Reproduction and Sex Steroid Axis - unfinished Flashcards Preview

RB Y2 Endocrine - 6 Reproductive > Reproduction and Sex Steroid Axis - unfinished > Flashcards

Flashcards in Reproduction and Sex Steroid Axis - unfinished Deck (27)
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1
Q

what is the mean duration of the menstrual cycle

A

28 days

ranges from 21-35

2
Q

average duration of menses and estimated blood loss

A

3-5 days

30ml

3
Q

when in the menstrual cycle does ovulation usually occur

A

mid cycle eg day 14

4
Q

describe follicular growth

A

begins when oestrogen levels are low, this provides feedback stimulating the anterior pitutiary to secrete LH and FSH stimulating follicles to develop

one leading follicle develops

the granulosa around the egg enlarge, and release oestrogen - this causes the lining of the uterine to thicken

5
Q

what hormone is responsible for the recruitment of the dominant follicle

A

FSH

6
Q

describe the ovulation phase

A

occurs at peak follicular growth in response to a surge of LH

follicles grow to at least 20mm in size before they can release an egg. LH and FSH continue to be released for 3-4 days, and LH continues further in response to oestradiol

after the peak in LH, the oocyte is released. the collagen wall of the follicle is digested by proteolytic enzymes and prostaglandins and rupture releasing the ova into the fallopian tubes

7
Q

describe the luteal phase

A

the secretory phase that starts after ovulation

beigns with the formation of the corpus luteum from the remaining granulosa cells

this releases progsterone by the action of 3ß- HSD

peak progesterone productionis noticed one week after ovulation takes place

8
Q

why is the corpus luteum yellow

A

due to keratin

9
Q

describe menstruation phase

A

in the absence of pregnancy, the CL disintegrates (luteolysis) and progesterone levels drop, the uterine lining detached adn menstruation begins

10
Q

what is in the discharge during menstruation

A

tissue, blood and unfertilized egg

11
Q

what is the suspensory (IP) ligament

A

attaches the ovary to pelvic side wall

12
Q

describe the ovary

A

has an outer cortex and inner medulla

the cortex contains the follicles

13
Q

describe the uterus

A

fibromuscular organ, conatins the body of the uterus and the cervix

the endometrium has a basal and superficial layer, and thickens in response to oestrogen release

if there is a lack of hCG and progesterone (CL), the endometrium sloughs off

14
Q

what is GnRH produced by

A

arcuate nucleus in the hypothalamus

15
Q

GnRH

A

deca peptide hormone

there are 3 types: GnRH 1 is responsible for reproductive function

it is released in a pulsatile manner and has a half life of 2-4 minutes

16
Q

FSH

A

glycoprotein that contains 2 subunits, and has a half-life of several hours

it is responsible for recruiting the dominant follicle, granulosa cell growth and the activation of aromatase activity

17
Q

LH

A

acts on the theca cells

responsibel for the uptake of choelsterol and the conversion of androgens to oestrogens

18
Q

inhibin

A

local peptide found in the follicular fluid

down regulates FSH secretion and locally enhances LH induced androstenedione production

19
Q

activin

A

found in follicular fluid

stimulates FSH induced oestrogen production

20
Q

what are the tubular components of the testis

A

sertoli and germ cells

21
Q

what are the interstitial components of the testis

A

leydig cells and capillaries

22
Q

sertoli cell function

A

facilitate the progression of germ cells to spermatozoa

23
Q

describe the development of spermatogonium to spermatozoa

A

a spermatogonium is an undifferentiated male germ cell

24
Q

what is the acrosome formed from

A

golgi

25
Q

what is the flagellum formed from

A

centriole

26
Q

describe the first steps in maturation of a sperm cell

A

excess cytoplasma and material in cells is eaten up by Sertoli cells

tails begin to develop and DNA is repackaged

the sperm cell has an acrosome and a tail (required for motility)

27
Q

acrosome

A

sperm has an acrosome that conains digeestive proteins that are rquired to digest the egg’s outer shell (zona pelludica) allowing haploid nucleus in sperm cell to join haploid nucleus in ovum