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Male reproductive system (Reproductory ducts
Sperm exit each testis…
Male reproductive system
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Internal genitalia
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Accessory sex glands
Prostate gland
- Fibromuscular gland: beneath bladder
- 70% glandular elements and 30% fibromuscular
- Beyond urethral angle, all major glandular elements of prostate open into prostatic urethra
- Prostate contributes to third of semen volume: nutrients and enzymes to activate sperm
- PSA: protease: regulate semen coagulation: ejact high concs
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Seminal vesicles
- Lateral outpouching of vas, contribute largest portion of fluid of ejaculate
- Lined by columnar secretory epithelium with goblet cells
- Secretes mucoid material:fructose, citric acid + prostaglandins and fibrinogen (60% semen)
- Each seminal vesicle empties its contents into ejact duct shortly after vas deferens empties sperm
Pair of testes
- Located in scrotum: sperm and testosterone
- Septa radiate from mediastinum, attach to inner surface of tunica albuginea: form 200-300 cone shaped lobules: each containing one to four convoluted seminiferous tubules
- Interstitial (leydig) cells lie in loose tissue surrounding seminiferous tubules: testosterone production
Seminiferous tubules
- Unique environment for sperm production
- Supporting cells include sustentacular cells of basement membrane and sertoli cells
- Germinal elements comprise of epithelial cells: primitive germ cells and supporting cells
Sertoli cells
- Large cells, slow mitotic activity: support and protect maturing sperms
- Tight junctional complexes with rest of sertoli membranes: barrier
- Present inside seminiferous tubule. Rest on basement membrane of seminiferous tubule and extend filamentous cytoplasmic ramifications toward lumen of the tubule
- Sertoli cells support and nourish sperm cells
- Secrete Mullerian regression factor (inhibit female chars)
- Secrete inhibin and activin (male hormones)
- Secrete androgen binding protein and oestrogen binding protein
- Create specialised microenvironemtn of adluminal compartment of seminferous epithelium
- Support germ cells through junctions between Sertoli and germ cells
- Facilitate migration of differentiating germ cells in seminiferous tubule (TOWARDS LUMEN)
BLOOD-TESTIS BARRIER
Epididymis
From rete testis: 12 to 20 efferent ductules pass into largest portion of epididymis, the caput: Efferent ductules enlarge to form lobule, the duct from each lobule drains into single epididymal duct: forms body and tail of epididymis: thickens and straightens to become VAS DEFERENS
Vas Deferens
Arise tail epididymis
- Inguinal canal - pelvis - base of prostate posteriorly
ROOT OF SCROTUM
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Anatomy
- Vas deferens
- Seminal vesicle
- Prostate gland
- Bulbourethral gland
- Urethra
- Seminiferous tubule
- Penis
- Testis
- Epididymis
Spermatogenesis
- Seminiferous tubules : stimulation of by anterior pituitary gonotrophic hormones
- Formation of embryo: primoridal germ cells migrate into testes: immature germ cells: spermatogonia
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Spermatogenesis:
- Spermatogonia migrate among Sertoli cells towards central lumen of seminiferous tubule
- Modified and enlarged: primary spermatocyte
- Primary spermatocyte: meiotic division: two secondary spermatocytes: these divide to form spermatids: modified to become SPERMATOZOA
- Entire period of spermatogenesis: 64 days
Sperm!
Spermatids into spermatozoa
- Each spermatzoon composed of head and tail
- Outside of anterior two thirds of head is a thick cap:acrosome : formed mainly from Golgi apparatus, similar to lysosomes
- Allow sperm to enter ovum adn feritlise
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Endocrine regulation
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Hypothalamus
GnRH
Anterior pituitary
1, LH
2, FSH
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Hormones
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Oestrogens
testost, Sertoli cells, stimulated by FSH: SPERMIOGENESIS