Case 1 - Normal Pregnancy Flashcards
what are the two cycles in female reproduction
menstrual (changes to uterus) and ovarian
what is a primordial follicle
ovum surrounded by one layer of granulose cells
what do GC do through childhood
provide nourishment to ovum and secrete oocyte maturation inhibiting factor to keep ovum suspended in primordial state in prophase of meiosis 1
what causes follicles to develop
stimulation of FSH
process of developing follicles
- FSH stimulation
- Only one follicle reaches maturity
- FSH = proliferation of GC = layers
- theca cells collect = primary follicle
- secrete androstenedione bc of LH. taken up by GC, converted to oestrogen via aromatase
- antrum formed = secondary follicle
- GC secrete oest filled fluid - TERTIARY
- oest released - inhibits FSH and LH
- also acts on GC = proliferation and sensitivity to FSH
- LH receptors promoted on gC cells, LH and FSH stimulation
- increase in secretion of rest
- positive feedback = increase in LH also = proliferation of theca cells = GRAAFIAN FOLLICLE
- increase in lH - completion of meiosis 1
what are the products of meiosis 1
oocyte and polar body
what is the theca externa
vascular connective tissue capsule that becomes capsule of developing follicle
process of ovulation
- theca externa releases proteolytic enzymes = dissolution of capsular wall
- growth of new BV into wall and prostaglandins secreted into follicular tissue
- plasma transudation = follicle swelling
- degeneration of stigma and ovum discharges
menstrual phase
1-5 days
- degeneration of endometrial lining of uterus bc of constriction of spiral arteries. reduces blood flow to endometrium = no oxygen or nutrients and it erupts and blood fills cavity
- 50 ml blood lost
- FSH - GC secretes estradiol, stimulates LH receptors on theca cells = prepares them for prog synthesis after ovulation
what causes cramps
liberation of prostaglandins from endometrium
proliferative/follicular phase
- single follicle becomes dominant. reduces FSH
- atresia for others = reabsorbed into follicular phase
- dominant: bulge forms bc of increasing pressure of filling antrum
- LH levels rise, prog released before ovulation
- oest stimulates repair of ends, cells of stratum basalis undergo mitosis = stratum functionalis
- endo thickens
ovulation phase
- rise in west, positive feedback so surge of FSH and LH
- if rising oest = no ovulation yet
- follicular rupture: 36h after LH surge
- oocyte expelled into fallopian tube
- during lH surge = LHG receptor binds to LH and GC produce progesterone
what happens to remaining follicle
converted to corpus lute to facilitate prog secretion
secretory/luteal
15-28
-uterine wall grows bc prog
if no fertilisation = CL degenerates, prog decreases
why is it called the secretory phase
endometrium becomes glandular under influence of prog
what is the CL cyst
after ovulation, cl MAY fill with blood or fluid instead of breaking down. harmless
stratum basalis
deepest layer
undergoes little change, not shed
stratum spongiosum
stroma w spongy appearance, middle layer
stratum compactum
compact stromal appearance
stratum functionalis
shed during menstruation
what are straight and spiral arteries in SF
straight - short, supply SB. not responsive to hormonal changes of MC
spiral - long, coiled and thick. to surface of endo, capillary plexus around glands and SC. responsive to hormonal changes. at end of cycle, less prog = ischaemic phase
impact of oest and prog on SF
oest - highly proliferative
prog - vascular and glandular
process of fertilisation
- in isthmus or ampulla
- infundibulum moves to site of follicle rupture - fijmbraie envelop and direct ovum into tube
- movement: peristaltic action due to long and circular SM layers of oviduct wall
- contractions of uterine muscles - accelerates sperm
- stimulated by prostaglandins in semen and oxytocin during orgasm
acrosome reaction
- many sperm penetrate CR
-hyaluronidase breaks bonds between adj follicle cells
acrosome head ruptures when spermatozoon binds to ZP - acrosin penetrates ZP
sperm fuses to vitelline membrane - sperm absorbed into oocyte
-inactivation of sperm receptors
-ZP hardens to prevent polyspermy. - meiosis 2 continues from metaphase in puberty
process of cleavage
subdivides cytoplasm of zygote asynchronous division initial division - 2 cells, then 4 etc morula (8 blasters w in ZP, 32 cell stage) morula to blastula then blastocyst trophoblast gives rise to placenta ICM gives rise to embryo
what is a blastula
hollow sphere of blastomeres surrounding inner fluid filled cavity called blastoceole
what is a blastocyst
blastula but w ICM called embryo blast - pluripotent SC which will form embryp
what is a trophoblast
insulator and supplier of nutrients
what are cytotrophoblasts
trophoblast cells closest ti interior
