5.11 Reproductive Hormones - Puberty & Menstrual Cycle

Question 1

What is the definition of puberty?

Answer 1

Period in which adolescents start to develop secondary sexual characteristics

Question 2

What do hormones do in females?

Answer 2

They regulate the female menstrual cycle - this is the monthly sequence of events in which the female body releases an egg (ovulation) and prepares the uterus (womb) in case the egg is fertilised

Question 3

Describe stage 1 of the menstrual cycle

Answer 3

Day 1 is when menstruation starts. The lining of the uterus breaks down and is released

Question 4

Describe stage 2 of the menstrual cycle

Answer 4

The uterus lining is repaired, from day 4 to day 14, until it becomes a thick spongy layer full of blood vessels ready for a fertilised egg to implant there

Question 5

Describe stage 3 of the menstrual cycle

Answer 5

An egg develops and is released from the ovary (ovulation) at about day 14

Question 6

Describe stage 4 of the menstrual cycle

Answer 6

The lining is maintained for about 14 days, until day 28. If no fertilised egg has landed on the uterus wall by day 28, the spongy lining starts to break down again and the whole cycle starts over

Question 7

What happens between days 1-5 in the menstrual cycle?

Answer 7

The uterus lining breaks down. This is called menstruation. The pituitary gland releases FSH

Question 8

What happens between days 5-14 of the menstrual cycle? (3)

Answer 8

• FSH causes an egg follicle inside the ovary to grow and mature
• Oestrogen is released from the egg follicle as it grows and matures
• Oestrogen makes the pituitary gland stop FSH and start LH, and causes the uterus lining to thicken

Question 9

What happens on day 14 of the menstrual cycle?

Answer 9

LH levels peak and the egg is released from the follicle. LH stops oestrogen release

Question 10

Which hormone is released between days 14-21 of the menstrual cycle?

Answer 10

Progesterone is released by the empty follicle. This maintains the uterus lining and stops LH

Question 11

What happens between days 21-28 of the menstrual cycle?

Answer 11

If the egg is not fertilised, levels of progesterone start to fall. The uterus lining will soon break down again. If a fertilised egg is planted in the uterus wall, progesterone levels stay and maintain the uterus lining.

Question 12

What is the role of FSH? (3)

Answer 12

• released by the pituitary gland
• causes a follicle to mature in one of the ovaries
• stimulates oestrogen production

Question 13

What is the role of oestrogen? (2)

Answer 13

• released by the ovaries
• causes the lining of the uterus to thicken and grow

Question 14

What is the role of LH (luteinising hormone)? (3)

Answer 14

• released by the pituitary gland
• an LH surge (rapid increase) stimulates ovulation at day 14 - the follicle ruptures and the egg is released
• stimulates the remains of the follicle to develop into a structure called a corpus luteum - which secretes progesterone

Question 15

What is the role of progesterone? (5)

Answer 15

• released by the ovaries
• maintains the lining of the uterus for the implantation of a fertilised egg
• along with oestrogen, progesterone inhibits the release of FSH and LH
• when the level of progesterone falls, and there’s a low oestrogen level, the uterus lining breaks down
• a low progesterone level allows FSH to increase (and then the whole cycle starts again)

Question 16

What happens as the oestrogen levels start to increase and what is this an example of?

Answer 16

• The oestrogen starts to inhibit FSH - this an example of negative feedback
• When oestrogen levels get high, they stimulate the release of LH which causes an LH spike and results in ovulation

Question 17

Which hormones are released by the pituitary gland? (2)

Answer 17

• FSH
• LH

Question 18

Which hormones are released by the ovaries? (2)

Answer 18

• progesterone
• oestrogen

Question 19

Which hormone stimulates the uterus lining to develop?

Answer 19

Oestrogen

Question 20

Which hormone stimulates the egg to be released around day 14 (ovulation)?

Answer 20

Luteinising hormone (LH)

Question 21

Which hormone stimulates the egg follicle to mature?

Answer 21

Follicle stimulating hormone (FSH)

Question 22

Which hormone maintains the lining of the uterus?

Answer 22

Progesterone