The West is blinking in disbelief â Vladimir Putin just invaded Ukraine. German diplomats, French Eurocrats and American pundits are all stunned.
A: The main organ in the circulatory system is the heart, according to Hillendale Health. The two other major parts of the circulatory system are the blood and the blood vessels. The heart is found slightly to the left at the center of the chest, and it is primarily responsible for pumping blood and keeping the blood moving throughout the body, explains Hillendale Health.
1. Bones. The most important organ of the skeletal system is the bones. Human skeleton is made up of 206 bones that in coordination not only provides support and protection to the viscera (with the help of muscles attached to them) but also produces blood cells for the body from the bone-marrow.