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U.S. ARMY MEDICAL DEPT. CENTER AND SCHOOL CORRESPONDENCE PHASE 91B BNCOC TECHNICAL TRAINING C2000104 1195 Anatomy and Physiology of the Respiratory System I. REFERENCES. Hafen, Brent Q., and Karren, Keith J., (1989). Prehospital Emergency Care and Crisis Intervention. (3rd ed.) Englewood Cliff, N.J.: Prentice-Hall. Memmler, R. L., & Wood, D.L., (1992). The Human Body in Health and Disease. (7th Ed). Phil, Penn: J.B. Lippincott. Tortora, Gerand J., and Anagnostakos, Nicholas P. (1984). Principles of Anatomy and Physiology. (4th ed.) New York: Harper and Row. II. OBJECTIVES. A. Terminal Learning Objective. Given a list, select the description of the anatomy and physiology of the respiratory system and the normal physiology of respiration which takes place in the human body IAW cited references. B. Enabling Learning Objectives. 1. Given the name of an anatomical part of the respiratory system and a statement about the structure or function of the part, match the name of the part to its structure or function IAW cited references. 2. Given a list of statements about the physiology of inhalation and exhalation, select the correct statements IAW cited references. 3. Given a list of statements about the regulation of ventilation, select the correct statement IAW cited references. 4. Given a list of respiratory rates and a list of age groups, choose the correct normal respiratory 1 C2000104 1195 rate for the age group IAW cited references. 5. Given a list of modified forms of respirations and a list of descriptions of forms of respira-tions, match the form to the description IAW cited references. III. EXPLANATION. Objective 1. A. NOTE: Given the name of an anatomical part of the respiratory system and a statement about the structure or function of the part, match the name of the part to its structure or function IAW cited references. Function of the Respiratory System. 1. Supply oxygen to the individual tissue cells. 2. Remove their gaseous waste product i.e., carbon dioxide. Respiration has two components. The first, called external respiration, takes place only in the lungs where oxygen from the outside air enters the blood and carbon dioxide leaves the blood to be breathed into the outside air. In the second, called internal respiration, gas exchanges take place between the blood and the body cells, with oxygen leaving the blood and entering the cells at the same time that carbon dioxide leaves the cells and enters the blood. B. The Respiratory System. 1. The nasal cavities. a. Structure. (1) Nostrils (NARES)--openings in the nose where air initially enters the body. (2) Nasal cavities--two spaces located between the roof of the mouth and the cranium. (a) Bone covered with mucous membranes. 2 C2000014 1195 b. 2. (b) Contains many blood vessels. (c) Secretes large amount of fluid (1 qt day). (3) Nasal septum--a partition that separates the nasal cavities. (4) Sinuses--small cavities lined with mucous membrane in the bones of the skull. (a) Closely connected to nasal cavities. (b) Highly susceptible to infection. Function of nasal cavities. (1) Foreign bodies, such as dust particles and pathogens, are filtered out by the hairs of the nostrils or caught in the surface mucus. (2) Air is warmed by the blood in the vascular membrane. (3) Air is moistened by the liquid secretion. The pharynx. a. b. Structure (divided into three parts). (1) Nasopharynx--upper portion located immediately behind the nasal cavity. (2) Oropharynx--middle section located behind the mouth. (3) Laryngeal pharynx--lowest portion opens into the larynx toward the front and to the esophagus toward the back. Function of the pharynx. 