(a) List the main constituents of mammalian blood.... | WAEC SSCE - Biology - 2002 (Essay)

Question 1 Report

(a) List the main constituents of mammalian blood.

(b) State two functions of each constituent.

(d) Name the main artery which transports blood to the:
(i) Lung
(ii) Kidney.

Answer

Answer Details

(a) Main constituents of mammalian blood

(b) Two functions of each constituent

Plasma: transports dissolved food (glucose, amino acids), salts, hormones and excretory wastes (urea, carbon dioxide); distributes heat evenly to regulate body temperature.
Red blood cells: carry oxygen from the lungs to the tissues as oxyhaemoglobin; help transport carbon dioxide from tissues to the lungs.
White blood cells: engulf and destroy invading germs by phagocytosis; produce antibodies and antitoxins for defence against disease.
Platelets: initiate blood clotting at wounds; help seal cuts to prevent excessive blood loss and entry of pathogens.

(c) Six differences between arteries and veins

Arteries	Veins
Carry blood away from the heart	Carry blood towards the heart
Have thick, muscular, elastic walls	Have thin, less muscular walls
Narrow lumen (bore)	Wide lumen (bore)
No valves (except at heart base)	Have valves along their length
Carry oxygenated blood (except pulmonary artery)	Carry deoxygenated blood (except pulmonary vein)
Blood flows under high pressure, in spurts	Blood flows under low pressure, evenly
Located deep within the body	Located more superficially

(d) Main artery transporting blood to the

(a) List the main constituents of mammalian blood. (b) State two functions of each constituent. (c) Tabulate six differences between arteries and veins. (d)...