Circulatory System

Circulatory System

A simple definition for the circulatory system would be that it is the main transportation and cooling system for the body. Red Blood Cells have an important job in this system in that they carry all sorts of packages that are needed by all the cells in the body. Red blood cells carry oxygen and nutrients to the cells, which is needed in order for cells to survive. Besides red blood cells there are also White Blood Cells moving in the circulatory system. White Blood Cells can be considered as the paramedics, police and street cleaners of the circulatory system. Anytime we have a cold, a cut, or an infection the white blood cells go to work. From research I also came to find out that white blood cells also help cuts or wounds to heal quicker. Something I did not know was that puss which appears during an infection are actually white blood cells that are attacking the infection.

The highway system of the Circulatory System consists off a lot of one-way streets. The main routes used by the circulatory system are the veins and arteries. Veins are used to carry blood to the heart. Arteries then carry blood away from the heart. Most of the time, blood in the veins is blood where most of the oxygen and nutrients have already been delivered to the cells. This blood is called deoxygenated and is very dark red. Most of the time blood in the arteries is loaded with oxygen and nutrients and the color is very bright red. There is one artery that carries deoxygenated blood and there are some veins that carry oxygenated blood. In order to get more research on this I had to look up some information on the heart and lungs.

The heart is not hard to imagine in ones mind because it is simply a two sided, four chambered pump. The heart is mostly made of muscle and is very unique because it is the only muscle that does not become tired like other muscles. . Imagine what would happen if every 15 minutes or so ones heart becomes tired and decides to take a little break! If this were to happen it basically means that in a few moments ones circulatory system will shut down since the heart is the powerhouse of this system. Since it never rest, the heart muscle is always expanding and contracting, usually at between 60 and 100 beats per minute.

Since the heart is divided into two sections this means that each section has a specific job. The right side of the heart is the low-pressure side. Its main job is to push the red blood cells up to the lungs so that they can get recharged with oxygen. Blood enters the right side of the heart through a chamber called the Right Atrium. Atrium is another word for an 'entry room.' Since the right atrium is located above the Right Ventricle, a combination of gravity and an easy squeeze pushes the blood though the Tricuspid Valve into the right ventricle. The tricuspid valve is a valve made up of three 'leaflets' that allows blood to go from top to bottom in the heart but closes to prevent the blood from backing up into the right atrium when the right ventricle squeezes. After the blood is in the right ventricle, the right ventricle begins its contraction to push the blood out toward the lungs. The blood then leaves the right ventricle and enters the pulmonary artery. This artery and its two branches are the only arteries in the body to carry deoxygenated blood.

When the blood leaves the pulmonary arteries it enters capillaries in the lungs. Capillaries are very, very small blood vessels that act as the connectors between veins and arteries. The capillaries in the lungs are very special because they are located against the alveoli or air sacks. When blood in the capillaries goes past the air sacks, red blood cells pick up oxygen. Capillaries are so small, in some places, that only one red blood cell at a time can get through. When the blood has picked up