The circulatory system of whales can also adjust to conserve or dissipate body heat and maintain body temperature. Some arteries of the flippers, flukes, and dorsal fin are surrounded by veins. Thus, some heat from the blood traveling through the arteries is transferred to the venous blood rather than the environment. This countercurrent heat exchange aids whales in conserving body heat. To dissipate heat, circulation increases in veins near the surface of the flippers, flukes, and dorsal fin, and decreases in veins returning the blood to the body core.
Excess heat is shed to the external environment.
Have students write a report comparing and contrasting the circulatory and respiratory systems of human athletes and whales. Explain how the circulatory and respiratory systems of athletes competing in the 1968 Olympic Games in Mexico City were affected and why. Since ancient times, humans have been fascinated with flight. As air moves over the upper surface of the wing it has further to travel, and therefore flows faster than air passing underneath. Because pressure falls as speed rises, air pressure above the wing is reduced and air pressure below is increased.