EVALUATION 2026 GUARANTEED PASS
ANSWERS GRADED A+
● What gas do we breathe in that diffuses into the blood? Answer:
Oxygen (O2).
● What gas do we exhale that is a metabolic byproduct? Answer: Carbon
dioxide (CO2).
● What are the small sacks of air in the lungs called? Answer: Alveoli.
● How many alveoli are approximately present in healthy lungs?
Answer: About 300 million.
● What is diffusion in the context of pulmonary circulation? Answer:
The passive movement of gases from an area of higher concentration to
an area of lower concentration.
● What does ventilation refer to? Answer: The movement of air into and
out of the lungs.
, ● What is the importance of the total available surface area in the lungs?
Answer: It is crucial for effective gas diffusion; a decrease in surface
area can lead to hypoxia.
● What is diffusion limitation? Answer: When the movement of O2 from
alveoli to pulmonary vasculature is impaired.
● What is the ventilation/perfusion ratio (V/Q)? Answer: A measure of
the efficiency of gas exchange in the lungs.
● What happens to pulmonary blood flow during exercise? Answer:
Cardiac output increases, reducing the time for oxygenation and
potentially causing transient hypoxia.
● What is bronchial circulation? Answer: The part of systemic
circulation that supplies oxygenated blood to the lungs.
● What percentage of the left ventricle's output does bronchial
circulation constitute? Answer: About 2%.
● What are the main components of the pulmonary circulation? Answer:
Arterial circuit, venous circuit, and lymphatics.