Male Reproduction

Question 1

what hormone is responsible for the secretion of testosterone? what cells secrete testosterone?

Answer 1

LH; leydig cells

Question 2

what hormone is responsible for the production of sperm? what cells secrete sperm?

Answer 2

FSH; sertoli

Question 3

how is aromatase important?

Answer 3

testosterone can be converted to estrogen/estradiol

Question 4

what pathway is used to produce testosterone? what genders does this pathway cover?

Answer 4

androstenedione pathway; both genders

Question 5

what medical condition relates to undescended testicles (aberrant retention of testes in the abdominal cavity)?

Answer 5

cryptorchidism

Question 6

for the male, what stage indicates the first signs of puberty? what is the enlargement of the testes?

Answer 6

stage 2

scrotum and testes are enlarged, pubic hair is sparse and manly at the base of the penis

enlargement of the testes to >2.5cm

Question 7

what is stage 1 of genital development?

Answer 7

preadolescent stage

the penis, scrotum, and testes are the same size relative to body size as in a young child

preadolescent, no pubic hair is present, only vellus hair, as on the abdomen

Question 8

what stage of development in the male is this?

the penis, scrotum, and testes are the same size relative to body size as in a young child

preadolescent, no pubic hair is present, only vellus hair, as on the abdomen

Answer 8

stage 1 of genital development or preadolescence

Question 9

what is stage 5 of genital development?

Answer 9

adult pattern for genital development and pubic hair

Question 10

what two primary functions are controlled by the Hypothalamic-pituitary-gonadal axis?

Answer 10

Production of male gametes (spermatogenesis) in the seminiferous tubules

Androgen biosynthesis in the Leydig cells in the testes

Question 11

what role do the sertoli cells play in the Hypothalamic-pituitary-gonadal axis?

Answer 11

Sertoli cells release inhibin under the control of FSH to provide negative feedback to the AP

Question 12

how are androgens released?

Answer 12

LH communicates w/ Leydig cells to release androgens

Question 13

how is spermatogenesis initiated?

Answer 13

FSH communicates w/ Sertoli cells to lead to spermatogenesis

Question 14

T/F, leydig cells have receptors for LH? what is the effect their binding?

Answer 14

Binding increases testosterone synthesis

Question 15

T?F, Sertoli cell has receptors for FSH? what is the effect of their binding?

Answer 15

Binding promotes synthesis of androgen-binding protein (ABP), aromatase, growth factors and inhibin

Question 16

what is the effect of the crosstalk b/w Leydig and Sertoli cells?

Answer 16

Leydig make testosterone, which acts on Sertoli cells. Sertoli cells convert some of the testosterone to estradiol (because of presence of aromatase), which can act on the Leydig cells.

Question 17

what cell is the primary testicular site of FSH action? what does FSH also regulate?

Answer 17

sertoli cells; regulates Leydig cell physiology via effects on Sertoli cells

Question 18

what proteins are synthesized by sertoli cells in response to FSH?

Answer 18

androgen binding proteins
P-450 aromatase
growth factors

Question 19

what is the function of androgen binding protein (ABP)?

Answer 19

secreted into luminal space of the seminiferous tubule, near the developing sperm cells. Helps keep local testosterone hugh.

Question 20

what is the function of P-450 aromatase?

Answer 20

inside sertoli cells, enzyme converts testosterone, which diffuses from Leydig cells to the Sertoli cells, into estradiol

Question 21

what is the function of growth factors?

Answer 21

support sperm cells and spermatogenesis