Use alveolar diagrams to identify gas-exchange cells, map capillary functions and explain how surfactant prevents collapse in IB Biology HL B3.1.4.
A supply of oxygen is needed for aerobic respiration in mitochondria. Describe the features of alveoli in human lungs that adapt them for efficient absorption of oxygen.
large surface area from having many alveoli;
single/flattened layer of (thin) cells in wall;
(surrounded by) dense network of capillaries/capillary bed;
short distance for gases/oxygen/carbon dioxide to diffuse;
moist lining / film of moisture on inside of alveolus;
moisture allows oxygen/gases to dissolve;
diffusion of oxygen down concentration gradient;