T5 - the human nervous system

Question 1

What is the role of the human nervous system?

Answer 1

The role of the nervous system is to allow humans to detect changes in their surroundings and coordinate responses.

Question 2

What are receptor cells?

Answer 2

Receptor cells are cells that detect stimuli, e.g. cells in the eyes detect changes in light levels.

Question 3

True or False? Information passes along neurones in the form of electrical impulses.

Answer 3

True. Information is passed along neurones and between the different parts of the nervous system in the form of electrical impulses.

Question 4

Which two organs make up the central nervous system (CNS)?

Answer 4

The CNS is made up of the brain and the spinal cord.

Question 5

What are effectors?

Answer 5

Effectors are the parts of the body that respond to changes in the environment. They can be muscles or glands.

Question 6

Write a flow diagram to show the pathway of an electrical impulse through the nervous system.

Answer 6

The pathway of an impulse is as follows: stimulus → receptor → sensory neurone → CNS → motor neurone → effector → response

Question 7

What are reflex actions?

Answer 7

Reflex actions are automatic, rapid actions that do not involve conscious thought.

Question 8

Why are reflex actions important?

Answer 8

Reflex actions are important because they protect the body from harm.

Question 9

Write a flow diagram to represent a reflex arc.

Answer 9

A flow diagram that represents a reflex arc would be as follows: stimulus → receptor → sensory neurone → relay neurone → motor neurone → effector → response

Question 10

True or False?

Answer 10

Sensory neurones in a reflex arc connect receptor cells with the conscious brain.

Question 11

What is a relay neurone?

Answer 11

A relay neurone is a neurone within the CNS that connects sensory and motor neurones.

Question 12

True or False?

Answer 12

Synapses in reflex arcs are located between the end of a sensory neurone and the start of a relay neurone.

Question 13

What is the role of a motor neurone in a reflex arc?

Answer 13

Motor neurones in reflex arcs connect relay neurones with effectors.

Question 14

Which factors could be chosen as independent variables when investigating the effect of a factor on reaction time?

Answer 14

Factors that could be chosen as independent variables when investigating the effect of a factor on reaction time include: caffeine intake; environmental factors, e.g. background noise, room temperature; time since last meal; hours of sleep

Question 15

How can a ruler be used to measure reaction time?

Answer 15

A ruler can be used to measure reaction time by dropping it vertically from a set height with 0 cm facing downwards and measuring the distance at which a volunteer catches it. The shorter the distance, the faster the reaction time.

Question 16

In an investigation into the effects of caffeine on reaction time, which variables should be controlled?

Answer 16

Variables that should be controlled when investigating the effect of caffeine on reaction time include: environmental factors, e.g. noise and temperature; the hand being used to catch the ruler, i.e. right vs left; the height from which the ruler is dropped; the time between caffeine consumption and the ruler drop test

Question 17

When investigating the effect of a factor on reaction time, what is the benefit of repeating the measurement several times at each level of the independent variable?

Answer 17

The benefit of repeating the measurement several times at each level of the independent variable when performing the ruler drop test is that it allows anomalous results to be identified. These can then be left out when calculating the mean.

Question 18

Which is the anomalous result in the table below?

Answer 18

Table showing the reaction times in milliseconds for three students across five attempts and their mean times. Student C has a notably high time in attempt 3.

Question 19

What is the role of the brain in the nervous system?

Answer 19

The role of the brain is to control complex behaviour, as well as regulating body functions.

Question 20

What are the brain structures labelled A-C on the diagram below?

Answer 20

IMAGE Structures A-C can be identified as follows: A = cerebral cortex; B = medulla; C = cerebellum

Question 21

What is the role of the cerebral cortex in the brain?

Answer 21

The cerebral cortex is responsible for higher brain functions such as consciousness, intelligence, memory and language.

Question 22

True or False?

Answer 22

The cerebellum in the brain is involved with the control of heart rate.

Question 23

Which body functions are regulated by the medulla in the brain?

Answer 23

The medulla in the brain regulates unconscious functions such as: breathing; heart rate; digestion

Question 24

Why is it difficult to study brain function and to treat damage in the brain? (Higher Tier Only)

Answer 24

It is difficult to study brain function and to treat damage in the brain because: the brain is delicate; brain function is highly complex; the functions of different brain areas are interconnected so it is difficult to study regions in isolation

Question 25

How can neuroscientists map brain function? (Higher Tier Only)

Answer 25

Brain function can be mapped by: studying patients with damage to known areas of the brain; electrical stimulation of the brain and observation of response; MRI scanning

Question 26

What are the structures labelled A-E on the diagram below?

Answer 26

IMAGE The structures labelled A-E are: A = ciliary muscles; B = suspensory ligaments; C = cornea; D = iris; E = retina

Question 27

Where is the sclera of the eye?

Answer 27

The sclera of the eye is the white layer that forms the outside of the eyeball.

Question 28

Define the term accommodation in the context of eye function.

Answer 28

Accommodation is the process by which the lens of the eye changes its shape to focus on objects at different distances.

Question 29

What is the role of the ciliary muscle in accommodation?

Answer 29

The ciliary muscles contract or relax to change the shape of the lens during accommodation.

Question 30

What happens to the ciliary muscles, suspensory ligaments and lens when focusing on a near object?

Answer 30

When focusing on a near object: The ciliary muscles contract; The suspensory ligaments loosen; This causes the lens to become thicker (more curved), increasing refraction of light for close vision.

Question 31

True or False?

Answer 31

When focusing on a distant object the ciliary muscles relax and the suspensory ligaments loosen.

Question 32

How does the eye adapt to deal with dim light?

Answer 32

The eye adapts to deal with dim light by dilating the pupil; this allows more light to enter the eye.

Question 33

Define the terms myopia and hyperopia.

Answer 33

The terms can be defined as follows: myopia = short sightedness; hyperopia = long sightedness

Question 34

What causes short or long sightedness?

Answer 34

Short and long sightedness are caused by an inability to focus light onto the retina.

Question 35

How can short and long sightedness be treated?

Answer 35

Short and long sightedness can be treated by: wearing spectacles that refract light correctly; use of hard or soft contact lenses; laser surgery; replacing the lens of the eye

Question 36

Which part of the brain monitors and controls body temperature?

Answer 36

The part of the brain that monitors and controls body temperature is the thermoregulatory centre.

Question 37

What is the role of receptors in the control of body temperature?

Answer 37

Receptors are involved with temperature control as follows: receptors in the thermoregulatory centre monitor blood temperature; receptors in the skin detect air temperature and send impulses to the thermoregulatory centre

Question 38

How does sweating increase heat loss from the body?

Answer 38

Sweating increases heat loss when sweat evaporates from the skin surface. The evaporation of sweat transfers heat energy away from the skin.

Question 39

Define the term vasodilation.

Answer 39

Vasodilation is a cooling mechanism in which the diameter of skin arterioles increases. This increases blood flow to capillaries in the skin surface, transferring heat to the environment by radiation.

Question 40

How do blood vessels and sweat glands respond to an increased body temperature?

Answer 40

An increase in body temperature leads to the following changes: Sweat glands release sweat which cools the skin by evaporation; Skin arterioles undergo vasodilation to increase blood flow to the capillaries at the surface of the skin

Question 41

True or False?

Answer 41

When a person enters a colder environment blood flow to the surface of the skin is reduced.

Question 42

How does shivering contribute towards temperature regulation?

Answer 42

Shivering occurs when body temperature is too low. The rapid muscle contractions generate heat, raising the core body temperature.

Question 43

True or False?

Answer 43

Constriction of the capillaries reduces blood flow to the surface of the skin.