These types of cells are the most numerous cells in the body and their main job is to carry oxygen to the cells of the body. They form in the bone marrow.

These pathways are large vessels that carry oxygenated blood away from the heart.

A fluid found in the blood that is 90% water. Makes up just over half of Blood’s content.

These are the cells that protect the body from disease.

These are the large vessels that return deoxygenated blood back to the heart.

This System is the transportation network that moves nutrients to the organs of the body and carries waste away.

These little thingies are found in the blood and their chief job is to start the clotting process during times of injuries to the body

This is the name for the tiny attacking forces that are determined to enter your body and cause mayhem. They include Viruses, bacteria, parasitic worms, fungi, protists, etc,etc.

This system acts like a team and is made up of organs, tissues and cells that keep you and your body healthy from foreign invading pathogens.

This is the main organ of the circulatory system. Pumps about 100,000 times a day. The chief of the heart is to pumps blood to and from all the parts of the body.

If you were to line up all the blood vessels in the average adult human body back to back, the length in distance would be about.......