Overview
of the Vascular System
The
vascular system, also called the circulatory system,
is made up of the vessels that carry blood and
lymph through the body. The arteries and veins
carry blood throughout the body, delivering oxygen
and nutrients to the body tissues and taking away
tissue waste matter. The lymph vessels carry lymphatic
fluid (a clear, colorless fluid containing water
and blood cells). The lymphatic system helps to
protect and maintain the fluid environment of
the body by filtering and draining lymph away
from each region of the body.
The
vessels of the blood circulatory system are:
- arteries - blood vessels
that carry oxygenated blood away from the heart
to the body.
- veins - blood vessels
that carry blood from the body back into the
heart.
- capillaries - tiny
blood vessels between arteries and veins that
distribute oxygen-rich blood to the body.
Blood
moves through the circulatory system as a result
of being pumped out by the heart. Blood leaving
the heart through the arteries is saturated with
oxygen. The arteries break down into smaller and
smaller branches in order to bring oxygen and
other nutrients to the cells of the body's
tissues and organs. As blood moves through the
capillaries, the oxygen and other nutrients move
out into the cells, and waste matter from the
cells moves into the capillaries. As the blood
leaves the capillaries, it moves through the veins,
which become larger and larger to carry the blood
back to the heart.
In addition
to circulating blood and lymph throughout the
body, the vascular system functions as an important
component of other body systems. Examples include:
- respiratory system
As blood flows through the capillaries in the
lungs, carbon dioxide is given up and oxygen
is picked up. The carbon dioxide is expelled
from the body through the lungs, and the oxygen
is taken to the body tissues by the blood.
- digestive system
As food is digested, blood flows through the
intestinal capillaries and picks up nutrients,
such as glucose (sugar), vitamins, and minerals.
These nutrients are delivered to the body tissues
by the blood.
- kidneys and urinary
system
Waste materials from the body tissues are filtered
out from the blood as it flows through the kidneys.
The waste material then leaves the body in the
form of urine.
- temperature control
Regulation of the body's temperature is
assisted by the flow of blood among the different
parts of the body. Heat is produced by the body's
tissues as they go through the processes of
breaking down nutrients for energy, making new
tissue, and giving up waste matter.
A vascular
disease is a condition that affects the arteries
and/or veins. Most often, vascular disease affects
blood flow, either by blocking or weakening blood
vessels, or by damaging the valves that are found
in veins. Organs and other body structures may
be damaged by vascular disease as a result of
decreased or completely blocked blood flow.
Causes
of vascular disease include:
- atherosclerosis
Atherosclerosis (a build-up of plaque, which
is a deposit of fatty substances, cholesterol,
cellular waste products, calcium, and fibrin
in the inner lining of an artery) is the most
common cause of vascular disease.
It is unknown exactly how atherosclerosis begins
or what causes it. Atherosclerosis is a slow,
progressive, vascular disease that may start
as early as childhood. However, the disease
has the potential to progress rapidly. It is
generally characterized by the accumulation
of fatty deposits along the innermost layer
of the arteries. If the disease process progresses,
plaque formation may take place. This thickening
narrows the arteries and can decrease blood
flow or completely block the flow of blood to
organs and other body tissues and structures.
- embolus/thrombus
A blood vessel may be blocked by an embolus
(a tiny mass of debris that moves through the
bloodstream) or a thrombus (a blood clot).
- inflammation
In general, inflammation of blood vessels is
referred to as vasculitis, which includes a
range of disorders. Inflammation may lead to
narrowing and/or blockage of blood vessels.
- trauma/injury
Trauma or injury involving the blood vessels
may lead to inflammation or infection, which
can damage the blood vessels and lead to narrowing
and/or blockage.
Because
the functions of the blood vessels include supplying
all organs and tissues of the body with oxygen
and nutrients, removal of waste products, fluid
balance, and other functions, conditions that
affect the vascular system may affect the part(s)
of the body supplied by a particular vascular
network, such as the coronary arteries of the
heart.
Examples
of the effects of vascular disease include:
- coronary vascular
disease - heart attack, angina (chest pain)
- cerebrovascular
disease - stroke, transient ischemic attack
(a sudden or a temporary loss of blood flow
to an area of the brain, usually lasting less
than five minutes but not longer than 24 hours,
with complete recovery)
- peripheral arterial
disease - claudication (limping because of pain
in the thigh, calf, and/or buttocks that occurs
when walking), critical limb ischemia (lack
of oxygen to the limb/leg at rest)
- vascular disease of
the great vessels - aortic aneurysm (a bulging,
weakened area in the wall of a blood vessel
resulting in an abnormal widening or ballooning),
coarctation of the aorta (narrowing of the aorta,
the largest artery in the body), Takayasu's
arteritis (a rare inflammatory disease affecting
the aorta and its branches)
- thoracic vascular
disease - thoracic aortic aneurysm (a bulging,
weakened area in the wall of a blood vessel
resulting in an abnormal widening or ballooning
in the thoracic, or chest, portion of the aorta)
- abdominal vascular
disease - abdominal aortic aneurysm (a bulging,
weakened area in the wall of a blood vessel
resulting in an abnormal widening or ballooning
in the abdominal portion of the aorta)
- peripheral vascular
disease - deep vein thrombosis (Also called
DVT; a blood clot in a deep vein located within
the muscles of the leg), varicose veins
- lymphatic vascular
diseases - lymphedema (swelling caused by interruption
of the normal drainage pattern in the lymph
nodes)
- vascular diseases
of the lungs - Wegener's granulomatosis
(an uncommon disease in which the blood vessels
are inflamed; mainly affects the respiratory
tract and the kidneys), angiitis (inflammation
of blood vessels), hypertensive pulmonary vascular
disease (high blood pressure in the lungs'
blood circulation due to vascular conditions)
- renal (kidney) vascular
diseases - renal artery stenosis (blockage of
a renal artery), fibromuscular dysplasia (a
condition that weakens the walls of medium-sized
arteries and occurs predominantly in young women
of childbearing age)
- genitourinary vascular
diseases - vascular erectile dysfunction (impotence)
Because
vascular conditions and diseases may involve more
than one of the body's systems at a time,
many types of physicians treat vascular problems.
Specialists in vascular medicine and/or surgery
work closely with physicians in other specialties,
such as internal medicine, interventional radiology,
cardiology, and others to ensure comprehensive
care of patients with vascular conditions.
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Resources of Cardiovascular Disease
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