The respiratory and circulatory systems include the lungs, heart and blood that keep us alive. The air we breathe depends on our lungs and heart working together delivering oxygen to the body's tissues and removing carbon dioxide. Along with the lungs and heart, blood transports vital nutrients to all areas of the body and removes waste products.
The respiratory system consists of the nose, mouth, throat, larynx (voice box), trachea (wind pipe) and the lungs. The entire system allows us to inhale and exhale air through the nose and mouth as well as speak. The circulatory system is made up of the heart, blood and blood vessels. There are five types of blood vessels in the human body: the arteries, arterioles, capillaries, venules and veins. The blood vessels are like tubes that branch off into smaller and smaller channels until they reach the muscle, epithelial, nervous and connective tissues inside the body.
The lungs are cone-shaped organs that are divided in the middle into two separate chambers so that if one lung is punctured the other will still transfer gases, allowing a person to breathe. The left lung is 10 percent smaller than the right due to space for the adjacent heart. The heart is about the size of a closed fist and weighs between 8 and 10 ounces. According to “Principles of Anatomy and Physiology,” the heart is relatively small for its responsibility A typical adult male has a gallon and a half of blood running through his body which is pumped by the heart.
The respiratory system allows the exchange of gases in the lungs due to contraction and expansion of the ribs, bringing air in and pushing it out. This exchange of gas takes place in the branches of the lungs called alveoli where blood is brought to the surface. The respiratory system also allows us to speak. The larynx is located in the throat; as air moves in and out of the trachea, it hits the vocal cords that produce sound. After oxygen binds with the red blood cells in the lungs, it's now the job of the circulatory system to distribute that blood. The heart pumps the blood through arteries into smaller arterioles and then even smaller capillaries that exchange carbon dioxide and waste materials with nutrients and oxygen.
The respiratory and circulatory systems never rest; if either system failed, it would result in death. The heart's ability to supply oxygen and nutrients to tissue is called cardiac output and can be measured to determine how efficient the body is at distributing blood. Because the respiratory and the circulatory systems distribute blood with nutrients, this process also allows hormones to be delivered to all tissues of the body. Hormones contribute to the growth and repair of the body.
The heart beats over 100,000 times every day, and 3,600 gallons of blood pass through the heart's chambers. A healthy adult will breathe 12 times a minute, each time inhaling and exhaling about 500mL of air. Because the two systems work together so well, muscles can receive all the nutrients and oxygen they need for athletes to perform at incredible levels.
