Theory question 101
Transport in Animals(a) State one function of each of the following structures: (i) Arteries; (ii) Capillaries; (iii) Veins; (iv) Xylem; (v) Phloem
(b) Describe the changes that take place in the composition of human blood as it passes through the:
(i) Lungs; (ii) Liver; (iii) Kidneys; (iv) Small intestine. (c) List the cellular components of blood.
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(a)(i) Arteries carry blood away from the heart (oxygenated, except the pulmonary artery).
(ii) Capillaries allow exchange of materials between blood and tissues; link arteries and veins.
(iii) Veins carry blood back to the heart (deoxygenated, except the pulmonary vein).
(iv) Xylem carries water and mineral salts from roots upwards; gives support.
(v) Phloem carries manufactured food (sugars) from leaves to other parts.
(b)(i) Lungs: oxygen added; carbon(IV) oxide and some water removed.
(ii) Liver: excess glucose removed (stored as glycogen) or added when low; amino acids removed and urea added; worn-out red cells and toxins removed; plasma proteins added.
(iii) Kidneys: urea, excess water and salts removed; blood leaving is purer.
(iv) Small intestine: digested food added – glucose, amino acids, vitamins, minerals and water (fats into lacteals); oxygen used up.
(c) Red blood cells (erythrocytes); white blood cells (leucocytes); platelets (thrombocytes).
One function per vessel/tissue in (a).