Something that is morally good and does no harm.

Something that can be changed, measured or controlled in an experiment.

A scientific prediction is a testable statement about a possible outcome of an experiment.

Human reaction time: practical

Biology

The human nervous system

Neurones and synapses

The structure and function of a reflex arc

The human eye

Common defects of the human eye

The human brain

Pupils will learn how hormones and glands of the human endocrine system enable us to coordinate and control changes in our bodies.

Pupils learned how substances essential for chemical reactions in living cells, and the products of the reactions, are transported into, around and out of the human body, and the implications of surface area:volume ratio.

This unit explores the structure and function of the nervous system, including the CNS, reflex arcs, and the eye. It covers brain structure, common eye defects, and the challenges in treating nervous system damage. It also addresses ethical considerations.

Coordination and control: the human nervous system

Physical activity and equipment requiring safe use

The time taken for a nerve impulse to travel along a motor neurone.

The time taken for a nerve impulse to travel along a sensory neurone.

The time taken for a stimulus to be detected by receptors.

What is the correct definition of reaction time?

Andeep: Poke them with a sharp pin and time their reaction to the pain.

Izzy: Time how long it takes for them to say “on” when a lamp is switched on.

Jun: Compare their reaction times before and after eating a large dose of sugar.

Some students plan investigations into reaction time in a human participant. Whose investigation would be considered ethical?

Hold ruler with the 0 cm end aligned with the subject’s thumb and forefinger.

Without any countdown, let go of the ruler.

The subject must catch the ruler as quickly as they can.

Record the distance at which the ruler was caught.

Put the method steps in order to describe how to measure the reaction time of a test subject using the ruler drop test.

The ruler drop test can be used to investigate reaction time. In one test, the person catches the ruler at a distance of 33 cm. Use the table to convert this result to a reaction time.

The left hand had the fastest reaction time.

The right hand had the fastest reaction time.

The test subject caught the ruler at 52 cm with their left hand, and at 59 cm with their right hand. Which hand had the fastest reaction time?

It’s not possible to conclude this from the results.

The left hand appears to be their dominant hand.

The right hand appears to be their dominant hand.

The test subject caught the ruler at 52 cm with their left hand, and at 59 cm with their right hand. What can you conclude about whether they are left-handed or right-handed?

If an insect flies towards our eye, we blink to protect our eye. Which common life processes enable us to react in this way?

The {{}} system of the human body enables us to detect and react to changes in our internal or external environment.

A change in our environment that is detected by our nervous system is called __________.

The eye contains sensory __________ that detect light. This enables us to see an insect flying towards us.

When sensory receptors in the eye detect light, they transmit impulses along sensory {{}} in the peripheral nervous system.

Muscles in the eyelid that contract to make us blink.

Nerve cell that transmits impulses from the CNS to the eye.

Structure in CNS, receives nerve impulses from receptors in the eye.

We blink in response to an insect flying towards our eye. Match each keyword to the correct structure.

Starter Quiz

If an insect flies towards our eye, we blink to protect our eye. Which common life processes enable us to react in this way?