Coordination & Control

Question 1

What are the nervous system & or oral system involved in?

Answer 1

Carrying messages around the body

Ringing abut a response

Question 2

What is a receptor?

Answer 2

Part of an organism which receives stimuli, e.g. eyes receive light

Question 3

What is a coordinator?

Answer 3

Information is passed to the brain & spinal chord, they coordinate response

Question 4

What is an effector?

Answer 4

Part of an organism which carries out action, usually muscle or gland

Question 5

What is the order of the CNS?

Answer 5

Receptor -> Co-ordinator -> Effector

Eye Brain Muscle

Question 6

What is the difference between voluntary and reflex action?

Answer 6

Voluntary responses are slower than reflex, as we have conscious control over them (walking)

Reflex action doesn’t involve brain, we have no control over them and they’re very fast, e.g. withdrawal of hand from hot object

Question 7

What is the order of the reflex arc?

Answer 7

1. Stimulus (heat)
2. Pain receptor stimulated
3. Signal sent along SENSORY NEURON
4. Signal passed along RELAY NEURON (message sent to brain)
5. Signal sent along MOTOR NEURON
6. Effector muscle contracts and moves hand away from heat (response)

Question 8

What is phototropism?

Answer 8

A growth response to light; it occurs in stems and is due to differential growth of cells caused by uneven distribution of hormone auxine (IAA)

Question 9

Give a summary of auxin

Answer 9

Auxin is a plant hormone, and produced at tip of shoot
Auxin travels down shoot
Light causes auxin to move to shaded side of stem
Auxin causes cells on shaded side to elongate
This results in bending of shoot towards light (positive phototropism)

Question 10

What are hormones?

Answer 10

Chemical messengers produced by special glands.
They’re carried in blood & only affect target organs.
They’re slow acting but bring about permanent changes, e.g. puberty

Question 11

What are the characteristics of a nervous system response?

Answer 11

Electrical impulses travel along Neurons
Only affects one part of body
Fast response

Question 12

How is insulin produced & what is its function?

Answer 12

Produced in pancreas in response to increasing blood sugar levels, acts in heart.
Lowers blood sugar levels by:
Converting glucose into glycogen to be stored
Causing an increase of respiration in cells

Question 13

Describe how insulin effects blood glucose levels

Answer 13

1. Blood glucose level normal
2. Meal rich in carbs
3. Blood level rises
4. Pancreas produces more insulin
5. More: respiration and uptake of glucose by cells. Glucose converted to glycogen
6. Blood glucose level falls
7. Blood glucose level back to normal
   Example of negative feedback

Question 14

Why is negative feedback important?

Answer 14

It controls our blood glucose levels & prevents them from falling too low

Question 15

Describe how insulin reaches the liver & how it causes liver to reduce blood glucose concentration

Answer 15

Goes into bloodstream
Insulin converts glucose into glycogen to be stored in liver
Rate of respiration increases to reduce glucose in blood
More glucose taken up by liver cells

Question 16

What is diabetes?

Answer 16

When the body doesn’t produce enough insulin to keep blood glucose levels at a controlled level.
Blood control mechanism fails

Question 17

What are short & long term effects of diabetes?

Answer 17

Short: 
High blood glucose 
Presence of glucose in urine 
Lethargy 
Thirst 
Long: 
Eye damage 
Kidney failure 
Heart disease 
Stroke

Question 18

Facts of type 1 diabetes?

Answer 18

Occurs in early life
Pancreas stops producing insulin
Medication is taken throughout life

Question 19

Facts of type 2 diabetes?

Answer 19

Occurs later in life progressive disease linked to obesity & lifestyle factors
Pancreas gradually stops producing insulin
Can be controlled by diet, but later may need medication or insulin injections

Question 20

What is a synapse & what happens there?

Answer 20

The point where one Neuron joins another
It’s a small gap, therefore electrical pulse can’t travel across it
So it is changed into a chemical message
Chemical message diffuses across gap, then changes back to electrical impulse