male repro Flashcards
functions of the male reproductive system
- prod of spermatozoa
- transmission of gametes thru male ducts and into female reproductive tract
spermatozoa
male gamete
testes and duct development
begin development on posterior abdominal wall, descend into developing scrotum
testis function
- prod morphologically diff gametes
- prod testosterone
testis germinal compartment
exocrine part
- seminiferous tubules
- prod: spermatozoa
testis interstitial compartment
endocrine part
- interstitial tissue (leydig cells)
- prod: testosterone
seminiferous tubules
2 cell populations in epithelium:
- spermatogenic cells + sertoli cells
- strat columnar
- fluid secretion by sertoli cells
- myoid cell contraction in tubule wall facilitates movement out of tubules
spermatogenic cells
germ cell line which diff into spermatozoa
sertoli cells
architectural element of seminiferous epithelium
- basal tight junction complexes (largest + tightest in the body)
basal: spermatogonial stem cell niche
blood-testis barrier
adluminal compartments
at apex: junctions disassemble to release sperm
- turnover of basal junctions without compromising barrier
spermatogenesis
differentiation, takes 64 days
1. proliferative phase
2. meiosis
3. spermiogenesis
- diff segments of tubules are always at diff stages of spermnatogenesis
- constant prod of sperm
proliferative phase
aka spermatocytogenesis
- spermatogonia on basal lamina starts proliferating
- replenishes spermatogonial population
- gives rise to spermatocytes
meiosis
- spermatocytes move up off the basal lamina
- meiosis: genetic material halved
- haploid spermatids
spermiogenesis
spermatids:
- condense nuclei
- prod acrosome + flagellum
- package all excess cytoplasm for eventual removal
blood-testis barrier
one of the tightest in the body
straight tubules
after seminiferous tubules
- sertoli cells, low columnar to cuboidal
rete testis
at hilum of testicle
- cuboidal epi with some microvilli and one cilium
- begins process of resorption
- wall: CT only
efferent ductules
leaving testis
- pseudostr epi
- low microvillar cells (major resorption)
- high ciliated cells (movement)
- Wall: first appearance of smooth muscle (movement)
epididymus functions
physiological maturation of spermatozoa (7-14 days)
- acquire movement
- ability to fertilize
Store spermatozoa until ejaculation (1 month)
epididymus histology
long coiled tube, 4-6 meters
epithelium: pseudostr high->low columnar
- mod for secretion and endocytosis
- stereocilia
- secretion of molec that prevent movement + acrosome rxn
wall: smooth muscle incr in thickness
- incr under control of symp nervous system
ductus deferens function
transport sperm from epididymis to urethra during sexual excitement + ejaculation (minutes)
ductus deferens location
passes from scrotum to inguinal canal, drops into pelvis to join urethra in prostate gland
ductus deferens histology
single tube 35 cm long
epithelium: pseudostr
wall: v thick circular and longitudinal smooth muscle
- symp nervous system control
seminal vesicle function
secretion of fructose and fibrinogen (70% of ejaculate)
seminal vesicle development
from blind ended tubular outgrowth from ductus deferens
- joins ductus deferens right before it penetrates into prostate
seminal vesicle histology
highly coiled tube
epithelium: pseudostr secretory
- mucosa highly folded to incr SA
wall: thick smooth muscle
- sympathetic nervous system
prostate gland development
30-50 tubuloalveolar glands that develop from epithelium of urethra and protrude into urethral wall
prostate gland function
secretes:
- clotting enzymes (fibrinogen -> fibrin)
- prostate specific antigen
- more
15% of ejaculate
prostate gland histology
epithelium: pseudostr secr
- glands surrounded by smooth muscle of urethral wall
- surrounds lumen of urethra
ejaculation process
- erection (vascular, PNS)
- During sexual excitement, internal urethral sphincter constricts (SNS)
- caudal part of epididymis and deferens constrict (SNS)
- vas, seminal vesicles, and prostate constrict and force ejaculate into base of urethra (SNS)
- Filling at urethra base sets off spinal reflex to contract skeletal muscles + move semen out of penis (somatic nervous system, bulbospongiosus muscle)
duct design features for transport
seminiferous tubules: myoid cell contraction + fluid prod
rete testis: single cilia
efferent ductules: smooth muscle + ciliated cells
epididymis + ductus deferens: massive incr in smooth muscle
internal + external urethral sphincters
capacitation
factors preventing acrosome reaction are removed in the female reproductive tract (4-7 hrs)
acrosome reaction
enzymes released from sperm head via exocytosis
