B13.3

Question 1

What is Homeostasis?

Answer 1

The maintenance of a constant internal environment

Question 2

Why is homeostasis important?

Answer 2

It keeps conditions (temp, bgc, bwc) at optimum levels so that enzymes and cells function properly

Question 3

3 examples of homeostasis

Answer 3

1. Temperature
2. Blood glucose concentration
3. blood water concentration

Question 4

Explain Temperature- Homeostasis

Answer 4

Body temperature must stay at 37C for optimum enzyme activity

Question 5

Explain Blood glucose conc- Homeostasis

Answer 5

keeping the blood glucose concentration isotonic to the blood cells (prevents bursting)

Question 6

Explain blood water conc- Homeostasis

Answer 6

keeping the blood plasma isotonic to the blood cells

Question 7

What is negative feedback?

Answer 7

a mechanism that detects a move away from the set point, and brings about actions that takes the value back towards the set point.

Question 8

Cycle of negative feedback [4]

Answer 8

1. deviates from the norm
2. detected by receptors
3. effectors stimulated and initiate corrective mechanism
4. restoration of the norm or the set-point

Question 9

Where does blood glucose come from?

Answer 9

Carbohydrates

Question 10

Why must the blood glucose levels be kept at a constant?

Answer 10

to prevent red blood cells from bursting or shriveling

Question 11

When is the hormone insulin released?

Answer 11

When blood glucose concentration is high

Question 12

What does insulin do?

Answer 12

Increases glucose uptake + Sends glucose to the liver (stores it as glycogen)

Question 13

Where is insulin released from?

Answer 13

Pancreas

Question 14

Why might the blood glucose level drop too low?

Answer 14

Not eating enough and exercising too much

Question 15

What happens if the blood glucose levels drop too low?

Answer 15

Pancreas secretes glucagon

Question 16

What does glucagon do?

Answer 16

Enables break down of glycogen by liver enzymes
- converted back to glucose

Question 17

What effects does glucagon have on blood glucose levels

Answer 17

Raises/increases the level of blood glucose

Question 18

The blood glucose level will keep on rising after pancreas secretes glucagon until…

Answer 18

Insulin is released

Question 19

Functions of hair erector muscles

Answer 19

Contract to make hairs stand up (goosebumps) trapping more air for insulation

Question 20

Define thermoregulation

Answer 20

The control of the body’s temperature at 37 C because it is optimum temperature for enzyme activity.

Question 21

How does insulation work + what does it do [3]

Answer 21

1. Fat cells- adipose tissue- traps heat
2. Hairs trap a layer of heat
3. increases temperature

Question 22

How does sweating work + what does it do? [3]

Answer 22

1. Sweat glandsreleases sweat onto the surface of the skin
2. it evaporates causing cooling effect
3. decreases temperature

Question 23

How does shivering work + what does it do [2]

Answer 23

1. involuntary contractin of skeletal muscles to generate heat
2. it increases temperature

Question 24

Role of the brain during thermoregulation

Answer 24

1. recieves information from receptors
2. sends message to effectors

Question 25

What are arterioles

Answer 25

small branches of arteries

Question 26

What are arterioles' role

Answer 26

Control the blood flow to the skin

Question 27

Explain Vasodilation + how it looks [3]

Answer 27

1. Arterioles widen to allow more blood flow to the capillaries 2. More heat is lost through radiation from the skin's surface 3. Cooling effect + looks red on the skin

Question 28

Explain Vasoconstriction + how it looks [3]

Answer 28

1. Arterioles narrow so that blood flow to the skin capillaries is decreased 2. less heat is lost by radiation from the skin 3. warming effect + looks pale on skin