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heart
heart
heart A hollow muscular organ that, by means of regular contractions, pumps blood through the circulatory system (see
circulation). The vertebrate heart has a thick wall (see
myocardium) composed of a specialized muscle (see
cardiac muscle); it is surrounded by the
pericardium. Mammals have a four-chambered heart consisting of two atria and two ventricles; the right and left sides are completely separate from each other so there is no mixing of oxygenated and deoxygenated blood (see illustration). Oxygenated blood from the pulmonary veins enters the heart through the left atrium, passes to the left ventricle, and leaves the heart through the
aorta. Deoxygenated blood from the
venae cavae enters the right atrium and is pumped through the right ventricle to the pulmonary artery, which conveys it to the lungs for oxygenation. The tricuspid and bicuspid valves ensure that there is no backflow of blood. The contractions of the heart are initiated and controlled by the sinoatrial node (see
pacemaker); in an average adult human the heart contracts about 70 times per minute. See also
cardiac cycle;
cardiac output.
The hearts of other vertebrates are similar except in the number of atria and ventricles (there may be one or two) and in the degree of separation of oxygenated and deoxygenated blood. Invertebrates, however, show great variation in the form and functioning of the heart.
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Heart failure: Public unaware of deadly signs and symptoms.
PR Newswire; 9/1/2003; 700+ words
; ...people across Europe are believed to have heart failure yet new data shows that just three...Hundreds of thousands of undiagnosed heart failure sufferers are, therefore, unlikely...specialists), to gauge public knowledge of heart failure. "The findings of SHAPE's study...
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Hearts lack guile to cut open stubborn Saints
Newspaper article from: The Scotsman; 2/19/2007; ; 700+ words
; Hearts 1 St Mirren 1 ALTHOUGH they applied themselves...the lack of zip which has distinguished Hearts' play for some time once again undermined...in any league game themselves this year, Hearts faced a daunting hurdle against St Mirren...
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Heart Disease; Overview.(Disease/Disorder overview)
Newspaper article from: NWHRC Health Center - Heart Disease; 2/28/2007; 700+ words
; Listen to your heart. Many women don't recognize the warning signs of coronary heart disease (CHD) until their health--and their lives--are in jeopardy. According to the American Heart Association, every year more than half a million...
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Heart Valve Surgery Patients Unite, Launch Online Surgeon Database.
News Wire article from: PRWeb; 5/19/2009; 700+ words
; ...via COMTEX) -- Following the successful heart valve operations of Robin Williams and Barbara Bush, the online community at www.Heart-Valve-Surgery.com has launched a...future patients and their caregivers locate heart valve surgeons. "I never expected this...
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 "St Louis Post-Dispatch (MO)")
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Heart disease isn't just a guy thing; it's the leading killer of American women.(St. Charles County Post)(The Doctor is in)
Newspaper article from: St Louis Post-Dispatch (MO); 2/7/2005; 700+ words
; Byline: HANK CLEVER Think of a heart attack victim and you'll probably picture...a common stereotype. The fact is that heart disease is more than just a man's disease...five women are known to have some form of heart or blood disease. By the time a woman...
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Heart Failure Consumes Significant Health Care Resources.
News Wire article from: Ascribe Higher Education News Service; 11/12/2003; 700+ words
; ...the first such analysis of the costs of heart failure, Duke University Medical Center...elderly patients with the debilitating heart disorder have health care expenditures...times higher than similar patients without heart failure. Additionally, the researchers...
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Heart Attack Survivor Lends Support To Walk
Newspaper article from: New Pittsburgh Courier; 9/3/1997; ; 700+ words
; Heart Attack Survivor Lends Support To Walk When Garfield resident...never live to tell of the good work done by the American Heart Association. Pittrell credits the work of the Heart Association as the reason she is alive today. At the age...
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 "Post-Tribune (IN)")
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HEART DISEASE CONTINUES TO TAKE ITS TOLL
Newspaper article from: Post-Tribune (IN); 3/9/1995; 700+ words
; ...Artis confers with staff regarding patient heart images. THIS ELECTRONIC VERSION MAY DIFFER...for The Methodist Hospitals. Coronary heart disease remains the community's No...full range of cardiac services through its Heart Institute. Women and heart disease The...
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Heart Pumping Variations Revealed Among African, Chinese Americans; Racial Differences May Explain Risk Levels.
News Wire article from: Ascribe Higher Education News Service; 3/26/2007; 700+ words
; ...that Chinese Americans' hearts had a consistently, if...groups. Researchers say that heart disease among Chinese Americans...surprise finding was that hearts in Chinese Americans contract...ethnic groups. Three of four heart walls were fully squeezed...
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 "Grayslake Review (IL)")
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Broken heart syndrome
Newspaper article from: Grayslake Review (IL); 2/14/2008; ; 700+ words
; ...patients who thought they were having a heart attack. The difference is broken heart patients rarely suffer damage to their hearts, and they recover relatively quickly...coronary artery is the cause for a heart attack, stress -- whether it's...
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Heart Failure
Encyclopedia entry from: Gale Encyclopedia of Medicine, 3rd ed.
Heart Failure Definition Heart failure is a condition in which the heart has lost the ability to pump enough blood to the body's tissues. With too little blood being delivered, the organs and other tissues do not receive enough oxygen and nutrients...
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Heart Murmur
Book article from: U*X*L Complete Health Resource
...usually lasts longer than a normal heart sound and can be heard between the normal "lubb-dubb" sounds. Heart murmurs occur in normal hearts. They are especially common among young children. Harmless heart murmurs are known as innocent...
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Heart Murmurs
Encyclopedia entry from: Gale Encyclopedia of Children's Health: Infancy through Adolescence
...of blood flowing through the heart can also cause an innocent heart murmur. Innocent murmurs may be heard in children because their hearts are very close to their chest...innocent murmurs. Pathologic heart murmurs are caused by structural...
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Heart Attack
Encyclopedia entry from: Gale Encyclopedia of Medicine, 3rd ed.
Heart Attack Definition A heart attack is the death of, or damage to, part of the heart muscle because the supply of blood to the heart muscle is severely reduced or stopped. Description Heart attack is the leading cause of death in the United...
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Heart Disease
Book article from: Nutrition and Well-Being A to Z
Heart Disease The heart, which is about the size of a human fist, is the body's largest, strongest, and most important muscle. The heart continuously pumps blood through the body, helps regulate and prolong...
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