Repro Flashcards
What is the embryonic origin of the urogenital ridge
intermediate mesoderm region
What does urogenital ridge give rise to?
Embryonic kidney
Gonad
What drives the male gonad development?
SRY gene on short (p) arm of Y chromosome
What happens to the gonad under the Y chromosome influence?
Primodal germ cells colonise the medulla
-> testis and thick tunica albuginea develop
What happens to the gonad without the Y chromosome influence
Primodal germ cells colonise the cortex
-> medullary cords degenerate and ovaries develop
What makes up the mesonephric/Wolffian duct ?
Urogenital sinus and anus divided by uroqrectal septum
What happens to the mesonephric/wolffian ducts under the influence of testosterone?
mesonephric duct sprouts ureteric buds
they make separate openings
->prostate and prostatic urethra forms
What happens to the mesonephric/ wolffian ducts without the influence of testosterone?
mesonephric duct sprouts ureteric buds
ureteric bud expands and mesonephtic duct regresses
Embryonic origin of the uterus and cervix?
Paramesonephric duct
AKA Mullerian duct
What prevents the uterus from forming in males?
Mullerian Inhibiting Substance
secreted by sertoli cells
What influences the development of the external genitalia?
Dihydrotestosterone -> male
What attaches the testis to the inguinal region?
gubernaculum
What prevents the ovary descend past the pelvic brim
paramesonephric ducts
Male gametes formation
Mitosis:
spermatogonia (before birth) -> raw material
-> A1 spermatogonia
-> primary spermatocytes (linked by cytoplasm)
Meiosis:
spermatogenesis -> spermatids (remodelled to..)
-> spermatozoa
Semen contains secretions of (4):
seminal vesicle (60% of vol)
prostate (20%)
bulbs-urethral glands
+ sperm
Female gametes formation
Oognia (primordiale germ cells in gonadal cortex) mitosis by mid-gestation.
- > primary oocyte (meiosis arrested at prophase 1)
- > primordial follicle (oocyte surrounded by granulose cells layer)
- > ovum
Ovum production
small number of primordial follicles begin to develop further at the beginning of the cycle -> 1/2 complete the the development
- > pre-antral ovum (indeed. of hormones)
- > antral ovum (LH and FSH cause…)
- > pre-ovulatory follicle
Pre-ovulatory follicle structure
theca (externa and int)
granulose cells
Antrum
primary oocyte
Origin of anterior pituitary
ratheke’s pouch
endocrine gland
Control of reproduction: the axis
hypothalamus -> GnRH
ant. pit. -> FSH and LH
Gonads
What has -ve feedback on GnRH?
testosterone
oestrogen (moderate levels)
What has +ve feedback on GnRH?
high levels of oestrogen
What effect does progesterone has on GnRH production?
Progesterone reduces the effects of oestrogen
-> GnRH can’t be +vely stimulated
-> no LH surge
also reduced frequency go GnRH pulses
What has -ve feedback on LH and FSH secretion?
testosterone
moderate oestrogen levels
What has +ve feedback on LH and FSH secretion?
high oestrogen levels
Role of inhibit in control of reproduction
selective FSH inhibition
-> LH, FSH proportions altered
inhibit levels increase as the rate of development increases
Male control of reproduction is under what feedback?
-ve
FSH effects in males
Sertoli cells (nursing cells) -> inhibin
LH effects in males
Leydig cells (endocrine cells)
- > testosterone
- > spermatogenesis stimulation
FSH effects in females
Granulosa cells (surrounding cells) -> stimulated to proliferate
LH effects in females
Theca cells -> theca interna stimulation -> oestrogen -> inhibin -> FSH release suppressed Maintains corpus lutem
LH surge effects in females
ovulation
theca externa’s collagen breaks down and ovum is released
Oestrogen effects in females
endometrial thickening
myometrium stimulation and activation (contractions)
thin, alkaline mucus (sperm sticks)
Progesterone effects in females
acts on cells that have been exposed to oestrogen
endometrium dev. into secretory form
myometrium thickening and loss of motality
thick, acid mucus (mucus cap formed)
mammary tissue changes
Pre-menopause changes
follicular phase shorthens -> ovulation early or absent less oestrogen secreted LH and FSH increase (FSH more) reduced fertility
Effects of menopause
vascular changes -> hot flushes oestrogen sensitive tissues -> regression of endometrium and myometrium -> thinning of cervix bone -> increased reabsorption
Testis structure
consist of seminiferous tubules
tunica albuginea and tunica vasculosa
leydig cells -> testosterone
Function of leydig cells
testosterone secretion
Germ cells at different stages of development
spermatogonia
spermatocytes
spermatids
Testis: nursing cells
Sertoli cells
What is epididymis formed of?
Rete testis- seminiferous tubules
they merge together to form epididymis
Epididymis function
first part: absorptive function
- digestion of the residual bodies lost from sperm during maturation
epithelial cells- secretory func.
- proteins which contribute to sperm maturation
Epididymis continues as…
vas deferens
Vas deferens function
transport of germ cells from the epididymis to the ejaculatory duct
Seminal vesicle: what is it?
outgrowths of ductus defers
coiled gubulocacular glands
Seminal vesicle: function
secretes fluid which forms bulk of the ejaculate
not storage site for sperm
