Respiratory+HW2+MC

Respiratory System (Chapter 9) Part 1. Describe structure and function of each of these terms (in great detail...read the pages in the book from 170 to 174) in this order (the pathway of air from the nasal cavities to the lungs). Inserting a picture of your respiratory system would be nice. Part 2. Describe the structure and function of alveoli in great detail. (Inserting a picture of an alveolus would be nice.) -It has a total cross sectional area of 50-70m(2). Each alveolar is surrounded by blood capillaries. Gas exchange occurs between air in the alveoli and blood in the capillaries. Oxygen diffuses across the alveolar wall and enters the bloodstream, while carbon dioxide diffuses from the blood across the alveolar wall to enter the alveoli, The alveoli of humans lungs are lined with a surfacant, a film of lipoprotein that lowers the surface tension of water and prevents them from closing. Part 3. (p. 178) Describe in great detail how Carbon Dioxide is carried in the blood and how Oxygen is carried in the blood. - Oxygen diffuses out of the blood into the tissues because the PO(2) of tissue fluid is lower than that of blood. Oxygen diffuses into plasma and then into red blood cells in the lungs because blood in the pulmonary capillaries is low in oxygen, and alveolar air contains a higher partial pressure of oxygen. Carbon Dioxide diffuses into the blood from the tissues because the PCO(2) of tissues is higher than that of blood. Gas exerts pressure, and the amount of pressure each gas exerts is called its partial pressure.
 * Nasal Cavity- the nasal cavities are narrow canals separated from each other by a septum composed of bone and cartilage. Air entering the nasal cavities are met by large stiff hairs that act as a screening device, filtering the air of dust so it doesn’t enter air passages. The rest of the nasal cavities are lined by mucosa membrane with a sub mucosa that has plentiful capillaries. The nasal cavities filter, warms, and moistens air.
 * The Pharynx is a funnel-shaped passageway that connects the nasal and oral cavities to the larynx. It has 3 parts: the nasopharynx,where the nasal cavities open above the soft palate; the oropharynx, where the oral cavity opens; and the laryngopharynx, which opens into the larynx. The tonsils form a protective ring at the junction of the oral cavity and the pharynx. The air passage and food passage cross because the larynx is in front of the esophagus, which receives food.
 * The glottis is space between the vocal chords and is an opening to the larynx. When air is expelled through the glottis, the vocal chords vibrate, producing sound.
 * The larynx is a cartilaginous structure that serves as a passageway for air between the pharynx and the trachea. It’s pictured as a triangular box whose apex, the Adam’s apple, is located at the front of the neck. It house all of the vocal chords.
 * Trachea is commonly called the windpipe, is a tube connecting the larynx to the primary bronchi. Its walls consist of connective tissue and smooth muscle reinforced by C-shaped cartilaginous rings. It lies ventral to the esophagus, and allows esophagus to expand when swallowing. The mucous lines the trachea and has an outer layer of pseudostratified ciliated columnar epithelium. The trachea divides into right and left primary bronchi, which lead to right and left lungs.
 * The bronchus is a passage of air to lungs. The bronchi resemble the trachea in structure, but as the bronchial tubes divide and subdivide, their walls become thinner, and the small rings of cartilage are no longer present.
 * The bronchioles come about when the bronchi branch into a few secondary bronchi that also branch, until the branches become about 1 mm in diameter.
 * The lungs are paired cone-shaped organs that occupy the thoracic cavity, except for the central area that contains the trachea, the heart, and esophagus. The right lung has 3 lobes, and the left lung has 2 lobes, allowing room for the heart, which points left. A lobe is further divided into lobules, and each lobule has a bronchiole serving many alveoli. They follow the contours of the thoratic cavity, including the diaphragm, the muscle that separates the thoracic cavity from the abdominal cavity. Each lung is enclosed by pleura, a double layer of serous membrane that produces serous fluid. Surface tension holds the two pleura layers together and therefore, the lungs must follow the movement of the thorax when breathing occurs.
 * The Diaphragm contracts and moves down during inspiration and it relaxes and moves up during expiration. It’s a skeletal muscle that functions in ventilation.

Part 4. Describe 4 respiratory disorders of your choice (in great detail). -Emphysema is a chronic and incurable disorder in which the alveoli are distended and their walls damaged, so that the surface area are available for gas exchange is reduced. It’s caused by smoking. Air trapped in the lungs leads to alveolar damage and a noticeable ballooning of the chest. The elastic recoil of the lungs is reduced. The heart has to work harder to force more blood through the lungs. You wuld have a lack of oxygen. -In chronic bronchitis, the airways are inflamed and filled with mucus. A cough that brings up mucus is common. The bronchi have undergone degenerative changes. Including the loss of cilia and their normal cleansing action. Smoking is the most frequent cause of chronic bronchitis. -Pulmonary Fibrosis is a condition in which fibrous connective tissue builds up in the lungs. The lungs can’t inflate properly and are always tending toward deflation. -Pneumonia is a viral or bacterial infection of the lungs in which the bronchi and alveoli fill with thick fluid. It’s preceded by influenza. High fever, chills, with headache and chest pains are symptoms of it. The more lobules involved the more serious is the infection. It’s causes by bacteria that is held in check but has gained the upper hanf due to stress and/or reduced immunity.