Concept preview

What you will be able to do

1. 01Compare the structure of arteries, veins and capillaries and relate each to its function.
2. 02Explain what blood pressure and pulse are and what they measure.
3. 03Describe how materials are exchanged between the blood and the tissues at capillary beds.
4. 04Explain how blood in the veins is returned to the heart against gravity.

Blood travels through a branching network of arteries, capillaries and veins. Arteries carry blood away from the heart, veins return it, and capillaries provide a short exchange distance in vascular tissues. The systemic circuit supplies body tissues, while the pulmonary circuit carries blood between heart and lungs. Some tissues, including cartilage and the cornea, are avascular and receive substances by diffusion from neighbouring sources.