B4.2 The blood vessels Flashcards
What are the three types of blood vessels?
Arteries
Capillaries
Veins
What are the purpose of arteries?
Carry blood away from your heart to the organs of your body
What type of blood do arteries carry?
Bright -red oxygenated blood
Why do arteries have thick walls?
They have thick walls containing muscle and elastic fibres - as the blood in the arteries is under pressure it is very dangerous if an artery is cut because blood will spurt out rapidly ever time the heart beats
What are the purposes of veins?
Carried blood away from the organs towards your heart
What type of blood do veins carry?
Deoxygenated blood
What are the purposes of valves?
Prevent the backflow of blood
How do valves work?
Valves open as blood flows though them to the heart - but if the blood stars to flow backwards the valves close and prevent a backflow of flood
How is the blood squeezed back toward the heart?
By the action of the skeletal muscles
What are capillaries?
Narrow with very thin walls
The capillaries are where gas exchange takes place as well as they also take waste products away from your tissue
How big are the lumens compared with veins and artery?
Veins have large lumens
Arteries have small lumens
How are capillaries adapted?
Thin walls which make the diffusion of waste products more efficient
What is the double circulatory system?
One transport system carries blood from your heart to the lungs and back again - allows CO2 and O2 to be exchanged
The other transport system carries blood from your heart to all the organs of your body and back again
Why is the double circulation important?
Very efficient
More parts of your body can be oxygenated quickly due to higher pressure
