Mid-unit Summary

The focus of this unit is the Cardiovascular system. Its function is vital to life because it is in charge of transporting oxygen and blood throughout the body and making the heart beat. The heart is composed of four major chambers, the left and right ventricle, and the left and right atrium. It is sometimes referred to as a double pump, because the left side transports oxygenated blood, and the right side deals with the returned deoxygenated blood. Blood vessels transport this blood between chambers and then disperses it throughout the body. Veins carry blood to the heart from tissue, and arteries are vise versa. Hypertension can occur in which the rate at blood is being pumped is faster than vessels can transport it. This can also be influenced by disorders such as atherosclerosis, where blood vessels can become obstructed and clot can occur. Atherosclerosis can trigger aneurysms when vessels burst due to blockage. The blood that is transported by vessels are two types: red blood cells, and white blood cells. Red blood cells are composed of hemoglobin which carry oxygen and do not have nuclei. Anemia can occur when there is a lack of oxygen carried in these cells and is genetically inherited. White blood cells have five types: neutrophils (ingest bacteria), basophils (inflammation and allergic reactions), eosinophils (also elevated in reactions), lymphocytes (destroy bacteria and attack threatening cells), monocytes (similar to lymphocytes but are larger with more intercellular space). Diseases can occur within the cardiovascular system like heart attacks and strokes. These occur when there is reduced blood flow to the heart or complete cut off. Symptoms may not show or are overlooked easily because blocked arteries do not always appear blocked.  Strokes however, occur in blood vessels in the brain or leading to the brain. When blood can not properly flow, arteries can burst, which can be life threatening.