Fantastic Voyage Term Paper Example | Topics and Well Written Essays - 1000 words

Fantastic Voyage - Term Paper Example 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 bod y 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 wh ich 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