Arteries, Arterioles, Veins, Venules, & Capillaries by CInbY41w

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									Arteries, Arterioles, Veins,
  Venules, & Capillaries
Arteries
           • Large hose-like vessels
           • Carry blood away from
             the heart.
           • Have thick, multi-
             layered muscular walls.
           • Walls are capable of
             stretching to
             accommodate the
             “pulse” of blood when
             the heart beats.
Arteries
• Capable of expanding
  and contracting to
  change and maintain the
  blood pressure.
• NO valves
• Blood spurts
• Blood inside them is
  high in oxygen & low in
  carbon dioxide except in
  pulmonary artery.
Arteries
• Blood inside is bright
  red
• Blood inside is under
  High pressure
• Examples:
   Coronary (heart),
   Brachial (arms),
   Carotid (head),
   Femoral (legs),
   Renal (kidney).
Arterioles
• Tiny branches off of the arteries.
• Cannot be seen with unaided eye -
  microscopic
• Thinner, less muscular walls (compared to
  arteries)
• Feed blood into the capillaries.
• Narrower than arteries, but wider than
  capillaries.
Capillaries
              • Flow and pressure of blood
                is controlled by sphincters
                that are outside of the
                capillaries.
              • Microscopic vessels ~ 8 µm
                in diameter.
              • Erythrocytes (rbc’s) pass
                through in single file.
              • Walls are only one cell thick
                (to facilitate diffusion of
                materials/exchange).
Capillaries
              • Thinness allows for
                easy diffusion
                outward or inward
                through the single cell
                layer.

              • Form capillary beds -
                networks of vessels
                linking arterial and
                venous blood.
Capillaries
• Oxygen , nutrients and other materials move
  out of the capillaries and into the extra-
  cellular fluid and then into cells.
• Carbon dioxide, wastes and other materials
  are picked up and move into the capillaries:
  (both involve diffusion for the movement).
Venules
• Vessels larger than capillaries but smaller
  (i.e. narrower and thinner walls) than veins.
Veins   • Larger inside diameter compared to
          arteries
        • Take blood towards the heart
        • Thinner, less muscular walls than
          arteries, but still 3 layers
        • No stretching or contracting of walls
          except by external muscles.
        • Contain valves to help return the
          blood to the heart (compensate for
          lower venous pressure, less muscle
          in walls, and large diameter).
Veins - Valves
Veins
    Blood:
•   Moves smoothly.
•   Low in oxygen except
    pulmonary circulation.
•   Dull red.
•   Low pressure.
•   Examples: cardiac (heart),
    brachial (arms), jugular
    (head), femoral (legs),
    renal (kidney).
Varicose Veins (copy this)

 • When the valves
   don’t function
   properly, blood
   leaks backwards
   and pools in veins

 • Veins sag, stretch
   and swell, creating
   bulging knarled
   vessels
The END!!

								
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