Hormones as chemical messengers
Hormones as chemical messengers

The endocrine system coordinates organs using hormones carried in the blood. The nervous system uses electrical impulses for fast, short-lived responses, while endocrine responses are usually slower but longer-lasting.
Step-by-step lessons covering OCR GCSE Biology Coordination and control – the endocrine system for Foundation and Higher tier. Each lesson works through exam-style questions in the written papers format. Start with the foundational topics and build up to the higher-tier material.