Circulatory System Flashcards
Blood
Made of 3 different types of cells and liquid called plasma
Red blood cells
Function
To carry oxygen
Structure
Does not have a nucleus and contains a chemical called haemoglobin which requires iron in the diet
White blood cells
Function
Decent against disease in 2 ways
(i) engulf bacteria that enter the blood
(ii) make antibodies to kill bacteria
Structure
Have a nucleus no def shape
Platelets
Function
Clot blood
Structure
Tiny fragments of cell
Plasma
It is the liquid part of the blood
Function
Carries dissolved substances around the body
Blood vessels
There’s 3 types
- Arteries
- Veins
- Capillaries
Arteries
Carry blood away from the heart
Arteries
Carry blood under high pressure it’s coming directly from the heart
Need thick walls
Lumen is narrow
Arteries
Blood is flowing fast in pulses
Don’t have valves
Veins
Carry blood to the heart
Veins
Under low pressure it is not coming from the heart directly
Have thin walls lumen is wide
Veins
Blood flows slowly not in pulses
Valves flowing backwards
Capillaries
Exchanges substances between the blood and cells
Capillaries
Join arteries and veins
Don’t have valves
One cell thick
Double circulation
Consists of 2 circuits
1: carries blood to the lungs then back to the heart
2: carries blood to the body and back to the heart
Happens because it stops oxygenated and deoxygenated blood mixing together