Heart ---- 

It is a small muscular organ which pumps blood through all over the body.

It helps to pump the blood through blood vessels and it helps to provide oxygen and nutrients.

Different Parts---

Heart consist of 4 chambers mainly -
1. Left Atrium
2. Right Atrium
3. Left Ventriculum
4. Right Ventriculum
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Heart is a pear shaped structure triangular. it is  covered by two layers of membranes which are called pericardial membranes. and the space betwwen them is filled with pericardial membrane. it supplies blood to all the parts of the body by arteries and veins.
different parts:
left auricle and left ventricle 
right auricle and right ventricle.