Male Reproductive System Flashcards
What is the major function of the testes?
Produce male gametes (spermatazoa)
produce androgens (sex hormones)
What are the genital excurrent ducts of the male reproductive system?
What is their combined function?
ductuli efferentes
ductus epididymidis
ductus (vas) deferens
help the sperm to become mature and deliver it to the urethra.
What are the accessory glands of the male reproductive system?
What is their combined function?
seminal vesicle
prostate
bulbourethral glands
produce important components of the semen and help lubricate the penile urethra
What are the layers that copose the capsule of the testis?
-
tunica albuginea: outer capsule
- dense connective tissue
-
tunica vasculosa: inner capsule
- loose connective tissue & large number blood vessels
-
mediastinum testis: thickening of the tunica albuginea on posterior surface that projects inward
- Blood vessels, lymphatic vessels, and rete testis pass through
Whats structures are contained within each testicular lobule?
1-4 seminiferous tubules
- short straight segment: straight tubule into rete testis
-
testicular interstitium: space between seminiferous tubules
- innervated & vascularized loose connective tissue
- Leydic cells: endocrine interstitial cells
Describe the structure & function of Leydig cells.
steroid-producing endocrine cells
- Structure:
- well-developed SER, mitochondria with tubular cristae, lipid droplets in cytoplasm, crystals of Reinke (protein)
- Function
- main source of testosterone
- to blood via lymphatic capillaries & into seminiferous tubules
When do Leydig cells begin producing testosterone?
early during fetal life
testosterone is necessary for normal develpment & function of male reproductive system
How is testosterone secretion by Leydig cells regulated?
LH (from atnerior pituitary) stimulates testosterone secretion
What cell types & tissue make up the seminiferous tubules/
- seminiferous epithelium
- sertoli cells
- supporting cells
- spermatogenic cells
- differentiate into sperm
- sertoli cells
- Tunica propria (surrounding seminiferous epithelium)
- fibroblasts
- collagen fibrils
Describe the structure of Sertoli cells
- Structure
- Extend from base to apex of seminiferous epithelium
- large surface area
- irregular & light staining euchromatic nucleus w/ well seen nucleolus
- specialized tight junctions that disassemble & reassemble
What are the 6 major functions of Sertoli cells?
- Function: interact with spermatogenic cells throughout their development
- nourish germ cells via secretory products
- help with germ cell movement & differentiation
- germ cells move from basal to adluminal compartment
- “streching” spermatids
- structural support of epithelium of seminiferous tubule
- well developed cytoskeleton
- divide seminiferous epithelium into basal & adluminal compartments
- barrier between blood & maturing sperm cells
- tight junctions that make immune responses limited/suppressed
- secrete endocrine substances to control functioning seminiferous tubules
- Androgen-binding protein (ABP)
- inhibin
- phagocitize residual bodies & degrade germ cells
Why is it important that Sertoli cells are able to create a barrier between the blood & the testis?
What situation can this barrier be broken?
composition of blood & lymph in testis is different from fluid in seminiferous tubule
immune system recognizes sperm as foreign - may attack the spermatozoa
this can happen in the case of a vasectomy when the sperm leaks into the body cavity via severed vas deferens
The Sertoli cells secrete what endocrine substances?
What are their respective functions?
Their secretion is regulated by what hormone?
- Androgen Binding protein (ABP)
- binds testosterone
- concentrates testotsterone within the seminiferous tubule & excurrent ducts
- secretion is stimulated by follicle stimulating hormone (FSH)
- from pituitary
- inhibin
- inhibits the release of FSH by the pituitary
