Blood vessels - Organisation P2 Flashcards
What do arteries do?
Carry blood away from the heart
A for Away
What is blood made of?
Main component is plasma
How is the pressure in arteries and why?
High pressure because it had just been pumped out of the ventricles
Describe the characteristics of arteries and function
- Thick wall
- Thick layer of muscle to keep the artery strong because of high pressure
- elastic fibres to expand and stretch and return to original shape
- Narrow lumen
What do capillaries do?
Take nutrients and oxygen to cells and take waste products away
What is the smallest blood vessel?
Capillaries
Characteristics of capillaries and functions
- 1 cell thick wall which is permeable - substances can easily diffuse
- Small lumen
How is the pressure in capillaries and why?
Low blood pressure which gives times for the blood to exchange things with the tissues
What do veins do?
Transport blood back to the heart
Which blood vessel has the biggest lumen?
Veins
Characteristics of veins and functions
- Thin outer wall
- Thin layer of muscle and elasticity fibres
- Valves prevent backflow of blood
What is the lumen?
The central hole
How is the pressure in veins?
Low pressure
