Homeostasis

Question 1

Definition of homeostasis?

Answer 1

Question 2

Explain the advantage of having separate negative feedback mechanisms to control deviations away from normal?

Answer 2

It gives a greater degree of homeostatic control

Question 3

What happens when body temperature is too low? (3)

Answer 3

• Less kinetic energy
• Less successful collisions
• less ESC

Question 4

What happens when body temperature is too high?

Answer 4

-Enzymes denatured

Question 5

What are endotherms?
How do they maintain body temperature?

Answer 5

• Mammals, birds
• By both physiological + behavioural means

Question 6

What are ectotherms?
How do they maintain body temperature?

Answer 6

All other animals (not mammals, birds)
- By behavioural means

Question 7

What is the range of blood glucose concentration in cells?

Answer 7

Question 8

Where is glucagon secreted?

Answer 8

Alpha Cells

Question 9

Where is insulin secreted?

Answer 9

Beta Cells

Question 10

Answer 10

Question 11

Answer 11

Question 12

Answer 12

Question 13

How does insulin reduce blood glucose concentrations? (3)

Answer 13

• Insulin binds to complimentary receptors on cell surface membrane of target cells
• Sends chemical signal so vesicle moves to membrane + incorporates more glucose carriers into membrane
• Activates enzymes that stimulates glycogenesis

Question 14

How does glucagon increase blood glucose concentration? (3)

Answer 14

Question 15

What does the second messenger model of hormone action do?

Answer 15

Increases blood glucose levels by adrenaline

Question 16

How does the second messenger model of hormone action work? (4)

Answer 16

Question 17

Answer 17

Question 18

Answer 18

Question 19

Answer 19

Question 20

Difference between type 1 + type 2 diabetes?

Answer 20

Type 1 - Severe insulin deficiency due to autoimmune killing of β cells

Type 2 - Insulin is produced but receptors in target cells are unresponsive

Question 21

Answer 21

Question 22

Answer 22

Question 23

Answer 23

Question 24

Answer 24

Question 25

Answer 25

Question 26

Answer 26

Question 27

Answer 27

Question 28

ADD QUESTION WHEN DONE QP AFTER Q12

Question 29

Explain how ADH causes movement of water from lumen to the collecting duct? (5)

Answer 29

- ADH causes vesicles containing aquaporins to fuse into membrane - Water enters cell through aquaporins - By osmosis - To capillary - Via interstitial fluid

Question 30

How does osmoregulation occur? (2)

Answer 30

- Cells in hypothalamus detect fall in water potential - ADH secreted into capillaries by pituitary gland

Question 31

How does reabsorption of glucose + water occur in the proximal convoluted tubule? (6)

Answer 31

Question 32

How is Na+ gradient maintained in the medulla by the loop of Henle? (6)

Answer 32