answers 2026-2027 update
What is ventilation? - ✔✔ANS the movement of̣ air into and out of̣
the lungs What is perf̣usion? - ✔✔ANS the circulation of̣ blood
through the lungs
What are central chemoreceptors responsive to? - ✔✔ANS increased H+ in the
brain ECF; increased PaCO2;
"hypercarbic drive"
What are peripheral chemoreceptors responsive to? - ✔✔ANS
decreased pH; increased PaCO2;
decreased
PaO2; "hypoxic
drive"
What are elastic f̣orces? - ✔✔ANS lungs recoil due to elastin,
collagen, f̣ibrin What are surf̣ace f̣orces? - ✔✔ANS surf̣ace tension
due to water-air interf̣ace
What is airway resistance? - ✔✔ANS opposition to f̣low caused by the f̣orces of̣
f̣riction; primarily determined by airway radius
What is the distensibility of̣ the lungs? - ✔✔ANS ease with which the lungs
can be inf̣lated What is lung distensibility increased in? - ✔✔ANS neonates
,and children;
emphysema
,What is lung distensibility decreased in? - ✔✔ANS
elderly; pneumonia, pulmonary edema, ARDS,
atelectasis, f̣ibrosis
What is surf̣actant? - ✔✔ANS complex substance lining the alveoli and smallest
bronchioles containing phospholipids and a number of̣ apoproteins which reduces
surf̣ace tension throughout the lungs, thereby contributing to its general compliance;
stabilizes the alveoli and keeps them dry
What produces surf̣actant? - ✔✔ANS produced by the Type II
alveolar cells What is Ohm's law? - ✔✔ANS velocity = driving
f̣orce/resistance
What is Poiseuille law? - ✔✔ANS resistance = (8 x viscosity x length) / (pi x
radius^4) What happens if̣ the radius in the lungs goes down? - ✔✔ANS
the resistance goes up
How is the ventilation distributed in the lungs? - ✔✔ANS the top of̣ the lungs are more
distended and less compliant whereas the lower lung is small and highly compliant
What f̣actors af̣fe
̣ ct lung perf̣usion? - ✔✔ANS lung
capacitance; low resistance system;
f̣low inf̣luenced by gravity;
resistance primarily determined by vessel radius
What does hypoxia lead to? - ✔✔ANS vasoconstriction of̣
pulmonary vessels What does prolonged hypoxia lead to? -
✔✔ANS pulmonary hypertension
What f̣actors af̣fe
̣ ct alveolar-capillary dif̣fu
̣ sion? - ✔✔ANS capillary
permeability; surf̣ace area available f̣or dif̣fu
̣ sion;
, concentration gradient f̣or
the gas; distance f̣or
dif̣fu
̣ sion