reproduction lectures Flashcards
gametogenesis?
production of gametes from undifferentiated germ cells
Chromosomes in sex determination?
if Y chromosome present then srY gene causes testes to develop
srY gene?
codes for testis-determining factor. when present fetus develops testes, when absent fetus develops ovaries
precursors to male and female ducts?
wolffian ducts become male tract
mullerian ducts become female tract
sex differentiation?
if present, testes secrete:
-testosterone
-mullerian inhibiting substane
these hormones both stimulate development of wolffian ducts and degeneration of mullerian ducts.
if no testes in absense of hormones, wolffian ducts regress and mullerian ducts develop
mullerian duct becomes?
fallopian tube, uterus and upper part of vagina
wolffian duct becomes?
seminal vesicle, vas deferens and epididymis
site of sperm production in testes?
seminiferous tubules
leydig cells?
secrete testosterone in testis
sertoli cells?
support sperm development
secrete luminal fluid that sperm develop in
secrete androgen-binding protein
before birth effects of testosterone?
masculinizes reproductive tract and promotes descent of testes into scrotum
testosterone effects sex-specific tissues after brith:?
promotes growth and maturation of the reproductive system at puberty
essential for spermatogenesis
maintains reproductive tract throughout childhood
testosterone non-reproductive actions?
exerts protein anabolic effect
promotes bone growth at puberty
closes epiphyseal plates after conversion to estrogen by aromatase
can induce aggressive behaviour
erection and ejaculation?
during sexual arousal erection occurs - blood engorges erectile tissue, penis swells and elongates
sperm ejaculated through urethra
scotum?
suspended beneath penis
thin walled sac outside of body as sperm can’t develop properly at body temperature
dartos and cremaster muscles?
in scrotum, contract to regulate temperature in the cold
male reproductive tract order?
seminiferous tubules - rete testis - efferent ductules - epididymis - vas deferens - ejaculatory duct - urethra
male reproductive accessory glands?
seminal vesicles - secrete alkaline fluid with fructose, enzymes and prostaglandins
prostate gland - secretes citrate and enzymes
bulbourethral glands - secrete viscous fluid wit mucus
androgen effect?
stimulate spermatogenesis
increase sex drive
promote protein synthesis in skeletal muscle
sperm structure?
Head = chromosomes and acrosome (enzymes)
midpiece = mitochondria
tail = whiplike movements propel sperm
sperm maturation?
released into lumen of seminiferous tubules, they are immotile for 20 days.
move to epididymis by peristaltic contractions and flow of fluid. here they acquire motility
move to vas deferens by peristalsis and remain until ejaculation.
ovarian follicles?
contain one ovum
start as primordial follicle
Granulosa cells?
target cells for estrogen and FSH
secrete inhibin (negative feedback for FSH)
secrete paracrines that support follicle development
birth canal?
cervix and vagina
cervix?
canal leading to the vagina from uterus
vagina inner surface?
bathed in acid fluid to protect against bacterial infection
uterine tube movement?
fimbrae pick up a released ovum
moves through uterine tube, initially through peristaltic contractions but mainly through ciliary actions
takes 4 days to reach the uterus
completion of oogenesis meiosis?
after fertilisation
after follicle ruptures what structure degenerates in ovary?
corpus luteum
result of estrogen and progesterone pill?
prevents release of LH and FSH
mode of action combined pill?
Follicles don’t develop due to changes in FSH
LH surge inhibited so no release of ova
progesterone only pill?
low dose progesterone, taken all year round
cervical mucous changes into thick sperm barrier
endometrium unsuitable for implantation
inhibition of LH and ovulation
GnRH?
gonadotropin-releasing hormone, responsible for the release of FSH and LH from the anterior pituitary.
post-coital contraception method?
levonorgestrel - progesterone antagonist
binds to progesterone receptors to prevent response
endometrial tissue sloughed off in absence of progesterone
female infertility causes?
pelvic inflammatory disease
anatomical abnormalities
obesity
treatment of excessive estrogen?
clomiphene - antiestrogen
administered during days 5-10 of the cycle, allows normal secretion of anterior pituitary hormones
alpha estrogen receptors?
breast and endometrium
beta estrogen receptors?
kidney, intestines, brain.
treating gonadotropin deficiency?
elevated prolactin levels cause.
dopamine is a prolactin inhibitory factor. bromocriptine and cabergolin are dopamine receptor agonists
azoospermia?
failure of testis to develop or descend, causes impaired semen profile
oligospermia?
previous inflammatory damage, causes impaired semen profile
how many days before ovulation must sperm be introduced into reproductive tract?
within 5 days.
events of fertilisation, getting to oocyte?
several sperm try to penetrate corona radiata
when through they bind to sperm binding protein
this triggers acrosome reaction and enzymes are released allowing sperm to break through zona pellucida and access oocyte
fertilisation, once a sperm reaches oocyte?
first sperm to reach binds to a receptor on the oocyte plasma membrane
this transports the sperm into the cytoplasm -fusion
sperm binding proteins become inactive and zona pellucida hardens preventing polyspermy
blastocyst, trophoblast becomes?
fetal placenta
blastocyst, inner cell mass becomes?
embryo
ectopic pregnancy?
fertilised ovum implants in fallopian tube not endometrial lining. growth of fetus and placenta can cause bleeding and possible rupture
trophoblast?
single layer of outer cells of blastocyst
required for implantation into endometrial lining and develops into placenta
blastocoele?
fluid filled cavity that develops into the amniotic sac
late embryonic and fetal development?
by 5 weeks the placenta is functioning and the heart is beating
placenta 3 main functions?
free exchange of energy, nutrients and waste products
immunological barrier between mother and fetus
secretes hormones to support development of fetus and prepare the mother to support newborn
HCG from placenta?
human chorionic gonadotropin sustains the corpus luteum which secretes estrogens and progesterone for the first 2 months of pregnancy
maternal changes in second trimester?
approx 6kg weight gain
heartburn due to progesterone induced relaxation of oesophageal muscle
constipation - progesterone induced relaxation of intestinal muscle
return of libido, improved skin tone
maternal changes third trimester?
deeper breaths - baby reduces abdominal movement of diagphragm
braxton-hicks contractions
tired and anxious
disorder of pregnancy - eclampsia?
elevated blood pressure - compromises blood flow to fetus, requires plenty of bed rest and even sedation
parturition?
birth
dilation required to accomodate head?
10cm
water breaking?
fetus bears down head first on the cervix, this ruptures amniotic sac and lubricates the cervical canal
duration of second stage of labour?
30-90mins
second stage of labour?
head of fetus activates cervical stretch receptors to synchronise abdominal and uterine contractions
third stage of labour?
30mins past-partum
second series of myometrial contractions expel the placenta
loss of placenta causes major fall in maternal progesterone and estrogen levels
trigger for parturition?
unknown but current theory is that signal comes from the fetus
spasmogens?
increase the force and frequency of contractions
oxytocin?
type of spasmogen
given by slow infusion
postaglandins F2 and E2
type of spasmogen
intravaginal tablets produce localised contractions so limit side effects.
relexants?
reduce frequency and force of contractions
relaxants clinical uses?
delay or prevent premature parturition for up to 7 days
slow arrest or delivery to undertake therapeutic measures
colostrum?
watery milk produced first few days after birth
mammary glands?
prolactin stimulates milk synthesis
oxytocin stimulates milk ejection reflex
how does suckling supress menstrual cycle?
inhibits LH and FSH
