Blood Vessels Flashcards Preview

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Flashcards in Blood Vessels Deck (12)
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1
Q

What are the different components that are utilised in some blood vessels? (3)

A
  • Elastic fibres - composed of elastin and can stretch/recoil, provides flexibility
  • Smooth muscle - Contracts/relaxes to change size of lumen
  • Collagen - Provides structural support to maintain shape and volume of vessel
2
Q

What kind of blood do arteries carry? Where do they take the blood from and to? (3)

A
  • Carry oxygenated blood EXCEPT pulmonary artery
  • Heart to the body
  • Pulmonary carries from heart to lungs
3
Q

What is the structure of arteries? (2)

A
  • Endothelium, elastic layer, muscle layer, tough outer layer (collagen)
  • Elastic fibres allow them to withstand the force of the blood and stretch to take larger blood volume - gives continuous flow
4
Q

What are arterioles and their structure? (5)

A
  • Link arteries to capillaries
  • Have more smooth muscle and less elastin
  • Little pulse surge but can constrict/dilate to control blood flow to individual organs
  • Smooth muscle contracts to prevent blood flowing into a capillary bed (vasoconstriction)
  • Can also relax to allow blood to flow through capillary bed (vasodilation)
5
Q

What are capillaries and what is their structure? (3)

A
  • Join the arterioles to venules
  • Single cell thick - only capillary wall
  • Allow diffusion to take place
6
Q

How are capillaries adapted for their function? (3)

A
  • Large SA:V to maximise diffusion into and out of blood
  • Cross-sectional are is smaller than arterioles - reduce pressure and blood flow - slows blood so that there is enough time for diffusion
  • One cell thick - reduced diffusion pathway
7
Q

What kind of blood do veins carry? Where do they take the blood to and from? (4)

A
  • Carry deoxygenated blood EXCEPT pulmonary vein and the umbilical vein
  • From body cells to the heart
  • Pulmonary carries oxygenated blood from lungs to heart
  • Umbilical vein carries oxygenated blood from placenta to fetus
8
Q

What are venules and their structure? (2)

A
  • Very small veins that connect capillaries to veins

- Similar structure to arterioles, but generally just increasing the lumen for blood to be carried to the heart

9
Q

What is the structure of veins? (5)

A
  • Endothelium, elastic layer, smooth muscle, tough outer layer
  • No pulse
  • Low pressure compared to arteries
  • Have valves to prevent back-flow of blood
  • Wide lumen, smooth lining to let blood flow easily
10
Q

Why do veins have valves? (2)

A
  • Low pressure

- Effect of gravity on blood

11
Q

How do valves work? (2)

A
  • When the blood moves forward, the valve opens to let blood through
  • When blood moves backwards, valve closes to prevent backwards movement
12
Q

How else do we prevent backflow? (2)

A
  • Muscle contraction squeezes veins, forcing blood towards the heart
  • Breathing movements of chest as a pump, squeezing the veins and forcing blood to move