Homeostasis

Question 1

What is homeostasis?

Answer 1

The ability of an organism to maintain a constant internal environment.

Question 2

Why is homeostasis necessary?

Answer 2

• Allows metabolic reactions to occur
• Allows enzymes to work at their optimum rate
• Involves many organs working together, coordinated by the brain
• Often requires organisms to exchange materials with their environment

Question 3

Give an example of homeostasis related to body temperature.

Answer 3

Maintaining body temperatures close to 37 degrees.

Question 4

What is the pH level that blood and tissue fluid are maintained close to?

Answer 4

7.4

Question 5

What is regulated in blood plasma to stay close to 0.1%?

Answer 5

Blood glucose levels

Question 6

Which organ is involved in temperature control for homeostasis?

Answer 6

The skin

Question 7

What is the difference between endotherms and ectotherms?

Answer 7

• Endotherms: Internal body temperature does not rely on the environment
• Ectotherms: Internal body temperature relies on the outside environment

Question 8

What happens to the body when we are hot?

Answer 8

• Hair lies flat
• Blood vessels dilate (vasodilation)
• We sweat to release heat

Question 9

What happens to the body when we are cold?

Answer 9

• Hairs rise to trap air as insulation (piloerection)
• Blood vessels constrict (vasoconstriction)

Question 10

What role do the kidneys play in homeostasis?

Answer 10

Involved in osmoregulation, regulating concentration of water and salts in the body.

Question 11

What does the respiratory system control?

Answer 11

Oxygen concentration and excretes water and carbon dioxide.

Question 12

What function does the liver serve in homeostasis?

Answer 12

Removes toxins and absorbs glucose.

Question 13

What structures in plants are involved in gas exchange?

Answer 13

• Lenticels
• Stomata

Question 14

What are methods used to improve diffusion and exchange?

Answer 14

• Flat structures (e.g., plant leaves) reducing distance for diffusion
• Respiratory system with a large surface area
• Systems that transport materials to the body surface

Question 15

Why do large organisms need a circulatory system?

Answer 15

To carry materials over long distances.

Question 16

What does homeostasis allow organisms to do?

Answer 16

• Function at their most efficient rate
• Function independently of external environments
• Slight internal changes if necessary