International A Level Biology / Muscles, movement and the heart

Negative and positive feedback revision notes

Edexcel International A Level Biology (YBI11), chapter 21: Muscles, movement and the heart, specification point 7.16. Part of the full course.

Watch the video lesson · International A Level Biology past papers

Feedback systems help keep conditions in the body steady. Negative feedback reverses a change and then switches off, while positive feedback makes a change bigger.

More lessons in Muscles, movement and the heart

• How muscles, tendons, ligaments and the skeleton produce movement
• The structure of a skeletal muscle fibre
• Fast and slow twitch muscle fibres
• The sliding filament theory
• The myogenic heartbeat: SAN, AVN, bundle of His
• Reading ECGs
• Cardiac output
• Controlling heart rate: the cardiovascular control centre
• Controlling breathing: the ventilation centre
• Core practical 17: spirometer traces and exercise