Lung Embryology Flashcards
Where do the lungs start to develop from?
The foregut
What are the 3 phases of lung development?
- Pseudoglandular phase
- Canalicular phase
- Alveolar phase
What does the systemic circulation do?
Delivering oxygen to hypoxic tissues
What does the pulmonary circulation do?
Picking up oxygen from oxygenated lungs
In the systemic circulation, what does oxygen act as?
A vasoconstrictor
In the pulmonary circulation, what does oxygen act as?
A vasodilator
Why is oxygen a vasoconstrictor in the systemic circulation?
As more blood is supplied to areas of less oxygen and therefore more oxygen, and the vessels constrict
Why is oxygen a vasodilator in the pulmonary circulation?
Less blood flows to areas of the lungs that are poorly contributing to gas exchange and therefore less oxygen, and the vessels constrict
In a foetus, where is most of the oxygen coming from?
The placenta
Why does blood flow to the placenta for oxygen and not the lungs?
As the placenta has a lower resistance so blood flows here to collect oxygen
What does the placenta contain?
- 1 umbilical vein
- 2 umbilical arteries
- 3 fetal shunts
What are the names of the fetal shunts?
- Foramen ovale
- Ductus arteriosus
- Ductus venous
What does the ductus venous do?
Passes fetal blood from the placenta, past the liver to the inferior vena cava to be pumped around the body
What does the foramen ovale do?
Shunts blood between the right and left atria as it does not need to be pumped to the lungs as it is already oxygenated
What does the ductus arteriosus do?
Shunts blood from the pulmonary artery to the descending aorta as there is a high resistance of blood going to the lungs as no need
