Nervous System

Question 1

Receptor function

Answer 1

Detect a stimulus and send electrical impulses down neurones to cns

Question 2

Function of CNS

Answer 2

Coordination system
= sends electrical impulses down other neurones to effectors
= effectors bring about a response

Question 3

Describe an effector

Answer 3

Normally a muscle that contracts or a gland which secretes a hormone

Question 4

Key role of the nervous system

Answer 4

• enables humans to react to their surroundings and co ordinate their behaviour
  = through the reflex arc

Question 5

Describe the reflex arc

Answer 5

• stimulus detected by receptor
• electrical impulses pass from receptor along sensory neurone to CNS
• at end of sensory neurone synapse a chemical is released
  = diffuses across to a relay neurone in the CNS
  = triggers electrical impulse
• impulse passes across relay neurone to reach another synapse (chemical released)
• chemical triggers electrical impulse in a motor neurone
• impulse passes down motor neurone to an effector

Question 6

Types of effectors

Answer 6

Muscle
= contraction
Gland
= secrete hormones/ enzymes

Question 7

Use of receptor on skin

Answer 7

Detect stimuli
Convert information to impulse

Question 8

Difference between reflex response and hormone response

Answer 8

Reflex action is quicker
Reflex involves impulses and hormone involves chemicals
Reflex action only affects one part of the body

Question 9

Describe negative feedback

Answer 9

Body produces opposite of something
Eg if glucose too high feedback acts to decrease it

Question 10

Define homeostasis

Answer 10

Maintaining a stable internal environment

Question 11

Describe neurone

Answer 11

Long, thin, a lot of branch connections
= can pass messages to other nerve cells

Question 12

How does synapse work

Answer 12

When electrical impulse hits end of nerve creates release of chemicals
= diffuse across gap to next nerve cell
= can trigger another electrical impulse
= impulse carried along new neurone

Question 13

Adv of reflex arc

Answer 13

Rapid and automatic

Question 14

How does body react to hot object

Answer 14

• receptor in skin detects stimulus
• neurones conduct electrical impulse signals
• sensory neurone conducts impulses to CNS
• impulses pass from sensory neurone to relay neurone
• synapse between neurones where chemical crosses gap
• chemical stimulates impulse to relay neurone and motor neurone
• synapse in spinal cord causes muscle contraction to pull hand away