2 - physiology pregnacy

Question 1

what day does blastocyst move & attach?

Answer 1

in first 8 days blastocyst moves from fallopian tubes & transports to uterus, day 8 attaches to lining of uterus

Question 2

what is blastocyst made up of?

Answer 2

inner cells = becomes embryo (making up foetus & amniotic sac)

outer cells = called trophoblast, becomes placenta

Question 3

describe what happens in development of placenta?

Answer 3

• formed from both foetal & maternal tissue
• outer layer develops into multinuclear, syncytiotrophoblast - as digs into endometrium & cell walls disintegrate making mass of tissue with lots of nuclei (syncytiotrophoblast) forms cavities & gets surrounded by mums blood
• embryo sends capillaires in to make placental villi

Question 4

do mum & baby blood mix in utero?

Answer 4

→if normal then no direct contact between mum & baby blood (important - when mixing can cause problems) - until get ot birth when some cross transfusion

Question 5

what function does placenta play for resp function?

Answer 5

• whilst foetus in utero lungs collapsed & filled with fluid so oxygen exchange in placenta, placenta connected to baby by umbilical cord - if this blocked baby gets no oxygen
• foetal haemoglobin attaches more oxygen so in placental villi foetal haemoglobin steals oxygen from mum haemoglobin

Question 6

why does trophoblast produce hCG?

Answer 6

hCG stimulates corpus luteum to keep producing progesterone (which maintains pregnancy by maintaining uterus lining) so until placenta takes over function (5-8 wks) of progesterone, corpus luteum makes it.

Question 7

how should hCG levels change throughout pregnancy?

Answer 7

• hCG should double every 48 hrs in healthy singleton pregnancy, hCG is responsible for symptoms like nausea & vomiting
• get high levels hCG if multiple pregnancies or molar pregnancy (severe hyperemesis)

Question 8

why does placenta make human placental lactogen?

Answer 8

human placental lactogen →made by placenta to increase mum’s insulin resistance so more sugar for baby - baby wants mum to have higher blood sugar levels since baby wants to grow

Question 9

what antibodies can cross placenta to give baby passive immunity?

Answer 9

IgG

Question 10

what is variation in mums BP in pregnancy?

Answer 10

gradually falls & reaches lowest at end of 2nd trimester then gradually increases again to term

Question 11

what is normal blood volume loss at term? what does body do to deal with this?

Answer 11

normal blood volume at term = 100ml/kg

= body increases circulating volume by increasing plasma volume (haemoglobin diluted) - pregnant women get more anaemic & need iron supplement

• also gte hypercoagulable state (to try protect from haemorrhage)

Question 12

what resp changes in mum in pregnancy?

Answer 12

progesterone helps adaptations like resp volume increases tidal volume increases - pCO2 falls since blowing out more CO2 since breathing more - common to see resp alkalosis

Question 13

how do womens reference ranges change in pregnancies?

Answer 13

get low creatinine *since so much blood going through kidney - in general low is in normal in pregnancy (normal/high levels concerning)

Question 14

what hormone changes help cause contractions & labour?

Answer 14

cervical stretching + oxytocin + prostaglandins = uterine contractions (just get vague idea, even they don’t know loads)

Question 15

what hormones impact lactation?

Answer 15

oestrogen = causes growth ductile system

progesterone = develops lobule-alveolar system

→these both inhibit milk production & at birth sudden drop

prolactin = increases milk production, takes a couple days after birth before milk comes in

oxytocin = also plays important role in milk reflex, women breastfeeding & hears baby cry →produce milk