Download Blood Vessels

Blood Vessels
Types of Blood Vessels
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_________- vessels that transport
blood away from the heart
Veins - _______________________
_______ - microscopic blood vessels
that allow exchanges between blood
and tissues
Differences between arteries
and veins
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Compared to veins, arteries
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______________
Have more smooth muscle and elastic fibers
______________
Vessel Structure - General
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All vessels same basic structure
3 wall layers (or tunics)
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___________(externa) - elastic
and laminar fibers
_______________
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Tunica_________(intima)
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_____________
elastic fibers and smooth
muscle fibers
endothelium – non-stick layer
_________________
internal elastic lamina
Lumen - __________
Blood flow through tissues
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From the heart blood flows into
 Aorta
 ___________
 Arterioles
 _________
 Venules
 ____________
 Superior/ Inferior Vena Cava
Back to the heart
Vessel Structure – Elastic Arteries
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Elastic (conducting)
arteries
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Near heart
_________
More elastic fiber,
less smooth muscle
Lose elasticity with
aging
Vessel Structure - Elastic Arteries
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Aorta and elastic arteries
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______________________
_______________
Large arteries expand,
absorb pressure wave then
release it with elastic recoil
- Windkessel effect
Help to push blood along
during diastole
______________________
______________________
Vessel Structure – Muscular Arteries
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Muscular
(distributing)
arteries
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Deliver blood to
organs
________________
_________
Less elastic fibers
Vessel Structure - Arterioles
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Arterioles
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__________________
_____________
Composition varies
depending on position
- more muscle, less
elasticity nearer heart
Regulate flow from
arteries to capillaries
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Flow = ΔP/R
vary resistance by
changing vessels
size
__________________
_______________
Vessel Structure - Capillaries
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Microcirculation connects
arteries and veins
____________________
__________________
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Higher the metabolic rate,
more capillaries in tissue
Muscle many caps
(>600/mm2)
Cartilage none
Vessel Structure - Capillaries
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Allow exchange of nutrients and wastes between blood
and tissue
_____________________
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Basal lamina - connective tissue
Endothelial cells
Structure/function
Mechanisms of Exchange
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Diffusion - major method used to
exchange substances such as O2, CO2,
glucose, and amino acids
Vesicular transport - endocytosis and
exocytosis of lipid-insoluble molecules
__________- involves filtration and
reabsorption
Veins
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Venules merge to form veins
Have 3 distinct layers; thinner walled
than arteries due to thin tunica interna
and media
_______________________
Varicose veins
______________________
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Help for venous return
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Skeletal muscle pump
 ___________________
 force blood back to heart
 valves prevent back flow
Important Terms
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Blood Flow
Blood pressure
Resistance
Blood Flow
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_________- is the amount of blood flowing
through a tissue in a given period of time
Velocity of blood flow is inversely related to
the diameter of the blood vessel
____________________________________
____________________________
Blood Pressure
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Force that the blood exerts against the
walls of a blood vessels
Factors affecting BP include cardiac output,
blood volume, viscosity, resistance, and
the elasticity of the arteries
Peripheral Resistance
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Resistance to blood flow due to the force of
friction between vessel wall and blood
_____________affected by blood viscosity,
vessel length and vessel radius
Sources affecting Resistance
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Blood viscosity- how thick or thin the blood
is. Measured by hematocrit.
__________-longer the vessel, the greater
the resistance, the greater the BP
___________-smaller the vessel the
greater the resistance