Heart

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.

Read more about Heart:  Structure, The Invertebrate Heart, Functioning, Early Development, History of Discoveries, Additional Images

Other articles related to "heart":

Echocardiography
... to cardiac echo or simply an echo is a sonogram of the heart ... and Doppler ultrasound to create images of the heart ... of patients with any suspected or known heart diseases ...
Heart Valve
... A heart valve normally allows blood flow in only one direction through the heart ... The 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 ...
William Buckland - Megalosaurus and Marriage
... “Talk of strange relics led to mention of the heart of a French King preserved at Nuneham in a silver casket ... 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 precious relic was lost for ever.” The heart in question is said ...
Digoxin - Mechanism of Action
... of the Na+/K+ ATPase pump in the membranes of heart cells (myocytes) and decreases its function ... 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 ...

Famous quotes containing the word heart:

    And my heart is like nothing so much as a bowl
    Brimming over with quivering curds!
    Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)

    O hiding hair and dewy eyes,
    I am no more with life and death,
    My heart upon his warm heart lies,
    My breath is mixed into his breath.
    William Butler Yeats (1865–1939)

    Although the good you do may not be seen by others, your good heart is known by Heaven.
    Chinese proverb.