Nervous System

Question 1

What are the two main parts of the nervous system

Answer 1

The central nervous system

The peripheral nervous system

Question 2

What is the central nervous system made up of

Answer 2

Brain and spinal cord

Question 3

What is the peripheral nervous system made up of

Answer 3

All nerves outside the brain and spinal cord that carry messages to and from the CNS and other parts of your body

Question 4

What is the nervous system made up of

Answer 4

Trillions of nerve cells or neurons

Question 5

What do neurones carry

Answer 5

Electrical messages called nerve impulses

Question 6

What direction do nerve impulses carry

Answer 6

In only one direction

Question 7

What are the four main parts of a neurone

Answer 7

Cell body
Dendrites
Knobs
Axons

Question 8

What does the cell body contain

Answer 8

The nucleus

Question 9

What is the nucleus

Answer 9

The control centre of the cell

Question 10

What are the dendrites

Answer 10

They branch out from the cell body and recieve messages from other nerve cells

Question 11

What is the axon

Answer 11

The axon or nerve fibres send nerve impulses in only one direction, away from the cell body

Question 12

What are the knobs

Answer 12

They pass messages on to the next neurone

Question 13

What are motor neurones

Answer 13

They carry messages from the CNS to effectors, which are muscles or glands, that out the messages into effect. They cause movement in muscles and glands

Question 14

What are sensory neurones

Answer 14

They carry messages from cells in the sense organs, (such as eyes ears tongue and skin) to brain and spinal cord

Question 15

What does the motor neurone look like

Answer 15

They have dendrites coming off the cell body which then goes into the axon, which has myelin sheath around it and Schwanns cells which then leads into the axon terminals, or knobs where the impulse finishes.

Question 16

What does the sensory neurone look like

Answer 16

It has dendrites which lead into the axon with myelin sheath, and the cell body comes off the axon. At the end of the axon are the knobs or axon terminals

Question 17

What does the connecting neurone look like

Answer 17

It is much smaller and have many dendrites coming off the cell body, which goes into the axon that has no myelin sheath, and into the axon terminals or knobs

Question 18

What is the connecting neurone

Answer 18

They are very small neurones which connect other neurones to other places. They don’t have myelin because of the short distance, and they have many dendrites.

Question 19

Explain what happens when impulses reach knobs

Answer 19

When they reach the end a chemical called neurotransmitter is released into the space between the neurones, or synapse. The neurotransmitter carries the message from the axon of one neurone to the dendrite of the nest. The dendrite receives the chemical message and sends off an electrical signal

Question 20

What is a myelin sheath

Answer 20

It electrically insulated the neurones from eachother and increases the speed of the nerve impulse

Question 21

What are the two separate parts of the peripheral nervous system

Answer 21

The somatic nervous system

The autonomic nervous system

Question 22

What is the somatic nervous system

Answer 22

It is in the PNS. It collects information about an animals surroundings through sensory organs

Question 23

What are the somatic nervous systems organ

Answer 23

Receptors

Question 24

What are receptors

Answer 24

They detect changes in environment. The changes stimulate the nerve endings to send messages to your brain

Question 25

What are some types of receptors

Answer 25

Mechanoreceptors - sensitive to touch
Photoreceptors - sensitive to light
Thermoreceptors - respond to changes of temperature
Chemoreceptors - sensitive to chemicals such as food

Question 26

What is the autonomic nervous system

Answer 26

They control the activities in our body that happen without us realising, such as heart beating etc

Question 27

What are the two parts of the autonomic nervous system

Answer 27

Sympathetic nervous system

Parasympathetic nervous system

Question 28

What does the sympathetic nervous system do

Answer 28

It speeds up the functions of your body and makes it work efficiently. It prepares your body for emergencies by making it more alert

Question 29

What does the parasympathetic nervous system do

Answer 29

It slows everything down. It is in control when you are resting

Question 30

What does the sympathetic nervous system do

Answer 30

It prepares your body for intense activity by diverting blood away from areas that will not be used

Question 31

What is a stimulus

Answer 31

It is what caused reflexes to react

Question 32

How does the nervous system respond to stimuli

Answer 32

Receptors stimulate the nervous system
Then sensory nerves send a message to the brain
The brain works out the response that is required
It then sends a message along the motor nerves to the effectors which are the muscles or glands that will put the response into effect

Question 33

What happens when you touch something hot?

Answer 33

Receptors detect the temperature in your skin which activates the sensory neurone. This sends nerve impulses to the spinal cord. Within the spinal cord a connecting neurone which passes it to the motor neurone which sends impulses to the arm muscles (effectors) to contract, lifting your hand away from the hot object. A message is send to the brain afterwards, only then can the brain register the pain

Question 34

What is a reflex arc

Answer 34

It is made up of the sensory neurone, connecting neurone and motor neurone. It is in the spinal cord and allows you to react very quickly to protect your body from harm