Nerves and reflexes — return questions

1. state

Complete the sentences. When something touches your thumb, a message travels along neurones as an (1) impulse. The neurones run together in a bundle called a (2), along your arm, which is part of the (3) nervous system. The message reaches the spinal cord, which is part of the (4) nervous system.

(1)

(2)

(3)

(4)

2. predict

After an accident, a person's spinal cord is cut through in the lower back. The nerves in the legs are not damaged. Predict what happens when something touches the person's foot.

Circle one answer.

• Impulses travel along the leg nerves straight to the brain, so it is felt.
• The foot stops making impulses, so its receptors no longer work.
• Nothing changes, because the spinal cord is part of the PNS.
• Impulses from the foot cannot reach the brain, so the touch is not felt.

3. identify

Four pupils each catch a falling metre rule five times. Which pupil has an anomalous catch?

Circle one answer.

• Pupil A
• Pupil B
• Pupil C
• Pupil D

4. identify

Which of these is an example of the nervous system regulating a body function?

Circle one answer.

• Your eyes and both hands work together to thread a needle.
• Your breathing rate rises in a run and stays high all evening.
• You catch a ball that a friend throws towards you.
• Shivering starts when your body gets cold and stops once you are warm.

5. identify

Which kind of neurone links the sensory neurone and the motor neurone inside the central nervous system?

Circle one answer.

• A sensory neurone.
• A relay neurone.
• A motor neurone.

6. state

A fly darts towards your face and you blink. Complete the sentences about this reflex arc. Light-sensitive cells in the (1) are the receptors. An impulse travels along a (2) neurone into the brain, where a (3) neurone passes it on. A (4) neurone carries the impulse out to the (5) of the eyelid, the effectors.

(1)

(2)

(3)

(4)

(5)

7. identify

A pupil's mean time for catching a falling metre rule is 0.21 s. When a doctor taps the tendon just below the same pupil's knee, the leg starts to kick about 0.05 s after the tap. Which statement explains why the knee jerk is so much quicker?

Circle one answer.

• A tap is a stronger stimulus than a falling rule, so the response comes sooner.
• Neurones in the leg carry impulses faster than those in the arm.
• The leg kicks every day, so the knee jerk is better practised.
• No decision is made, and the impulse passes along fewer neurones.

8. identify

An impulse passes from touch receptors in the skin of a toe, along a sensory neurone and a relay neurone, to a motor neurone. At which of these places is there a synapse?

Circle one answer.

• The cell body of the sensory neurone, on its side branch.
• Where the end of the sensory neurone meets the relay neurone.
• Where a nerve leaves the spinal cord.
• Half way along the fibre of the motor neurone.

9. identify

Supplement. Match each structure of a synapse to what it does.

Write the number of the matching option.

1. the space that neurotransmitter molecules diffuse across
2. bind with neurotransmitter molecules on the next neurone
3. hold neurotransmitter molecules until an impulse arrives

• Vesicles: ______
• Synaptic gap: ______
• Receptor proteins: ______

10. identify

Supplement. What happens straight after neurotransmitter molecules bind with receptor proteins on the next neurone?

Circle one answer.

• The vesicles release neurotransmitter.
• The neurotransmitter diffuses back across the gap.
• The neurotransmitter travels along the next neurone.
• An impulse is stimulated in the next neurone.

11. identify

Supplement. Which change would let impulses cross a synapse in both directions?

Circle one answer.

• Both neurones had vesicles of neurotransmitter and receptor proteins.
• The synaptic gap were made twice as wide as it is now.
• The vesicles were in the next neurone and the receptors on the first.
• The impulse arriving at the synapse were made stronger.