Mammalian Nervous System (Cambridge O Level Biology)

Exam Questions

49 mins13 questions
1a
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3 marks

The following terms are all components involved in passing a signal along the nervous system.

    coordinator                       receptor                   response 

 effector                            stimulus           

State the correct order of components during a nervous response.

1b
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1 mark

State the name of the sense organ that contains receptor cells that respond to changes in light?

1c
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1 mark

Fig. 1 shows the junction between two neurones.

neurones_receptors

Fig. 1

State the name of this junction.

1d
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3 marks

Many general anaesthetics inhibit the release of signalling chemicals (called neurotransmitters) across some junctions like the one shown in Fig. 1.

Explain what impact this would have on the nerve impulse.

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1a
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1 mark

Define the term sensitivity.

1b
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3 marks

Fig. 1 shows the reflex arc involved in a simple reflex action.

cie-igcse-2020-specimen-p4-q3b-reflex-arc

Fig. 1

On Fig. 1, use label lines to identify and name the three types of neurone shown. 

1c
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2 marks

A reflex is an involuntary action.

Explain what is meant by the term involuntary action.

1d
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4 marks
(i)
Define the term synapse.

[1]

(ii)
Describe how impulses are transmitted across a synapse.

[3]

1e
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2 marks

When a body senses danger, more adrenaline is secreted from the adrenal glands.

Describe two ways in which the hormone adrenaline affects the body in preparation for action.

1f
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1 mark

State one difference between nervous and hormonal control systems.

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2
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5 marks

This question is about neurones and reflex actions.

Choose words from the list to complete the sentences.

Each word may be used once, more than once, or not at all.

endocrine                      fast                           impulses

motor                       nervous                         receptor                       sensory

slow                        stimuli                         synapses

Neurones are cells that are part of the (i)............................................... system.

There are three types of neurone involved in a simple reflex action: a sensory neurone, a relay neurone and a (ii)............................................... neurone.

The nerves conduct electrical (iii)............................................... . These are transmitted from one neurone to the next at junctions called (iv)............................................... . 

A reflex action is automatic, co-ordinated and (v)............................................... .

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1a
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5 marks

Complete the five sentences about the eye and the nervous system.

Structures in the eye change the shape of the lens so that the eye can focus on near and distant objects. This is called ............................................... .

The radial and circular muscles in the iris of the eye are a pair of .............................................. muscles that work against each other.

Muscles in the eye are controlled by the nervous system.

The .............................................. nervous system contains only sensory and motor neurones.

The .............................................. nerve from the eye contains sensory neurones that conduct impulses to the ............................................... .

1b
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3 marks

Transmission of impulses relies on the flow of ions through the cell membranes of neurones down their concentration gradients. Active transport is responsible for maintaining the concentration gradients of ions across the membranes of neurones.

Explain how ions are moved across membranes by active transport.

1c
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6 marks

Fig. 1 shows the junction between two neurones.

cie-igcse-2019-paper4-3c

Fig. 1

Many drugs interfere with the action of neurotransmitters at the junctions between neurones.

Two drugs that influence the transmission of impulses between neurones are atropine and eserine. The actions of these drugs are shown in Table 1.

Table 1

drug action at junctions between neurones
atropine blocks receptor molecules for neurotransmitters
eserine blocks the enzyme that breaks down neurotransmitters

Explain the effects of these two drugs on the nervous system using the information in Fig. 1 and Table 1.

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