Heart 

The heart is a fist-sized muscular organ that pumps blood throughout the body throughout the body, delivering oxygen and nutrients to the tissues. It is located slightly to the left of the middle of the chest and is composed of four chambers (two atria and two ventricles). The heart is controlled by an electrical system and beats approximately 60-100 times a minute, increasing during physical activity. 

(some additional facts)

• The average adult heart weighs 280-340 grames (male) or 230-280 grames (female).

• An adult's heart pumps about 7,500 liters of blood a day. 

• At rest, an adult's heart beats approximately 60-100 times per minutes, while a newborn's heart may beat 90-190 times per minute. 

• lifestyle factors such as diet and exercise affect heart health.