Starter – What is the difference between the blood in the arteries, veins and capillaries

Explain the difference between the terms open and closed circulatory system Describe the structure and functions of arteries, veins and capillaries

Lumen The gap in the middle of the vessel

Remember its all about structure and function Small lumen – for high pressure Smooth endothelium – Reduce friction Elastic fibres – allow for stretch and recoil Smooth muscle – Allow for constriction of the artery if needed Collagen fibres – To with stand the high pressure and stop you popping

Its still about structure and function Large lumen – pressure has dropped so lowering resistance Smooth endothelium – Reduce friction Collage fibres, smooth muscle and elastic fibres – all relatively few as the pressure has dropped Valves – This is the key point, prevent back flow

One cell think – allows for easy diffusion Narrow lumen – allows only one blood cell down at a time, this slows the flow rate and allows time for diffusion

TRANSVERSE SECTION THROUGH AN ARTERY Connective tissue Smooth muscle and elastic tissue LUMEN Endothelium