3 C2000104 1195 3. NOTE: Carries air into the respiratory system. (2) Carries food and liquid into the digestive system. The larynx. a. NOTE: (1) Structure--consists of nine cartilages bound together by an elastic membrane and moved by muscles--lined with mucous membrane. (1) Located between the pharynx and the trachea. (2) Larger in male than female. (3) Vocal cords are located at upper end. Vocal cords are set into motion by air flow from the lungs, difference in size of larynx makes voice high or low. (4) Space between vocal cords called glottis. (5) Epiglottis--leaf-shaped cartilage that covers the larynx during swallowing. You can feel the epiglottis move by placing your fingertips over your larynx as you swallow. b. 4. (6) Lined with ciliated mucous membrane. Function of larynx. (1) Serves in the production of speech. (2) Cilia traps moving them expelled by blowing the The trachea. a. Structure. 4 dust and other particles, upward to the larynx to be coughing, sneezing, or nose. C2000014 1195 b. 5. (1) Tube that extends from the lower edge of the larynx to the upper part of the chest above the heart. (2) Framework C-shaped of cartilage keeps it open. (3) All the open sections of the cartilages are to the back so the esophagus can bulge into this region when swallowing. Function--conducts air between the larynx and the lungs. The bronchi and bronchioles. a. Structure. (1) Trachea branches off into two bronchi which enter the lungs. (2) Right bronchus considerably larger in diameter than left. (3) Right extends downward in a more vertical direction than the left. (4) b. NOTE: The notch or depression where the bronchus enters the lung is called the hilus. Function--passageways to bring air to alveoli. Blood vessels and nerves also connect the lung at this area. 6. The lungs. a. Structure. (1) Extremely thin and delicate lung tissues. (2) Where external respiration takes place. 5 C2000104 1195 NOTE: (3) Two lungs sit side by side in thoracic cavity. (4) Two cone-shaped structures with their bases lying on the diaphragm. (5) "Bronchial Tree"--subdivisions of the bronchus. (6) Bronchioles--smallest division of the bronchi. (7) Terminal bronchioles--attached to the alveoli. (8) Alveoli--cluster of air sacs, resembling a bunch of grapes. (9) Surfactant--a substance that prevents the alveoli from collapsing by reducing the surface tension of the fluids that line them. Lungs contain about 3 times more lung tissue as is necessary for life. Due to its number of air spaces, lung is very light weight and will float in water. b. 7. Function of the lungs--gas exchange takes place as blood passes through capillaries around the alveoli. The lung cavities. a. Lungs occupy considerable portion of thoracic cavity. b. Separated from abdominal cavity by diaphragm. c. Pleura--double sac of serous membrane enveloping each lung. (1) Parietal pleura--portion of pleura that lines the thoracic cavity. (2) Visceral pleura--portion that encloses 6 C2000014 1195 the surface of the lung. Objective 2. C. d. Mediastinum--region between the lungs-contains the heart, great blood vessels, esophagus, trachea, and lymph nodes. e. Pleural space--space between the two membranes of the parietal and visceral pleura. Given a list of statements about the physiology of inhalation and exhalation, select the correct statements IAW cited references. Physiology of Respiration. 1. Accomplished through pressure changes in the lungs--two phases. a. Two phases: (1) (2) Inhalation--active process. (a) Initiated by contracting of the respiratory system muscles. (b) Diaphragm flattens and drops down. (c) Intercostal muscles contract causing ribs and sternum to move up and out. (d) Enlargement of the thorax causes pressure in the lungs to fall and forces air into the lungs. Exhalation--passive phase. (a) Respiratory muscles relax. Diaphragm moves up. (b) Chest wall recoils. (c) Intrathoracic pressure rises. 7 C2000104 1195 (d) NOTE: Sign of respiratory distress is the use of accessory muscles such as muscles in the neck. 2. 3. Respiratory volumes. a. Total lung capacity--volume of gas contained in the lung at the end of maximal inhalation-6000 cc. b. Tidal volume--volume of gas inhaled or exhaled during each normal respiratory cycle-500 cc. c. Dead air space--amount of air that remains in the upper air passages where it is unavailable for gas exchanges--150 cc. d. Alveolar air--amount of air which reaches the alveoli and participates in gas exchange with the capillary blood--350 cc. Gas exchange in the lungs. a. Alveoli supply oxygen to and remove carbon dioxide from the lungs. b. NOTE: Air is pushed out. Exchange is made by diffusion across the cell wall of the alveoli and capillaries. Diffusion is the movement of molecules from an area of greater concentration to an area of lesser concentration. 