Exam questions · Biology
The Nervous System
- 28 exam questions
- 81 marks
- 32 quick checks
Neurones and the Nervous System
Just this lesson-
1 State [2 marks]
State the two parts of the central nervous system.
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Model answer
The brain and the spinal cord.
Mark scheme
- Brain — 1 mark
- Spinal cord — 1 mark
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2 Name [3 marks]
Figure 1 shows a motor neurone. Name the parts shown at A, B and C.
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Model answer
A is the cell body. B is the axon. C is the myelin sheath.
Mark scheme
- A: cell body — 1 mark
- B: axon — 1 mark
- C: myelin sheath — 1 mark
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3 State [3 marks]
Figure 2 shows the path from a stimulus to a response. Name the parts shown at A, B and C.
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Model answer
A is a receptor. B is the central nervous system. C is an effector.
Mark scheme
- A: receptor — 1 mark
- B: central nervous system — 1 mark
- C: effector — 1 mark
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4 Describe [3 marks]
Describe the functions of sensory neurones, relay neurones and motor neurones.
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Model answer
Sensory neurones carry impulses from receptors to the central nervous system. Relay neurones carry impulses inside the central nervous system. Motor neurones carry impulses from the central nervous system to effectors.
Mark scheme
- Sensory: receptor to the central nervous system — 1 mark
- Relay: within the central nervous system — 1 mark
- Motor: central nervous system to effectors — 1 mark
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5 Explain [3 marks]
Explain how a nerve impulse crosses a synapse.
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Model answer
The impulse arrives at the nerve ending, which releases neurotransmitter. The neurotransmitter diffuses across the gap. It binds to receptors on the next neurone, which starts a new impulse.
Mark scheme
- Neurotransmitter released at the nerve ending — 1 mark
- Diffuses across the gap — 1 mark
- Binds to receptors on the next neurone to start an impulse — 1 mark
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6 Explain [2 marks]
Explain why a myelin sheath is an advantage to a long neurone.
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Model answer
The myelin sheath insulates the axon. This makes the impulse travel much faster, so the response is quicker.
Mark scheme
- Insulates the axon — 1 mark
- Impulse travels faster — 1 mark
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7 Explain [4 marks]
Explain how the nervous system produces a coordinated response.
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Model answer
Receptors of different types detect stimuli and send impulses. The central nervous system receives the impulses through many connections. It sends impulses along nerves, which reach all parts of the body, to the effectors. The effectors, muscles or glands, then carry out the response.
Mark scheme
- Different receptors detect stimuli — 1 mark
- Many links in the central nervous system — 1 mark
- Nerves reach all parts of the body — 1 mark
- Effectors carry out the response — 1 mark
Quick check
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1
What is the job of a sensory neurone?
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B: To carry impulses from a receptor to the central nervous system
A sensory neurone carries impulses from a receptor to the central nervous system.
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2
Which two structures make up the central nervous system?
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D: The brain and the spinal cord
The central nervous system is the brain and the spinal cord.
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3
What is an effector?
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A: A muscle or a gland
Effectors are muscles and glands that carry out a response.
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4
What is the function of the myelin sheath?
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C: To speed up the impulse
The myelin sheath insulates the axon and speeds up the impulse.
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5
What is a synapse?
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B: A gap between two neurones
A synapse is the small gap between two neurones.
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6
What crosses a synapse?
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D: Neurotransmitters
Neurotransmitter chemicals diffuse across the synapse.
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7
Which cells detect a stimulus?
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A: Receptors
Receptors detect stimuli and start impulses.
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8
Which of these carries impulses from the central nervous system to an effector?
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C: A motor neurone
Motor neurones carry impulses to effectors.
Reflex Arcs
Just this lesson-
1 State [1 mark]
State what a reflex action is.
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Model answer
A rapid, automatic response to a stimulus.
Mark scheme
- Rapid, automatic response — 1 mark
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2 Name [3 marks]
Figure 1 shows a reflex arc. Name the neurones shown at A, B and C.
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Model answer
A is the sensory neurone. B is the relay neurone. C is the motor neurone.
Mark scheme
- A: sensory neurone — 1 mark
- B: relay neurone — 1 mark
- C: motor neurone — 1 mark
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3 Name [3 marks]
Figure 2 shows a synapse. Name the parts shown at A, B and C.
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Model answer
A is a vesicle (containing neurotransmitter). B is a neurotransmitter (molecule). C is a receptor.
Mark scheme
- A: vesicle — 1 mark
- B: neurotransmitter — 1 mark
- C: receptor — 1 mark
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4 Describe [5 marks]
Describe the pathway taken by the impulse when a person touches a sharp pin and pulls their hand away.
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Model answer
The receptors in the skin detect the pin. An impulse passes along a sensory neurone to the spinal cord. A relay neurone passes it to a motor neurone. The motor neurone carries the impulse to a muscle in the arm, the effector. The muscle contracts and the hand is pulled away.
