Journey to the Bottom of the Lung
Tracy Brown
HS130
Unit 4 Assignment
Kaplan University
March 26, 2013

Hello everyone! My name is Tina Tiny. I am a reporter for WHBN. The Whole Human Body Network. Today Dr. Tracy Brown has agreed to miniaturize me and a specially equipped submarine to about the size of 8 microns. That is incredibly small! I am about the same size as some red and white blood cells. Red blood cells are approximately 8 microns in diameter. White blood cells can be anywhere from 7-21 microns in diameter (Wikidot). Today I am being injected into the femoral vein of a healthy female. Dr. Brown would like for me to map my route through her body and describe what I will be seeing. She warns us that anything is likely to happen and we should be expecting quite an adventure! I am excited so let’s get started! I must say that being drawn into a needle this large, preparing for injection is not my idea of a pleasant feeling. Normally I am on the outside of these needles and on the inside, it’s a bit claustrophobic. The vein I am being injected into, like I said before, is the femoral vein. The femoral vein is a large vein that runs down both legs of the human body (Thibodeau and Patton, 2008). Just as I have been injected into the vein, Dr. Brown is informing me that a bacterium has invaded the lower lobe of this female’s right lung. Dr. Brown would now like for me to journey to this infected area and describe how this female’s body will deal with this infection. As I move up the thigh of this woman in the femoral vein, my sub is approaching the pelvic region of her body. In the pelvic region we first pass the external iliac vein and the common iliac vein. The femoral vein, the external iliac vein and the common iliac vein all run down both sides of the female’s legs and join together in the hypogastric region of her body (Thibodeau and Patton, 2008). In this huge vein I continue up the center of the female’s body and towards her lungs. My sub is really rocketing through her body now! I have just traveled under her spleen and I am approaching her liver. On the right side of her liver, I will pass the hepatic portal. When the femoral vein passes through her liver it now becomes the hepatic vein. Just after locating the hepatic vein I find I am approaching the inferior vena cava (Thibodeau and Patton, 2008). The inferior vena cava branches off into the heart where it carries de-oxygenated blood from the lower half of the body into the right atrium (WebMD, 2013). From the right atrium I am moving quickly now, pat the tricuspid valve and into the right ventricle. The contraction of the smooth muscle of the heart and incredibly strong and are pushing my tiny sub into the pulmonic artery. Dr. Brown says that this is a fascinating place to be because it is the only artery in the body that carries “oxygen-poor” blood (Surgery About, 2013). I have to make a sharp left turn in my sub to make it to her right lung. The blood moves swiftly through the heart and this pulmonary artery is divided to allow blood to travel back to both lungs. When this blood moves through the lungs it will pick up oxygen and be re-distributed throughout the body (Science, How Stuff Works, 2013). Now that I am in the lung, it is easy to see that the right lung has three lobes whereas the left lung has only two lobes. In the right lung, Dr. Brown says, the names of the lobes are superior, middle, and inferior. The lobes in the left lung are the superior and inferior (Thibodeau and Patton, 2013). It is to this female’s right inferior lobe that we are traveling. As I am entering the lung, via the pulmonary artery, I am then lead into smaller blood vessels called arterioles. Arterioles then lead into capillaries which are even smaller. Capillaries in the lungs are responsible for the exchanging of carbon dioxide for oxygen (Thibodeau and Patton, 2013).
The lungs are supplied with air