Homeostasis

Question 1

what is homeostasis

Answer 1

The maintenance of the relatively constant internal environment despite external changes.

Question 2

Why is homeostasis important? give example

Answer 2

Any changes can upset the body’s equilibrium
enzymes ae sensitive to changes in pH and temperature, and can denature.
Changes in water potential of blood and tissue fluids can cause cells to take up more water by osmosis.

Question 3

Explain how homeostasis is maintained ( Sensory receptor Cells; Communication System; Effector cells; feedback loop

Answer 3

Sensory receptor cells detect any deviation from a set point
Communication system coordinates information to effectors
effector cells brings necessary change to return system to set point

Question 4

Describe negative feedback diagram

Answer 4

Optimum temperature—— change away from optimum——- receptor cells detect change ——- communication system informs effector ——-effector reacts to reverse change ——- return to optimum conditions

Question 5

Explain positive feedback diagram

Answer 5

Optimum condition——change away from optimum—— receptors detects change —— communication system informs effector ——
Effector reacts to increase change

Question 6

Define positive feedback

Answer 6

A mechanism that increases any change detected by the receptors. Tends to be harmful, does not lead to homeostasis

Question 7

Define negative feedback

Answer 7

A mechanism that brings about a reversal on any change in normal conditions- maintains optimum steady state, therefore essential for homeostasis

Question 8

Suggest how responses to adrenaline (fight or flight) may have evolved

Answer 8

Adrenaline cause fight or flight response
May have evolved because any response that allows the organism to run more quickly or fight more aggressively will help it to survive

Question 9

What’s an ectotherm?

Answer 9

An organism that relies on external sources of heat to regulate its body temperature

Question 10

What’s an endotherm?

Answer 10

An organism that can use internal sources of heat, such as heat generated from metabolism in the liver to maintain its body temperature

Question 11

Advantages and disadvantages of being endothermic?

Answer 11

+
Able to remain active in all seasons
Able to survive in different environments
Because enzymes are always at optimum temperature
So metabolic reactions fast at all external temperatures
-
Require more food for respiration- to release the heat to maintain body temperature above environmental temperature