lecture - 37 female reproductive

Question 1

what is oogenesis

Answer 1

the formation and development of the oocyte from oogonia

Question 2

what is an oogonium

Answer 2

in gonad (diploid 2n = 46)

Question 3

what happens before birth in oogenesis

Answer 3

• population of oogonia increase by mitosis
• oogonia differentiate to form primary oocytes
• primary oocytes starts meiosis

Question 4

how many oocytes will complete development and ovulate (within the dominant follicle)

Answer 4

one

Question 5

what happens when the primary oocyte completes meiosis I

Answer 5

will form a secondary oocyte and a 1st polar body

Question 6

what happens to the oocyte when it starts meiosis II

Answer 6

halts at metaphase II, suspended until fertilisation

Question 7

when will meiosis II resume in oogenesis

Answer 7

when the sperm penetrate the plasma membrane of the ovum at fertilisation

Question 8

what happens to the ovum if it is not fertilised

Answer 8

will degenerate (called atresia) and therefore never complete meoisis II

Question 9

where does oogenesis occur

Answer 9

within developing follicle

Question 10

what cells in a developing follicle produce estradiol

Answer 10

granulosa cells

Question 11

what is ovulation

Answer 11

oocyte and corona radiata released into peritoneal cavity

Question 12

what do primary oocytes start meiosis and stop

Answer 12

starts prior to birth but halts at prophase I until puberty begins

Question 13

the influence of GnRH causes a small number of what …. to be recruited each ovarian / menstrual cycle

Answer 13

small number of follicles - one of these goes on to ovulate (the dominant follicle)

Question 14

what will the dominant follicle do in terms of meiosis

Answer 14

start meiosis II, but process halts at metaphase II until fertilisation occurs

Question 15

where is GnRH released from and what does it stimulate

Answer 15

from the hypothalamus and stimulates the release of FSH and LH

Question 16

where is LH released from and what does it stimulate in females

Answer 16

anterior pituitary, involved in ovulation - the formation of the corpus luteum

Question 17

where is estradiol released from and what does it do

Answer 17

developing follicles
- assists follicle growth (with FSH) - bone and muscle growth
- endometrial growth
- secondary sex characteristics

Question 18

where is inhibin released from and what does it do

Answer 18

granulosa cells = negative feedback to anterior pituitary to suppress FSH

Question 19

where is progesterone released from and what does it do

Answer 19

corpus luteum
- negatively feedbacks to supress GnRH (therefore LH and FSH),

Question 20

what is menarche

Answer 20

first menstrual period

Question 21

what is menopause

Answer 21

cessation of menstruation

Question 22

what does menopause cause

Answer 22

• reduction of estradiol and progesterone due to absence or lack of response by follicles
• anterior pituitary feedback no longer active = therefore FSH / LH high

Question 23

what is the follicular phase and what does it cause in anterior pituitary

Answer 23

days 1-14

• increased FSH from anterior pituitary = stimulates follicular growth

Question 24

what does the follicular phase cause in growing follicles

Answer 24

secretion of estradiol and inhibin

• reduces FSH from anterior pituitary (negative feedback)
• growing follicles undergo atresia (degeneration) , except dominant follicles

Question 25

what occurs in the follicular phase to the dominant follicle

Answer 25

secretes large amounts of estradiol

Question 26

what does high amounts of estradiol in the follicular phase cause

Answer 26

stimulates surge of LH (positive feedback) = stimulates ovulation

Question 27

what is the luteal phase and what occurs to the ovulated follicle

Answer 27

ovulated follicle collapses and forms corpus luteum = secretes progesterone, estradiol and inhibin

Question 28

what does progesterone, estradiol and inhibin secretions from corpus luteum do in the follicular phase

Answer 28

• decrease FSH and LH secretion = negative feedback on the hypothalamus

Question 29

what happens if fertilisation and implantation does not occur

Answer 29

• corpus luteum atrophies
• progesterone levels fall
• spiral arteries contract
• endometrial tissue breaks down and bleeding occurs
• shed tissue and blood removed via cervix and vagina

Question 30

what occur sin the menstural and Proliferative phase and what days is this

Answer 30

1-14

• endometrium breaks down and bleeds during menstration
• estradiol stimulates endometrial growht from approx days 6-14
• rapid tissue growth, including growth of glands and vasculature

Question 31

what days are the secretory pahse and what happens

Answer 31

15-28

• after ovulation (day 14) - corpus luteum secretes progesterone
• progesterone promotes endometreial maturation = glands become secretory, spiral arterioles grow and coil