what are syncytiotrophoblasts
CT that have lost membranes and cytoplasms have been fused to make multinucleate cells
process of implantation
1 blastocyst exposed to glycol rich fluid secreted by endometrium n enlarges
2 blastocyst contacts endo
3 trophoblasts cells divide
4 CT remain intact
5 CT differentiate into SCT
6 SCT break down SF by secreting hyaluronidase (eroding path through endometrium)
7 SCT produces hug - goes to ovaries, binds to receptors on CL to sustain prod of O & P
8 prog = uterine more glandular n vascular
9 enlarged cells in endo
10 blastocyst burrows into SF - development occurs here
11 SCT expand and erode glands w in endo = nutrients released
12 ICM n trophoblasts use nutrients to develop embryo blast
13 trophoblastic extensions penetrate endometrial blood supply and increases it around day 9
where is implantation normally
posterior wall of fundus
how is the amniotic cavity formed
sep between ICM and trophoblast increasing
what happens at day 12
gastrulation
cells move to primitive streak
what are the three germ layers
endoderm
mesoderm
ectoderm
what does mesoderm form
CVS and renal system, musculoskeletal
ectoderm forms?
nervous system, hair skin and nails
endoderm forms?
respiratory, GI and urinary tracts
what is a yolk sac
first site of blood cell formation
amnion?
surrounds embryo, makes cavity filled w amniotic fluid
chorion
becomes principle part of placenta
what is the allantois
becomes vascular connection between embryo n placenta
what type of SC are embryonic
pluripotent (can give rise to any embryonic cell except placental)
process of placentation
1 blastocyst surrounded by chorionic villi and chorion enlarges
2. 4th week - embryo, amnion and yolk sac suspended in fluid
3 body stalk contains distal portions of allantois and BV that carry blood to n from placenta
what is a yolk stalk
narrow connection between endoderm n yolk sac
decidua capsularis?
thin portion of endo, not used in nutrient exchange or chorionic villi disappears
decidua basalis?
placental functions conc in deeper region
decidua parietalis?
rest of endometrium
development of NS
19-21 days after gastrulation cephalic region= brain caudal regoion = spinal cord neural tube closure - neural plate rolls up to form tube neural plate - groove - fold - tube failure to close = spina bifida
somite development
19-21 days
alongside neural tube in pairs
anterior to posterior
muscle, vertebral and rib bones
ear development
week 4 visible, w5 not visible on surface = forms component of inner ear
from placodes - ectoderm thickening visible on surface
eye development
optic placed - end of w4 visible
forms lens
limb development
external structures vis from w4 buds that go outward forelimb then hindlimb week 7: hands and feet visible week 8: sep of digits by apoptosis
development of heart
from tube
beats on day 22, circ on day 27
first organ to function
lung development
branching morphogenesis
endoderm and mesoderm supply most of alveoli
ectoderm = neural innervation
mesoderm = musculoskeletal support
kidney developemnt
pronephros d18, mesonephros d24, metanephros d35
GI development
week 2-3
foregut: oral cavity, oesophagus, trachea, stomach
midgut: SI, pancreas develops through herniation
hindgut: colon
will enter body wall as they become finely packed
what is the CR length at w11 and at full term
6-8cm
30-40cm
FSH origin, function, regulation
APG
target: testes n ovaries
to promote follicle development n stimulate secretion of oest. stimulates sustentacular cells in M
reg: stopped by inhibin, reg by GnRH
LH
APG, to testes n ovaries
induces ovulation, promotes secretion of prog n oest in F, stimulates prod of sex hormones by interstitial testes cells
prog
ovary/placenta
prepares uterus for preg, maintenance of preg, development of alveolar system in mammary glands
oest
ovary, testes, placenta
tim bone n muscle growth, sex charac. affects CNS (sex drive in HT)
growth n repair of endo
reg: FSH and LH
inhibin
sustentacular cells, follicler cells
targets APG
inhibits FSH
stimulated by FSH from APG
HCG
origin: SCT in CL
maintains integrity of CL n promotes continued secretion of prog
appears in blood after implantation
relaxin
origin: CL and placenta
incr flexibility of PS, pelvis expands during delivery. dilation of cervis, suppresses oxytocin by HT, delays onset of labour contractions
what is the ductus arteriosus
connects right V and aorta
ductus venosus
first point of contact from placenta
blood then goes to RA
foramen ovale
embryo, connects right and left A together
what is folic acid and what is its function
synthetic form of vitamin b9
maintain and produce new cells, prevent DNA damage, reduce spina bifida risk
what should prenatal vitamins include
calcium
iodine
iron
how does a pregnancy (immunoassay) test work?
