Fantastic Voyage - Term Paper Example

? Fantastic Voyage HS 130 Section # Unit 4 Assignment Kaplan Purpose The purpose of this essay is to trace the path of blood flow from the right femoral vein into the lower right lobe of the lung through the right pulmonary artery. Once we reach the lung we will describe cells found within that contribute to our immunity, describing innate and specific immunity. Finally we will describe the exchange of oxygen with the delicate alveolar and the pathway used in inspiration and expiration. Body The femoral vein travels from the inside of the right leg, parallel to the femoral artery, upwards towards the center of the body. The femoral vein is a larger vein which receives blood from the popliteal, the great saphenous vein and the femoris (Femoral…). The femoral vein first comes into the external iliac vein and from there flows into the common iliac vein and into the inferior vena cava. The iliac veins form the common iliac at the small of the back around the fifth lumbar vertebra. It is the function of the vena cava to carry blood from the lower portion of the body directly to the heart (Inferior…). The vena cava empties into the right atrium, the lower right back side of the heart. The blood arrives into the right atrium un-oxygenated and is a darker color due to the lack of oxygen. The vena cava are the two largest veins in the body and the inferior runs alongside and behind the abdominal cavity and where the vena cava meets the right atrium is a valve known as the Eustachian valve. Though the Eustachian valve remains its primary functions are in the developing fetus, where it helps to direct blood flow through the foramen ovale into the left atrium. Once breathing begins this is no longer necessary and the foramen ovale closes and the amount of blood flow between the left and right atrium is limited. The vena cava are responsible for collecting blood from lumbar veins, hepatic veins, gonadal veins, renal veins and the phrenic veins (Cardiovascular…). All of this blood is un-oxygenated. Blood then flows through the tricuspid valve and is pumped into the right ventricle. Cardiac muscle provides rhythmic regular contractions to keep the blood flowing smoothly. After passing through the pulmonary valve the blood enters the pulmonary trunk (Right…). The contraction of the myocardium causes pressure which forces the blood into the pulmonary truck where there is a left and right division. The trunk has a pulmonary semilunar valve that opens during contraction and closes when the muscle relaxes, thus preventing the blood from flowing back into the ventricular chamber. The right pulmonary artery carries the blood to the lower right lung. Within the right lower lung there are three lobes whereas the left lung has two lobes. Structures within the right lung include lateral, anterior, posterior, dorsal and medial bronchus (Chest…). A bronchial tree contains these bronchus and alveoli on these branches resemble grapes. Alveoli are thin membrane air sacs within the lung and the bronchial tree is the passage way through which air is passed in inspiration and expiration. Surfactants within the alveoli keep them from collapsing during exhalation and they remain slightly open. Without this surfactant the thin sacs would close in and stick to each other as air passes in and out of them and they inflate and deflate. The passageways into the lungs are lined with epithelia and cilia whose primary function is to move debris and foreign particles from out of the lungs. These provide the first line of defense within the lungs. Dendritic cells are scattered throughout the lungs and increase when there is an inflammatory response. These cells are antigen presenting cells that contain lysosomes and endosomes with three separate functions; antigen presentation and activation of T cells, inducing and maintaining immune tolerance, and maintaining immune memory with B cells (Wieder). These dendritic cells are the only cell that is able to activate naive T cells and lay dormant until there are pathogens or other foreign bodies to attack. They are attracted to areas of inflammation where they are able to capture this foreign body or to capture T cells. T cells are white blood cells and are activated when dendritic cells present antigens and then work to kill these cells. Macrophages ingest foreign material then presenting it to T cells or B cells. B cells produce antibodies in response to foreign protein in the form of parasites, bacteria, viruses and tumor