Circulatory System
Functions:
In anatomy and physiology, the Circulatory System is the course taken
by the blood through the arteries, capillaries, and veins and back to the
heart. Or in other words, the nutrient and oxygen-poor blood that comes
from the outer-most parts of the body, goes to the right auricle(in the
heart), down into the right ventricle(still in the heart), and from there to the
lungs. From the lungs, the blood becomes filled with oxygen cells, and is
pumped into the left auricle(back in the heart again) and down into the left
ventricle(the fourth chamber of the heart). From the left ventricle, the
oxygen-rich blood gets distributed through all of the body through arteries.
Arterioles branch off the arteries, and capillaries branch off the arterioles. In
the capillaries, the oxygen cells seep through the capillary walls. The
capillaries then carry the oxygen-poor blood, that�s filled with waste carbon
dioxide, to the nearest venule, which goes to the nearest vein, which returns
to the right auricle to start the process all over again.
Major parts and organs:
Some of the major parts/organs are the heart, the blood, the arteries,
and the veins. The heart, by far, is the most important part of the
Circulatory System. It is about fist sized, and weighs one-half to
three-quarters of a pound. The heart is actually two pumps joined together.
Both pumps have an upper chamber and a lower, larger, thicker walled,
chamber. The heart�s walls are made of cardiac muscle, which contracts
about 70 times per minute. It takes blood around a minute to complete a
circuit, and the heart pumps ten pints of blood through the average adult
body more that 1000 complete circuits a day. So the heart is actually
pumping 5000 to 6000 quarts of blood a day.
During strenuous exercise, heavy physical labor, or any kind of stress,
the heart may pump eight or nine times as much blood as compared to a time
of relaxation-as many as twelve gallons a minute. When the blood demand in
the body is high and persists, the heart adjusts. It�s muscles thicken, and
it�s chambers enlarge. In high blood pressure, a variety of things happen
ranging from kidney malfunction to nervous system malfunction. These
things combine to create a resistance to the flow of blood through the
arterioles, causing the heart to pump harder to get around this obstacle.
Whatever the cause, when the heart has to consistently overwork, it pumps
less efficiently. It tries to keep up by beating more franticly, until it can�t
keep up, and fails.
Blood is another part of the Circulatory system that plays a vital role.
It contains the nutrients, oxygen, and other cells that the body needs. The
actual blood is composed mainly of red, white, and Thrombocytes cells.
The red blood cells transport oxygen to the body�s cells where it releases the
oxygen and picks up the carbon dioxide and transports it back to the lungs
to be expired. The white blood cells destroy bacteria, and produce
antibodies. Thrombocyte cells form clots when an blood vessel breaks, or
you get a scratch.
Arteries carry the oxygen and nutrient filled blood from the left
ventricle to the different parts of the body to be distributed there. Veins
carry the poor blood from the different parts of the body to the right auricle.
Arteries have thick, elastic walls, and veins have thinner and rougher walls.
Interactions with other systems:
This system also works with the Skeletal, Respiratory, Digestive,
and Nervous systems. The bone marrow of the Skeletal system makes a
different type of blood cell, and the skeleton forms the framework which
your blood vessels flow around and are protected by. The blood gathers
oxygen from the lungs in the Respiratory system. The Digestive system
makes the food for the blood to carry around the body. The Nervous
system controls the rate of heartbeat.
Diseases:
Some Diseases that are in the Circulatory System are Rheumatic
fever, hypertension, and Atherosclerosis. With Rheumatic fever, the
heart inflates and damages the heart valves. One treatment for rheumatic
fever is to limit activity for the patient. Hypertension is the physiological
condition involving increased pressure on the arterial walls. Headaches are
common with hypertension. Antihypertensive drugs are used for treatment,
but there is no cure. With Atherosclerosis, fatty deposits called plaque
build up on the inner walls of the coronary arteries. Gradual narrowing of
the arteries throughout life restrict the blood flow to the heart muscles.
Treatment of atherosclerosis is directed at its complications such as ischemic
stroke or heart failure.