Mark scheme
- Receptor detects the stimulus — 1 mark
- Sensory neurone to the spinal cord — 1 mark
- Relay neurone — 1 mark
- Motor neurone to the effector — 1 mark
- Muscle contracts — 1 mark
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5 Explain [3 marks]
Explain why a reflex action is faster than a voluntary action.
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Model answer
The reflex arc is a short pathway with few neurones and synapses. The impulse goes through the spinal cord without going to the brain. No conscious thought is needed, so the response is faster.
Mark scheme
- Short pathway with few neurones and synapses — 1 mark
- Does not go through the brain — 1 mark
- No conscious thought — 1 mark
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6 Explain [3 marks]
Explain how the structure of a reflex arc is related to its function.
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Model answer
The sensory and motor neurones are long, so they can reach from the skin to the spinal cord and back to the muscle. The myelin sheath makes the impulse fast. The relay neurone in the spinal cord makes the pathway short, so the response is rapid and protects the body.
Mark scheme
- Long neurones reach receptors and effectors — 1 mark
- Myelin sheath speeds up the impulse — 1 mark
- Short pathway through the spinal cord gives a rapid response — 1 mark
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7 Calculate [2 marks]
A student catches a dropped ruler at 12 cm, 15 cm and 18 cm. Calculate the mean distance. Give a unit.
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Model answer
15 cm
Mark scheme
- \(12 + 15 + 18 = 45\), then \(45 \div 3\) — 1 mark
- 15 cm — 1 mark
Quick check
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1
What is a reflex action?
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C: A rapid, automatic response to a stimulus
A reflex is a rapid, automatic response to a stimulus.
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2
Where is the relay neurone in a reflex arc?
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A: In the spinal cord
The relay neurone is in the spinal cord.
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3
Which of these is the correct order for a reflex arc?
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D: Receptor, sensory neurone, relay neurone, motor neurone, effector
The impulse passes from the receptor along a sensory neurone, relay neurone and motor neurone to the effector.
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4
What crosses the gap at a synapse?
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B: Neurotransmitter
Neurotransmitter diffuses across the synapse.
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5
Why is a reflex action so fast?
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C: The pathway is short
The pathway is short, with few neurones and synapses, and does not go through the brain.
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6
Which is an example of a reflex action?
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B: Pulling a hand away from a hot object
Pulling a hand away from a hot object is a reflex.
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7
In the ruler drop test, what does a smaller distance caught mean?
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D: A faster reaction
A shorter distance means the person reacted faster.
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8
What does the effector in a reflex arc do?
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A: Produces the response
The effector, a muscle or gland, produces the response.
The Eye
Just this lesson-
1 State [2 marks]
State the function of the iris and the function of the retina.
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Model answer
The iris controls the amount of light entering the eye. The retina contains the receptor cells that detect light.
Mark scheme
- Iris controls the amount of light entering — 1 mark
- Retina contains the light receptor cells — 1 mark
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2 Name [3 marks]
Figure 1 shows a section through the eye. Name the parts shown at A, B and C.
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Model answer
A is the cornea. B is the lens. C is the optic nerve.
Mark scheme
- A: cornea — 1 mark
- B: lens — 1 mark
- C: optic nerve — 1 mark
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3 Explain [3 marks]
Explain how the pupil changes when a person moves from a dim room into bright sunlight.
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Model answer
The circular muscles of the iris contract and the radial muscles relax. The pupil gets smaller. This reduces the amount of light that enters, which protects the retina from damage.
Mark scheme
- Circular muscles contract and radial muscles relax — 1 mark
- Pupil gets smaller — 1 mark
- Less light enters, protecting the retina — 1 mark
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4 Explain [4 marks]
Explain how the eye focuses on a near object.
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Model answer
The ciliary muscles contract. This slackens the suspensory ligaments. The lens becomes thicker and more curved. It refracts the light more, so that the light is focused on the retina.
Mark scheme
- Ciliary muscles contract — 1 mark
- Suspensory ligaments slacken — 1 mark
- Lens becomes thicker — 1 mark
- Light is focused on the retina — 1 mark
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5 Explain [3 marks]
A person is short-sighted. Explain why distant objects look blurred and how the problem can be corrected.
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Model answer
The lens is too strong or the eyeball is too long, so the light from distant objects is focused in front of the retina. The image on the retina is blurred. A concave lens in spectacles spreads the light out so that it is focused on the retina.
Mark scheme
- Light focused in front of the retina — 1 mark
- Image on the retina is blurred — 1 mark
- Concave lens corrects it — 1 mark
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6 Describe [3 marks]
Describe three ways in which a focusing problem in the eye can be overcome.
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Model answer
Wearing spectacles with the correct lenses, wearing contact lenses, laser eye surgery to reshape the cornea, or replacing the lens with an artificial one.
Mark scheme
- Any three of spectacles, contact lenses, laser surgery, replacement lens — 3 marks
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7 Explain [3 marks]
Explain why a person who is colour blind cannot be helped by spectacles.
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Model answer
Colour blindness is caused by faulty cone cells in the retina, which cannot detect one or more colours. Spectacles only change how light is focused, so they cannot fix the receptor cells.
