Question 1

Which of the following best describes homeostasis in the human body?

Accepted Answer

The maintenance of a relatively stable internal environment despite external changes.

Question 2

A patient’s blood glucose level rises after eating a meal. Which hormones are primarily responsible for returning blood glucose to normal, and how do they function?

Accepted Answer

Insulin decreases blood glucose by promoting uptake into cells; glucagon increases blood glucose by stimulating glycogen breakdown.

Question 3

Which of the following is an example of dynamic equilibrium in the body?

Accepted Answer

Blood pH fluctuating slightly around 7.4 due to ongoing metabolic reactions.

Question 4

During exercise, which physiological changes occur to help maintain homeostasis?

Accepted Answer

Increased breathing rate, vasodilation to muscles, and adrenaline release.

Question 5

What is the primary function of negative feedback loops in homeostatic regulation?

Accepted Answer

To counteract changes and return the system to its set point.

Question 6

Which of the following best illustrates a positive feedback mechanism in the human body?

Accepted Answer

Uterine contractions during childbirth increasing in response to pressure on the cervix.

Question 7

A person is exposed to cold weather and begins to shiver. Which homeostatic process is being activated, and what is its purpose?

Accepted Answer

Negative feedback; shivering generates heat to restore body temperature.

Question 8

Which equation best represents the relationship between blood glucose concentration ($[G]$), insulin ($I$), and glucagon ($Gg$) in a simplified homeostatic model?

Accepted Answer

$[G] = [G]_0 - I + Gg$

Question 9

If a person’s body temperature drops below the normal range, which of the following responses is most likely to occur?

Accepted Answer

Vasoconstriction to reduce blood flow to the skin and conserve heat.

Question 10

Which of the following best describes the role of effectors in a feedback loop?

Accepted Answer

They carry out the response to restore homeostasis after receiving signals from the control center.

Question 11

A patient with hypothermia has a body temperature of $34^\circ C$. Which of the following best explains why this is dangerous?

Accepted Answer

Enzyme activity decreases significantly, impairing cellular metabolism.

Question 12

Which of the following scenarios best demonstrates the concept of a cascade effect in homeostasis?

Accepted Answer

A change in the respiratory system triggers changes in the circulatory and nervous systems during exercise.

Question 13

Which of the following is the correct sequence of events in a negative feedback loop?

Accepted Answer

Stimulus → Sensor → Control Center → Effector → Response

Question 14

If blood pH drops below 7.4, which organ system is primarily responsible for correcting this imbalance, and what is its main mechanism?

Accepted Answer

Renal system; excreting hydrogen ions and reabsorbing bicarbonate.

Question 15

Which of the following best explains why homeostasis is described as a dynamic equilibrium?

Accepted Answer

Internal conditions fluctuate within a narrow range due to ongoing regulatory processes.

Question 16

A person is running a marathon on a hot day. Which combination of physiological responses would most effectively help maintain homeostasis?

Accepted Answer

Increased sweating, vasodilation to the skin, and increased breathing rate.

Question 17

Which of the following best describes the function of vasodilation during thermoregulation?

Accepted Answer

It increases blood flow to the skin, allowing heat to be lost to the environment.

Question 18

Which of the following is the initial event (stimulus) that triggers a feedback loop?

Accepted Answer

A change in a physiological variable away from its set point.

Question 19

Which of the following best explains why positive feedback is less common than negative feedback in maintaining homeostasis?

Accepted Answer

Positive feedback amplifies changes, which can lead to instability if not controlled.

Question 20

A person with hyperthermia has a body temperature of $40^\circ C$. Which of the following is a likely consequence if homeostasis is not restored?

Accepted Answer

Enzyme denaturation and impaired cellular function.

Homeostasis and Dynamic Equilibrium in the Human Body

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