Neurones such as the one shown in Figure 1 form part of the nervous system.
Figure 1
Describe the role of the myelin sheath surrounding the axon.
Humans have reflexes.
Describe the route of an impulse through a reflex arc.
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Neurones such as the one shown in Figure 1 form part of the nervous system.
Figure 1
Describe the role of the myelin sheath surrounding the axon.
Humans have reflexes.
Describe the route of an impulse through a reflex arc.
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Motor neurones are found in the nervous system.
Figure 1 shows a motor neurone.
Figure 1
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The human eye is a highly specialised sense organ.
Figure 1 shows a section through the eye.
Figure 1
Shade in the part of the eye that changes shape to alter the refraction of light onto the retina.
Figure 2 shows the eye from a different angle.
When the eye is exposed to bright light, the pupil gets smaller.
Figure 2
Describe how the circular and radial muscles respond to bright light in order to change the size of the pupil.
Short-sightedness is a treatable eye defect.
Explain why short-sightedness occurs and identify the method usually used to correct short-sightedness
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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.
State the name of the sense organ that contains receptor cells that respond to changes in light.
Figure 1 shows the junction between two neurones.
Figure 1
State the name of this junction.
Many general anaesthetics inhibit the release of signalling chemicals (called neurotransmitters) across some junctions like the one shown in Figure 1.
Explain what impact this would have on the nerve impulse.
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State the two main components of the human nervous system.
Sensory neurons have a unidirectional structure, with dendrites branching off the cell body and an axon.
Define the function of sensory neurones.
Identify the three main types of neurones.
☐ | A | Central neurones, peripheral neurones, and relay neurones. | |
☐ | B | Motor neurones, sensory neurones, and peripheral neurones. | |
☐ | C | Sensory neurones, relay neurones, and motor neurones. | |
☐ | D | Relay neurones, central neurones, and sensory neurones. |
Higher Tier Only
The imaging technique illustrated in Figure 1 uses radioactive tracers to study brain function.
Figure 1
☐ | A | CT Scanning | |
☐ | B | PET Scanning | |
☐ | C | MRI Imaging | |
☐ | D | X-ray Radiography |
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Figure 1 shows the structures of two neurones, A and B.
Figure 1
Identify the kind of neurone that Neurone A is.
Identify the destination of the impulse carried by Neurone B.
The boxes in Figure 2 show the structures and impulses that form part of a processed (voluntary) response. The stimulus is a person tapping another person on the shoulder. The second person decides to turn around (to see who tapped them on the shoulder) as their response.
Figure 2
Place the boxes from Figure 2 into chronological order to describe the pattern of events in a processed response. The first one has been completed for you.
Sequential number | Event / organ |
1. | Stimulus |
2. | |
3. | |
4. | |
5. | |
6. | |
7. | |
8. | |
9. |
Describe two features of a processed response that distinguish it from a reflex response.
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Describe the differences between the structures and functions of a sensory neurone and a motor neurone.
The speed of a nervous impulse travelling along a myelinated axon is around 150 metres per second.
A sensory impulse generated in a man's toe travels 1.5 metres along myelinated axons to his central nervous system, crossing 4 synapses on its journey.
The average time required for a synapse to transmit an impulse is 2 milliseconds, (or 2 × 10-3 seconds).
Calculate the overall time taken for the nervous impulse to reach the man's central nervous system.
Suggest and explain how the time taken to transmit the impulse would differ if the impulse were to travel along unmyelinated axons.
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Figure 1 shows an eye.
Figure 1
☐ | A | the lens gets thinner to bend the light rays more | |
☐ | B | the lens gets thicker to bend the light rays more | |
☐ | C | the lens gets thinner to bend the light rays less | |
☐ | D | the lens gets thicker to bend the light rays less |
A student was given the hypothesis ‘People with brown eyes are more likely to be short-sighted than people with blue eyes.’
Devise a plan to test this hypothesis.
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Figure 1 shows a picture seen through healthy eyes and the same picture seen through eyes affected by cataracts.
Figure 1
☐ | A | retina | |
☐ | B | iris | |
☐ | C | cornea | |
☐ | D | lens |
Figure 2 shows the estimated number of people with cataracts in the world between 1980 and 2020.
Describe the change in the estimated number of people with cataracts between 1980 and 2020.
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The effect of age on focusing distance was investigated.
Volunteers of different ages had their eyes tested.
Each volunteer was asked to read words from a book. The book was moved closer to their eyes.
When the words became out of focus, the distance was recorded.
Figure 1 shows the results.
age of volunteers |
distance (mm) | mean distance (mm) |
||
person 1 | person 2 | person 3 | ||
40 | 256 | 261 | 257 | 258 |
45 | 282 | 275 | 280 | 279 |
50 | 292 | 301 | 297 | ? |
55 | 311 | 309 | 307 | 309 |
Figure 1
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.......................................... mm
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Which part of the eye detects coloured light?
☐ | A | iris | |
☐ | B | lens | |
☐ | C | cones | |
☐ | D | cornea |
Figure 2 shows light rays entering the eye of a person with normal vision.
Figure 2
Figure 3
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Figure 1 shows the number of neurones in the brain of different animals.
animal | number of neurones in the brain |
lobster | 1.0 × 105 |
frog | 1.6 × 107 |
rat | 2.0 × 108 |
human | 8.6 × 1010 |
Figure 1
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........................................ neurones
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Figure 2 shows a sensory neurone.
(1)
(2)
Explain how impulses are transmitted at synapses.
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Figure 1 shows a diagram of the human eye.
