Question

1. the model below shows how the human body responds to changes in temperature.

5a. complete the model by filling in the spaces provided.
thermoregulation in the human body
response a
normal body
temperature
response b

Explanation:

• Response A (Heat - related response):
• When the body is overheated (stimulus A: high environmental temperature or physical activity generating excess heat), the brain initiates responses. Capillaries dilate (more heat can be radiated from the blood near the skin surface) and glands release sweat (evaporation of sweat cools the body). The effect of these responses on body temperature is a decrease (to bring it back to normal).
• Response B (Cold - related response):
• When the body is too cold (stimulus B: low environmental temperature), the brain causes capillaries to constrict (reduce heat loss from the blood near the skin) and muscles to shiver (muscle contractions generate heat). The effect of these responses on body temperature is an increase (to return it to normal).

Answer:

• Stimulus A: High environmental temperature (or physical activity causing over - heating).
• Effect on Body Temperature (Response A): Decrease.
• Effect on Body Temperature (Response B): Increase.
• Stimulus B: Low environmental temperature.