Question 1

Which of the following best describes a negative feedback loop in physiological regulation?

Accepted Answer

A change in a variable causes an effect that counteracts the change.

Question 2

In the diagram of a negative feedback loop, what role does 'D' play when it accumulates?

Accepted Answer

It blocks a step, inhibiting Process 1 and stabilizing the system.

Question 3

Which scenario is an example of a positive feedback loop?

Accepted Answer

A person feels frustrated after a low score and studies less, resulting in an even lower score.

Question 4

Which of the following is NOT a feedback loop?

Accepted Answer

A person gets a low score, studies the same way, and scores higher because the material is easier.

Question 5

Which of the following variables is homeostatically regulated in humans?

Accepted Answer

Body temperature

Question 6

Which component is missing from the homeostatic regulation of heart rate, making it not truly homeostatic?

Accepted Answer

Sensor

Question 7

Which of the following is a correct sequence for a homeostatic circuit?

Accepted Answer

Regulated Variable → Sensor → Control Center → Effector → Response

Question 8

If a mammal is exposed to cold temperatures, which physiological responses will occur to maintain core body temperature?

Accepted Answer

Muscles shivering, blood vessels constricting (vasoconstriction)

Question 9

Which equation best represents the surface area to volume ratio for a cube?

Accepted Answer

$$SA/V = \frac{6l^2$}{l^3$}$$

Question 10

Why do penguins huddle together in cold environments?

Accepted Answer

To decrease their surface area to volume ratio and retain heat.

Question 11

Which animal has a higher surface area to volume ratio, and what is the consequence?

Accepted Answer

Mouse; it loses heat easily and needs to generate more heat.

Question 12

A desert animal with large ears is most likely adapted to:

Accepted Answer

Lose heat by increasing surface area to volume ratio.

Question 13

Which of the following is an example of endothermy?

Accepted Answer

A human maintaining a constant body temperature regardless of environment.

Question 14

During a fever, the set point for body temperature is raised. If the current body temperature is below the new set point, what response will occur?

Accepted Answer

Muscles shivering, blood vessels constricting (vasoconstriction)

Question 15

Is fever an example of a positive or negative feedback loop?

Accepted Answer

Negative, because the temperature will go back down once you are well.

Question 16

Which of the following statements about feedback loops is correct?

Accepted Answer

Positive feedback loops amplify changes, while negative feedback loops stabilize variables.

Question 17

Which of the following is a homeostatically regulated variable in the human body?

Accepted Answer

Blood glucose

Question 18

If the surface area to volume ratio decreases, what happens to heat loss in an organism?

Accepted Answer

Heat loss decreases.

Question 19

Which formula best describes the relationship between metabolic power and body mass according to Brody's curve?

Accepted Answer

$$Power \propto $$Mass^{0.734}$$

Question 20

Which of the following is a mechanism used by mammals to cool their bodies?

Accepted Answer

Sweating and vasodilation

Feedback Loops and Homeostasis in Multicellular Organisms

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