Chapter: 3 Movement in & out of Cells

Reflex arcs

• Figures 12.4 and 12.5 show how these electrical impulses travel.
• If your hand touches a hot plate, a sensory receptor in your finger detects this.
• The receptor starts off an electrical impulse, which travels to the spinal cord along the axon from the receptor cell.
• This cell is called a sensory neurone, because it is carrying an impuse from a sensory receptor.
• In the spinal cord , the neurone passes the electrical impulse to several other neurons.
• These neurons are called relay neurons, because they relay the impulse on to other neurons.
• The relay neurons pass the impulse on the brain.
• They also pass it on to a motor neurone to pass to an effectors.
• In the case, the effectors are the muscles in your arm.
• The electrical impulse travels to the muscle along the axon of a motor neurone.
• The muscle then contracts, so that your hand is pulled away.

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

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

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