The function of arteries is to transport blood rapidly under high pressure from the heart to the tissues. The muscle layer is thick compared to the veins. This means that smaller arteries can be constricted and dilated in order to control the volume of blood passing through. The elastic layer is relatively thick compared to veins.During systole the elastic layer stretches and during diastole the elastic layer recoils. The stretching and recoiling action of the elastic layer maintains high blood pressure. The overall thickness of the wall is great as it resists bursting the vessel under high pressure. There are no valves as the blood tends not to flow backwards as the blood is under high pressure. However, there are valves in the arteries leaving the heart.
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Specification: OCR Biology A (H020), AS-level, 3.1.2 Transport in animals. Topic: Transport in Animals.
Key terms in this lesson
- systole
- The phase of the cardiac cycle in which the heart muscle contracts, forcing blood out of a chamber.
- diastole
- The phase of the cardiac cycle in which the heart muscle relaxes, allowing a chamber to fill with blood.
More in Transport in Animals
- Closed Circulatory Systems
- Single Closed Circulatory Systems
- Double Closed Circulatory Systems
- Blood Vessels
- Arterioles
- Veins and Venules
- Capillaries
- Tissue Fluid
All 32 lessons in Transport in Animals · All OCR AS-level Biology topics