cells. Neutrophil’s are found on the alveolar surface and are surveillance cells that also prevent an inflammatory response from being initiated inappropriately at the alveolar gas-exchange level. Other cells include Eosinophil’s, basophils and mast cells. Eosinophil’s increase in response to allergies and asthma among other conditions and high counts of these are able to give sign of these conditions. Basophils are usually found at the site of allergic inflammation, they are effector cells for the immune response against parasites. These immunity cells within the lung are constantly surveying for foreign proteins. Macrophages also contribute to tissue repair while neutrophils use phagocytosis to kill invading organisms. Innate or non-specific immunity is immunity that is antigen dependent though not antigen specific, it responds immediately and there is no immunological memory against the invader. The cilia within the lung are non-specific immunity. The main lines of defense in innate immunity are neutrophils, macrophages, and eosinophils. Individuals are born with innate immunity. Specific immunity has a response that is antigen dependent also but there is an amount of time between exposure and response and it is antigen specific resulting in memory. This type of immunity comes from exposure to proteins and the buildup of antigens against them such as in the case of vaccinations. Alveoli within the lung are the only site for gas exchange. Blood that enters capillaries around the alveoli is high in CO2 and low in oxygen. Because there is a different concentration gradient CO2 diffuses from the blood to the alveolar air and O2 goes from the alveolar air into the blood, blood leaving the lungs has tripled its oxygen content. Air that enters the nose first passes into the nasal cavity and into the pharynx. It then moves through the larynx and the trachea. The trachea leads directly to the bronchi and the bronchus containing the alveoli. Cilia line this passageway, capturing any foreign invaders. They are non-specific and will launch an attack against anything they do not recognize. The secretion of mucous keeps this passage way moist which is important to keep tissues from drying out. We breathe out through the same passageways though the quality of the air has been altered. Conclusion While the pathway to the lung using the femoral vein is but one starting point the structure and function within the lung does not change. The process of gas exchange is a well-defined and highly functional pattern unless respiratory difficulties occur such as infection or foreign body inhalation. The immune system found within the lungs combats allergies, asthma and other condition affecting the circulatory system. Most are effectively dealt with without intervention by our highly complex cellular abilities. References Cardiovascular System - Cardiovascular System. (n.d.). InnerBody.com | Human Body, Anatomy Charts, Anatomical Models. Retrieved 2012, from http://www.innerbody.com/image/cardov.html Cardiovascular System - Cardiovascular System. (n.d.). InnerBody.com | Human Body, Anatomy Charts, Anatomical Models. Retrieved 2012, from http://www.innerbody.com/image/cardov.html Chest Radiology, chest tutorial, chest anatomy, lung anatomy, lung tutorial, chest x-ray, cxr, chest xray, chest CT, chest MRI, radiology lectures. (n.d.). Chest Radiology, Chest Tutorial, Chest Anatomy, Lung Anatomy, Lung Tutorial, Chest X-ray, Cxr, Chest Xray, Chest CT, Chest MRI. Retrieved 2012, from http://www.chestradiology.net/anatomy.cgi Femoral Vein Anatomy, Location & Function | Body Maps. (n.d.). Medical Information for Healthy Living | Healthline. Retrieved 2012, from http://www.healthline.com/human-body-maps/femoral-vein Inferior Vena Cava Function, Anatomy & Definition | Body Maps. (n.d.). Medical Information for Healthy Living | Healthline. Retrieved 2012, from http://www.healthline.com/human-body-maps/inferior-vena-cava Pulmonary Immunobiology and Inflammation in Pulmonary Diseases: NHLBI Workshop. (n.d.). NIH Heart, Lung and Blood Institute. Retrieved 2012, from http://www.nhlbi.nih.gov/meetings/workshops/pul_inflam.htm Right Pulmonary Veins Function, Anatomy & Diagram. (n.d.). Medical Information for Healthy Living | Healthline. Retrieved 2012, from http://www.healthline.com/human-body-maps/right-pulmonary-veins Wieder, E. (2003, May). Dendritic Cells- A Basic Review. Cell Therapy Society. Retrieved 2012, from http://www.celltherapysociety.org/files/PDF/Resources/OnLine_Dendritic_Education_Brochure.pdf Read More