(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.
Explanation
(a)(i) Arteries:
carry blood away from the heart. transport oxygenated blood with the exception of pulmonary artery.
(ii) Capillaries: -
permit exchange of materials between blood and tissues. . links the arteries and veins.
(iii) Veins: -
carry blood to the heart. transport deoxygenated blood except pulmonary vein.
(iv) Xylem: -
transports water/dissolved mineral salts serves as a supporting tissue/strengthening tissue.
oxygen is added to the blood. carbon dioxide is removed from the blood. water is removed from the blood.
(ii) Liver: -
urea is added to the blood. hormonal level is reduced. glucose level reduced. worn out erythrocytes are removed from the blood.
(iii) Kidneys: Water, urea, some glucose; mineral salts are reduced in the blood. (iv) Small Intestine: - simple sugars/glucose, amino acids; water; salts and vitamins are added to the blood. (c) Cellular Components of blood: Red blood cells/erythrocytes; white blood cells/leacocytes; and platelets/ thrombocytes.
