PHYSIOLOGY OF PREGNANCY

Question 1

whats the normal pregnancy length?

Answer 1

37-42 weeks

Question 2

what period of time is trimester 1 ?

Answer 2

1-12 weeks

Question 3

what period of time is trimester 2?

Answer 3

13-26 weeks

Question 4

what period of time is trimester 3?

Answer 4

27-40 weeks

Question 5

what happens to the foetus in trimester 1?

Answer 5

fertilisation, implantation, initial development, placentation

Question 6

what happens to the foetus in trimester 2?

Answer 6

nervous system and hair form, spine straightens, pain can be felt, proportions change

Question 7

what happens to the foetus in trimester 3?

Answer 7

rapid growth
fat depositions
brain growth
blood cell formation
lung development

Question 8

what symptoms miht the mother experience in trimester 1?

Answer 8

weight gain and nausea

Question 9

what happens to the mother during trimester 2?

Answer 9

placental growth
uterus rises
hypervolemia
cardiac remodelling
breast remodelling

Question 10

why do we get hypervolemia during pregnancy?

Answer 10

Elevated levels of estrogen and progesterone increase plasma aldosterone levels and renin activity
these promote sodium retention and an increase in total body water

Question 11

what symptoms might the mother experience in the 3rd trimester?

Answer 11

Braxton hicks
fatigue
restricted breathing
lactation

Question 12

what are braxton hicks?

Answer 12

womb contractions in preparation for delivery

Question 13

what is average foetal heart rate?

Answer 13

between 110 and 160 bpm

Question 14

what are some signs of pregnancy?

Answer 14

suppression of menses
tender and enlarged breasts
fatigue
urinary frequency
nausea and vomiting
constipation

Question 15

what is the amnion?

Answer 15

a metabolically active membrane that is involved in solute and water maintaining amniotic fluid homeostasis
its the innermost layer of the placenta

Question 16

what is the chorion?

Answer 16

the outermost membrane around the embryo.

Question 17

what is the yolk sac?

Answer 17

a membranous sac attached to an embryo for nutrient uptake and secretion as well as the origin of the first blood cells

Question 18

outline the different in affinity in maternal placental and foetal blood?

Answer 18

maternal blood is 50mmHg PO2 and foetal is 30 - allows foetal blood to take oxygen from maternal haemoglobin

Question 19

what does the placenta allow into the foetus?

Answer 19

respiratory gases
glucose
VLDLs and chylomicrons
FFA, glycerol and cholesterol

Question 20

what does the placenta allow out from the foetus into mother?

Answer 20

hCG to maintain the corpus luteum
oestrogen
progesterone
somato-mamotropin

Question 21

outline how oedema can form in pegnancy?

Answer 21

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

Question 22

how much can cardiac output increase by during oregnancy?

Answer 22

45%

Question 23

what changes of the respiratory system do we see during pregnancy?

Answer 23

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

Question 24

what changes do we see in the kidneys during pregnancy?

Answer 24

enlarging of them due to increase in excretion of waste products
ureters are displaced and enlarged too

Question 25

what breast changes do we see during pregnancy and why?

Answer 25

growth of breast, nipple and areolar enlargement, breasts feel swollen and tender

progesterone causes growth of alveoli and lobules in the breasts
oestrogen stimulates milk duct development

Question 26

whats the average weight gain in oregnancy?

Answer 26

24 lbs (only around 7 lb being the foetus)

Question 27

what should the additional caloric intake be during pregnancy?

Answer 27

100-300 calories (gain 2-4lb a week for first trimester and then 1lb a week after that)