The Double Circulatory System
The Double Circulatory System

The heart is a muscular organ that works as two pumps side by side. In a double circulatory system, blood passes through the heart twice during one complete circuit: once through the lungs and once through the rest of the body.
Step-by-step lessons covering AQA GCSE Biology 2.2.2 The heart and blood vessels for Foundation and Higher tier. Each lesson works through exam-style questions in Paper 1 and Paper 2 format. Start with the foundational topics and build up to the higher-tier material.