Testicular function

Question 1

What is the function of the testicles

Answer 1

Production of sperm

Secretion of androgens

Question 2

What are the 2 main tissue types in the testicles?

Answer 2

Leydig cells

Seminiferous tubules

Question 3

Describe the cell types in seminiferous tubules

Answer 3

Spermatogonial stem cells: sperm production
Sertoli cells: support, support, nutrition, protection, secretory, excretory.
Gets rid of bad sperm cells. Interconnected by tight junction. Separates sperm cells from stem cells, they have new antgens they could otherwise (if not separate) cause antisperm-antibody release (blood-sperm barrier)

Question 4

At what rate are sperm cells produced

Answer 4

1,500 per second

Question 5

Describe the anatomy of a sperm cell

Answer 5

Head with nucleus covered in an acrosome
Midpiece with mitochondria
Tail piece

Question 6

What androgens are released by leydig cells?

Answer 6

Testosterone (95%)

Question 7

What are the actions of testosterone in the male

Answer 7

Anabolic
Primary and secondary sexual characteristics
Libido and sexual behavior
Stimulates sertoli cells and spermatogenesis

Question 8

How do sertoli cells create negative feedback with the hypothalamic-pituitary-gonado axis to regulate spermatogenesis?

Answer 8

By secreting inhibin which acts on the anterior pituitary

Question 9

How does prolactin affect spermatogenesis

Answer 9

Prolactin causes an increase in the population of LH receptors in Leydig cells therefore having a facilitatory action on spermatogenesis

Question 10

What is the pathway that sperm will follow to get to the egg

Answer 10

Ejaculation - deposition into the vagina
Cervix - mucous barrier and crypts act as a sperm reservoirs - motility is important here
Uterus and tubes - mild contraction to propel sperm towards egg
Ampullary portion of tube - fertilisation

Question 11

What is acrosome reaction in sperm when coming into contact with the egg

Answer 11

Triggered by contact with oocyte (interaction with ZP3 protein on oocyte membrane)
Leads to exposure of hyluronidase and acrosin enzymes
Facilitates oocyte penetration

Question 12

Describe oocyte activation

Answer 12

Release of cortical granules - blockade to polyspermic penetration

Resumption of meiosis

Formation of the male and female pronuclei (fertilisation)

Question 13

What are some factors that may lead to disturbance in regulation of testicular function?

Answer 13

Genetic level
Hypothalamic level
Pituitary level
Target tissue level

(endocrine + genetic really)