IGCSE Biology glossary
Double circulation
Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Definition
A circulatory system in which blood passes through the heart twice for each complete circuit of the body. Once in the pulmonary circuit (to the lungs) and once in the systemic circuit (to the rest of the body).
What to include in an exam answer
The advantage is the paying point at Extended: blood can be pumped at higher pressure to the body after gaining oxygen at the lungs, increasing the rate of oxygen delivery. 'Blood goes through the heart twice' alone is only the definition mark.
Example in context
Stating the advantage: 'In double circulation, blood returns to the heart after the lungs so it can be pumped at higher pressure to the body, increasing the rate of oxygen delivery.'
Related syllabus topic
Transport in animals