Hormonal Control of the Male Reproductive System

Question 1

Which gene only located on the Y chromosome will cause the embryonic development of the testes?

Answer 1

SRY gene makes you MALE

Question 2

Which protein does the SRY gene encode for causes testis development?

Answer 2

DNA binding protein called TDF. TDF stimulates other genes that cause testis development.

Question 3

The testes develop from the embryonic gonads at what stage of pregnancy? What stage of embryonic development is it at and what length is this stage (literally length)?

Answer 3

8th week of pregnancy. Embryo is becoming a fetus. 30 mm long.

Question 4

Production of which hormone leads to the development of male genetalia?

Answer 4

Testosterone produced by the Leydig cells during the development of the testis in the 8th week of pregnancy. The Leydig cells are in the interstitial space between the seminiferous tubules.

Question 5

How long is testosterone produced for?

Answer 5

From the 8th week til the 15th week.

Question 6

What is the function of testosterone secretion beginning during puberty?

Answer 6

Stimulate production of sperm, stimulate the secondary sexual characteristics: increased body hair, deepening of voice (growth of larynx), and enlargement of the penis.

Question 7

Which part of the brain regulates the production and release of testosterone?

Answer 7

Hypothalamus releases gonadotropin releasing hormone (GnRH) which stimulates the anterior pituitary lobe. Anterior pituitary releases gonadotropins

Question 8

Gonadotropins. Which hormones are they?

Answer 8

Hormones that regulate the function of the gonads.
Lutenizing hormone (LH) and follicle stimulating hormone (FSH)

Question 9

Match the description with the gonadotropin: “released by the anterior pituitary gland, stimulates production of sperm cells in the seminiferous tubules”

Answer 9

Males, FSH

Question 10

Production and function of LH in males?

Answer 10

Produced by the anterior pituitary gland. Testosterone production stimulation in the Leydig cells Testosterone stimulates spermatogenesis.

Question 11

Why is the hormonal regulation of the male reproductive system a negative feedback loop?

Answer 11

To ensure constant levels of testosterone and adequate numbers of sperm cells. There is no major physiological event taking place that would make this a positive feedback loop.

Question 12

Which hormone regulates the number of sperm cells?

Answer 12

Inhibin released by the sertoli cells. Inhibin interacts with the hypothalamus and the pituitary gland to inhibit FSH production and reduce release of GnRH.

Question 13

How are testosterone levels regulated?

Answer 13

The level regulates itself by interacting directly with the anterior pituitary gland. This reduces the production of LH. Interaction with the hypothalamus reduces the release of GnRH (indirect effect on production and release of GnRH.

Question 14

GnRH

Answer 14

Gonadotropin releasing hormone. Stimulates anterior pituitary gland to release gonadotropins (FSH and LH).

Question 15

Testosterone

Answer 15

Interstitial cells (Leydig cells).

• Stimulates spermatogenesis
• Promotes and regulates the development of secondary sexual characteristics
• Sex drive levels

Question 16

FSH

Answer 16

Follicle stimulating hormone. From the anterior pituitary gland. Stimulates the production of sperm cells in the seminiferous tubules.

Question 17

LH

Answer 17

Luteinizing hormone. From the hypothalamus. Stimulates production of testosterone by the interstitial (Leydig) cells.