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: The '''heart''' is mostly [[muscle]].

: The [[muscle]]s in the '''heart''' squeeze and relax to pump [[blood]].

==Key Stage 3==

===Meaning===

The [[heart]] is an [[organ]] which pumps [[blood]] around the body.

===About the Heart===

: The [[muscle]]s in the [[heart]] [[contract]] and relax to pump [[blood]].

: A healthy [[heart]] beats around 70 times per minute when you are resting.

: The [[heart]] is protected by the [[Rib Cage|rib cage]].

: The [[heart]] has 4 separate chambers; the [[Right Atrium]], [[Right Ventricle]], [[Left Atrium]] and [[Left Ventricle]].

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|[[File:HeartChambers.png|center|300px]]

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| style="height:20px; width:300px; text-align:center;" |A [[diagram]] showing the 4 chambers of the [[heart]].

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: [[Deoxygenated]] [[blood]] enters the [[Right Atrium|right atrium]]. The [[atria]] contract, pushing the [[blood]] from the [[Right Atrium|right atrium]] into the [[Right Ventricle|right ventricle]]. The [[ventricle]]s contract pushing the [[blood]] out of the [[Right Ventricle|right ventricle]] towards the [[lung]]s. [[Oxygenated]] [[blood]] returns from the [[lung]]s and enters the [[Left Atrium|left atrium]]. The [[atria]] contract, pushing the [[blood]] from the [[Left Atrium|Left atrium]] into the [[Left Ventricle|Left ventricle]]. The [[ventricle]]s contract pushing the [[blood]] out of the [[Left Ventricle|Left ventricle]] to the rest of the body.

{| class="wikitable"

|[[File:CG_Heart.gif|center]]

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| style="height:20px; width:300px; text-align:center;" |A [[diagram]] showing the features of the [[heart]].

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