Neonates - Physiology Flashcards
Describe the passage of oxygenated blood in a foetus?
Placenta –> Umbilical Vein –> Ductus Venosus (through liver) –> IVC
The foetal lungs aren’t functional, how does a foetus get oxygenated blood from the right heart to the left?
Bypasses the pulm circulation by 2 shunts:
- Foramen Ovale (atria)
- Ductus Arteriosus (PA to Aorta)
Where does a foetal O2 sat sit?
60-70%
Newborns lack shivering thermogenesis, how do they resist cold?
Use of brown fat
Cold Stress –> Lipolysis –> Heat generation
(A sympathetic process)
Physiological jaundice occurs around 2/3 days up to 7-10. What do we do if the bilirubin is high enough to cause problems?
Blue Light Phototherapy
Exchange Transfusion
It’s quite normal for a newborn to lose up to 10% of its weight, why is this?
Fluid moves from interstitium to intravascular and triggers diuresis
why can’t premature babies regulate their fluids properly?
Less Fat
More loss through kidney
More insensible loss (immature skin/lungs)
How does physiological anaemia come about in newborns
Produce much less RBCs after birth –> anaemia in the first few weeks before erthropoieting production steps up
Most common cause of anaemia is iatrogenic blood letting (e.g. taking blood samples from a septic baby)