Week 9 - lecture 2 Flashcards
Explain foetal circulation and how it is achieved
The mother provides O2 and nutrients to the foetus and removes CO2 and waste products, it is achieved via the Placenta
Umbilical vein
Carries O2 and nutrients from the placenta to the foetus
How many umbilical arteries are there?
Two
What does the umbilical artery do?
Transport venous blood from foetus to placenta for re-oxygenation and elimination of wastes
What is different about foetus circulation compared to our circulation?
Feotus only pumps 10-15% of blood through the lungs, the rest is moved from the right to left side of the heart through two shunts.
What are the two shunts called in the foetus heart and where are they?
Foramen Ovale - through septum between right and left atrium
Ductus arteriousus - Small vessel which connects the pulmonary artery to the aorta
Ductus Venosus
Temporary vessel from umbilical vein to inferior vena cava, this bypasses the liver
Circulatory changes after birth (3)
Metabolic link between mother and foetus is severed, Inflation of lungs, closure of foramen ovale which creates fossa ovalis, ductus arteriosus closes and creates ligamentum arteriosum
Growth of heart after birth, which side grows quicker and why?
Left side grows more rapidly as the left has higher pressure or resistance
Heart size at birth
40cm cubed
6 month heart size compared to birth
doubled
2 years heart size compared to birth
4x
When does foetal HR bein
Week 4
HR as newborn, 6 years, 10 years
~140 bpm, ~80 bpm, ~70 bpm
Why do infants and childrean have higher HR’s? (3)
Smaller amount of blood with a large surface area to reach, myocardium produces less forceful contractions as it isn’t fully developed, small SV means HR needs to increase to maintain a normal CO
