Topic. 10 Homeostasis

Question 1

What is homeostasis?

Answer 1

Maintenance of constant internal environment

Question 2

Why is homeostasis important?

Answer 2

Cells -> only function if in tissue fluid w/:
1. Optimum ph (enzymes!!)
2. Temp
3. Conc of solutes

Question 3

What are endocrine glands?

Answer 3

Secrete hormones directly into blood

Question 4

What is controlled by homeostasis?

Answer 4

Body water content
Body temp

Question 5

What are hormones?

Answer 5

Chemical messengers used in body by endocrine system
Produced by glands

Question 6

What produces insulin?

Answer 6

Pancreas

Question 7

What happens when hormones are transported in the blood?

Answer 7

To specific target organs
Target organs have receptors complementary to the hormone
Organ responds and recognises

Question 8

What does insulin do?

Answer 8

Negative feedback loop (change in body detected and bring about events that return conditions to normal)
Pancreas detects change in blood glucose levels
Insulin released
Glucose converted to glycogen -> stored in liver and muscles
Can also reduce quantity released if blood glucose too low

Question 9

What does adrenaline do?

Answer 9

Prepare body for physical activity

Question 10

What is vasodilation?

Answer 10

Cooling mechanism

1. Hypothalamus detects high body temp
2. Arteries near skin surface dilate
3. Heat lost through skin by radiation

Question 11

What is vasoconstriction?

Answer 11

1. Hypothalamus detects low body temp
2. Arteries constrict
3. Reduction of blood flow to skin -> less heat loss

Question 12

What about sweating?

Answer 12

1. Hypothalamus detects high temp
2. Sweat secreted by sweat glands
3. Water in it is heated by body and evaporates of skin
4. Creates cooling effect