18. Fertilisation 2

Question 1

what are the two types of menstral cycles?

Answer 1

mestral cycle

oestrous cycle

Question 2

in a human, what is the menstral cycle phases?

Answer 2

the pre-ovulatory (follicular) phases - 1-14 days

post-ovulatory (luteal) phase - 14-28 days

day 1 is mensturation

Question 3

what is a follicle

Answer 3

the egg inside the ovary before it has been released into the uterine tube

Question 4

what days are the proliferation (uterine) /follicular (overine) phase?

Answer 4

5 days post mensturation and lasts 11 days (day 16)

Question 5

1. how does the hypothalamus release hormones to stimulate the menstral cycle?

Answer 5

the hypothalamus releases gonadotropin which stimulates the anterior pitutitary gland to release FSH and LH

Question 6

2. what does follicle stimulating hormone stimulate in the human mentstral cycle?

Answer 6

stimulates follicles to develop

causes ovaries and developing follicle to secrete estrogen

Question 7

3. proliferation phase - follicular phase. what does the estrogen that has been secreted stimulate? 2 points

Answer 7

stimulates the endometrium to grow

estrogen stimulates lutenising hormone (LH)

Question 8

proliferation phase - follicular 4. what does lutenising hormone stiumlate?

Answer 8

the final matruation of the follicle (ovulation- release of the egg from the ovaries)

Question 9

when does the luteal phase occur?

Answer 9

after the proliferation phase - so after day 16 and before the period starts

Question 10

1. luteal phase - what is the corpus luteum? what are the two things it secretes?

Answer 10

a temporary endocrine structure involved in ovulation and early pregnancy.

it secretes large amounts of progestrone and estrogen

Question 11

2. luteal - what do progestrone and estrogen together do after being secreted from the corpus lutem? why do they do this?

Answer 11

they inhibit the secretion of GnRH, FSH and LH which stops further follicular development

Question 12

3. luteal - what does progestrone itslef do after being secreted by the corpus luteum? three points

Answer 12

1. inhibits myometrium contactions
2. enables swelling of endometrium
3. encourages secretions of endometrium for nutrients for embryo

Question 13

1. menstruation - what happens if the oocyte (cell in ovary) is not fertilised?

Answer 13

the corpus luteum degenrates within about 8 days because of prostaglandin

Question 14

2. menstruation - what happens to prostaglandin and the corpus luteum if fertilisation does not occur?

Answer 14

prostaglandin is released which causes the corpus luteum to destruct - luteolysis

Question 15

3. menstruation - how does the decrease in progestrone and estrogen cause menstruation?

Answer 15

decreases in progestrone and estrogen constricts arteries to the endometrium which means the endometrium cells and and menstruation occurs