Homeostasis

Question 1

Homeostasis

Answer 1

the maintenance of a constant internal environment in the body

Question 2

Factors in controls

Answer 2

• body temperature
• glucose levels in blood
• water levels

Question 3

Why enzymes environment needs to be controlled

Answer 3

enzymes are catalysts that control the speed of reactions
if they get too hot they denature and stop working
if the cells get too cold reactions run too slowly

Question 4

Mechanisms in homeostasis need:

Answer 4

1. receptor cells to detect a stimulus (a change in the environment)
2. a coordination centre (brain/pancreas) to process information received and to determine what action should be taken
3. effectors – glands or muscles that bring about a suitable response to restore levels within set limits

Question 5

Mechanisms to control body temperature

Answer 5

• sweating if the temperature rises

- shivering if the temperature falls

Question 6

Vasodilation

Answer 6

widening of blood vessels that causes more blood to flow in the skin capillaries, so more heat is lost from the body

Question 7

Vasoconstriction

Answer 7

the narrowing of blood vessels that causes less blood to flow in the skin capillaries, so less heat is lost from the body

Question 8

Response to high glucose concentration

Answer 8

pancreas secretes insulin

stimulates the liver to turn glucose into glycogen

Question 9

Response to low glucose concentration

Answer 9

pancreas secretes glucagon

stimulates liver to convert stored glycogen into glucose