Homeostasis

Question 1

What type of feedback mechanisms are most homeostatic control mechanisms?

Answer 1

Negative feedback mechanisms

Negative feedback mechanisms shut off the original effect of the stimulus or reduce its intensity.

Question 2

What is the purpose of negative feedback mechanisms in homeostasis?

Answer 2

To change the variable in a direction opposite to that of the initial change, returning it to its ‘ideal’ value

This is essential for maintaining stability in the internal environment.

Question 3

What role does the nervous system play in maintaining homeostasis?

Answer 3

Regulation of body temperature and the withdrawal reflex

The withdrawal reflex is a neural control mechanism that causes the hand to jerk away from a painful stimulus.

Question 4

What is an example of a hormonal negative feedback mechanism?

Answer 4

Control of blood sugar by insulin

As blood sugar rises, insulin is secreted to help cells absorb glucose.

Question 5

What happens when blood sugar rises?

Answer 5

Receptors sense the change and the pancreas secretes insulin

Insulin helps body cells absorb more glucose, reducing blood sugar levels.

Question 6

What is the primary goal of all negative feedback mechanisms?

Answer 6

Preventing severe changes within the body

This is crucial for maintaining homeostasis.

Question 7

List some variables regulated by negative feedback mechanisms.

Answer 7

• Body temperature
• Blood sugar
• Heart rate
• Blood pressure
• Rate and depth of breathing
• Blood levels of oxygen, carbon dioxide, and minerals

Regulation of these variables is essential for the body’s internal stability.