Tutorial 8 - reproductivity

Question 1

Define the components of ovaries and testes.

Answer 1

1. Gonades (ovaries and testes) produce gametes (oocytes and sperm respectively).
2. Ovaries produce two oestrogens (estradiol and estrone), progesterone, relaxin and inhibin.
3. Testes produce testosterone (Leydig cells). Sertoli cells are involved in spermatogenesis and also release inhibin - amongst other hormones

Question 2

What gland does GnRH stimulate and which hormones are produced as a result of GnRH stimulation?

Answer 2

GnRH stimulates the anterior pituitary to produce FSH (follicle stimulating hormone) and LH (leuteinising hormone).

Question 3

Which glands do the gonadotropins produced by the anterior pituitary gland stimulate?

Answer 3

FSH and LH stimulate the testes in males and the ovaries in females.

Question 4

What effect does luteinising hormone (LH) have in a male?

Answer 4

LH is also known as interstitial cell-stimulating hormone (ICSH) in males. LH stimulates Leydig (interstitial) cells in the testes to secrete testosterone.

Question 5

What effect does the follicle-stimulating hormone (FSH) have in a male?

Answer 5

FSH activates cells surrounding the seminiferous tubules (called sustentacular or Sertoli cells) in the testes to bind testosterone and stimulate spermatogenesis.

Question 6

What are the effects of testosterone in a male?

Answer 6

1. completes spermatogenesis (FSH initiates spermatogenesis)
2. stimulates the formation and maintenance of male reproductive organs
3. promotes secondary sex characteristics (e.g. bigger bones & muscles, deep voice, body hair, higher metabolic rate etc)
4. is responsible for libido and aggression

Question 7

Do females produce testosterone? Where is testosterone produced in a female? What are the effects of testosterone in a female?

Answer 7

1. Females produce testosterone but only in small quantities.
2. In females testosterone is produced in the ovaries and in the adrenal cortex.
3. Most of the testosterone produced by a female is converted to oestrogen.
4. Testosterone in a female contributes to libido and production of axillary & pubic hair.
5. Note: males also produce small amounts of oestrogen in the same way i.e. a small amount of a male’s testosterone is converted to oestrogen

Question 8

What effect does FSH have in a female?

Answer 8

FSH stimulates follicles to develop in the ovarian cortex. Each ovarian follicle consists of an oocyte (immature ovum) surrounded by cells.