The reflex arc

A scientist uses the method shown in Figure 7 to investigate the reaction times of some students.

Which measurement should be recorded to compare reaction times?

Figure 8 shows the results of five students.

Which is the mean of the results in Figure 8?

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

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

Figure 9 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.

Malaria is a disease that causes damage to the blood and liver.

Which type of pathogen causes malaria?

State how the pathogen that causes malaria is spread.

Measles is a disease caused by a virus.

Figure 9 shows the number of measles cases reported in England and Wales from 1985 to 2015.

Explain one conclusion that can be made about the change in the number of measles cases reported from 1985 to 2015.

Describe two ways the immune system will respond to an infection by a pathogen.

Beriberi is a disease caused by a lack of vitamin B1 in the diet.

Give one reason why beriberi is classed as a non‑communicable disease.

*(ii) Beriberi can affect reflexes.

Figure 10 shows a reflex arc.

When the skin is pricked by a pin, electrical impulses travel through a reflex arc.

Describe the path taken by electrical impulses from the skin to the muscles in the arm.

Include the names of neurones X, Y and Z in your answer.

A person’s mass is partially influenced by the alleles they inherit from their parents.

Give two other factors that can influence a person’s mass.

Figure 8 shows the data obtained from a patient by a doctor doing a health check.

The guidance used by the doctor is also listed in Figure 8.

Comment on the data and the health risks to this patient.

* (c) The doctor also tested the reaction time of the patient.

Describe the structure and function of a reflex arc.

Motor neurones are found in the nervous system.

Figure 8 shows a motor neurone.

Draw an arrow on Figure 8 to show the direction of travel of an electrical impulse along the motor neurone.

Name both structure K and structure L.

K_........

L_........

Figure 9 shows part of a reflex arc in the spinal cord.

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

Explain the function of a reflex arc.

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 10 shows the results for the five students.

Which is the median result for these students?

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.

Figure 1 shows part of a reflex arc in the spinal cord.

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

Explain the function of a reflex arc.

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.

Which is the median result for these students?

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.