Homeostasis in mammals — common mistakes

For homeostasis questions, always ensure you identify the stimulus, the receptor, the coordinating centre, the effector(s), and the response(s). Use precise biological terms (e.g., 'vasoconstriction' instead of 'blood vessels getting smaller') and explain how the response contributes to bringing the condition back to the set point. For calculation questions, show your working clearly and always include units.

The primary mechanism of homeostasis in mammals is negative feedback. This system ensures that any change detected from a set point triggers a response that counteracts the initial change, bringing the internal condition back to normal. Understanding this is key for success in Cambridge 9700 Biology Paper 4, and our free revision lessons cover this in detail, along with practice questions and past papers.

Mammals regulate body temperature through thermoregulation, controlled by the hypothalamus. If the body gets too hot, mechanisms like vasodilation and sweating increase heat loss. If too cold, vasoconstriction, shivering, and increased metabolism generate and conserve heat. This complex control is a frequent topic in A Level Biology exams.

Hormones like insulin and glucagon, produced by the pancreas, are vital for maintaining stable blood glucose levels. Insulin lowers high blood glucose by promoting uptake and storage, while glucagon raises low blood glucose by stimulating glucose release from the liver. These hormonal controls are a classic example of negative feedback.