Nervous System

Question 1

What is your nervous system?

Answer 1

Your nervous system works by detecting changes in your external environment. This info is sent to your brain where it is processed. Your brain decides an appropriate response and sends an impulse to another part of your body telling it how to respond.

Question 2

What are the 3 main stages to a nervous response?

Answer 2

1. There is a change in environment (stimulus).
2. A group of cells detect the stimulus. These are the sensory receptors.
3. A response occurs from the effectors, which are muscles or glands.

Question 3

What do sensory receptors do?

Answer 3

The sensory receptors detect when there is a change in the environment.

Question 4

What is the role of effectors in a nervous response?

Answer 4

Effectors are muscles or glands that respond to an impulse. Muscles respond by contracting, which causes movement.

Question 5

What passes along nerve cells?

Answer 5

Electrical impulses

Question 6

What is the gap between two neurones called?

Answer 6

Synapse

Question 7

What is released across a synapse?

Answer 7

Chemicals

Question 8

Which of these is part of the central nervous system (CNS)?

Answer 8

Brain
Spinal cord

Question 9

What is the role of a receptor?

Answer 9

To detect a stimulus

Question 10

What is the role of a sensory neurone?

Answer 10

To transfer a signal from a receptor to the CNS

Question 11

What is the role of a motor neurone?

Answer 11

To transfer a signal from the CNS to an effector

Question 12

What is the role of a relay neurone?

Answer 12

To transfer a signal from a sensory neurone to a motor neurone

Question 13

What is a reflex?

Answer 13

An automatic response to a stimulus

Question 14

The pathway of a reflex arc

Answer 14

stimulus ➔ receptor ➔ sensory neurone ➔ relay neurone ➔ motor neurone ➔ effector ➔ response

Question 15

What are the two main types of effectors?

Answer 15

Muscles

Glands

Question 18

Reflexes are ?

Answer 18

Fast
Automatic

Question 18

Why are reflexes important?

Answer 18

They protect us from harm

Question 19

An example of a reflex

Answer 19

Blinking when you get dust in your eye
Sneezing

Question 19

A man accidentally touches a hot stove and quickly moves his hand away from it.

This is a reflex action.

Describe the path of the nervous reaction to coordinate a reflex action.

Answer 19

the stimulus (heat from the hot stove)

is detected by receptors in skin

an electrical impulse is sent along the sensory neurone

to spinal cord

allow 'CNS'

via chemical transmission

allow 'neurotransmitters across synapse'

the electrical impulse travels via the relay neurone

and finally the impulse is sent along the motor neurone

to hand/arm muscles

allow effector in place of muscles

the muscle/effector contracts, moving the hand away from the hot stove

Question 19

How can you tell that a reflex action is not a conscious action?

Answer 19

it is not connected to brain

OR

it is coordinated only by the spinal cord

Question 20

Write down one advantage of a reflex arc not involving the brain.

Answer 20

impulse is faster which reduces chance of being hurt

Question 20

Explain why reflex actions are helpful adaptations that increase chances of survival.

Answer 20

eflex actions are automatic and are rapid protects body from danger/damage

Question 20

Neurones develop from undifferentiated cells. State the name of these cells.

Answer 20

stem cells

Question 20

Most neurones are longer than other types of animal cell. Suggest why most neurones are very long.

Answer 20

neurones must transmit impulses from one part of the body to another so the impulse transmission is fast

Question 20

Describe the role of sensory neurones.

Answer 20

(sensory neurones) transmit electrical impulses from receptors/sense organ to the CNS/brain/spinal cord/relay neurone

Question 20

Motor neurones connect to effector organs. Give one example of an effector organ.

Answer 20

muscle OR gland

Question 21

Name three receptor types a rabbit might use to help detect food in its environment. For each receptor type suggest where that receptor is likely to be found on the rabbit's body.

Answer 21

light receptors in eye smell receptors in nose taste receptors on tongue

Question 21

A branch falls off a tree near a rabbit. The rabbit jumps at the noise. Describe the processes by which the rabbit responds to the stimulus of the fallen branch.

Answer 21

receptors in ear detect sound waves/vibrations impulses OR electrical signals are sent to brain impulses travel through sensory neurones brain coordinates response electrical impulses are sent from the brain electrical impulses travel along motor neurones impulses travel to muscles/effectors which contract to bring about response/jump

Question 21

What is the name given to cells that are sensitive to stimuli?

Answer 21

receptors

Question 21

The child stretches his leg involuntarily. What is the effector in this response?

Answer 21

muscle

Question 22

This response is one example of a reflex action. The nerve pathway followed by a reflex action is called a reflex arc. Reflex arcs start with a stimulus and end up with a response from an effector. A girl picks up a hot plate. A reflex action causes her to drop it. Describe this example of a reflex action in terms of: stimulus ➔ receptor ➔ coordinator ➔ effector ➔ response

Answer 22

stimulus: heat OR hot plate receptor: skin coordinator: spinal cord OR CNS effector: arm muscle response: dropping the plate

Question 30

Some people have a condition in which information from the skin does not reach their brain. Explain why this is dangerous.

Answer 30

brain is not aware of pain possibility of permanent damage

Question 31

The man could feel the sharp object touching his arms but not his legs. Suggest what this information could tell the doctors about the damage to the man’s spinal cord. Explain your answer.

Answer 31

damage must be between arms and legs allow 'below arms' since information from nerves in arms still reaches the brain OR information from the legs doesn’t reach the brain

Question 32

What is the cornea?

Answer 32

A transparent layer at the front of the eye which refracts light

Question 33

What is the pupil?

Answer 33

The gap through which light passes to reach the lens

Question 34

What are the names of the two types of receptor cells in the retina?

Answer 34

Rod cells Cone cells

Question 35

Which light-sensitive cells in the retina enable you to see in colour?

Answer 35

Cone cells

Question 36

The eye is a sense organ. Which two stimuli are the receptor cells of the eye sensitive to?

Answer 36

Colour Light intensity

Question 37

Which light sensitive cells in the retina enable you to see in the dark?

Answer 37

Rod cells

Question 38

The point where light focuses on the retina is called the ____ .This region contains the highest concentration of cone cells and gives the sharpest image.

Answer 38

fovea

Question 39

What is the purpose of the iris reflex?

Answer 39

To ensure the optimum amount of light enters the eye

Question 40

When the pupil is very large, do we describe it as 'constricted' or 'dilated'?

Answer 40

Dilated

Question 41

Which two muscles make up the iris?

Answer 41

Radial muscles Circular muscles

Question 42

When the eye is exposed to bright light, will the pupil constrict or dilate?

Answer 42

Constrict

Question 43

What happens to the circular and radial muscles when the pupil constricts?

Answer 43

The circular muscle contracts The radial muscle relaxes