The Blood System Flashcards
What does the circulatory system do?
Transport substances around the body
What is the heart?
An organ that pumps blood around the body
What is much of the heart wall made from?
Muscle tissue
How many main chambers are there in the heart?
4
What are the main chambers?
Left and right atria, left and right ventricles
Where does the blood enter in the heart?
Atria
How do the atria force blood into the ventricles?
They contract
How do the ventricles force the blood out of the heart?
They contract
What do valves in the heart ensure?
That blood flows in the right direction
Where does blood flow from the heart to?
The organs
What type of blood vessel does blood flowing towards the organs travel in?
Arteries
What type of blood vessel does blood flowing towards the heart travel in?
Veins
How many circulatory systems are there?
2
What is each of the circulatory systems for?
One for the lungs, one for all the other organs of the body
What type of walls do arteries have?
Thick walls
What do artery walls contain?
Muscle and elastic fibres
What type of walls do veins have?
Thinner walls
What are often found in veins? Why?
Valves, to prevent back-flow of the blood
When are stents used?
When arteries begin to narrow and restrict blood flow
What are capillaries?
Very narrow, thin walled blood vessels
Where are capillaries found?
In organs
Where do substances needed by cells in body tissues pass out of the blood through?
The walls of the capillaries
Where do substances produced by cells pass into the blood through?
Walls of the capillaries
Why are stents good? 3
They open arteries almost anywhere in the body, no anaesthetic needed, lower the risk of heart attacks in people with coronary diseases
Why are stents bad? 3
They can’t open blocked arteries, stents can irritate the artery and make scar tissue grow, the patient has to take drugs to stop the blood clotting on the stent
