IBDP Biology- Arteries

The 3 main blood vessels are Arteries, Veins and Capillaries. In this IBDP Biology Post we will be focusing on Arteries, their functions and structure.

Structure and Function

Function: convey blood at a high pressure from the heart to the tissues of the body and lungs.

Specialised structure to do so:

• Relatively narrow lumen (compared to relatively thick walls) - to maintain blood pressure.
• Relatively thick walls with outer layer of collagen - prevents artery rupturing under high pressure.
• Arterial wall contains inner muscle layer and elastic fibres - maintain pulse flow (can contract and stretch) 

Flow of Blood

Blood is expelled from the heart by ventricular contraction-flows through arteries in pulses (repeated surges). 

This blood flows at high pressure - muscle and elastic fibres assist in maintaining pressure between pumps.

• The muscle fibres form a rigid arterial wall - capable of wihstanding high blood pressure without rupturing.
• can also 

contract to narrow lumen - increases pressure between pumps, maintains bp throughout cardiac cycle.

• The elastic fibres allow the arterial wall to stretch upon the flow of a pulse through lumen.
• the pressure on artetrial wall is returned to blood when artery returns to normal size (elastic recoil)
• elastic recoil helps to push the blood forward through the artery as well as maintain arterial pressure between pump cycles. 

Summary

• The small lumen maintains the high blood pressure
• Thick muscular wall and fiburous outerlayer help the artery to withstand high pressure
• Elastic fibres stretch to increase the lumen with each pulse. After the pulse the fibres recoil decreasing lumen size to help maintain high blood pressure

That's all for the structure and functions of arteries!

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References:

• https://www.google.com/url?sa=i&url=http%3A%2F%2Fib.bioninja.com.au%2Fstandard-level%2Ftopic-6-human-physiology%2F62-the-blood-system%2Farteries.html&psig=AOvVaw1rkFSWZkBk79mk5KStOjnX&ust=1625669893674000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCPiw1LTbzvECFQAAAAAdAAAAABAD

Drafted by Venetia (Biology)