4.5.3.4 Hormones in Human Reproduction

Question 1

What takes place during puberty?

Answer 1

during puberty reproductive hormones cause secondary sex characteristics to develop

Question 2

What main hormone is produce in the ovary?

Answer 2

oestrogen is the main female reproductive hormone produced in the ovary

Question 3

What happens to eggs in females at puberty?

Answer 3

at puberty eggs begin to mature and one is released approx. every 28 days - ovulation

Question 4

What is the main male reproductive hormone and what does it stimulate?

Answer 4

testosterone is the main male reproductive hormone produced by the testes and it stimulates sperm production

Question 5

Where is FSH secreted?

Answer 5

secreted from pituitary gland

Question 6

What does FSH do?

Answer 6

• causes maturation of an egg in the ovary
• stimulated ovaries to produce oestrogen

Question 7

Where is LH secreted?

Answer 7

pituitary gland

Question 8

What does LH do?

Answer 8

• stimulates the release of the egg
• increased levels of oestrogen causes increased levels of LH
• stimulates tissue of a mature egg

Question 9

Where is oestrogen produced?

Answer 9

made and secreted from the ovaries

Question 10

What does oestrogen do?

Answer 10

• stimulates and maintains uterus lining to build up ready for pregnancy
• slows down production of FSH

Question 11

Where is progesterone produced?

Answer 11

produced by empty egg follicle

Question 12

What does progesterone do?

Answer 12

• maintains uterus lining ready for implantation of fertilised egg
• limits production of FSH and LH → preventing release of more eggs

Question 13

How do hormones interact in the control of the menstrual cycle?

Answer 13

1. Levels of all 4 hormones decrease if not pregnant and uterus wall breaks down at start of menstruation
   
   1. lining of uterus breaks down as egg is not fertilised
   2. progesterone decreases (what keeps uterus lining thick)
2. Pituitary gland secretes FSH and this stimulates:
   
   1. Ovum to mature in ovary
   2. Ovary to produce oestrogen
3. Ovary secretes oestrogen:
   
   1. Inhibits FSH production by pituitary gland
   2. Stimulates pituitary gland to produce LH
   3. Stimulates thickening of uterus lining
4. Pituitary gland secretes LH - stimulates ovum to be released from ovary (ovulation) in middle of cycle
5. Pituitary gland secretes progesterone from empty follicle that contained the egg
   
   1. Inhibits (prevents) production of FSH or LH
   2. Maintains the lining of the uterus during second half of the menstrual cycle, in readiness for receiving a fertilised egg