physiology of pregnancy and lactation Flashcards
what happens at 3-5 days after fertilisation
transport of the blastocyst to the uterus
what happens at 5-8 days after fertilisation
blastocyst attaches to the lining of the uterus
what does the blastocyst turn into
-inner cells develop into embryo
-outer cells burrow into uterine wall and become placenta
when is the placenta (and fetal heart) functional?
5th week of pregnancy
what signals the corpus luteum to continue secreting progesterone
hCG
what does the progesterone do in placental development
stimulates decidual cells to concentrate glycogen, proteins and lipids
how does the placenta work as an atriovenous shunt
-extends villi into uterine wall
-which means nutrients and waste materials can be exchanged between the placenta and uterus
-blood vessels from the embryo devleop in the villi
-there is no direct contact between fetal and maternal blood
what facilitates to supply of oxygen to the fetus by the placenta
-fetal Hb
-higher Hb concentration in fetal blood
-Bohr effect (fetal Hb can carry more oxygen in low pCO2 than in high pCO2)
what does hCG do in pregnancy
-prevents inovulation of corpus luteum
-development of sex organs in male fetus
when is HCS (human chorionic somatomammotropin)/human placental lactogen produced
around week 5 of pregnancy
what does human placental lactogen do
- Growth hormone-like effects - protein tissue formation
- Decreases insulin sensitivity in mother - more glucose for the fetus
- Involved in breast development
when do hCG levels drop off
fall from 12-14 weeks
side effects of. hCG
nausea
vomiting
hCG in an ectopic pregnancy
static or slow rising
hCG in a failing pregnancy
falling
hCG in an ongoing viable pregnancy
doubling or >60% rise
what does progesterone do in pregnancy
- Development of decidual cells
- Decreases uterus contractility
- Preparation for lactation
what does estrogen do in pregnancy
- Enlargement of uterus
- Breast development
- Relaxation of ligaments
cardiovascular changes in pregnancy
-increase in cardiac output
-functional murmurs
-heart sounds
-HR increases
-BP drops during second trimester
ECG changes in pregnancy
-relative sinus tachycardia
-slight left axis deviation
-inverted or flattened T waves
-Q-wave
-atrial and ventricular ectopic beats more common
haematological changes in pregnancy
- Plasma volume increases proportionally with cardiac output
- Erythropoesis increases, thus Hb is decreased by dilution (decreases blood viscosity)
- Iron requirements increase significantly - iron supplements needed
what do lung function changes happen due to
partly due to progesterone increases and partly because of the enlarging uterus interfering with lung function
what are the respiratory changes during pregnancy
-lower CO2 levels
-O2 consumption increases
-respiratory rate increases
urinary system changes in pregnancy
-GFR and renal plasma flow increases
-increased reabsorption of ions and water
-slight increase in urine formation
