Name three structures that enable the body temperature to be regulated. (3)
Sweat glands, hair, erector muscles, blood vessels to skin. (Any 3)
Narrowing of blood vessels in cold weather. (1)
Vasoconstriction
State the function of the sabaceous gland. (2)
Nourishes the hair by secreting oil and keeps hair and skin supple and waterproof.
Describe how the human skin maintains the core body temperature on a day when the environmental temperature is around 40°C. (5)
Heat receptors in the skin are stimulated by high temperature.
Impulses sent to hypothalamus and blood vessels.
Vasodilation occurs, arterioles to the skin become wider, more blood flows to the capillaries.
More heat reaches the skin surface and is lost to the surroundings.
More blood flows to the sweat glands and sweating increases.
More heat is lost through evaporation of sweat.
Which graphs, A or B represents a homeothermic animal? (2)
A
Explain why the temperature of animal B as shown on the graph is not constant. (2)
Animal B is an exothermic animal where their body temperature fluctuates with that of their environment.
Explain why the temperature of animal B reaches its maximum at the time shown. (2)
Mid-day is the hottest time of the day.
What is the approximate body temperature of animal B at 9:00? (2)
16°C
Give an example of an animal represented by B.
Lizard
