Cardiovascular System
PA 544
Clinical Anatomy
Tony Serino, Ph.D.
General Circulatory System
1. Cardiovascular
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–
–
–
Consists of a closed
system of vessels which
transport blood
Two circuits: Systemic
and Pulmonary
Arteries move blood away
from the heart
Veins move blood toward
the heart
General Circulatory System
2. Lymphvascular –
moves lymph
–
–
Consist of blind end
tubes which collect
interstitial fluid (now
called lymph) and
returns it to circulation
The lymph is cleaned
before returned to the
blood vessels
Blood Vessels
• Arteries –conduct blood away from heart
– Elastic arteries, Muscular arteries, arterioles
• Veins –conduct blood toward heart
– Venules, small and large veins
• Capillaries –thinnest blood vessel; used in
exchange, is the functional unit of
circulatory system (Microcirculation)
– AV shunts, metarterioles, pre-capillary
sphincters, and capillary bed
Blood Vessels Types
Vessel Anatomy
Capillary Anatomy
Three types: tight,
fenestrated and sinusoids
Capillary Types
Tight Capillary
Fenestrated Capillary
Sinusoidal Capillary
Capillary Bed
Arteries and
Veins
• Arteries are known as resistance vessels,
especially the arterioles
– Arteries withstand the greatest BP
• Veins are capacitance vessels, they are able to
change the diameter to hold more or less blood
BP through Vascular Tree
Small
changes in
arteriolar
diameter
produce big
changes in
resistance;
termed total
peripheral
resistance
(TPR)
TPR (total peripheral resistance)
• TPR is the opposition to blood flow through the
vessel (caused by friction)
• Arteries with their smaller lumen resist blood flow
• Arteriolar diameter contribute the most to TPR
– Arteriolar compliance (the ability of the vessel to
distend) controls the TPR
– Sympathetic innervation controls arteriolar radius
• The viscosity of the blood also affects resistance
Blood Flow Velocity in Vascular Tree
Blood Flow Changes During Exercise
Atherosclerotic plaque
Pressure Points
Skeletal Muscle Pump