The nervous system

Animals produce coordinated responses when there are changes to their internal or external environments.

An animal’s nervous system is important in coordinating responses.

Put a tick (✓) next to any statements that correctly describe the functions of parts of an animal’s

Hormones are responsible for coordinating longer lasting responses.

Describe how low thyroxine levels would stimulate a response by the body.

Use the words in the list within your answer.

hypothalamus pituitary gland TRH TSH

* IVF is a treatment some people use when they have difficulty getting pregnant.

This treatment involves the use of hormones involved in the menstrual cycle and eggs being fertilised by sperm in a laboratory.

Embryos are then transferred into a female’s uterus.

This treatment has different results depending on age:

• females under 35 have a 32% success rate

• females aged 40–42 have an 11% success rate.

Name the hormones which are used in IVF treatment and explain their function. Evaluate the effectiveness of using IVF treatment.

Doctors can test your eye reflexes by touching the eye to make you blink. Fig. 14.1 shows the reflex arc involved in blinking.

Fig. 14.1

Explain how the components of the nervous system produce the response of blinking. Use Fig. 14.1.

The endocrine system also controls the body.

Which endocrine gland releases thyroxine into the blood?

Describe two effects of adrenaline on the human body.

Hormones are used in the contraceptive pill.

Explain how the progesterone contraceptive pill prevents pregnancy.

Identify hormone Y.

Explain why hormone X is glucagon.

Compare the functions of glucagon and hormone Y.

A student draws and labels a diagram of a reflex arc.

The diagram shows their labelled drawing.

What mistake has the student made in their drawing?

Tick (✓) one box.

The spinal cord coordinates nervous responses.

Which other part of the central nervous system coordinates responses?

The body is also controlled by the endocrine system.

Complete the table to show two differences between the nervous system and the endocrine

Oestrogen and testosterone are both hormones.

Write down one role of oestrogen and one role of testosterone in the body.

A person with type 1 diabetes tests their blood sugar level before they eat any food.

The diagram shows their results. The units for blood sugar level are mmol / l.

The person then compares their results with the information in this table.

Explain why the person will need to take insulin.

The diagram shows the central nervous system (CNS).

Complete the sentence to describe the structure of the CNS. Use the diagram.

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

Hot objects can burn your skin. Removing your hand from a hot object is a reflex action. The response is a reflex action because it is controlled by a reflex arc.

Suggest two other reasons why the response is a reflex action.

Draw lines to connect each part of the reflex arc to its correct function when responding to a hot object.

A student uses a computer program to measure the reaction times of their friends.

The table shows their results.

Identify the median reaction time for the five friends.

Calculate the mean reaction time for the five friends.

Use the data in the table to suggest one reason why friend D has the fastest reaction time.

Adrenaline is a hormone that speeds up reaction times.

Describe the typical features of hormonal coordination such as adrenaline in the body.

The diagram shows a sensory neurone.

What is the part labelled X ?

A Axon

B Dendrite

C Cell body

D Nucleus

A student investigates coordination.

They set up the apparatus shown in diagram Fig. 14.1.

The student asks a friend to draw around the star, keeping between the two lines.

The friend can only see the star in the mirror.

The student measures how many seconds it takes the friend to draw around the star. He also counts the number of errors they make.

This is repeated five times.

The student records the results in Table 14.1.

The student investigates how the number of attempts affects the accuracy of drawing the star.

What are the independent variable and dependent variables for this investigation?

independent variable........

dependent variables........ and........

The friend has improved their time and the number of errors they make.

Calculate percentage change in the number of errors in Table 14.1.

Give your answer to 2 significant figures.

The student makes this conclusion about their results.

My results show that practising a task will always help you improve.

Explain why this conclusion may not be valid.

*(c) The diagram in Fig. 14.1 and Table 14.1 are repeated below.

Drawing around the star is a coordinated response.

Explain how the body coordinates the response and suggest an explanation for the pattern in the results in Table 14.1.

The diagram shows a motor neurone.

Label 1 and 2 on the diagram.

Nerve impulses can travel along axons at different speeds.

The graph shows the relationship between the speed of a nerve impulse and the diameter of the axon.

Describe the relationship between diameter and speed of impulse.

The data was measured as part of an investigation by a scientist. The scientist made this statement.

‘The data collected is mostly precise.’

What evidence is there in the graph to support this statement?

The diagram shows a motor neurone.

What is the function of part X ?

A Generates an impulse

B Insulates the axon

C Slows down the speed of an impulse

D Stops an impulse travelling the wrong way