Male Reproductive System Flashcards
The optimal temperature for spermatogenesis in humans is in the order of?
32 - 34°C
Need to be 2°C below body temp which is why testis is outside of pelvic cavity
Which of the following statements regarding spermatogenesis is INCORRECT?
-Spermatozoa are transported through the epididymis by peristaltic waves of contraction of the smooth muscle in its walls.
-Throughout spermiogenesis the spermatids that arise from a particular primary spermatocyte remain joined by a cytoplasmic bridge.
-Spermatozoa are stored in the vas deferens until they are ejaculated.
-Spermatozoa swim from the lumen of the seminiferous tubles into the epididymis.
-It takes between 64 and 74 days from the initial mitotic division of a spermatogonium for the spermatozoa to be into the lumen of the seminiferous tubule.
Spermatozoa swim from the lumen of the seminiferous tubles into the epididymis.
Spermatozoa are not matured so cannot swim. Are instead washed away to epididymis via seminiferous tubule fluid
During spermiogenesis, which cytoplasmic organelle develops into the acrosome?
Golgi apparatus
On which of the following cell types would you expect to find the highest concentration of receptors for luteinising hormone (LH)?
-Spermatocytes
-Leydig cells
-Spermatids
-Sertoli cells
-Spermatocytes
Leydig cells
Which of the following statements about the blood-testes barrier is INCORRECT.
-The blood-testes barrier consists of specialised junctions between the endothelial cells of blood vessels supplying the testes.
-Because of the blood-testes barrier, all the nutrients required by the developing sperm cells have to pass through Sertoli cells.
-Developing spermatogonia move through the blood-testes barrier by remodelling of the barrier around them.
-The blood-testes barrier prevents the movement of blood-borne substances into the lumen of the seminiferous tubules.
-The blood-testes barrier consists of specialised tight junctions between adjacent Sertoli cells.
The blood-testes barrier consists of specialised junctions between the endothelial cells of blood vessels supplying the testes
Which of the following substances has a positive effect on the rate of spermatogenesis?
testosterone
follicle stimulating hormone
androgen binding protein
All 3
What is process of spermatozoa development?
Type A spermatogonia undergoes mitosis to become 1 Type A and 1 Type B spermatogonia. Type B spermatogonia undergoes 2 mitotic divisions to become 4 primary spermatocyte. Each primary spermatocyte undergoes meiotic division to become 2 secondary spermatocytes. Each secondary spermatocyte undergoes meiotic division to become 2 spermatids. Each spermatid becomes a spermatozoa via spermiogenesis.
(Type A -> Type A + Type B) (Type B -> -> 4 Primary Spermatocytes -> 8 secondary spermatocytes -> 16 spermatids -> 16 spermatozoa)
What are Leydig cells?
Produce + secrete testosterone and are clustered around blood vessels so it can be transported easily into blood supply. High concentration of LH receptors
What is structural basis for blood-testes barrier?
Plasma membrane of sertoli cells have tight junctions which prevents movement of blood borne substances into lumen of seminiferous tubules. Barrier remodels for developing spermatogonia
Why are spermatids often observed in a tetra cluster?
Spermatids share the same cytoplasm (coupled by narrow cytoplasmic bridges)
What does lumen of seminiferous tubules contain?
Seminiferous tubule fluid (from sertoli cells), spermatozoa
What is pathway of spermatozoa for ejaculation?
Developed in seminiferous tubules in testis, collected and stored in epididymis, sent through vas deferens into ejaculatory duct where spermatozoa combine with seminal fluid from seminal vesicles to become semen. Sent through prostatic urethra (where prostatic fluid combines with semen) then to membranous urethra then penile urethra
What is a vasectomy?
Cutting and sealing of vas deferens. Ejaculation is seminal fluid, prostatic fluid and bulbourethral fluid. NOT sperm
Which of the following is NOT a function of Sertoli cells?
-secretion of seminiferous tubule fluid
-regulation of spermatogenesis.
-supply of nutrients to developing sperm cells
-phagocytosis of cellular debris
-secretion of testosterone
secretion of testosterone
Which structure empties into the ejaculatory duct?
Vas deferens
Which of the following blood test results would be most likely to come from a man with a tumour in the anterior pituitary which caused hypersecretion of luteinising hormone (LH)? (Testosterone and GnRH)
increased testosterone and decreased GnRH
Testosterone would increase in response to the increased secretion of LH and would subsequently exert a negative feedback effect on the hypothalamus, decreasing GnRH levels.
The major constituent of semen volume comes from which structure?
Seminal vesicles
In which of the structures would you expect to find spermatozoa and seminal fluid but NOT prostatic fluid?
Ejaculatory duct
Which is the shortest part of the urethra?
Membranous urethra
What is C shaped structure on posterior surface of each testis?
Epididymis
What has a detrimental effect on generation of an erection?
Decreased parasympathetic tone to penile arterioles
Sertoli cells secrete what and what is their function?
Androgen binding protein- binds to testosterone, enhances concentration, stimulatory for spermatogenesis
Inhibin- Inhibitory to anterior pituitary gland, reduces FS hormone secretion, inhibition to spermatogenesis
What does seminal fluid contain and how do they facilitate fertilisation?
Fructose- energy source for sperm
Prostaglandins- stimulate male ductal system, stimulate spermatozoa motility, stimualte contraction of female ductal system
Semenogelin- coagulates semen into gel-like mass following ejaculation to help adhere to wall of vagina and retain semen in female reproductive tract
