • Ejaculatory duct • Urethra

Genita Ducts

Epididymis Efferent duct

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Extending from the rete testis, forming the head of the epididymis  Tall columnar cells, ciliated:  Secret some fluid  Short columnar cells, nonciliated, numerous microvilli:  Absorption of fluid and granulated matter

Scallop-like

Genita Ducts

Epididymis Epididymal duct

4-6 m in length, 0.4 mm in diameter C-shaped Head, body and tail Pseudostratified columnar epithelium 

Principal cell 

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Tall in the head, low columnar in the tail with long microvilli

Basal cell 

Small, round and pale-staining, located in the base

Smooth muscle

Genital Ducts

Epididymal duct

Excretory Genita Ducts

Function of Epididymal duct   

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Absorption Secretion Promoting functional maturation of the sperm Storing mature sperm Forcing the sperm into the ductus deferens by the contraction of smooth muscle

Excretory Genita Ducts

Ductus deferens thick wall, narrow lumen: mucosa, muscularis and adventitia mucosa: similar epithelium to that of the epididymal duct with long microvili in the tall columnar cell

Excretory Genita Ducts

Ductus deferens Muscularis 

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Highly-developed, three layers  inner and outer: longitudinal  middle: circular  Responsible for the firm consistence of the ductus deferens, making it easily palpable in the spermatic cord The powerful contraction rapidly transports the sperm through the ductus deferens during ejaculation

Accessory Genital Glands

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Prostate seminal vesicles bulbourethral glands

Accessory Genital Glands

Prostate

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Consisting of 30-50 compound tubuloalveolar glands Embedded in a stroma consisting mainly of smooth muscles Covered by a capsule (thin but strong) Three concentric zones around the urethra

Accessory Genital Glands Prostate

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Irregular lumen of the glands Pseudostraitified columnar epithelium Smooth muscle Prostatic fluid: making up seminal fluid

Prostatic concretion eosinophilic body

Accessory Genital Glands Prostate

Benign prostatic hypertrophy Prostatic enlargement, common in aged men Occluding effect on the outlet of the bladder at the proximal portion of the urethra (transitional zone) rostatectomy to alleviate benign obstruction Prostatic cancer: peripheral zone