Transcript Male genital system

Male genital system
Histology and embryology
Development
 Development of gonads
 Development of genital ducts
 Development of external genital
Origin
Gonads – intermedial
mesoderm of
mesonephros
 Primordial germ cells
– endoderm of yolk
sac
 External genitalia –
ectoderm and
mesoderm

Indiferent stage
 Both sexes has same first stage
• coelomic epithelium
– primary germ cords
• primordial germ cells
• mesonephric duct (Wollfian) and tubules
• paramesonephric duct
Male gonads
 Y – chromosome
• SRY -> TDF (testes determining factor)
 if produced -> development of testis
• usually from 7th week
 if not produced -> development of ovarium
• usually from 12th week
• „waiting period“
Development of testis
 TDF stimulates proliferation of primary
germ cord -> medullary cords
• origin of seminiferous tubules and rete testis
• origin of Sertoli cells
 intermedial mesenchyme
• origin of Leydig cells
 rest of coelomic epithelium changed to
tunica albuginea
Seminiferous tubules
 spermatogonia – from primordial germ
cells
 Sertoli cells – surrounds spermatogonia
• secrete AMH – anti-müllerian hormone
– inhibition of paramesonephric duct (Müllerian)
 interstitial Leydig cells
• produce testosteron from 8th week
 no lumen till puberty
Descensus of the testis
 from thoracolumbal area to scrotum
• AMH, testicular growth, elongation of body
• gubernaculum – connective cord between
testis and scrotum
 from 26th week
 mark of fetal maturity
 cryptorchism vs. ectopic testis
Genital ducts
 Connected medullar cords
• rete testis
 Mesonephric tubules
• Efferent ducts
 Mesonephric duct (Wollfian)
• Epididymal duct, ductus deferens, vesicular glands,
ductus ejaculatorius
• (ureter, pelvis, calices, collecting duct and tubules)
 Paramesonephric duct (Müllerian) disappear
External genitalia
indiferent stage

genital tubercle
 urogenital folds
 labioscrotal folds



male genital
penis
 spongious urethra
 scrotum
Histology
Testis
Ducts
Accesory glands
Testis
 Tunica albuginea
• dense connective tissue - collagenous
 Lobuli testis
• Seminiferous tubules
• Interstitium
Seminiferous tubules

Stages of spermatogonia surrounded by Sertoli
cells
• hemato-testicular barrier – occluding junctions
between medial part of Sertoli cells
• nutrition, support
• earlier stages are on the periphery of tubule
• production of AMH, inhibin
• regulated by follicle stimulating hormone
Spermatogenesis
 development of sperm from spermatogonia
 multiple division – two times meiotic
 spermiogenesis – maturation of spermatid
into sperm
Sperm
• maturation is 64 days long (from first division of
spermatogonia A)

Head
• Acrosome (enzymes), nucleus
• Connecting piece - pair of centrioles

Middle piece
• mitochondrial sheet, outer dense fibers (9), axonema

Principal piece
• ribs of the fibrous sheet, outer dense fibers (7),
axonema
Testicular interstitium
 Blood vessels
 Lymphatic vessel
 Leydig cells
• production of testosteron
– stimulation of spermatogenesis, maintanance of
sex glands, sebaceous glands ...
– regulated by luteinizing hormon of hypophisis
Testis (M1)
Sperm maturity and transport
pathway
 Tubuli recti et rete testis
 Epididymis
 Ductus deferens
 Ejaculatory duct
Tubuli recti et rete testis
 cuboideal Sertoliho cells
 no spermatogenic cells
 surrounded by lymphatic channels, blood
vessels and Leydig cells
Epididymis
 Ductuli efferentes - in head
• columnar epitheluim with stereocilia and cilia
– non-motile sperm
– scalloped outline
• smooth muscle layer
Epididymis
 Ductus epididymidis - in body & tail
• highly coiled one tubule - 4-6 m long
• pseudostratified columnar epi with stereocilia
• two layers of smooth muscle - thicker
 function
• maturation
• storage
• transport
Epididymis HE (M2)
Spermatic cord
 Vessels, muscles, lymphatic vessels,
nerves
 Ductus defernes (Vas deferens)
• pseudostratified columnar epi
• lamina propria
• 3 layers of smooth muscle (L, C, L)
Spermatic cord HE (M3)
Ejaculatory duct + Ampulla
 pseudostratified columnar epi
 lamina propria
 muscular layer only in ampulla
Accesory Genital glands
 Seminal vesicles
 Prostate
 Bulbourethral glands
Seminal vesicles (Glandulae
vesiculosae)
 cuboidela-to-pseudostratified epi
 folded mucosa
 smooth muscle layer (C+L)
 adventitia + serosa on apex !
 function: 50-70% of seminal fluid
• fructose
Seminal vesicles HE (M4)
Prostate
 30-50 tuboalveolar glands in
fibromuscular stroma
 3 regions of glands
• periurethral mucosal gl.
• periurethral submucosal gl.
• peripheral main gl.
Prostate
 simple-to-pseudostratified epi
 prostatic concrements (corpora amylacea)
• protein rich material, calcifications
 function: enrich the semen fluid,
fibrinolysin, amylase, PSA
Prostate HE (M5)
Prostate WvG (M6)
Bulbourethral glands
 mucus secreting glands
 +galactose
 lubrication function
Penis
 three masses of erectil tissue
• 2x corpora cavernosa
• 1x corpus spongiosum
 communicating blood spaces (sinuses)
surrounded by connective tissue
 artery -> sinus -> vein
 dilatation of artery (NO) compress vein,
sinuses fill with blood -> erection occurs
Penis HE (M7)