dip stick in urine in morning
stick has mobile mAB with blue latex particle attached
hcg acts as an antigen and moves up stick
binds to mAB bc complementary
complex binds to immobilised mAB in first window
marker molecule accumulates and forms coloured line to show pregnancy
2nd window: uncombined mAB continue to move up dipstick to 2nd line = bind and show test is working
what are the two types of USS
transvaginal = time of missed period transabdominal = 5 weeks
what do uSS at 12 and 20 weeks check
12 = viable and number of fetuses, date of pregnancy, CVS defects 20 = sex and structural defects
what are the CVS maternal changes during pregnancy
hypertrophy plasma volume increases hypercoagubility vasodilation pre-eclampsia raised cardiac output and rbc volume
what is pre-eclampsia
rapid rise in arterial blood pressure in last few months of pregnancy
proteins in urine
water and salt retention
gfr and renal BF too low
trophoblasts change arterioles of endometrium into larger bv with low resistance = doesn’t happen in PE
resp changes in mother?
relative hyperventilation = po2 and pco2
tidal volume increases = prog relaxed ligaments attaching sternum to ribs
musculoskeletal changes?
sciatica
stretch marks
carpal tunnel syndrome
lordosis
renal changes?
increased BF
increased GFR rate = more urination
bigger kidneys and ureter
GI changes?
prog causes relaxed valves = heartburn
soft ligaments = abdominal pain
other symptoms of pregnancy
sore breast
nausea
constipation
tiredness
what is the process of labour
cervical dilation = 10cm, takes 6-12 hours
positive feedback
uterine contractions stretch cervix = dilates
stretching = reflexive contractions = dilates
dilation = oxytocin = powerful contractions
how is fetus adapted at birth
blood from placenta to DV
moves to RA, through FO to LA
moves from RV to aorta via DA
LV: blood to body and internal iliac artery to UC and placenta
what are changes to infants lungs when it is born
more o2 in lungs = less BF resistance to lungs
fluid drains
lungs inflate and move o2 into blood and co2 out
what is surfactant and what does it do
substance that lines alveoli
prevents collapsing when breathing
what happens if baby has no surfactant
alveoli collapse
more force to breathe
tire out diaphragm
tear lung tissue
how can low surfactant levels be treated
steroid injections
how long do you take combined pill for
21 days, 7 free
what does oestrogen in combined pill do?
inhibits FSH = no follicle development
what does prog in combined and mini pill do?
prevent ovulation, hinder implantation, thicken cervical mucus and inhibits endometrial proliferation
how long do you take mini pill for?
daily
why do some people take mini pill instead?
older, breastfeeding or overweight women
why is age of first pregnancy increasing
high divorce rates
marrying later bc careers
waiting till financially stable
don;t know about fertility ages and rates
how many appointments should you have when pregnanr
10 for nulliparous, 7 for others
what is the criteria for a c-section
baby in breech position low lying placenta pre-eclampsia baby not getting enough nutrients untreated HIV choice = non medical reasons
what is the process of gastrulation
cells move towards the primitive streak on the surface of the epiblast, which is base of amniotic cavity
they slip beneath it
invagination = leads to formation of 3 germ layers
more cells move and migrate, extend beyond margin and come into contact with extra-embryonic mesoderm covering amnion and yolk sac
