How do we breath?

Question 1

Describe foetal circulation

Answer 1

Forman ovule and ductus arteriosus prevent most of the blood from going to the lungs during foetal circulation

Question 2

Changes at birth to breathing

Answer 2

First breath lungs fill with air
Increase in 02 in lungs 
Decrease in pulmonary vascular resistance 
Increase blood flow to lungs 
Increase blood return to LA
Pressure in LA
Foramen ovale closes
Increase blood flow to lungs 
Umicilical cord clamped 
increase systemic venous return 
Increase blood flow to lungs

Question 3

Why does ductus arteriosus close?

Answer 3

due to increase blood supply diverted through pulmonary artery to lung and rising 02 tension

Question 4

Describe normal circulation

Answer 4

RA-RV-pulmonary artery-left+right pulmonary artery-lungs (picks up oxygen)
Oxygen returns through pulmonary vein in blood-LA-LV-aorta (to body)