lung development Flashcards
birth: explain the cardiorespiratory changes that occur at birth
1
Q
describe lung at birth
A
small volume, related to body weight; all airways present and differentiated; blood gas barrier; only 33-50% alveoli to allow normal gas exchange; most arteries and veins present
2
Q
mechanisms to increase flow after birth
A
big cry/inhalation to fill lungs with air, allowing expansion of alveoli to dilate arteries, increasing blood flow; expansion stimulates vasodilator agents (NO, PGI2); inhibition of vasoconstrictors to prevent pulmonary hypertension; direct effect of O2 on smooth muscle cells
