PHYSIOLOGY OF PREGNANCY Flashcards
(27 cards)
whats the normal pregnancy length?
37-42 weeks
what period of time is trimester 1 ?
1-12 weeks
what period of time is trimester 2?
13-26 weeks
what period of time is trimester 3?
27-40 weeks
what happens to the foetus in trimester 1?
fertilisation, implantation, initial development, placentation
what happens to the foetus in trimester 2?
nervous system and hair form, spine straightens, pain can be felt, proportions change
what happens to the foetus in trimester 3?
rapid growth fat depositions brain growth blood cell formation lung development
what symptoms miht the mother experience in trimester 1?
weight gain and nausea
what happens to the mother during trimester 2?
placental growth uterus rises hypervolemia cardiac remodelling breast remodelling
why do we get hypervolemia during pregnancy?
Elevated levels of estrogen and progesterone increase plasma aldosterone levels and renin activity
these promote sodium retention and an increase in total body water
what symptoms might the mother experience in the 3rd trimester?
Braxton hicks
fatigue
restricted breathing
lactation
what are braxton hicks?
womb contractions in preparation for delivery
what is average foetal heart rate?
between 110 and 160 bpm
what are some signs of pregnancy?
suppression of menses tender and enlarged breasts fatigue urinary frequency nausea and vomiting constipation
what is the amnion?
a metabolically active membrane that is involved in solute and water maintaining amniotic fluid homeostasis
its the innermost layer of the placenta
what is the chorion?
the outermost membrane around the embryo.
what is the yolk sac?
a membranous sac attached to an embryo for nutrient uptake and secretion as well as the origin of the first blood cells
outline the different in affinity in maternal placental and foetal blood?
maternal blood is 50mmHg PO2 and foetal is 30 - allows foetal blood to take oxygen from maternal haemoglobin
what does the placenta allow into the foetus?
respiratory gases
glucose
VLDLs and chylomicrons
FFA, glycerol and cholesterol
what does the placenta allow out from the foetus into mother?
hCG to maintain the corpus luteum
oestrogen
progesterone
somato-mamotropin
outline how oedema can form in pegnancy?
oestrogen increases nitric oxide and decreases endothelin 1 = increased angiogenesis, blood flow and venous distensibility
oestrogens increase formation of angiotensin 2, renal re-absorption and aldosterone
progesterone increases vasodilation and decreases peripheral resistance
progesterone increases aldosterone too
how much can cardiac output increase by during oregnancy?
45%
what changes of the respiratory system do we see during pregnancy?
diaphragm is elevated 4cm, displacing ribcage upwards and compressing the lung volume. sensitivity to chemoreceptors is lowered to result in deeper breathing with increased responsiveness to pCO2. increased tidal volume at the expense of residual volume
what changes do we see in the kidneys during pregnancy?
enlarging of them due to increase in excretion of waste products
ureters are displaced and enlarged too
