Question

model 2 - thermoregulation in humans
hypothalamus senses that temperature is too low. sends out signals to heat the body.
temp too low.
hypothalamus senses that temperature is too high. sends out signals to cool the body.
temp too high.
normal body temperature 36 - 38 °c
blood vessels in skin constrict, reducing heat loss.
muscles begin to shiver, generating heat.
blood vessels in skin dilate to radiate heat.
sweat glands increase sweat production.
body temperature increases.
body temperature decreases.

1. examine model 2. based on what you see in the model, propose a definition for \thermoregulation.\
2. according to model 2, what portion of the brain contains sensors that monitor body temperature?
3. according to model 2:

a. what are two mechanisms the body uses to cool itself?
b. what are two mechanisms the body uses to heat itself?

1. consider the feedback loop that cools the body when it is too warm.

a. identify the \stimulus\ and
esponse\ in the feedback loop.
b. is this feedback loop positive or negative feedback? justify your reasoning.

Explanation:

1. Thermoregulation is the process by which the body maintains its internal temperature within a normal range (36 - 38°C) through various physiological responses. When the hypothalamus senses the body temperature is too low, it signals for responses like blood - vessel constriction and shivering to generate heat. When it senses the temperature is too high, it signals for blood - vessel dilation and increased sweat production to cool the body.
2. The hypothalamus contains sensors that monitor body temperature as indicated in the model.

10a. Two mechanisms the body uses to cool itself are dilation of blood vessels in the skin to radiate heat and increased sweat production by sweat glands.
10b. Two mechanisms the body uses to heat itself are constriction of blood vessels in the skin to reduce heat loss and shivering of muscles to generate heat.
11a. In the feedback loop that cools the body when it is too warm, the stimulus is a body temperature that is too high, and the response is the dilation of blood vessels in the skin and increased sweat production.
11b. This is a negative feedback loop. Negative feedback loops work to counteract changes and return the body to a stable state. Here, when the body temperature is too high (a deviation from the normal range), the body's responses (dilation of blood vessels and sweating) act to lower the temperature back towards the normal range.

Answer:

1. Thermoregulation is the process by which the body maintains its internal temperature within a normal range (36 - 38°C) using physiological responses.
2. Hypothalamus

10a. Dilation of skin blood vessels, increased sweat production
10b. Constriction of skin blood vessels, muscle shivering
11a. Stimulus: High body temperature; Response: Blood - vessel dilation and increased sweating
11b. Negative feedback. It counteracts the high - temperature change to return to normal body temperature.