4. Carbon dioxide in the blood. a. Acid-base balance is directly related to the CO2 produced and CO2 eliminated. b. CO2 is transported from tissues to lungs in 3 ways: (1) 10% dissolves into plasma and fluid in RBCs. 8 C2000014 1195 c. NOTE: 20% combines with plasma proteins and hemoglobin protein. (3) 70% is transported as bicarbonate ion (HC03-) and H+ ion. (a) Forms slowly in plasma. (b) Enzyme (carbonic anhydrase) in RBCs causes rapid change of CO2 and H20 into HC03- and H+ with RBC. (c) HC03-) and H+ diffuse into plasma until blood reaches lungs; then it re-enters RBCs and is converted back into CO2 and H20. CO2 can then enter alveoli and be blown off. (4) Increased CO2 in blood leads to elevation of H+ ion (lower pH) and can cause respiratory acidosis (may be seen in patients that are hypoventilating due to decreased rate or alveolar filling. (5) Decreased CO2 in blood leads to decrease of H+ ion (higher pH) and may cause respiratory alkalosis (as seen in hyperventilation syndrome). Increase in CO2 produced causes the need to increase the CO2 eliminated as seen in hyperventilation due to acidosis metabolic. The larger the volume of air that moves in and out of the lungs, the more CO2 that is eliminated. 5. Oxygen in the blood. a. NOTE: (2) Fluid in the alveoli may prevent adequate oxygen exchange. Fluid accumulation on the lungs may be due to such pulmonary problems as pulmonary edema from heart failure; toxic inhalations; or drowning. 9 C2000104 1195 b. Alveoli may be collapsed (Atelectasis) therefore preventing adequate oxygenation of blood. NOTE: Alveoli may collapse from either external forces such as pneumothorax and/or a flail chest or internal causes such as secretions plugging the airways and/or poor cough and sigh mechanisms. NOTE: The amount of oxygen in the blood is directly proportional to the amount of oxygen delivered to the alveoli. Objective 3. 6. NOTE: Given a list of statements about the regulation of ventilation, select the correct statement IAW cited references. Regulation of ventilation. a. Respiratory function is involuntary although we can consciously hold our breath or take deep breaths, etc. b. Rate and depth of breathing is controlled primarily in the respiratory center located in the brain stem. c. Body detects an increase in acidic level of the blood then compensates by increasing the respirations to increase the CO2 elimination. Patients with chronic respiratory diseases are unable to rely on the brain stem to regulate respirations. Their bodies are accustomed to high levels of CO2, so rely on other control centers located in the aorta and carotid arteries. Objective 4. 7. Given a list of respiratory rates and a list of age groups, choose the correct normal respiratory rate for the age group IAW cited references. Respiratory rates. a. Adult--12-20 per minute. 10 C2000014 1195 Objective 5. 8. b. Children--20-40 per minute. c. Infants--> 40 per minute. Given a list of modified forms of respirations and a list of descriptions of forms of respirations, match the form to the description IAW cited references. Modified forms of respiration. a. Coughing--forceful exhalation produced with a greater than normal volume of breath (mouth). b. Sneezing--forceful exhalation produced with a greater than normal volume of breath (nose). c. Hiccuping (singultus)--sudden inhalation, due to spasmodic contraction of the diaphragm, cut short by closure of the glottis. d. Sighing--slower and deeper than usual inhalation followed by a prolonged and sometimes quite audible exhalation. 11 C2000104 1195 HANDOUT INSTRUCTIONAL AIDS Lung Lobule 12 C2000014 1195 HANDOUT INSTRUCTIONAL AIDS Respiratory System 13 C2000104 1195 HANDOUT INSTRUCTIONAL AIDS Respiratory Organs Review 14