Structure and function of a REFLEX ARC (Edexcel GCSE Biology & Combined Science)

This resource contains a detailed and engaging PowerPoint and accompanying worksheets, all of which have been designed to cover point 2.14 of the Edexcel GCSE Biology or Combined Science specification. This specification point states that students should be able to explain the structure and function of a reflex arc including sensory, relay and motor neurones. The lesson builds on the knowledge from point 2.13 where students learnt about the structures in the nervous system.

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 the three neurones.

This lesson contains a wide range of activities which include quiz competitions to introduce key terms and values in a fun and memorable way as well as understanding and prior knowledge checks so that students can assess their grasp of the critical content.

It has been written for students studying the Edexcel GCSE Biology or Combined Science courses but is also suitable for younger students looking at the nervous system or A-level students who need to recall the key details and structures