Nerves

Question 1

What is a stimulus?

Answer 1

A change in the animals surroundings

Question 2

What is a receptor?

Answer 2

The organ which detects the change

Question 3

What is the effector?

Answer 3

Muscles are the effectors which contract in response to the stimulus.

Question 4

How is the response made?

Answer 4

By the endocrine or nervous system.

Question 5

What are the examples of a receptor?

Answer 5

Sense organs: eye, ear, tongue, nose, skin

Question 6

What does the central nervous system consist of?

Answer 6

The brain and the spinal cord.

Question 7

What does the Central nervous system do?

Answer 7

Coordinates all of the nervous responses such as moving or reflexes.

Question 8

What is the peripheral nervous system?

Answer 8

It contains all of the other nerves which send impulses to all the effectors.

Question 9

What are the three types of neurone?

Answer 9

Relay, motor, sensory

Question 10

Describe the path of impulses in terms of neurones.

Answer 10

Impulses from receptors pass along sensory neurones until they reach the brain and spinal cord. Impulses pass to relay neurones in the CNS. The impulse is then passed to effectors along motor neurones.

Question 11

What is the dendrite?

Answer 11

Tree like projections which connect to different neurones. One neurone can connect to many other neurones.

Question 12

What is the axon?

Answer 12

The long section - electrical impulses travel long distances through the axon.

Question 13

What is the myelin sheath?

Answer 13

Insulates the axon and speeds up the transmission of the impulse.

Question 14

What are reflexes?

Answer 14

Automated actions which do not involve the brain.

Question 15

What is the movement of the impulse from receptor to effector called?

Answer 15

The reflex arc

Question 16

Describe the steps involved in the reflex arc.

Answer 16

The receptors detect the stimulus and send an impulse along the sensory neurone.
The sensory neurone passes the impulse to the spinal cord to a relay neurone. The relay neurone then passes the impulse through the spinal cord to a motor neurone.
The motor neurone causes the effector to contract and move the arm away from the stimulus.

Question 17

What is the small gap between two neurones called?

Answer 17

The synapse

Question 18

What happens at the synapse?

Answer 18

An electrical impulse travels along an axon.
This triggers the nerve ending of a neuron to release chemical messengers called neurotransmitters.
These chemicals diffuse across the synapse and bind with the receptor molecules on the membrane of the next neuron.
The receptor molecules on the second neuron bind only to the specific chemicals released for the first neuron. This stimulates the second neurons to transmit the electrical impulse.

Question 19

What can be an effector?

Answer 19

Muscles or glands

Question 20

What is a neurotransmitter?

Answer 20

A chemical that transmits the impulse across the synapse.