Answer :
The heart is the hardest working muscle in the human body. Situated nearly in the center of the chest, the heart of a healthy adult is about the size of an adult's clenched fist.
Your heart is a vital organ. It is a muscle that pumps blood to all parts of your body. The blood pumped by your heart provides your body with the oxygen and nutrients it needs to function. Its heart is the size of a clenched fist and weighs between 300 and 450 g. The human heart is a four chambered muscular organ, similar in shape and size to a man's clenched fist, with two-thirds of the mass to the left of the midline. The heart is enclosed in a pericardial sac that is lined with the parietal layers of a serous membrane. The heart is a fist-sized muscular organ located just behind and slightly to the left of the breastbone. The heart pumps blood through the network of arteries and veins called the cardiovascular system.
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