Rules of the Road free essay sample

As we journey from the right femoral artery to the lower lobe of the right lung, we see many amazing sights. Starting at the femoral vein which is located in the upper right thigh and pelvic region of the body and runs close to the femoral artery. The femoral vein returns blood in the leg to the heart via the iliac vein. As we go north pass through the external and common iliac veins on our way to the small intestines where we can see most of the colon. The  common  iliac vein  is one piece of a large system that allows blood circulation from the lower  abdomen  and legs. This  vein  is where the external  iliac  veins and internal  iliac  veins unite (WiseGeek). It has 2 main veins, which are joined together to form the inferior mesenteric or the lower half of the large intestines. The function of this vein is to bring the de-oxygenated blood from the legs as well as the other lower regions of the body to the right atrium. We will write a custom essay sample on Rules of the Road or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Up through the inferior mesenteric, we can see the spleen, which holds extra blood, the stomach, which is where digestion starts, and the liver, which is so large it fills the entire upper right section of the abdominal cavity and part way into the left side. Traveling farther north we pass through the inferior vena cava with the kidneys to our right and left. The kidneys provide a wide range of functions to our body by removing wastes and water from the blood, balances chemicals, releases hormones, controls blood pressure, produces red blood cells, and vitamin D. We are now passing the liver which is an organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds. The right atrium is part of the heart, which is in the upper chamber of the chest, which receives the de-oxygenated blood from our body moving into the vena cava and is then pumped into the right ventricle of the heart, which is the lower chamber of the heart. After doing so it will move through the pulmonary artery on its way to the lungs under low pressure, and there the blood will be turned into oxygenated blood. The right atrium of the heart with the deoxygenated blood and then through the vena cava as it enters the right atrium of the heart and flows through the tricuspid value into the right ventricle, from there it is pumped through the pulmonary valve into the pulmonary arteries which go to the lungs. Pulmonary arteries carry deoxygenated blood to the lungs and divide into very fine branches called capillaries which have very thin walls. As we leave the right pulmonary artery out of the heart and into the right lung, we notice that the right lung has three lobes, unlike the left lung which only has two. These three lobes are known as the superior lobe, at the top, the middle lobe, and the inferior lobe at the bottom. Lungs are delicate and exposed to the environment, almost like an open wound. Because of this the body has developed an elaborate immuno-defense system to combat inhaled pathogens and bacteria (Bacteria Museum). In a healthy individual, this system effectively blocks hundreds of potential illness-inducing assaults daily. To fight infection in the lungs, airway epithelial cells initiate an immune response to inhaled bacteria by signaling white blood cells to move from the bloodstream into the lungs and airway to fight potential infection. Getting white blood cells to the site of an infection can be dangerous. On the one hand, having as many white blood cells as possible at the site of an infection is beneficial. On the other hand, too many white blood cells can lead to excessive inflammation, interfering with breathing and damaging the airways. As we travel further north on our way out of the lungs you will also notice many tree like structures that are called primary bronchi. As you can see the primary bronchi branch into smaller secondary bronchi so the walls of the secondary bronchi can be kept open by rings of cartilage so air can pass into the lung. The secondary bronchi subdivide into smaller and smaller tubes, which are known as the bronchioles. The bronchioles then divides into microscopic tubes called alveolar ducts which as you can see resemble the main stem of a bunch of grapes. As we approach closer we can see each alveolar duct ends in a group of alveolar sacs and the walls are made up of numerous alveoli which might look like one grape. These alveoli help promote the rapid and effective exchange of oxygen and carbon dioxide between the blood circulating through the lungs capillaries and the alveolar air. From the alveoli we are going to pass through the superior vena cava where we will be traveling with the deoxygenated blood from the right atrium.