Neurones

Figure 5 shows a human brain.

Which is a function of the cerebellum?

Label the cerebral hemisphere on Figure 5.

State two functions of the cerebral hemispheres.

The brain sends information to the muscles in the iris of the eye.

Name the type of neurone that transmits nerve impulses from the brain to the muscles in the iris of the eye.

Figure 6 shows a human eye.

Explain how the pupil changes size.

Short-sightedness is a defect of the eye.

State one cause of short-sightedness.

A scientist uses the method shown in Figure 11 to investigate the reaction times of some students.

• suddenly lets the ruler fall

Which measurement should be recorded to compare reaction times?

Figure 12 shows the results of five students.

Which is the mean of the results in Figure 12?

Explain which of the five students had the slowest reaction time.

Give two variables that need to be controlled during this investigation.

Figure 13 shows a motor neurone.

State the role of a motor neurone in a reflex arc.

Explain the function of the myelin sheath.

Describe how a nerve impulse passes across the gap between two neurones.

Reaction time can be tested by dropping a ruler and measuring the distance it travels before it is caught.

Figure 9 shows how the test works.

This method was used to test the reaction times of three students.

Each student completed the test five times and the distances were recorded.

State how the median distance for each student could be determined from the results.

State and explain one variable that needs to be controlled in this investigation.

Figure 10 shows the results recorded for the three students.

Explain one conclusion that can be made from the results in Figure 10.

A student wanted to investigate the effect of two different drinks containing caffeine on reaction time using this method.

Devise a plan the student could use.

Figure 11 shows a myelinated sensory neurone.

Identify structure Z.

Figure 12 shows how the diameter of neurones affects the speed of electrical impulses.

Comment on how the diameter of a neurone affects the speed of the electrical impulses.

An optician tested the eyesight of 240 people.

35% of these people could read the normal vision row without wearing glasses.

The rest of the people need glasses to correct their vision.

Calculate the number of people who need glasses to correct their vision.

An optician can use the chart to diagnose short-sightedness.

Give one reason why people are short-sighted.

Which diagram shows how short-sightedness can be corrected?

Cataracts can affect a person’s vision.

Figure 20 shows what a person with normal vision and a person with cataracts can see for the top letter on the optician’s chart.

person with normal vision person with cataracts

Figure 20

Describe why a person with cataracts would see the image shown in Figure 20.

State the treatment for cataracts.

Figure 21 shows the structure of the brain.

Which region of the brain is labelled structure X?

When a person reacts to a stimulus, messages from the brain are sent to their muscles.

Describe how messages are sent from the brain to muscles.

Figure 5 shows a chart used by opticians to test a person’s vision.

The person’s vision is judged by the lowest row of letters they can read.

An optician tested the eyesight of 240 people.

35% of these people could read the normal vision row without wearing glasses.

The rest of the people need glasses to correct their vision.

Calculate the number of people who need glasses to correct their vision.

An optician can use the chart to diagnose short-sightedness.

Give one reason why people are short-sighted.

Which diagram shows how short-sightedness can be corrected?

Cataracts can affect a person’s vision.

Figure 6 shows what a person with normal vision and a person with cataracts can see for the top letter on the optician’s chart.

person with normal vision person with cataracts

Figure 6

Describe why a person with cataracts would see the image shown in Figure 6.

State the treatment for cataracts.

Figure 7 shows the structure of the brain.

Which region of the brain is labelled structure X?

When a person reacts to a stimulus, messages from the brain are sent to their muscles.

Describe how messages are sent from the brain to muscles.

8 (a) Motor neurones are found in the nervous system. Figure 16 shows a motor neurone.

Figure 16

(i) Draw an arrow on Figure 16 to show the direction of travel of an electrical impulse along the motor neurone.

(ii) Name both structure K and structure L.

(b) Figure 17 shows part of a reflex arc in the spinal cord. sensory neurone

relay neurone

Figure 17

(i) Describe how an impulse passes from the relay neurone to the motor neurone.

(ii) Explain the function of a reflex arc.

(c) 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 18 shows the results for the five students.

Figure 18

(i) Which is the median result for these students?

(ii) The scientist wanted to investigate if the colours of the squares used on the computer program affected reaction time. The computer program started with blue squares that turned into yellow squares. Describe how the scientist could compare the reaction times of these students when they respond to red squares turning into yellow squares.

2 (a) Figure 2 shows part of a reflex arc in the spinal cord. sensory neurone

relay neurone

Figure 2

(i) Describe how an impulse passes from the relay neurone to the motor neurone.

(ii) Explain the function of a reflex arc.

(b) 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 3 shows the results for the five students.

Figure 3

(i) Which is the median result for these students?

(ii) The scientist wanted to investigate if the colours of the squares used on the computer program affected reaction time. The computer program started with blue squares that turned into yellow squares. Describe how the scientist could compare the reaction times of these students when they respond to red squares turning into yellow squares.

The reaction time of five people was tested using a computer.

These people were then given 100 cm³ of a liquid to drink.

Their reaction times were recorded 10 minutes after drinking the liquid.

Figure 9 shows the results.

Calculate the mean difference in reaction time.

Give your answer in milliseconds.

The drinks manufacturer wants to advertise the effect of the drink on reaction time.

The manufacture needs to confirm the effect on reaction time by improving the investigation.

Give two improvements the manufacturer would need to make to this investigation.

Figure 10 shows a neurone.

Name the type of neurone shown in Figure 10.

Which row identifies structure P and structure Q ?

*(c) Some painkillers prevent neurotransmitters binding to receptors in a synapse.

Explain how a signal is transmitted at a synapse and how the painkillers reduce the pain felt by the person.

Figure 16 shows the number of neurones in the brain of different animals.

Calculate the difference between the number of neurones in the brain of the rat and the brain of the frog.

Give your answer in standard form.

Most neurones in the brain are unmyelinated whereas motor neurones are myelinated.

Explain why myelination is needed on motor neurones but not on neurones in the brain.

Figure 17 shows a sensory neurone.

Label the axon on Figure 17.

Describe the role of sensory neurones.

Explain how impulses are transmitted at synapses.