types of blood vessels

3blood vessels

Arteries

Veins

Capillaries

what do arteries do

Carry blood away from heart at high pressure

What is the largest artery

Aorta

Artery features

Thick, elastic walls to withstand high pressure

Snall lumen

Strong pulse

2movements at arteries

Vasodilation

Vasoconstriction

What do artery walls contain

Smooth muscle, allowing vasodilation and vasoconstriction to occur

What is vasoconstriction

Decreasing diameter of artery

What is vasodilation

Increasing diameter

Vasodilation effect on blood pressure

Lowers blood pressure

Vasoconstriction effect on blood pressure

Increases blood pressure

Why is vasoconstriction and vasodilation importnant

Crucial for regulating blood flow during exercise

What do veins do

Carry blood to the heart at low pressure

What is the largest vein

Vena cava

What are smaller veins called

Venules

What do venules do

Collect blood from capillaries

Features of vein

Thin less muscular walls

Large lumen

No pulse

Valve to prevent backflow

Features of capillaries

Thin walls made of one single cell layer

Small lumen

Large surface area

What do capillaries do

Facilitate efficient gas exchange

Connect arteries and veins

What does having a very narrow lumen do

Means red blood cells pass through slowly, allowing efficient gas exchange

2 reasons why capillaries have a smaller diameter than arteries and veins

• to maximise the amount of oxygen that can diffuse into bloodstream and muscle tissues

• To maximise the amount of carbon dioxide that can be diffused away from nucleus

How are red blood cells crucial during exercise

Transport oxygen from the lungs to the muscles

How do red blood cells transport oxygen

Oxygen binds to Haemoglobin in red blood cells to form oxyhaemoglobin, enabling efficient oxygen delivery