Which of the following statements is not true when a human is subjected to cold temperatures?
Answer
a.blood vessels dialate to help dissipate heat
b.shivering causes the muscles to generate more heat
c.blood vessels in the extremities constrict to reduce the loss of heat
d.reactions in the body slow down
a is not true.
To determine which statement is not true, let's analyze each option:
a. Blood vessels dilate to help dissipate heat: This statement is true. When a human is subjected to cold temperatures, blood vessels in the skin and superficial tissues dilate to bring warm blood closer to the skin's surface, allowing heat to escape and cool down the body.
b. Shivering causes the muscles to generate more heat: This statement is true. Shivering is a reflex action where muscles contract and relax rapidly, generating heat through muscle activity. This helps to increase the body's core temperature in response to cold.
c. Blood vessels in the extremities constrict to reduce the loss of heat: This statement is true. When exposed to cold temperatures, the body's blood vessels in the extremities, such as hands and feet, constrict or narrow. This constriction reduces the blood flow to the extremities, minimizing heat loss and redirecting warm blood to vital organs in the core.
d. Reactions in the body slow down: This statement is generally true. When exposed to cold temperatures, the body's metabolic rate decreases, which can lead to slower reactions and decreased energy expenditure. However, this does not mean all reactions completely stop, as essential processes like maintaining core body temperature and organ function continue.
After analyzing the statements, we can conclude that option a is not true when a human is subjected to cold temperatures. The correct answer is:
a. Blood vessels dilate to help dissipate heat.