2.90: Describe the Structure and Functioning of a Simple Reflex Arc Illustrated by the Withdrawal of a Finger from a hot Object

REFLEX: Fast involuntary reaction that protects body from damage

WITHDRAWAL OF FINGER FROM HOT OBJECT:

REFLEX ARC

Diagram showing the Reflex Arc in Response to a Hot Object

PROCESS: When Hand is near a hot object, heat (stimuli) is detected by the Finger (receptor), stimulating Sensory Neurons to send electrical impulses to the Central Nervous System - Brain and Spinal Cord Central Nervous System will receive and interpret message, determining the appropriate reaction of pulling hand away from the hot object This impulse is relayed across the Synpase to Relay Neurons via synaptic transmission Relay Neurons relays impulse to Motor Neurons in the Bicep As a result, Bicep will contract to quickly draw hand away from the heat, allowing a rapid response to prevent harm to the body