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The Nervous System

  • 8 subtopics
  • 24 things to know
  • A2 Unit 3

What The Nervous System covers

The Nervous System is examined on A2 Unit 3 of WJEC Biology, Energy, Homeostasis and the Environment. 84 recall questions across 8 subtopics.

Where it is assessed

A2 Unit 3

Energy, Homeostasis and the Environment.

Check the WJEC specification ↗

The 8 subtopics

Each one has its own page.

What you need to know

Answer each one before you reveal it.

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Process

What is the sequence of components in a nervous response, and why are receptors described as transducers?

Key term

What triggers neurotransmitter release, what does acetylcholine bind to, and why is synaptic transmission one-way?

Key term

Describe the position and appearance of grey matter in a transverse section of the spinal cord.

Key term

When examining a prepared transverse section of spinal cord, how can the dorsal side be told from the ventral side?

Key term

Predict the effect of cutting the dorsal root of a spinal nerve supplying a limb.

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Distinguish between a dendron and an axon.

Key term

What causes the brief hyperpolarisation seen after an action potential?

Numbers

An oscilloscope trace shows an action potential beginning at 1.0 ms and ending at 4.0 ms. State its duration.

Process

Why must acetylcholine be broken down after it has acted?

Key term

Explain the term agonist as applied to a psychoactive drug.

Key term

Which three neurones are involved in a spinal reflex arc, and in what order?

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If the brain is not needed for a spinal reflex, why is the person still aware of the stimulus?

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What are the structures in the cell body of a motor neurone that are rich in rough endoplasmic reticulum called?

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Explain how repolarisation is brought about.

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Define saltatory conduction.

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Why is summation necessary at some synapses?

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Define the term effector.

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Which type of nerve fibre enters the spinal cord through the dorsal root?

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Give two reasons why conduction in a nerve net is slower than in a mammalian nerve.

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Which cells produce the myelin sheath around a peripheral axon?

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State the all-or-nothing law as it applies to nerve impulses.

Key term

Explain why myelination increases the speed of conduction.

Key term

Define the term synapse.

Key term

Explain why organophosphate poisoning causes muscle spasms.

Take The Nervous System further

The same content, four other ways.

Questions from this topic

Each one with the model answer underneath.

  1. 1

    What is the sequence of components involved in a nervous response, from stimulus to response?

    Model answer

    A stimulus is detected by a receptor, which sends impulses along a sensory neurone to a coordinator in the central nervous system; a motor neurone then carries impulses to an effector, which brings about the response.

  2. 2

    Why are receptors described as transducers?

    Model answer

    They convert the energy of a stimulus into the electrical energy of a nerve impulse.

  3. 3

    Define the term effector.

    Model answer

    An effector is a muscle or a gland that brings about a response when stimulated by a motor neurone.

  4. 4

    Which two organs make up the central nervous system?

    Model answer

    The brain and the spinal cord.

  5. 5

    What are two examples of an internal stimulus that receptors detect?

    Model answer

    A rise in the carbon dioxide concentration of the blood and a change in blood pressure.

  6. 6

    What is a generator potential?

    Model answer

    It is the small local depolarisation produced in a receptor by a stimulus, which triggers an action potential if it reaches threshold.

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The Nervous System revision questions

What does The Nervous System cover in WJEC A-Level Biology?
8 subtopics: organisation of the nervous response: receptors to effectors and spinal cord, organisation of the nervous response: spinal nerves, dorsal and ventral roots, organisation of the nervous response: simple reflex arc and the cnidarian nerve net compared, neurones and the nerve impulse: motor neurone structure and nature, neurones and the nerve impulse: transmission of the impulse and oscilloscope traces, neurones and the nerve impulse: speed of conduction, synapses: structure and synaptic transmission and synapses: effects of organophosphates and psychoactive drugs. Each one has its own page with questions and model answers.
How is The Nervous System organised?
By the WJEC 601-5290-0 specification, subtopic by subtopic, so it matches the order you are taught it in.

Every question in The Nervous System, on a schedule.

Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.

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