True or False: As ATP is used in the myofilaments, mitochondrion, and cytoplasm of muscle cells, heat is released. The circulatory system takes heat to the skin’s surface to dissipate to the environment. People sweat to help cool down.

- As ATP is used in the myofilaments, mitochondrion, and cytoplasm of muscle cells, heat is released. True

- The circulatory system takes heat to the skin’s surface to dissipate to the environment. True

- People sweat to help cool down. True

Explanation:

Muscle contraction occurs when myosin heads bind to actin to pull it inwards. The energy for muscle contraction is provided by the hydrolysis of ATP molecules. ATP hydrolysis also provides energy for cellular processes in the mitochondria and cytoplasm of muscle cells. During ATP hydrolysis, heat is released, thereby the increase in ATP hydrolysis increases heat production (approx. 60% of the energy released from ATP hydrolysis produces metabolic heat). Moreover, on hot days, the cardiovascular system composed of the heart and blood vessels dissipates heat through the blood flowing in veins and arteries, which moves closer to the skin surface (and therefore heat is lost). Finally, sweating refers to the process of exocrine secretion of the sweat glands that release salty water through the pores of the skin. As sweat evaporates, it helps to cool down the body and regulate its temperature.