The Ovarian Cycle

Question 1

What does the ovarian cycle consist of?

Answer 1

• development of Graafian follicle
• ovulation
• formation of the corpus luteum

Question 2

What is the first part of the ovarian cycle?

Answer 2

• the follicular phase

Question 3

What occurs during the follicular phase?

Answer 3

1. the primary follicles mature and get ready to release an egg cell
2. under the influence of FSH from the pituitary gland, a primary follicle develops into a fluid-filled Graafian follicle

Question 4

What happens during the process of the development of a Graafian follicle?

Answer 4

• the primary oocyte in the follicle undergoes meiosis
• develops into a haploid egg cell (ovum)

Question 5

What does the Graafian follicle contain?

Answer 5

• the egg cell (ovum)

Question 6

What happens to the Graafian follicle as it matures?

Answer 6

• it enlarges and moves to the surface of the ovary

Question 7

What is ovulation?

Answer 7

• luteinizing hormone (LH), released from the pituitary
• causes the Graafian follicle to rupture
• releasing an egg cell

Question 8

When does ovulation take place?

Answer 8

• approximately on day 14 of the cycle

Question 9

What happens after ovulation?

Answer 9

• the remains of the Graafian follicle
• under the influence of FSH and LH
• changes into glandular tissue
• called the corpus luteum (yellow body)

Question 10

What does the corpus luteum produce?

Answer 10

• large amounts of progesterone
• as well as oestrogen

Question 11

What happens to the corpus luteum if pregnancy does not occur?

Answer 11

• it will begin to disintegrate and disappear 10-14 days after ovulation

Question 12

What happens to the corpus luteum if pregnancy occurs and why?

Answer 12

• it remains
• as it is needed to sustain a healthy pregnancy

Question 13

What makes human ovulation unique in terms of sexual activity?

Answer 13

• human females can be sexually active at any time in their cycle, even when they are not about to ovulate
• other mammal females are only sexually active in the oestrus phase of their cycle and are about to ovulate

Question 14

What makes human ovulation unique in terms of physical signs?

Answer 14

• there are no obvious external signs to signal ovulation
• it is pure chance as to whether fertilisation occurs (unlike in other animals)