Nervous System

Question 1

What is a stimulus?

Answer 1

A stimulus is a change in your environment which you may need to react to.

Question 2

Name your 5 sense organs

Answer 2

Eyes, ears, nose, tongue and skin

Question 3

How do sense organs work?

Answer 3

Sense organs sense STIMULI

They have RECEPTORS which are sensitive to a stimulus.

The receptors change the STIMULUS ENERGY into ELECTRICAL IMPULSES.

Question 4

There are 8 types of stimulus. Name them

Answer 4

Light
Sound
Touch
Pressure
Pain
Chemical
Position (change in)
Temperature (change in)

Question 5

What receptors are in the eyes?

Answer 5

LIGHT RECEPTORS - sensitive to LIGHT - they have a nucleus, cytoplasm and cell membrane.

Question 6

What receptors are in your ears?

Answer 6

SOUND RECEPTORS - sensitive to SOUND.

BALANCE RECEPTORS - sensitive to changes in POSITION

Question 7

What receptors are in your nose?

Answer 7

SMELL RECEPTORS - sensitive to CHEMICAL stimuli

Question 8

What receptors are in your tongue?

Answer 8

TASTE RECEPTORS - sensitive to BITTER, SALT, SWEET AND SOUR.

Sensitive to CHEMICAL stimuli

Question 9

What are the receptors on your skin?

Answer 9

Sensitive to TOUCH, PRESSURE, PAIN and TEMPERATURE CHANGE

Question 10

What are sensory neurones?

Answer 10

These are the NERVE CELLS that carry signals as ELECTRICAL IMPULSES from the RECEPTORS in the sense organs to the CENTRAL NERVOUS SYSTEM

Question 11

What are Relay Neurones?

Answer 11

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

Question 12

What are Motor Neurones?

Answer 12

The nerve cells that carry signals from the central nervous system to the effector muscles or glands

Question 13

What are Effectors

Answer 13

Effectors are the muscles or glands that respond to the nervous impulse. Muscles contract and Glands secrete hormones.

Question 14

What is the Central Nervous System?

Answer 14

This is the brain and spinal chord.

It is where all of the information from the sense organs is sent and where reflexes and actions are coordinated.

Question 15

How does the CNS work?

Answer 15

Neurones (nerve cells) transmit the information (as electrical impulses) very quickly to and from the CNS.

INSTRUCTIONS from the CNS are sent to the EFFECTORS (muscles and glands) which respond accordingly.

Question 16

What do Neurones do?

Answer 16

Neurones transmit information very quickly to and from the brain and your brain decides very quickly how to respond to the stimulus.

Question 17

What is the connection between two neurones called?

Answer 17

This is called a synapse.

Question 18

What is the nerve signal transmitted between the synapse?

Answer 18

The nerve signal is transmitted by chemicals which DIFFUSE (move) accross the gap. These chemicals then set off a new electrical signal in the next neurone.

Question 19

What is a reflex?

Answer 19

A reflex is an automatic response to certain stimuli which will normally reduce the chances of being injured

Question 20

Give two examples of a reflex

Answer 20

1. When you shine light into your eyes, the pupil gets smaller.
2. If you get a shock your body automatically releases the hormone adrenaline (it does not wait until you decide if you are shocked).

Question 21

What is the passge of information in a reflex called?

Answer 21

A reflex arc is the term to describe the passage of information from the receptor to the effector.

Question 22

Explain the process from a bee sting from receptor to effector?

Answer 22

1. A cheeky little bee stings the finger.
2. The pain receptor senses the pain and sends impulse along the SENSORY NEURONE.
3. IMPULSE is passed along a relay neurone, via a SYNAPSE.
4. Impulses travel along a motor neurone via SYNAPSE
5. When the impulse reaches the muscle it contracts.

Question 23

What is the 7 stage process of the bee stong to reaction in 7 words.

Answer 23

1. Stimulus (bee sting)
2. Receptor
3. Sensory neurone
4. Relay neurone
5. Motor neurone
6. Effector
7. Response