(a(i))[1]
Identify the tissue marked T in Fig. 5.1.
(a(ii))[2]
Describe the role of smooth muscle in the bronchus.
(b(i))[2]
Every lamellar body is enclosed by a single membrane. Draw a diagram to show how phospholipid molecules are arranged in the membrane around the lamellar body.
(b(ii))[2]
Scientists investigating the production and release of lung surfactant have found that lowering cholesterol in the cell surface membrane of type II epithelial cells reduces surfactant secretion. Suggest why a reduction in cholesterol in the cell surface membranes of type II epithelial cells affects surfactant secretion.
(b(iii))[1]
Lung surfactant is engulfed by macrophages that are closely associated with the type II epithelial cells. Suggest why macrophages engulf surfactant.