Figure 1
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function of structure X | function of structure Y | |||
☐ | A | refracts light | detects light | |
☐ | B | detects light | refracts light | |
☐ | C | refracts light | detects light | |
☐ | D | refracts light | refracts light |
(2)
Eye tests can detect some brain tumours.
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(2)
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Figure 1 shows part of a reflex arc in the spinal cord.
Figure 1
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A scientist investigated the reaction times of five students using a computer program.
The computer screen showed a blue square at the start.
As soon as the blue square turned yellow, each student had to press a key on the keyboard as fast as possible.
Figure 2 shows the results for the five students.
student | reaction time in milliseconds |
1 | 245 |
2 | 200 |
3 | 210 |
4 | 215 |
5 | 225 |
Figure 2
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☐ | A | 200 milliseconds | |
☐ | B | 210 milliseconds | |
☐ | C | 215 milliseconds | |
☐ | D | 225 milliseconds |
(3)
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Figure 1 shows the responses, A and B, of a human eye to differing environmental conditions.
Suggest and explain the differing environmental conditions and their effects on the eye as shown in Figure 1.
Using your knowledge of the eye, suggest why Phrase A is more accurate than Phrase B below to describe the change of shape of the lens during a change of focus from a distant object to a close-up object.
Age-related long-sightedness is a common feature of the ageing process and tends to affect people from around age 40 onwards. Sufferers are unable to focus on close-up objects such as when reading a book.
Suggest and explain a possible reason for age-related long-sightedness and a remedy. You may use the sketches in Figure 2 to illustrate your answer.
Name the eye condition that usually affects only males, and is hereditary and untreatable.
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Figure 1 shows a human brain with four regions labelled A - D.
Figure 1
Identify regions A - D and give an example of a role of each region.
Region | Name | Function |
A | ||
B | ||
C | ||
D |
Ancient scientists including Aristotle (4th Century BCE) believed that the brain's main function was to allow excess heat to be radiated from the body. This has since been disproved by other scientists.
Suggest and explain an aspect of the brain's appearance that caused Aristotle to put forward this theory of the brain's function.
In 1975, a woman standing on a railway station platform was hit from behind by the open carriage door of a moving train. Sadly, she sustained a serious injury to the back of her head and was blinded instantly.
Explain why the woman lost her sight after this incident.
Sophisticated scanning techniques like CT and PET have allowed doctors to visualise brain function and diagnose disease, as an alternative to the use of invasive procedures like surgery. This has allowed information to be gathered much more safely and quickly in hospitals.
Contrast the techniques of CT and PET for providing information on brain function.
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A measles infection can cause inflammation of the brain.
Figure 1 shows a brain.
(1)
(3)
..................................... people
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Figure 1 shows a neurone found in the human nervous system.
Figure 1
State the name of the type of neurone seen in Figure 1 and describe its role in the nervous system.
(2)
(ii)
Label the dendrites on Figure 1.
(1)
The optic nerve is responsible for carrying electrical impulses to the brain from the eye
The eye responds to changes in the environment, such as changing light levels. Figure 2 shows a section of the eye.
Figure 2
State the structure and function of parts A, B and C in Figure 2.
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Astigmatism is an eye condition that causes blurred vision and short-sightedness.
Explain, in terms of light entering the eye, how short-sightedness is caused.
(4)
(ii)
Suggest what type of lens could be used to correct astigmatism and explain how this would work.
(3)
The nervous system contains important structures called synapses.
Explain how a signal is transmitted at a synapse.
Some painkillers work by reducing the ability of synapses to transmit signals.
One scientist investigated the effect of different painkillers on the amount of pain felt by the patient. They tested paracetamol, ibuprofen and a placebo (sugar tablet containing no medication).
The results are shown in Figure 3 below.
Figure 3
State why the scientist decided to use a placebo in the experiment.
(1)
(ii)
A student concluded that paracetamol was the most effective painkiller.
Evaluate this conclusion.
(4)
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The human nervous system is responsible for detecting and responding to changes in our environment.
Describe how impulses in the reflex arc are transmitted in order to decrease the chances of getting hurt when accidentally touching a hot saucepan.
Two students decided to investigate the speed of transmission of electrical impulses in the nervous system.
They decided to test how caffeine affected their reaction times. Student A drank a 330ml caffeinated sports drink while Student B drank a 330ml glass of water. They tested their reaction times every 5 minutes by dropping a ruler between their fingers and timing how long it took to catch the ruler.
The results of their experiment are shown in Table 1 below.
Table 1
Time after drinking caffeinated drink (mins) | Reaction time time (s) | |
Student A | Student B | |
0 | 0.16 | 0.16 |
5 | 0.15 | 0.16 |
10 | 0.13 | 0.15 |
15 | 0.11 | 0.12 |
20 | 0.09 | 0.11 |
25 | 0.10 | 0.10 |
30 | 0.11 | 0.10 |
35 | 0.14 | 0.12 |
40 | 0.18 | 0.17 |
45 | 0.18 | 0.17 |
50 | 0.18 | 0.18 |
Impulses in neurones in the reflex arc can travel at 120 metres per second.
The sensory neurone in a single reflex arc is 76mm long.
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Higher Tier only
Advances in brain scanning mean that signs of MS can be picked up much earlier than in previous years.
Magnetic Resonance Imaging (MRI) scans are the most effective way to detect changes in the brain tissue that highlight MS. The paler the appearance of the tissue, the greater the damage to the myelin sheath.
Figure 1 shows an MRI scan comparing a brain of a person without MS to a brain of a person that has MS.
Figure 1
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