Homeostasis and negative feedback (CIE International A-level Biology)

This is a detailed and engaging lesson which has been designed to cover specification points 14.1 (a, b and c) of the CIE International A-level Biology specification which states that students should be able to explain the importance of homeostasis and the roles of negative feedback and the communication systems in this control.

As homeostasis is a topic met at GCSE, this lesson has been written to build on this knowledge as well as to check on their prior knowledge of earlier A-level topics such as osmosis when considering blood water potential. Discussion points are written into the lesson at regular intervals to encourage the students to consider why a particular process or method takes place and understanding checks allow them to assess their progress. Students will recall how body temperature, blood water potential and blood glucose concentration are maintained within strict limits and the importance of these systems are looked into in detail. They will also learn that carbon dioxide concentration and blood pressure are aspects that are controlled in the body and key terminology such as chemoreceptors and baroreceptors are used throughout so that students are confident with the meaning when met later in the module. The key components of the control system are recalled and then time is taken to focus on the cell signalling that occurs between the coordination centre and the effectors. Students will learn to associate the response with either the use of the neuronal or hormonal system. The final part of the lesson looks at the importance of negative feedback in reversing the change in order to bring it back to the optimum and the differences to positive feedback are also explored.

This lesson has been written for students who are studying the CIE International A-level Biology course and ties in well with the other uploaded lessons on this topic such as those on the kidney