C - The Nervous System

Question 1

Sense organs detect _______

Answer 1

Stimuli

Question 2

What is a stimulus? E.g.?

Answer 2

A change in your environment - which you may need to react to e.g a grizzly bear

Question 3

What are the 5 different sense organs?

Answer 3

Eyes
Ears
Nose
Tongue 
Skin

Question 4

Sense organs have ______ inside them

Answer 4

Receptors

Question 5

What are receptors?

Answer 5

GROUPS OF CELLS which are sensitive to a stimulus. They change stimulus energy into ELECTRICAL IMPULSES.

Question 6

A stimulus can be lots of different things such as … name a few

Answer 6

Light, sound, touch, pressure, chemical, a change in position or temperature

Question 7

List at least one receptor for each of the following sense organs:

Eyes 
Ears
Nose
Tongue
Skin

Answer 7

Eyes - light receptors 
Ears - sound and balance receptors
Nose - smell and chemical receptors 
Tongue - taste and chemical receptors 
Skin - sensitive to touch, pressure and temperature change

Question 8

DO NOT get sense organs and receptors mixed up… what’s the difference? E.g.?

Answer 8

The sense organs have receptors inside them!!

An eye is a sense organ - it contains light receptors

Question 9

Information from the sense organs is sent to the…

Answer 9

CNS

Question 10

What does the Central nervous system do?

Answer 10

It’s where all the information from the sense organs is sent, and where all the REFLEXES and ACTIONS are coordinated

Question 11

What two parts of the body does the central nervous system consist of?

Answer 11

THE BRAIN and the SPINAL CORD

Question 12

Instructions (electrical impulses) from the CNS are sent to the _______

Answer 12

EFFECTORS which respond accordingly

Question 13

What are the sensory neurones?

Answer 13

The nerve cells carry signals as electrical impulses from the receptors in the sense organs to the CNS

Question 14

What are the relay neurones?

Answer 14

The nerve cells that carry signals from sensory neurones to motor neurones

Question 15

What are the motor neurones?

Answer 15

The nerve bells that carry signals from the CNS to the effector

Question 16

What are effectors? And how do they react?

Answer 16

MUSCLES AND GLANDS

Muscles - contract
Glands - secrete hormones

Question 17

What do synapses do?

Answer 17

They connect the neurones

Question 18

Explain what happens at a synapse

Answer 18

The nerve signal is transferred by CHEMICALS which DIFFUSE (move) across the gap. These chemicals then set off a NEW ELECTRICAL SIGNAL in the NEXT neurone.

Question 19

What are reflexes?

Answer 19

Automatic responses to certain stimuli which can reduce the chances of being injured

Question 20

The neurones in a reflex arc go through the _______ _____ or the _____________ _____ __ ___ ________

Answer 20

Spinal cord or the unconscious part of the brain

Question 21

Recall the sequence of a reaction using these key words:

Relay neurone, effector, receptor, stimulus, sensory neurone, response, motor neurone, CNS, synapse

Answer 21

1. Stimulus
2. Receptor
3. Sensory neurone
4. CNS
5. Synapse
6. Relay neurone
7. Motor neurone
8. Effector
9. Response

Question 22

What’s quicker, a response or a reflex arc? Why?

Answer 22

A reflex arc because you don’t have to think about the response (which takes time!)

Question 23

When you can get ‘perfect’ on recalling the sequence of a reaction, try doing it without the key words!!

Answer 23

1. Stimulus
2. Receptor
3. Sensory neurone
4. CNS
5. Synapse
6. Relay neurone
7. Motor neurone
8. Effector
9. Response

Question 24

Information from the CNS is sent to the…

Answer 24

Effectors (muscles and glands)