Hormones

Question 1

What is oogenesis?

Answer 1

Same as male sperm production but…
many years to complete
Begins in utero

Question 2

Describe a primordial germ cell

Answer 2

Earliest recognisable germinal cell
Capable of mitosis
Migrate to genital ridge by week 6 of embryo development

Question 3

Describe oogonia?

Answer 3

Completion of last pre-meiotic division –> oocytes which enter meiosis

Question 4

What are primary oocytes?

Answer 4

1st meiotic division

Question 5

What are secondary oocytes?

Answer 5

2nd meiotic division

Question 6

When is the first polar body formed?

Answer 6

First stage of meiosis

Question 7

How much cytoplasm do the polar bodies contain?

Answer 7

Very little

Question 8

What does 2 polar bodies mean?

Answer 8

Sperm entry and successful 2nd meiotic division

Question 9

Describe the follicular phase

Answer 9

1st half of the cycle

Maturation of egg, ready for ovulation at midcycle-ovulation signals end of phase

Question 10

Describe the luteal phase

Answer 10

2nd half of cycle
Development of corpus luteum
Induces preparation of reproductive tract for pregnancy

Question 11

What surrounds the primary oocyte before birth?

Answer 11

Single layer of granulosa cells

Question 12

What is atresia?

Answer 12

Degenerative scar tissue

Question 13

By how much does the secondary oocyte grow?

Answer 13

X1000

Question 14

How many will ovulate?

Answer 14

~400 (99.98% undergo atresia)

Question 15

What happens to the follicular cells left behind after ovulation?

Answer 15

They undergo luteinisation

- transformation to the corpus luteum

Question 16

What does the corpus luteum secrete?

Answer 16

Progesterone

Question 17

When is oestrogen secreted?

Answer 17

Follicular phase

Question 18

How long does the corpus luteum grow for after ovulation?

Answer 18

8-9 days

Question 19

Describe GnRH?

Answer 19

Secreted by the hypothalamus

Acts upon the anterior pituitary

Question 20

Explain FSH?

Answer 20

Secreted by anterior pituitary
Acts on ovary
Stimulates follicle development

Question 21

Explain LH

Answer 21

Acts on ovary

Stimulates follicle maturation, ovulation and development of corpus luteum

Question 22

What do FSH and LH do together?

Answer 22

Stimulate secretion of oestradiol and ovulation

Question 23

Describe androgen

Answer 23

Produced by theca cells which is converted by the granulosa (aromatase) to oestradiol (Thickens the endometrium/thin cervical mucus)

Question 24

What is FSH production suppressed by?

Answer 24

Oestrogen

Question 25

LH receptor is expressed by what in the dominant follicle?

Answer 25

Granulosa

Question 26

What does high levels of oestrogen cause at mid cycle cause?

Answer 26

Hypothalamus to release GnRH | FSH and LH from the anterior pituitary

Question 27

What happens in ovulation?

Answer 27

``` Increase in follicular fluid and granulosa numbers Cumulus oophorus loosens Follicle wall weakens Ovulation - oocyte, ZP, cumulus COC picked up by oviduct LH and FSH levels fall ```

Question 28

What does the corpus luteum become if no fertilisation?

Answer 28

Corpus albicans

Question 29

What do theca cells do to androgen?

Answer 29

Convert to estrogen

Question 30

What is produced by the embryo if pregnancy occurs?

Answer 30

hCG (chronic gonadotrophin) | this maintains the corpus luteum

Question 31

At what stage does the placenta take over?

Answer 31

6 weeks, the corpus luteum then becomes the corpus albicans

Question 32

When is surgical sperm aspiration indicated?

Answer 32

Azoospermia