The heart is a hollow muscle that pumps blood throughout the blood vessels by repeated, rhythmic contractions. It is found in all animals with a circulatory system (including all vertebrates).
The term cardiac (as in cardiology) means "related to the heart" and comes from the Greek καρδιά, kardia, for "heart".
The vertebrate heart is principally composed of cardiac muscle and connective tissue. Cardiac muscle is an involuntary striated muscle tissue found only in this organ and responsible for the ability of the heart to pump blood.
The average human heart, beating at 72 beats per minute, will beat approximately 2.5 billion times during an average 66 year lifespan. It weighs approximately 250 to 300 grams (9 to 11 oz) in females and 300 to 350 grams (11 to 12 oz) in males.
Other articles related to "heart":
... extracellular aspect of the α-subunit of the Na+/K+ ATPase pump in the membranes of heart cells (myocytes) and decreases its function. 4 and phase 0 of the cardiac action potential, which leads to a decrease in heart rate ... This leads to increased contractility (the force of contraction) of the heart without increasing heart energy expenditure ...
... “Talk of strange relics led to mention of the heart of a French King preserved at Nuneham in a silver casket ... at it, exclaimed, ‘I have eaten many strange things, but have never eaten the heart of a king before,’ and, before anyone could hinder him, he had gobbled it up, and the ...
... echo or simply an echo is a sonogram of the heart ... and Doppler ultrasound to create images of the heart ... management, and follow-up of patients with any suspected or known heart diseases ...
... A heart valve normally allows blood flow in only one direction through the heart ... four valves commonly represented in a mammalian heart determine the pathway of blood flow through the heart ... A heart valve opens or closes incumbent upon differential blood pressure on each side ...
... be given by IV injection in urgent situations (the IV injection should be slow, and heart rhythm should be monitored) ... For congestive heart failure, levels between 0.5 and 1.0 ng/ml are recommended ... For heart rate control (atrial fibrillation), plasma levels are less defined and are generally titrated to a goal heart rate ...
Famous quotes containing the word heart:
“It is the heart which experiences God, and not the reason. This, then, is faith: God felt by the heart, not by the reason.”
—Blaise Pascal (16231662)
“While I wrought out these fitful Danaan rhymes,
My heart would brim with dreams about the times
When we bent down above the fading coals
And talked of the dark folk who live in souls
Of passionate men, like bats in the dead trees....”
—William Butler Yeats (18651939)
“Spring is here.
Why doesnt my heart go dancing?”
—Lorenz Hart (18951943)