Case 2 ovarian cycle - histology Flashcards Preview

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Flashcards in Case 2 ovarian cycle - histology Deck (13)
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1
Q

what surrounds primordial follicles?

A

enclosed by single layer squamous pre-granulosa cells and basal lamina

2
Q

what triggers the development of primordial follicles?

A

FSH = menstrual phase

3
Q

what is the difference between an early and late primary follicle?

A

early - single layer - cuboidal granulosa cells with developing zona pellucida
late - multi layer - stratified granulosa cells and enlarged zona pellucida/ stromal cells in concentric layers surrounding granulosa = theca interna

4
Q

what happens in the proliferative phase?

A

FSH stimulates production of oestrogen by granulosa cells which cause further production of oestrogen themselves and primary follicles develop into secondary folliclesq

5
Q

what is the defining feature of a secondary follicle?

A

antrum - containing follicular fluid

6
Q

what is the effect of oestrogen on uterus?

A

endometrial proliferation - development of stratum functionalis from stratum basalis
- endometrial glands and spiral arteries proliferate
in uterine tubes:
- cilia elongate and beat rate increases
- increased secretion from peg cells

7
Q

what is the name of the matured follicle? when does this occur?

A

graafian follicle - tertiary

after first meiotic division - pre-ovulation

8
Q

describe the features of a graafian follicle

A

oocyte eccentrically located it has distinctive zona pellucida enclosed by corona radiata (cumulus oophorus attaches it to wall) and large antrum

9
Q

what happens in ovulation

A

graafian follicle protudes onto surface of ovary = stigma
LH surge -stimulates proteolytic activity in the theca externa and tunica albuginea then the ovum is expelled into the entrance of the uterine tube

10
Q

what occurs in the luteal phase?

A

LH stimulates luteinisation - transformation of corpus luteum from granulosa cells (blood clot surrounded by collapsed layers of granulosa in thecal capsule and lipid inclusions)

11
Q

what do the granulosa and theca interna cells secrete in the luteal phase?

A

granulosa secrete progesterone - thcikens endometrium for implantation/ stimulate glands/ develop stroma
theca interna secrete oestrogen

12
Q

what happens if fertilisation does not occur?

A

decrease in LH - involution of corpus luteum into corpus albicans (cells replaced by collagen) - decrease in progesterone secretion and oestrogen

13
Q

what precipitates the next menstrual cycle?

A

decreased progesterone lvels leads to contraction of spiral arteries -ischaemia/ degeneration of stratum functionalis and shed as menses