The components of a REFLEX ARC (WJEC GCSE Biology)

This lesson resource contains a engaging PowerPoint and accompanying worksheets, all of which have been designed to cover the content of specification point 2.5 (d) on the WJEC GCSE Biology specification. This specification point states that students should know the components of a reflex arc. This lesson builds on the knowledge from the previous lesson on the structure and function of the nervous system (2.5b).

The lesson begins by challenging the students to come up with the word reflex having been presented with 5 other synonyms of the word automatic. This leads into a section of discovery and discussion where students are encouraged to consider how a reflex arc can be automatic and rapid despite the fact that the impulse is conducted into the CNS like any other reaction. Students will be introduced to the relay neurone and will learn how this provides a communication between the sensory neurone and the motor neurone and therefore means that these arcs do not involve processing by the brain. Moving forwards, the main task of the lesson challenges the students to write a detailed description of a reflex arc. Assistance is given on the critical section which involves the relay neurone in the spinal cord before they have to use their knowledge of nervous reactions to write a paragraph before and after to complete the description. As a final task, students will have to compare the structure and functions of sensory, motor and relay neurones.

Although this lesson has been designed for students studying on WJEC GCSE Biology course, it is also suitable for older students who are studying reflex reactions at A-level and need to recall the main details.