Did you know that your lungs are the “only place in your body where gases in the blood are exchanged with gases from the atmosphere” in the respiratory system (Biology textbook, 852)? The respiratory and circulatory systems have many jobs, but their main purpose is to allow the body to maintain homeostasis. The definition of the respiratory system is “the body system in which gas exchange takes place.” The blood can gather oxygen or O? and can remove any carbon dioxide or CO? from the body (Biology textbook, 852). On the other hand, the definition of circulatory system is “the body system that transports blood and other materials” (Biology textbook, 852). It can carry essential materials to the cells and take away any waste. Oxygen-poor blood can combine or mix with oxygen-rich blood pretty easily, so the circulatory system helps the blood vessels from doing so. There are about ten functions of the respiratory system that are made up of three major parts called the the airway, the lungs, and the muscles of respiration. First, we have the nose and nasal cavity. This “forms the main external opening for the respiratory system and is the first section of the body’s airway or where air moves.” Next, the mouth or oral cavity is the secondary external opening of this system’s tract. As humans we normally breathe out of our nose, but the mouth has a shorter pathway of air to enter the body than the nose does. It also had a greater diameter to get air into the body. One disadvantage to breathing through your mouth is not allowing the extra hairs or mucus, filter the air like it does when breathing through the nasal cavity. Then, there is the pharynx or the throat. It is a muscular funnel that stretches from the back of the nasal cavity to the primary end of the esophagus and larynx. The pharynx has three parts: the nasopharynx, oropharynx, and laryngopharynx. The nasopharynx is found in the back of the nasal cavity. The oropharynx connects the nose and the back of the mouth to the esophagus. And the laryngopharynx is where food and air goes through. After that, there is the larynx which is the voice box. It is a short region that attaches the trachea and the laryngopharynx. It is located in the neck. “The epiglottis is a cartilage piece that covers the larynx when swallowing.” If you are a singer, the thyroid would be your best friend because it protects the vocal folds. The vocal folds vibrate to make vocal sound when you talk and sing. Next, is the trachea or the windpipe. It is a five inch long tube that connects the larynx to the bronchi. Then, at the end of the trachea, the airway breaks into two branches called the primary bronchi. Each branch, right and left goes into each lung accordingly. Then they branch off into smaller secondary bronchi and then those divide into even smaller tertiary bronchi. “The tertiary bronchi split into many smaller bronchioles that spread throughout the lungs. Finally, millions of tiny terminal bronchioles conduct air to the alveoli of the lungs.” Most importantly, there are the lungs which are a pair of large organs that are found by the heart and diaphragm (Respiratory System, Tim Taylor, Anatomy and Physiology Instructor). They absorb oxygen from the air you inhale . If you have ever seen a tree with many branches and twigs, that’s what they look like when they divide into smaller and smaller bronchi that end in clusters of tiny air sacs called alveoli. The lungs have about 300 to 600 billion alveoli (Biology textbook, 853). Finally, the lungs are able to inhale and exhale by being enclosed by sets of muscles called the muscles of respiration (Respiratory System, Tim Taylor, Anatomy and Physiology Instructor). This muscle is better known as the diaphragm which is a dome-shaped sheet of skeletal muscle that is at the base of the rib cage. When you inhale, the muscles of the rib cage contract and when you exhale, the muscles relax. (Biology textbook, 854). The respiratory system uses positive and negative feedback loops. An example of a positive feedback loop is coughing. When you cough you are getting rid of any waste that your body does not need. On the other hand, an example of a negative feedback loop is when you have an increased breathing rate. It commands your breathing and energy that your muscles have to use when you are exercising (Respiratory System, Amy Nicholson). Additionally, homeostasis is maintained in the respiratory system by gas exchange and regulation of blood potential hydrogen or ph (Human Physiology/The Respiratory System). Many things can go wrong in the respiratory system. People can experience asthma, bronchitis, common colds, a cough, cystic fibrosis, laryngitis, tonsillitis, influenza, lung cancer, or pneumonia (Teens Health). There is no way to completely eliminate disease, infection, or illness in the respiratory system, but their are some ways you can decrease the risk of getting one. You can wash your hands often, keep your hands away from your mouth, nose and eyes as much as possible because this is where viruses come from the most. You should also not smoke your use tobacco. You should keep your body fit, so try to exercise regularly. You should most importantly get any vaccines needed to help prevent these sorts of diseases like the flu (Respiratory Problems, Age 12 and Older – Prevention). The circulatory system must keep blood constantly circulating. The main parts are the heart, blood, and blood vessels. The heart is about the size of your fist. It is a muscular pump that keeps the blood circulating through every part of the body. The average adult body contains about 5 liters or more than 5 quarts of blood. About every 60 seconds your blood circulates from your heart, all the way through your body, and back to your heart (Biology textbook, 854). There are three different types of blood vessels in the circulatory system. The “arteries are blood vessels that carry blood away from the heart to the rest of the body.” The “veins are blood vessels that carry blood from the rest of the body back to the heart.” In this picture to the left, it shows that “arteries carry oxygen-rich blood,” which is the red, and “veins carry oxygen-poor blood,” which is the blue. Your blood is not blue, even the oxygen-poor blood. Every part of your body’s blood, oxygen-rich or oxygen-poor is red or a darker red. “Arteries and veins are connected by a system of capillaries. Capillaries are tiny blood vessels that transport blood to and from the cells of the body” (Biology textbook, 855). These vessels are very, very small. The circulatory system can signal positive and negative feedbacks to the body. An example of a negative feedback would be when your body gets too hot, you will start to sweat and when your body gets too cold, you will start to shiver (Heart Circulatory System, Yibelis Abreu). Also, an example of a positive feedback loop would be blood clotting. When “a blood vessel is damaged, chemicals begin a chain reaction that causes platelets to stick to the vessel wall. The platelets release more chemicals that accelerate the clotting process. This process ends once the vessel wall has been repaired by a clot” (Positive Feedback: Blood Clotting). In addition, the circulatory system has two other significant functions that help maintain homeostasis. First, this system gathers waste materials made by digestion and cell metabolism. This gets delivered to the liver and kidneys to be drained out of the body. Second, the circulatory system helps maintain body temperature by dispersing heat that cells generate in the muscles and internal organs (Biology textbook, 855). Many things can go wrong in the circulatory system. People can get congenital heart defects, arrhythmia, heart failure, cardiomyopathy, atherosclerosis, strokes, Abdominal aortic aneurisms, Peripheral artery disease, coronary artery disease, hypercholesterolemia, hypertension, heart attacks, or rheumatic heart disease. There are some ways you can prevent yourself from getting a circulatory disease. You can exercise daily and keep your body at a normal weight. You should not smoking or drink too much alcohol. You should try to keep your stress levels down, and keep a good healthy diet. If you are at risk of any of these conditions you should contact your doctor about how to prevent your blood pressure getting too high, or having high cholesterol levels. Even on how to avoid getting diabetes (Circulatory System Diseases: What You Should Know).In conclusion, the respiratory and circulatory systems are very important in the human body.