Topic 1: Blood vessels Flashcards
Name all the {structures/properties} of the artery
8 parts
- Outer collagen coat / connective tissue
- Thick smooth muscle layer
- Thick elastic fibre layer
- Thick wall
- Smooth endothelium
- Folded endothelium
- Narrow lumen
- No valves
Why does an artery have an outer collagen coat / connective tissue?
(2 points)
- Strength to WITHSTAND increased blood pressure
2. and prevent artery bursting
Why does an artery have a thick smooth muscle cell layer?
2 points
- Muscle contraction constricts the artery, this is vasoconstriction, to control blood flow
- and MAINTAIN high pressure
Why does an artery have a thick elastic fibre layer?
2 points
- Allow the artery to stretch (as the blood pressure is high), then recoil to push the blood forward
- and MAINTAIN high blood pressure
Why does an artery have a thick wall?
1 point
- To WITHSTAND the high blood pressure
Why does an {artery/vein} have a smooth endothelium?
1 point
- Reduces resistance to blood flow
Why does an artery have a folded endothelium?
1 point
- Stretches to accommodate blood
Why does an artery have a narrow lumen?
1 point
- To MAINTAIN high blood pressure
Why does an artery have no valves?
1 point
- Not needed, blood is forced forward by heart contraction and elastic recoil
Name all the {structures/properties} of the vein
6 parts
- Outer collagen coat
- Thin smooth muscle cell layer
- Thin elastic fibre layer
- Smooth endothelium
- Wide lumen
- Valves
Why does a vein have an outer collagen coat?
1 point
- For strength
Why does a vein have a thin muscle cell layer?
1 point
- Less contraction to constrict vein
Why does a vein have a thin elastic fibre layer?
1 point
- Less elastic recoil, as blood is moved by skeletal muscle contraction
Why does a vein have a wide lumen?
3 points
- Reduces friction between walls and blood
- prevents low pressure blood slowing down
- Vein may be easier to squeeze between skeletal muscles (along with thin walls)
Why does a vein have valves?
1 point
- Prevents backflow of blood
Name all the {structures/properties} of the capillary
3 parts
- Capillary wall (endothelium) is THIN - one cell thick and flattened cells
- Have tiny PORES (holes) in walls
- Very NARROW lumen
Why is the capillary wall thin, one cell thick, and made of flattened cells?
(1 point)
- SHORTER DIFFUSION DISTANCE - helps exchange of dissolved substances between the blood and {tissue fluid/cells}
Why does a capillary have tiny pores (holes) in walls?
1 point
- To allow the passage of materials through the wall, aiding formation of tissue fluid
Why does a capillary have a very narrow lumen?
2 points
- Slows down the flow of blood - allows time for exchange for oxygen etc. between blood and cells to take place more efficiently.
- Walls of red blood cells are in contact with the wall of the capillary, reducing distance for oxygen to enter cells
Also capillaries are numerous – creates a large ________ _____
for gas exchange. Every cell is close to a capillary.
surface area
What are the structural DIFFERENCES between an artery and a vein?
(3 points)
- Artery has a narrowER lumen
- artery has a thickER wall - {more/thicker} layer of elastic fibres and more smooth muscle
- artery does not have valves, veins do
What are the structural SIMILARITIES between artery and vein?
(4 points)
Both have:
1. {connective tissue/collagen outer wall}
- elastic fibres
- smooth muscle
- endothelium
What are the key features of an artery?
5 features
- carry blood under high pressure, so no valves needed
- divide into smaller vessels called arterioles, then capillaries
- blood in most arteries is oxygenated (not pulmonary)
- carry blood away from the heart to body cells
- a pulse, due to stretch and recoil, can be felt in arteries
What are the key features of a vein?
5 features
- carry blood under very low pressure
- have valves to prevent backflow of blood
- formed when smaller vessels called venules combine
- blood in most veins is deoxygenated (not pulmonary)
- carry blood to the heart from body cells
