IGCSE 0654 B9 Coordination and response

Front

What is the function of the retina in the eye?

Back

The retina contains light receptor cells that detect light and convert it into electrical signals for the brain.

Front

What is a nerve impulse?

Back

A nerve impulse is an electrical signal that passes along nerve cells called neurones.

Front

What type of neurone is responsible for transmitting signals from sensory receptors to the central nervous system?

Back

Sensory neurone.

Front

What is the role of a relay neurone?

Back

A relay neurone transmits signals between sensory neurones and motor neurones within the central nervous system.

Front

What is a reflex arc?

Back

A reflex arc is the pathway taken by nerve impulses in a reflex action, typically involving a receptor, sensory neurone, relay neurone, motor neurone, and effector.

Front

What happens to the lens of the eye when looking at a close object?

Back

The suspensory ligaments slacken, and the lens becomes fatter to focus on the object.

Front

What is the role of the cornea in the eye?

Back

The cornea helps to focus light onto the retina and provides protection for the eye.

Front

What is the function of the iris?

Back

The iris controls the size of the pupil and regulates the amount of light entering the eye.

Front

What is the difference between sensory and motor neurones?

Back

Sensory neurones carry signals from sensory receptors to the central nervous system, while motor neurones carry signals from the central nervous system to effectors (muscles or glands).

Front

What is the role of the effector in a reflex action?

Back

The effector is the muscle or gland that responds to the nerve impulse, producing a reaction.