Chapter: 3 Movement in & out of Cells

The pathway along which the nerve impulse passes – the sensory neurone, relay neurons and motor neurone – is called reflex arc.

• The pathway along which the nerve impulse passes – the sensory neurone, relay neurons and motor neurone – is called reflex arc.
• The three types of neurone that are involved in a reflex arc have different shapes.
• The reaction that happens after the impulse has sped around the reflex arc called a reflex action.
• You do not need to think about reflex action, but you only consciously realize what is happening after the electrical impulse has been sent on to your muscles.
• Reflex action very useful because information gets from the receptor to the effector as quickly as possible.
• You do not waste time in thinking about what to do.
• Reflex action are automatic actions.
• They help to coordinate our actions.
• If you receive more than one stimulus at once – such as the sound of a roar and the sight of a lion leaping towards you – these stimuli will be integrated to produce electrical impluses in sensory neurons, which will travel very quickly around a reflex arc and produce an appropriate and very fast response.

Ziad ahmed – IGCSE-AS-A-Level-IB Biology Teacher WhatsApp: [phone]

Ziad ahmed – IGCSE-AS-A-Level-IB Biology Teacher WhatsApp: [phone]