Male Reprod Flashcards
What is the route of the spermatic cord?
Over the ilium through the inguinal canal into the pelvis.
What is the name of the thick connective tissue covering the testis?
Tunica albuginea
Invagination of the ____ creates ____, which contain seminiferous tubules
Tunica albuginea; lobules
Where is sperm produced?
Seminiferous tubules
Trace the route of a sperm from production to exit of the testis
Seminiferous tubule –> straight tubule –> efferent ducts –> epididymis –> vas deferens
Which cells secrete testosterone?
Interstitial cells of Leydig
Where are the interstitial cells of Leydig found?
Connective tissue between seminiferous tubules
What are the “nurse cells” for developing sperm?
Sertoli cells
What are the functions of the Sertoli cells?
- Exchange of metabolites and removal of waste
- Phagocytize abnormal germ cells
- Secrete fluid that helps sperm move downstream
- Maintain blood-testis border
- Secretion of androgen-binding protein and inhibin
What cells secrete androgen-binding protein and what is its function?
Sertoli cells; binds testosterone and increases its concentration in seminiferous tubules
What cells secrete Inhibin and what is its function?
Sertoli cells; Inhibits FSH from pituitary, which prevents FSH from stimulating secretion of androgen-binding protein
Name the steps in the maturation of sperm
Spermatagonia (stem cells) –> Primary spermatocytes –> Secondary spermatocytes –> early spermatids –> Late spermatids (w/ tail)
At what stage of spermatogenesis does the reduction from 2n to n chromosomes occur?
Secondary spermatocytes (via meiosis)
How long does spermatogenesis take?
74 days
What does the acrosomal vesicle do?
Helps with penetration of the zone pellucida
How long do sperm live in the female reproductive system?
2-3 days
How is the blood-testis barrier formed?
By tight junctions between adjacent Sertoli cells
What are the two compartments of the blood-testis barrier and what do they contain?
Basal compartment: Spermatagonia and early primary spermatocytes
Luminal compartment: Late primary spermatocytes onwards
What is the purpose of the blood-testis barrier?
Create a special physiological environment for developing sperm; Sperm remains isolated from the immune system
What can be found on the epithelium of the efferent ducts and why is it important?
Cilia (w/ underlying circular SM layer); Helps propel the sperm onward
Where are mature sperm stored?
Epididymis
How long does the sperm take to move through the duct of the epididymis?
6 weeks
What two abilities do sperm gain as they travel through the epididymal duct?
Ability to move
Ability to fertilize (Remains blocked until they enter female tract)
What do the epithelial cells of the epididymal duct do?
Reabsorb fluid
Phagocytize residual bodies and degenerating sperm
Secrete substances to aid in sperm maturation
What does the seminal vesicle secrete?
Alkaline, fructose-rich secretion; substance that aids in clotting of semen
Responsible for 60% of semen volume
Where do sperm cells receive citric acid from and how is it utilized?
From prostate; used to make ATP
What fuels sperm?
Fructose
What does relaxin do?
Enhance sperm motility
Why are alkaline secretions important to sperm?
Neutralize acidic environment of vagina
What do fibrinogen and fibrinolysin do?
Fibrinogen: Clots sperm
Fibrinolysin: Liquifies sperm
What is the difference in blood flow in the flaccid vs. erect state?
Flaccid: All blood via dorsal arteries
Erect: Opening of branches of the deep artery
How does Viagra work?
Acteylcholine release stimulates NO release. NO causes cGMP production, which in turn leads to SM relaxation and filling of corpora cavernosa.
Also, Viagra inhibits phosphodiesterase, the enzyme that degrades cGMP
