Male reproductive system Flashcards
male inner genital organs
- testes (male gonads)
- Genital ducts (Conduct sperm to urethra –>epidydimis, ductus deferens, ejaculatory duct)
- Accessory Glands (seminal vesicles, prostate, bulbourethral Gland)
Main function of testes
- production of male gametes
- Secretion of male sex hormones
Testicular capsule
- tunica vaginalis (layers of Peritoneum)
- tunica albuginea (dense CT with fibromyocytes)
- tunica vasculosa (loose CTwith blood and lymph vessels)
Stroma and Parenchyma of the testes
Stroma: loose CT
Parenchyme: Epithelium
seminiferous tubules –> straight tubules (columnar) –> rete testis (cuboidal) –> efferent ductule (pseudostratified) –> epidydimis (pseudostratified)
Development of the testes
- genital ridges in Mesoderm
- ceolomic Epithelium forms sex Cords
- 5-6th week: primordial germ cells migrate from the yolk sac to sex Cords
- from 7th week: sex determining Region of Y chromosome
- sex Cords: into seminiferous tubules and rete testis
- Primordial germ cells: into spermatoginia
- Epithelium of sex Cords: into Sertoli cells
- tubules of mesonephros: into efferent ductules
Wall of seminiferous tubules
spermatogenic Epithelium
Lamina propria
Spermatogenic epithelium
- supporting Sertoli cells
- Spermatogenic cells in various stages
>Spermatogonia
>Primary spermatocytes
>Secondary spermatocytes
>Spermatids
>Spermatozoa
von unten nach oben
Phases of spermatogenesis
- Proliferation (mitotic divisions of spermatogonia)
- Maturation (Meiosis of spermatocytes)
- Formation (Spermatids –> spermatozoa) “Spermiogenesis”
Spermatogonia
- in basal layer of spermatogenic Epithelium
- Round
- divide mitotically
- Three types (A dark, A pale, B)
Type A dark spermatogonia
- dark nucleus
- part of this type remains as stem cell
- other parts undergo mitotic divisions and become A pale spermatogonia
Type A pale spermatogonia
- pale nucleus
- eccentric nucleus
- become B spermatogonia
Type B spermatogonia
- pale nucleus
- nucleus in Center
- beceome Primary spermatocytes
Primary Spermatocytes
- migrate to abluminal compartment of seminiferous tubules
- first meiotic division to two daughter cells (secondary spermatocytes)
Secondary spermatocytes
- undergo second meiotc division to produce two spermatids
Spermatids
- round
- with set of haploid chromosomes
- transform into spermatozoa
- 1/3 of the 4 spermatids are phagocytosed by Sertoli cells
Events during spermiogenesis (Formation of spermatozoa)
- Golgi produces acrosomal head cap to cover nucleus
- nucleus elongates
- Distal centriole forms Flagellum
- Mitochondria concentrate in middle piece of tail
- residual Body is phagocytosed by Sertoli cells
Syncytium
- gametes do not completely separate from each other
- stay connected by narrow cytoplasmic bridges
Syncytium determines
- close communication
- Connection to Sertoli cells
- Synchonous development of spermatozoa
Spermatozoa
- detach from tubule wall
- are functionally immature
- moved passivley to epidydimis
Sertoli cells
- supporting epithelial cells
- Columnar_ rest in b.m., apical part extends into lumen
- connected by junctional complex –> divides spermatogenic Epithelium
- –> Basal compoartment: with spermatogonia
- –> Adluminal comparment: with spermatocytes and spermatids
Functions of Sertoli cells
- support the gametes
- blood-testis-barrier
- phagocytosis
- secretion of:
>ABP
>Tubular fluid
> Müllerian inhibiting substance (MIS)
–> stimualted by FSH
Lamina propria of seminiferous tubules
- contains the myoid cells -_> contraction causes a fluid current
Testicular stroma
loose CT with blood vessels and nerves
also with Leydig cells
Leydig cells
- large
- Lipid vacuoles
- secrete testosterone into blood
- stimulated by LH (also called ICSH)
Functional significance of Leydig cells
Fetal period: testosterone stimualtes development of male genitals
Puberty: induce Formation of secondary sexual characteristics
Male reproductive period: spermatogenesis, sexual behaviour…
Hormonal Regulation of spermatogenesis
LH –> Leydig cells –> testosterone
FSH –> Sertoli cells –> ABP
Testosterone binds to ABP to stimulate spermatogenesis
Descent of testes
From abdominal cavity to scrotum through
GUBERNACULUM TESTIS
–> condensation of mesenchyme
Male genital ducts
Intratesticular:
straight tubules
Rete testis
Extratesticular: Efferent ductules duct of epidydimis ductus deferens ejacolatory duct male urethra
Development of male genital ducts
- during indifferent stage: Mesonephric and paramesoneohric ducts (wolffian and müllerian ducts)
- from 8th week:
Mesonephric tubules –> efferent tubules
Mesonephric duct –> duct of epidydimis, ductus deferens, seminal vesicle, ejaculatory duct
Straight tubules
- lined by columnar supporting Sertoli cells
- short
Rete tesis
- simple cuboidal epithelium
Efferent ductules
- connect channels of rete testis to duct of epididymis
Wall of efferent ductule
- pseudostratified columnar
- 3 types of cells
- Columnar ciliated
- Cuboidal (with microvilli for Reabsorption of fluid)
- Basal cells
lamina propria with myocytes that contract
Epididymis
- head, Body, tail
- consists of efferent tubules and duct of epididymis
Duct of epididymis
- very convoluted
- spermatozoa are stored and matured
Wall of duct of epididymis
- pseudostratified columnar
- 2 types of cells
- Principla columnar with stereocilia for Reabsorption
- Basal (stem) cells
lamina propria with myocytes that contract
Wall of ductus deferens
Mucosa:
- pseduostratified
- Lamina propria
Muscular layer:
- inner logitudinal
- middle circular
- outer longitudinal
Adventitia
Ejaculatory duct
through prostate Gland –> looses muscular layer and Adventitia!!
Mucosa either with pseudostratified or simple columnar
Male accessory glands
Seminal vesicles
Prostate Gland
Bulbourethral glands
Seminal vesicles
Mucosa:
- pseudostratified / simple columnar
- lamina propria
Muscular layer
- inner circular
- outer longitudinal
Adventitia
–> secrete fluid that contains Fructose, aa and prostaglandins
Prostate gland
- size of walnut
- stroma: dense irregular CT with large amount of muscle fibers
- parenchyma: epithelial tissue
- 30-50 tubuloalveolar Glands
- -> irregular in shape
- -> pseudostratified, simple columnar, cuboidal
- -> secrete alkaline fluid
3 layers of Glands
- Periurethral Glands (mucosa) directly in urethra
- from submucosa and peripeheral layer: have ducts
Moprhological and functional zones of prostate gland
- Transitional Zone: surrounds proximal prostatic urethra
- Central Zone: surrounds ejaculatory ducts
- Peripheral Zone: surrounds central Zone
- Anterior fibromuscular stroma: co glandular tissue, anteriorly
Bulbourethral glands
- tubuloalveolar Glands
- structure similar to seminal vesicles
- secrete mucus-like secretion with is the preseminal fluid
Semen
Spermatozoa, secretion of seminal vesicles, prostatic Glands and bulourethral glands
