Nervous System

Question 1

What are changes in the environment called

Answer 1

• Stimuli

Question 2

What does the central nervous system consist of?

Answer 2

• The central nervous system consists of the brain and spinal cord

Question 3

What is the purpose of Reflexes and Fast involuntary Actions?

Answer 3

• To protect the body from danger

Question 4

What is a receptor with examples?

Answer 4

• A group of specialised cells that detect change in the environment

e.g finger tip

Question 5

What is an effector with examples?

Answer 5

• Part of the body that will produce the Response

e.g Muscle

Question 6

Reflex Arc (6 marks)

Answer 6

• a stimulus is present
• a receptor detects the change
• a sensory neurone passes electrical nerve impulses from the receptor towards the relay neurone in the
  spinal cord
• Chemical neurotransmitters are released and diffuse across the synapses between the sensory and relay
  neurone
• The electrical impulse travels through the relay neurone towards the motor neurone
• Chemical neurotransmitters are released and diffuse across the synapses between the relay and motor
  neurone
• The electrical impulse travels through the motor neurone, towards the effector
• The effector carries out a response, e.g. a muscle contracts to pull your hand away

Question 7

What is a synapse?

Answer 7

• A junction between neurones or neurone and effector

Question 8

What are Axons covered in?

Answer 8

• Myelin sheaths - increase speed of impulses

Question 9

what does the Motor neuron connect

Answer 9

• the relay neuron within the CNS and the effector

Question 10

Compare the Structure of a Sensory and Motor neuron

Answer 10

-Sensory neurons have cell bodies in the middle of the neuron, whereas motor neurons have their cell bodies at one end, often within the central nervous system.

Question 11

function?

Sensory neuron

Answer 11

• Neuron carries the electrical impulses to the relay neuron within the CNS

Question 12

Relay Neuron

Answer 12

• neuron found within the CNS inbetween the sensory and motor neuron

Question 13

Why are reflex arcs important?

Answer 13

• Involuntary response = leavens brain free to carry out complex responses.
• Protect body from harmful stimuli
• Fast

Question 14

Synapse Movement

Answer 14

• A Neurotransmitter from the end of the axon is released and diffuses across the synapse to attatch onto the post synaptic membrane