Theory question 102
Transport in Animals(a) (i) Draw and label the mammalian heart. (ii) Explain briefly pulmonary circulation in mammals.
(b) State five processes by which the mammalian body reduces its temperature.
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(a)(i) Drawing of the vertical section of the heart with labels: right and left auricles, right and left ventricles, septum, tricuspid valve, bicuspid valve, semilunar valves, chordae tendineae, anterior and posterior vena cava, pulmonary artery, pulmonary vein, aorta (aortic arch).
(ii) The right ventricle contracts and pumps deoxygenated blood through the pulmonary artery to the lungs; in the lung capillaries carbon dioxide is given out and oxygen taken in; the oxygenated blood returns through the pulmonary veins to the left auricle.
(b) Any five: more sweating (evaporation cools the skin); vasodilation of skin arterioles; relaxation of hair erector muscles so hair lies flat; panting (in dogs); reduced metabolic rate; less muscular activity; seeking shade/cool places; taking cold drinks; licking fur (in some animals).
Pulmonary circulation: right ventricle → lungs → left auricle.