The Human Nervous System (AQA GCSE Biology: Combined Science)

Nerve tissues that communicate with muscles contain a receptor called the nicotinic acetylcholine receptor.

Figure 1 shows how a nerve impulse passing along neurone X causes an impulse to be passed along a motor neurone.

The motor neurone in Figure 1 is connected to the diaphragm, a muscle involved in breathing.

Figure 1

(a)

What type of neurone is cell X?

[1 mark]

(b)

Describe the series of events that would result in the diaphragm contracting, from X onwards.

Refer to Figure 1 in your answer.

[4 marks]

(c)

Anatoxin is a neurotoxin that is also known as ‘Very Fast Death Factor’ because when it was injected into mice it induced paralysis and death within a few minutes.

Anatoxin is similar in shape to the neurotransmitter that usually binds to the nicotinic acetylcholine receptor.

Suggest how anatoxin can lead to death.

[3 marks]

(b)

The skin surface temperature and core body temperature of a cyclist were monitored before, during and after a race, as shown in Figure 1.

Figure 1

Core body temperature rises during exercise. When an individual stops exercising, their core body temperature starts to decrease.

How long did it take for the cyclist’s temperature to recover after the race?

[1 mark]

(a)

The nerve pathway linking the light receptors in the retina of the eye to the eyelid muscle is about 0.5 m metres in length.

It would take a nervous impulse 0.006 seconds to travel this distance along neurones.

However it takes about 0.3 seconds for the blink reflex response to the ball to occur.

Explain the difference.

[2 marks]

[3 mark]

[2 marks]

[1 mark]

On a warm day it usually feels hotter when the humidity (how much water vapour is in the air) is high.

The heat index shown in Table 1, is an index that combines air temperature and relative humidity, it indicates the human-perceived ambient temperature.

Table 1

Endurance athletes such as marathon runners need to be careful when competing in hot humid conditions as their bodies can overheat causing heatstroke, which can be fatal.

Explain how temperature regulation can fail in endurance athletes, leading to overheating in hot, humid conditions.

[4 marks]

A person is playing a game tennis and hits the ball back over the net with their racket.

Suggest what the stimulus, receptors and effectors are in this action.

[3 marks]

The CNS is termed a coordination centre.

Describe what a coordination centre is.

[2 marks]

Figure 1

Complete Figure 1 by listing the correct order of events during a voluntary response.

This should include some structures through which impulses pass between the stimulus and the response. 

[3 marks]

Figure 2

[1 mark]

Neurones pass information around the body.

Explain how information is passed from one neurone to another.

[4 marks]

Reflex actions help to protect the body from damage.

Figure 3 represents the nervous pathway for a reflex action when a person accidentally steps on a sharp pin.

Figure 3

Table 2

Complete Table 2

[3 marks]

A student carried out an investigation to see if playing computer games improves reaction time.

The test consisted of pressing the 'return key' on a keyboard every time an image appeared on the screen.

The student tested two groups of five people. One group were Gamers (experienced players of computer games) and the other group were people who do not play computer games.

Table 3 shows the results.

Table 3

The student concluded:

"Playing computer games improves reaction time"

Calculate the value Y and suggest why this may not be an accurate statement.

[4 marks]