Adaptations at Birth Flashcards
what are the functions of the placenta (6)
foetal homeostasis, gas exchange, nutrient and waste transport, IgG transport, acid-base balance, hormone production (oestradiol)
the foetal heart pumps deoxygenated blood to placenta via ___ ____
umbilical arteries
placenta returns oxygenated blood to the foetus via ____ ___
umbilical veins
what is the purpose of the ductus venosus
shunts blood from umbilical vein to IVC (blood goes straight to heart)
what is the purpose of the foramen ovale
shunt between RA to LA - allows oxygenated blood to left side of heart around the body and bypass the lungs
what is the purpose of the ductus arteriosus
branch off of pulmonary trunk straight to descending aorta, blood bypasses the lungs to the body as lungs are non-functioning yet
what changes happens to hormones and lungs in labour (3)
increased catecholamines (adrenaline) and cortisol, synthesis of lung fluid stops, vaginal delivery squeezes lungs
what is visibly expected in a baby in the first few seconds if life (4)
blue –> pink, starts to breath, cries, cut cord
what is the apgar score
a measure of how well the perinatal adaption is going measured at 1, 5 and 10 mins
what components of the apgar score are there and what is normal
10 points maximum out of 5 categories, give 0 ,1 or 2 points for: HR, RR, colour, responsive and tone. normal is 8
what can lead to low apgar scores
difficult birth, C section, fluid in lungs
what circulatory changes happen at birth (6)
pulmonary vascular resistance drops, systemic resistance rises, oxygen tension rises, circulating prostaglandins drop, ductus arteriosus and venosus constrict, foramen ovale closes
what happens in persistent pulmonary hypertension of the new born (PPHN)
pulmonary resistance remains high, ductus arteriosus does not shut and blood continues to bypass the lungs (no oxygenation)
what are symptoms of PPHN
breathing problems eg grunt, hypoxia (blue), cold extremities, low systemic BP, low o2 sats
how do you manage PPHN
ventilate and NO
what is the main source of thermoregulation in babies and when does it kick in
non-shivering thermogenesis: breakdown of stored brown adipose tissue in response to catecholamines - not effective in first 12 hours
what babies are at risk of hypothermia and why
preterm/ small babies: low stores of brown and subcut fat, large SA: volume
how are babies kept warm in first few hours
keep dry, hat, skin to skin, blankets, incubator/ heated mattress
what happens in regards to glucose homeostasis in first few hours of life (3)
drop in insulin and rise in glycogen, hepatic glycogen stores for glucose, ketones for brain
wha reflex should be present at birth for breast feeding
rooting and sucking
what happens to a babies oxygen curve at birth and why
shifts to the right as increased 2-3 BPG and feotal Hb becomes less useful
where does haemotopoesis move to in a new born and what physiological blood abnormality doe they have
bone marrow - aneamia
what causes physiological jaundice in a new born
liver enzyme pathway immature, rise in unconjugated bilirubin, breakdown of foetal Hb
when does physiological newborn jaundice become pathological
when it is early or prolonged
