Answer:
(a) The atrioventricular valves are located between the atria and ventricles of the heart, and the semilunar valves are located between the ventricles and the great arteries leaving the heart, specifically the pulmonary artery and aorta.
(b) The atrioventricular valves prevent the backflow of blood from the ventricles into the atria during ventricular contraction, while the semilunar valves prevent the backflow of blood from the great arteries into the ventricles during ventricular relaxation.
(c) The valves are important for survival because they ensure the unidirectional flow of blood through the heart and prevent the mixing of oxygenated and deoxygenated blood. Without functioning valves, blood would not be able to efficiently circulate through the body, leading to decreased oxygen supply to the tissues and potentially life-threatening conditions such as heart failure.
(d) The atrioventricular valves are made up of two flaps or cusps, the mitral valve on the left side and the tricuspid valve on the right side. The semilunar valves, on the other hand, consist of three half-moon-shaped cusps that open and close in response to changes in pressure within the ventricles and arteries. The structural differences reflect the differences in the function of these valves and the mechanical forces they need to withstand to prevent backflow of blood.
Step-by-step explanation:
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