oogenesis

Question 1

female germ cells proliferate by mitosis in the ovaries to form a large no of what?

Answer 1

oogonia

Question 2

oogonia is diploid or haploid?

Answer 2

diploid, containing two x chromosomes, and will become haploid mature oocytes via process of oogenesis

Question 3

what is the adult ovary made up of?

Answer 3

connective tissue that supports a large no of follicles
blood vessels and nerves are concentrated within the central medulla whereas follicles are found in the outer cortex in varying stages of development

Question 4

meiosis I begins at what week of embryonic development

Answer 4

week 12
the cell at this stage is known as the primary oocyte and is surrounded by a thin layer of squamous epithelial cells

Question 5

in its very early stages of development what is the primary oocyte in its thin layer of epithelial cells known as?

Answer 5

primordial follicle

Question 6

the primary oocyte at week 12 is developmentally arrested in what phase of meiosis I?

Answer 6

prophase
this pause in development can continue for 45 years or more
no of primordial follicles inc during foetal period but many degenrate. leaving around 400,000 follicles available at puberty

Question 7

after birth do any new oocytes form?

Answer 7

no

Question 8

with the onset of puberty the primary oocyte becomes large and follicular cells thicken and becomes cuboidal. what is follicle now known as?

Answer 8

primary follicle

Question 9

the oocyte and granulosa (follicle) cells produce a layer of glyoproteins on the surface of the oocyte called?

Answer 9

zona pellucida

Question 10

when the follicle forms more than one layer of granulosa cells it is called a ?

Answer 10

secondary follicle

Question 11

what is the name given to the cavity formed between the granulosa cells?

Answer 11

antrum
-> follicle is now called cumulus oophorus

Question 12

connective tissue cells of the ovary around the follicle respond by differentiating and forming what two layers?

Answer 12

theca interna
theca externa

-> at this stage follicle is now a graafian follicle

Question 13

theca interna role?

Answer 13

hormonal role

Question 14

theca externa role?

Answer 14

supportive role

Question 15

thecal and granulosa cells of developing follicles produce what hormone that causes what process to occur in the uterus?

Answer 15

oestrogen
thickening of the endometrial lining of the uterus and other preparations for receiving a fertilised oocyte
(occurs day 5 - 14 of the menstrual cycle)

Question 16

the primary oocyte of the graafian follicle responds to surges in FSH and LH produced by pituitary gland on days 13-14 of the menstrual cycle resuming what process?

Answer 16

meoiosis I and continuing its stalled cell division.

Question 17

when the primary oocyte divides it forms one large cell and one smaller remnant of the division known as?

Answer 17

polar body

Question 18

at the end of meiosis I the oocyte has become?

Answer 18

secondary oocyte

Question 19

what are polar bodies?

Answer 19

non-functional cells. receive v little of the available cytoplasm and degenrate soon after division.

Question 20

how many polar bodies are formed in meiosis I and meiosis II?

Answer 20

1
2 in meiosis II

Question 21

Meiosis II is halted in what phase of the cycle?

Answer 21

metaphase II
-> this will only continue if the oocyte is fertilised.

Question 22

with ovulation of the secondary oocyte, what structure is left behind?

Answer 22

follicle remains within the ovary and becomes the corpus luteum.

Question 23

in repsonse to LH the corpus luteum produces what hormones?

Answer 23

progesterone and oestrogen to thicken endometrium and develop its vasc, form glands in prep for implnatation

Question 24

if fertilisation does not occur, corpus luteum degenerates 14 days later and becomes a scar tissue remnant of itself called?

Answer 24

corpus albicans

Question 25

when is the endometrium shed?

Answer 25

when corpus luteum degenerates and hormone production ceases