Practise IB Biology HL 3.1.4 through exact HL questions on pneumocytes, capillary interfaces, surfactant, alveolar stability and emphysema.
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; Reject one-cell membrane/thin membrane. (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;