The Blood Vessels Flashcards
What are the names of the 3 blood vessels?
- Arteries
- Veins
- Capillaries
What type of blood do the arteries carry? Is there an exception?
Oxygenated blood from the heart to the rest of the body. Th only exception is the pulmonary ARTERY which carries DEoxygenated blood to the lungs (getting rid of CO2).
Arteries have THICK WALLS: what are they made from and what does this allow them to do?
They are made from MUSCLE and ELASTIC FIBRES to allow them to EXPAND as blood is pulsed through.
What do the elastic fibres specifically do?
They give strength to prevent them from bursting.
In the arteries, what happens after a high pressure pulse?
The elastic fibres RECOIL and the muscle fibres CONTRACT to SMOOTH OUT the flow of blood.
Out of the three blood vessels, what one has valves?
Veins!
Is the LUMEN in the arteries wider or narrower than the veins’?
Narrower than veins’ lumen.
What kind of blood does there veins carry? Is there an exception?
Deoxygenated (rich in CO2) from the body back to the heart. The exception to this is the pulmonary vein which carries oxygenated blood from the lungs to the heart.
In the veins, are the walls thicker or thinner than those in the arteries, why?
The walls are thinner as blood is carried at LOW pressure.
There is less pressure and NO PULSE in the veins, what does this mean in terms of fibres?
They have less muscle and elastic fibres.
Why do the veins have valves?
As the blood flows at LOW pressure, the valves prevent the BACKFLOW of blood and ensure the blood flow is UNIDIRECTIONAL.
Why do the veins have a large lumen?
To REDUCE FRICTION and allow blood to flow easily.
What happens at the capillaries?
This is the site at which exchange of oxygen, carbon dioxide, and nutrients take place.
How thick are capillaries?
The capillaries are only ONE CELL thick and have VERY THIN PERMEABLE walls meaning that substances can DIFFUSE out of them very easily.
What is the impact of there being lots and lots of capillaries? What does this allow?
This slows down the rate of blood flowing through them. This means there is more time for the EXCHANGE OF MATERIALS between the capillaries and the body fluids.
What USEFUL substances diffuse out of the blood in the capillaries and into the cells?
Oxygen, glucose and food.
What happens to the waste products such as carbon dioxide in terms of the capillaries?
They diffuse from the body’s cells and are REABSORBED back into the blood in the capillaries.
Out of the three blood vessels, what one has HIGH blood pressure?
The arteries.
What is the direction of blood flow in the capillaries?
Carries blood from the arteries to the veins.
What is the direction of blood flow in the arteries?
Carries blood from the heart to the rest of the body (OXYGENATED-APART FROM THE PULMONARY!).
What is the direction of blood flow in the veins?
Carries blood back towards the heart from the rest of the body (DEOXYGENATED-APART FROM THE PULMONARY!)
What is the function of the pulmonary vein?
Carries OXYGENATED blood from the lungs to the heart.
What is the function of the aorta?
Carries OXYGENATED blood from the heart around the body.
What is the function of vena cava?
Carries DEOXYGENATED blood from the body back to the heart,
