Nervous System

Question 1

Central Nervous System

Answer 1

Brain and spinal cord

Question 2

Peripheral Nervous System

Answer 2

Consists of nerves carrying messages to and from the CNS in the form of nerve impulses. Cranial nerves (above neck) and spinal nerves (neck and below). The nervous system controls activities (voluntary or involuntary) and responses to stimuli.

Question 3

Nerve and Neurone

Answer 3

Nervous system is made up of nervous tissues. These tissues consists of nerve cells known as neurone
Nerve is made up of several bundles of nerve fibres enclosed by connective tissue and blood vessels. Each nerve fibre contains many neurones. Each neurone consists of Cell Body (nucleus and cytoplasm) Dendrons/ Dendrites (branches to from cell body) Axon (branches away from cell body)

Question 4

Direction of impulse flow

Answer 4

Dendrites-dendrons-cell body-axon

Question 5

Sensory neurone

Answer 5

Transmits nerve impulses from receptors that detect conditions both inside and outside of the body and brings this information to the central nervous system. One axon, dendrons

Question 6

Relay neurone

Answer 6

Interconnects with other neurones. Found only in the central nervous system (brain and spinal cord) and convey nerve impulses between neurones. Have numerous short fibres.

Question 7

Motor neurone

Answer 7

Transmits nerve impulses from the nervous system to organs or tissues which prompts some kind of action
One axon, numerous dendrons

Question 8

Synapse

Answer 8

Junction between 2 neurones or a junction between a neurone and effector.

Question 9

Transmission of nerve impulses

Answer 9

When nerve impulses reach the end of the axon, certain chemicals known as neurotransmitters are released into the synapse. The neurotransmitters triggers an impulse in the dendrites of the next neurone and stimulate the effector to act.

Question 10

Receptors

Answer 10

Can detect changes in the environment which are called stimuli and turn them into electrical impulses. Receptors are often located in the sense organ.

Question 11

Effectors

Answer 11

Any part of body that produce/carry out response.

Question 12

How does the nervous system process information?

Answer 12

1. Determine the stimulus
2. Information is first detected by receptors and then produced into nerve impulses.
3. The nerve impulse are transmitted via the sensory neurone in the peripheral nerve to the central nervous system.
4. Relay neurones can be found in the CNS. The CNS interprets the nerve impulses and decide on the course of action,
5. The CNS then initiates and transmits nerve impulses via the motor neurone to the effectors.
6. The effectors will then carry out the intended course of action.

Question 13

Grey Matter

Answer 13

Consists of mainly cell bodies, dendrites and synapses.

Question 14

White matter

Answer 14

consists of mainly nerve fibres with their insulating sheaths

Question 15

Dorsal Root Ganglion

Answer 15

Contains the cell bodies of the sensory neurone

Question 16

Spinal Nerve

Answer 16

Contains nerve fibres from both the dorsal and ventral root

Question 17

Ventral root

Answer 17

Only contain motor neurone

Question 18

Reflex Action

Answer 18

An immediate response to a specific stimulus without conscious control

Question 19

Reflex Arc

Answer 19

Shortest pathway by which nerve impulses travels from the receptor to effector in a reflex action.

Question 20

Simple Reflex Action

Answer 20

1. The heat on the object stimulates the nerve endings (receptors) in the skin. Impulses are produced by pain receptors.
2. The nerve impulses travel along the sensory neurone to the spinal cord.
3. In the spinal cord, the nerve impulses are transmitted first across a synapse to the relay neurone and across another synapse to motor neurone.
4. The motor neurone transmit nerve impulses from the spinal cord to the effector.
5. Effector muscle contract and (action).