Respiratory+Questions+SLS

September 16, 2008 Science-Human Bio**
 * Shelby Smith


 * 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.**
 * Nasal cavity:** Narrow canals separated from each other by a septum composed of bone and cartilage.
 * Pharynx:** A funnel shaped passageway that connects the nasal and oral cavities to the larynx.
 * Glottis**:The slit between the vocal cords.
 * Larynx**: Cartilaginous structure that serves as a passage way for air between the pharynx and the trachea.
 * Trachea**: A tube connecting the larynx to the primary bronchi. It’s walls consist of connective tissue and smooth muscle reinforced by C-shaped cartilaginous rings. This is commonly called the ‘windpipe’.
 * Bronchus**: The trachea divides into right and left primary bronchi, which leads into the right and left lungs.
 * Bronchioles**: The branches from the bronchi which are about 1 mm in diameter.
 * Lung**: Paired, cone-shaped organs that occupy the thoracic cavity, except for the central area that contains the trachea, the heart and the esophagus.
 * Diaphragm**: Skeletal muscle that functions in ventilation.

The lungs have around 300 millions alveoli. The alveoli are contained in alveolar sacs that are surrounded by blood capillaries, with the wall of the sac and the walls of the capillaries being simple squamous epithelium –which are thin flattened cells which facilitate gas exchange. The gas exchange occurs between air in the alveoli and the blood in the capillaries. Oxygen diffuses across the alveolar wall and enters the bloodstream, while carbon dioxide diffuse from the blood across the alveolar wall. The alveoli of the human lungs are lined with a surfactant, which is a film of lipoprotein that lowers the surface tension of water and prevents them from closing.
 * Part 2. Describe the structure and function of alveoli in great detail. (Inserting a picture of an alveolus would be nice.)**

Carbon dioxide is carried in the blood by diffusing from the capillaries into the alveolar sac. CO2 diffuses from the plasma and into the lungs. When CO2 enters the blood it becomes a bicarbonate ion, which is carried in the plasma. Oxygen enters the blood and hemoglobin carries the oxygen to the tissues. During internal respiration, O2 exits the blood while CO2 enters.
 * Part 3. (p. 178) Describe in great detail how Carbon Dioxide is carried in the blood and how Oxygen is carried in the blood.**

Laryngitis: This is an infection of the larynx, which is accompanied with hoarseness, which leads to inability to talk in an audible voice. Laryngitis can be treated with URI. Acute Bronchitis: This is an infection of the primary and secondary bronchi. Usually it is preceded with a viral URI, which can lead to a secondary bacterial infection, There is a cough that can perhaps produce mucus or pus. Emphysema: This is an untreatable, incurable disease where the alveoli are distended and their walls are damaged, so that the surface area of gas exchange is reduced. This is often caused by smoking. Air trapped in the lungs can lead to alveolar damage, and because of the less surface area oxygen may have a harder time getting to the brain. Asthma: This is a disease of the bronchi and bronchioles that is marked by wheezing, breathlessness, and sometimes a cough and expectoration of mucus. The airways become inflamed, making it difficult for the one affected to breathe.
 * Part 4. Describe 4 respiratory disorders of your choice (in great detail).**