The Cardiovascular System

The cardiovascular system's job in the human body is to provide the whole body with oxygen, nutrients and hormones. It is made up of three parts:

• The Heart is the main organ of the body, it pumps blood through it.
• Blood vessels including veins, arteries, and capillaries all contain blood that is pushed through the body.
• Blood is a fluid that is pumped through the body.

There are three types of blood cells:

• Red blood cells are responsible for carrying oxygen and carbon dioxide.
• White blood cells are cells of the immune system that help fight viruses or diseases.
• Platelets are fragments of cytoplasm, and they help heal cuts and stop clots.

The heart has three main types of cells:

• Pacemaker cells fire impulses at intervals to cause the heart muscle to contract.
• Smooth muscle cells compose the heart and allow it to contract.
• Endothelial cells form a thin, protective layer on the inside of the heart that prevents blood from sticking and forming clots.