5.1.1 communication and homeostasis

Question 1

What is homeostasis?

Answer 1

The dynamic equilibrium in which the body maintains to respond to any changes in the body.

Question 2

What is negative feedback?

Answer 2

Negative feedback counteracts any change in internal conditions. This means that all changes are reversed to restore the optimum conditions.

Question 3

What is positive feedback?

Answer 3

Positive feedback reinforce the internal change and increases the response.

Question 4

What are Endotherms?

Answer 4

Organisms which rely on their metabolic processes to maintain a stable body temperature (can control their own body temperature).

Question 5

What are Ectotherms?

Answer 5

Organisms which use their surroundings to warm their body (not able to control body temperature).

Question 6

What are the behavioural mechanisms ectotherms use?

Answer 6

-expose body to sun.
-orientate body to sun.
-orientate body away from sun.
-hide in burrows.
-alter body shape.
-increase breathing movements.

Question 7

What are the physiological mechanisms ectotherms use?

Answer 7

-dark colours absorb more radiation than light colours.
-alter heart rate to increase or decrease metabolic rate.

Question 8

What advantages do ectotherms have?

Answer 8

-use less food in respiration.
-need to find less food.
-can survive longer periods without food.
-greater proportion of energy used for growth.

Question 9

What disadvantages do ectotherms have?

Answer 9

-less active in cooler temperatures-more at risk of predation.
-may not be capable of activity in winter months.
-metabolic reactions are slower.

Question 10

What advantages do endotherms have?

Answer 10

-constant body temperature, regardless of external.
-activity possible even when cool-less risk of predation.
-can inhabit cooler parts of the planet.

Question 11

What disadvantages do endotherms have?

Answer 11

-significant amount of energy used to maintain constant temperature.
-more food required.
-less energy used in growth.

Question 12

What ways do endotherms cool down?

Answer 12

Vasodilation
Increased sweating
Reducing the insulating effect of hairs of feathers.

Question 13

What is vasodilation?

Answer 13

Vasodilation is when the arterioles near the surface of the skin dilate when temperature rises.

Question 14

What ways do endotherms warm up?

Answer 14

vasoconstriction
decreased sweating
raising the body hair or feathers
shivering.

Question 15

What is Vasoconstriction?

Answer 15

Vasoconstriction is when the arterioles near the skins surface constrict.

Question 16

What are the two thermoregulation control centres?

Answer 16

The heat loss centre= increase in blood temperature through hypothalamus.
The heat gain centre= decrease in blood temperature through hypothalamus.