Mark scheme
- Caused by faulty cone cells — 1 mark
- Spectacles only change how the light is focused — 1 mark
- They cannot repair the receptor cells — 1 mark
Quick check
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1
Which part of the eye controls the amount of light that enters?
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C: The iris
The iris changes the size of the pupil.
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2
Which part of the eye contains the light receptor cells?
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A: The retina
The retina contains the rods and cones.
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3
What happens to the pupil in bright light?
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D: It gets smaller
The circular muscles contract, so the pupil gets smaller.
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4
When the eye looks at a near object, what happens to the lens?
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B: It becomes thicker
The ciliary muscles contract, the ligaments slacken and the lens becomes thicker.
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5
Which lens corrects short-sightedness?
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C: A concave lens
A concave lens spreads the light before it enters the eye.
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6
What are rod cells used for?
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A: Seeing in dim light
Rods are sensitive to dim light but do not detect colour.
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7
What causes colour blindness?
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D: Faulty cone cells
One or more types of cone cell do not work.
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8
What do the suspensory ligaments connect?
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B: The ciliary body to the lens
The suspensory ligaments connect the ciliary body to the lens.
The Brain
Just this lesson-
1 State [1 mark]
State the part of the brain that controls the heart rate and breathing.
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Model answer
The medulla.
Mark scheme
- Medulla — 1 mark
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2 Name [3 marks]
Figure 1 shows a section through the brain. Name the parts shown at A, B and C.
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Model answer
A is the cerebrum. B is the cerebellum. C is the medulla.
Mark scheme
- A: cerebrum — 1 mark
- B: cerebellum — 1 mark
- C: medulla — 1 mark
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3 Describe [3 marks]
Describe the functions of the cerebrum, the cerebellum and the hypothalamus.
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Model answer
The cerebrum controls conscious thought, memory, language and voluntary movement. The cerebellum coordinates movement and balance. The hypothalamus controls body temperature and water balance.
Mark scheme
- Cerebrum: thought, memory, language — 1 mark
- Cerebellum: coordination and balance — 1 mark
- Hypothalamus: temperature and water balance — 1 mark
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4 Explain [3 marks]
A person has a stroke that damages their cerebellum. Suggest and explain one problem the person might have.
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Model answer
The person may have difficulty with coordination and balance. The cerebellum coordinates movement and keeps balance, so with damage their movements may be clumsy and they may fall over.
Mark scheme
- Problem with coordination or balance — 1 mark
- The cerebellum coordinates movement and balance — 1 mark
- Movements are clumsy / they may fall — 1 mark
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5 Explain [3 marks]
Explain why it is difficult to investigate the functions of different parts of the brain.
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Model answer
The brain is very complex, with billions of connected neurones. It is protected inside the skull and hard to reach. There are also ethical issues in doing experiments on people or animals, so much of the evidence comes from case studies of damaged brains, where each injury is different.
Mark scheme
- The brain is complex — 1 mark
- It is hard to reach — 1 mark
- Ethical issues limit experiments — 1 mark
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6 Explain [3 marks]
Explain why it is hard to treat a person who has damage to the brain or to the spinal cord.
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Model answer
Neurones in the brain and spinal cord have a very limited ability to repair themselves, so the damage is often irreversible. Some parts are difficult to access, and surgery can damage the surrounding tissue. A cut spinal cord stops impulses crossing the injury.
Mark scheme
- Limited ability to repair nervous tissue — 1 mark
- Damage may be irreversible / surrounding tissue damaged — 1 mark
- Difficult to access parts of the nervous system — 1 mark
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7 Evaluate [4 marks]
A doctor studies a patient who has damage to one region of the brain and has lost the ability to speak. Evaluate how far this case study shows that this region controls speech.
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Model answer
It suggests that the region has a role in speech, because the function was lost when it was damaged. However, it is only one patient, and every injury is different. The damage may extend beyond the region, or other regions may be involved, so more evidence from other patients and from scans is needed.
Mark scheme
- It suggests a link between the region and speech — 1 mark
- Only one patient / every injury is different — 1 mark
- Damage may be wider or other regions involved — 1 mark
- More evidence needed, such as more patients or scans — 1 mark
Quick check
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1
Which part of the brain coordinates movement and balance?
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B: The cerebellum
The cerebellum coordinates movement and balance.
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2
Which part of the brain controls breathing?
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C: The medulla
The medulla controls breathing and heart rate.
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3
Which part of the brain controls body temperature?
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A: The hypothalamus
The hypothalamus monitors and controls body temperature.
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4
What does the pituitary gland release?
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D: Hormones
The pituitary gland releases hormones.
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5
Which part of the brain is responsible for conscious thought and memory?
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B: The cerebrum
The cerebrum controls conscious thought, memory, language and voluntary movement.
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6
Why is the pituitary gland called the master gland?
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C: It controls other glands
It releases hormones that control other glands.
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7
Why is it hard to repair a damaged brain?
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A: Neurones repair poorly
Neurones in the brain and spinal cord have a very limited ability to repair themselves.
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8
Which of these is a limitation of a case study of brain damage?
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D: Each injury is different
Every injury is different, and the damage is hard to measure exactly.