Reflex actions (OCR A-level Biology A)

This lesson describes the nervous pathways of a range of reflex actions, including spinal reflex arcs and a cranial reflex, and their survival value is explored. The PowerPoint and accompanying resources have been planned to cover the content of point 5.1.5 (i) of the OCR A-level biology A specification.

The lesson begins with a challenge, where the students have to spot the connections between 3 groups of 3 terms, and this will introduce different neurones, muscle tissues and reflexes for reference throughout. There are prior knowledge checks throughout the lesson, and one is immediately used to check on the students’ knowledge of the functions of the different structures in a nervous pathway and the order they are involved. The spinal reflex after an individual presses on a sharp pin is used to check that they can apply their knowledge to a real biological example. At this point, the potential for a reflex to be overridden if an unmyelinated relay neurone is involved is introduced and this is explained in detail later in the lesson. The knee jerk reflex is then discussed and students will understand that this is the choice for a reflex test because of the direct communication between the sensory and motor neurone.

The final part of the lesson describes the corneal reflex as a cranial reflex and students will learn how it can be inhibited through conscious control by the higher part of the brain, as happens when an individual puts contact lenses on.