FREE ESSAY ON UNDERSTANDING THE SILENT KILLER

UNDERSTANDING THE SILENT KILLER

Uncontrolled high blood pressure, hypertension, is one of the leading causes of disability
or death due to stroke, heart attack, heart failure and kidney failure. High blood
pressure has been described as the silent killer because it often occurs without
symptoms. Headaches, blurred vision, nosebleeds, or dizziness may occur, but these
symptoms are not specific to high blood pressure. 
Everybody has, and needs blood pressure. Without it, blood cannot circulate through the
body. And without circulating blood, vital organs cannot get the oxygen and food that
they need to work. So it's important to know the role of blood pressure, and the organs
and systems that help regulate it.
The explanation of blood pressure begins with the cardiovascular system, the system
responsible for circulating blood through the heart and blood vessels. When the heart
beats, a surge of blood is released from the left ventricle, which is the heart's main
pumping chamber, into an intricate web of blood vessels that spread throughout the body.

The arteries are the blood vessels that carry nutrients and oxygenated blood from the
heart to the body's tissues and organs. The largest artery, aorta, is connected to the
left ventricle and serves as the main channel for blood leaving the heart. The aorta
branches off into smaller arteries, which turn into even smaller arteries, called
arterioles. (1)
Within the body's tissues and organs are microscopic blood vessels called capillaries.
The capillaries exchange nutrients and fresh oxygen from the arterioles for carbon
dioxide and other waste products produced by our cells. This used blood is sent back to
the heart through a system of blood vessels called veins. When it reaches the heart,
blood from the veins is routed to the lungs, where it releases carbon dioxide and picks
up a new supply of oxygen. This freshly oxygenated blood is sent back to the heart, ready
to begin a new journey. Other waste products are removed as blood passes through the
kidneys. (1) 
To keep this process working and all of the 11 pints of blood in our body moving, a
certain amount of pressure is required. Blood pressure is the force that's exerted on the
artery walls as blood passes through. This force helps keep blood in the arteries flowing
smoothly.
Several factors help control blood pressure and keep it from increasing too high or
decreasing too low. They include three major organs; heart, arteries, and kidneys.
When the heart releases blood into the aorta, a certain amount of force is created by the
pumping action of the heart muscle. The harder the heart muscle has to work to release
blood, the greater the force exerted on the arteries. 
To assist the surge of blood coming from the heart, the arteries are lined with smooth
muscles that allow them to expand and contract as blood flows through. The more elastic
the arteries are, the less resistant they are to the flow of blood and the less force
exerted on their walls. When arteries lose their elasticity or become narrowed,
resistance to blood flow increases and additional force is needed to push blood through
the vessels. (1)
The kidneys regulate the volume of water circulating in the body and the amount of sodium
the body contains. More sodium in the body means that more water is retained in the
circulation and may cause an increase in blood pressure. More sodium in the body also may
increase the tendency for blood vessels to narrow. 
The central nervous system, hormones, and enzymes are other factors that also influence
blood pressure. Within the walls of the heart and several blood vessels, are tiny
structures called baroreceptors. The baroreceptors' job is to monitor the pressure of
blood through the arteries and veins. If a change is noticed, the baroreceptors send
signals to the brain; to slow down or speed up the heart rate, or to widen or narrow the
arteries to keep the blood pressure within a normal range. (1)
The brain reacts on the messages from the baroreceptors, by signaling the release of
hormones and enzymes that affect the functioning of the heart, blood vessels, and
kidneys. Epinephrine, adrenaline, is one of the most significant hormones to affect blood
pressure. Epinephrine is released during high periods of stress or tension. The release
of Epinephrine, causes the arteries to narrow and heart contractions become stronger and
rapid, increasing the pressure on the arteries. 
Blood pressure is the measure of the force generated by the heart against the artery
walls. This force is expressed as two numbers, such as 110 over 80 mm Hg (millimeters of
mercury). The first number, the systolic blood pressure, represents the amount of force
used by the heart to initially fill the blood vessel circuit; the second number, the
diastolic blood pressure, is a measure of the resistance to that force. Combined, these
numbers give a picture of how hard the heart is working to get blood to the tissues in
the body.
High blood pressure, is blood pressure that consistently reads above 140 over 90 mm Hg.
There are 3 separate stages of high blood pressure, based on increased severity. They are
simple referred to as stages 1, 2, and 3. Among people whose blood pressure is
uncontrolled, about 75 percent, have stage 1 high blood pressure. About 20 percent of
people have stage 2, and about 5 percent have stage 3 high blood pressure. (2) 
High blood pressure causes undue stress to the circulation of key organs, particularly
the brain, heart and kidneys. This leads to increased risk of stroke, heart attack and
kidney failure. High blood pressure also can cause an aneurysm, a small balloon-like
weakening of the artery wall, which can be life-threatening. 
Nearly one-third of the people affected by high blood pressure do not even know they have
it. They may go for years without knowing it. Among people whom are aware of their
condition, only about half are being treated. And even fewer, only about one-quarter of
the people with high blood pressure, have their blood pressure under control.
High blood pressure can occur in children or adults, but is particularly prevalent in
blacks, middle-aged and elderly people, obese people, heavy drinkers and individuals who
are taking oral contraceptives. Hypertension can be especially hard to manage when
combined with other disorders, such as diabetes or obesity. 
The more you know about blood pressure, hopefully, the more willing you will be to take
the necessary steps to lower your blood pressure and keep it under control. 
Bibliography
Bibliography
1. Sheldon G. Sheps, M.D. Mayo Clinic on High Blood Pressure; 1999 Mayo Clinic Research
and Development
2. American Heart Association, About High Blood Pressure; 1999