The Cardiovascular system is the body's transporting system that brings oxygen in, and carbon dioxide out. The heart is the main organ in the body as many should know. Its job is to pump blood through out the body so we can function properly among other things. The heart consists of two pumps, the right-hand and the left-hand pumps. The right-hand pump takes the used blood from the body, which is oxygen poor blood, and pumps it to the lungs were the lungs will provide more oxygen and pump it back out. In the meantime, the left-hand pump is receiving fresh blood (oxygen rich blood) from the lungs and is pumping it out into the body. Each pump is made up of two chambers, the atria and ventricles. The atria are thin, weak, muscular chambers that fill with blood. When the heart beats, the atria contract and pump the blood into the ventricles. Not too long after the atria contract, the ventricles do also and the blood is released into the body. In order to keep the blood flowing in the right direction, there are two different types of valves in the heart. The atrioventricular valves are set right between the atria and ventricles, hence the name. These valves are responsible for keeping the blood from flowing back into the atria after it is pumped into the ventricle. The semilunar valves lie between each ventricle and its corresponding vessel it uses to transport blood. These valves are also one-way to keep the blood from flowing in the wrong direction or from getting sucked back into the heart.
The Respiratory system is a little different than the cardiovascular system. The respiratory system is responsible for getting good air in our body's and bad air out. Air first enters the body through either the nose or the mouth. This is where the air is filtered and particles are taken out. Something weird about the respiratory system is that all of the branches lead to dead ends and therefore the airflow travels in both directions. Despite this fact, the respiratory system does a fine job of keeping our body's supplied with fresh air or else we probably wouldn't be here. Your main airway is the trachea or windpipe which is connected directly to the lungs. Two tubes, one for each lung, are connected to the trachea. These tubes are called bronchi and are basically branches off of the trachea. Each bronchi tube is made up of tons of smaller tubes called bronchioles. At the end of the bronchioles, are small sacs called alveoli. These tiny structures allow oxygen and carbon dioxide to flow across their surfaces and into the bloodstream.