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The Respiratory System Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. Functions and Overview of Respiration 1. Respiratory system works with the circulatory system a. Provides oxygen to the body b. Removes waste products of metabolism c. Helps to regulate pH of the blood Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 2 1. Exchanges oxygen (O2) and carbon dioxide (CO2) between atmosphere and body cells 2. 1 respiration occurs every 3-5 seconds 3. Pons & medulla oblongota stimulate breathing 3. Blood transports the gases to and from the tissue cells RESPIRATION Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 3 Conducting Passages 1. Upper respiratory tract: nose, pharynx, larynx 2. Lower respiratory tract: trachea, bronchial tree, lungs Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 4 Nose and Nasal Cavities 1. Nose-where the respiration starts 2. Nasal cavity divided by nasal septum. 3. Internal nares openings from the nasal cavity into the pharynx 4. Nasal conchae: three bony ridges that project into nasal cavity Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 5 Oral Cavity • Palate: separates nasal cavity from oral cavity a. Hard palate: anterior portion supported by bone b. Soft palate: posterior portion, no bony support c. Uvula: posterior projection of the soft palate • Helps direct food into oropharynx Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 6 Sinues • Paranasal sinuses: air-filled cavities in frontal, maxillae, ethmoid, and sphenoid bones a. Surround nasal cavity and open into it b. Functions: • • • Reduce weight of skull Produce mucus that drains into nasal cavity Influence voice quality: act as resonating chambers Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 7 Pharynx Pharynx 1. Commonly called the throat 2. Serves both respiratory and digestive systems a. Receives air from the nasal cavity b. Receives air, food, and water from oral cavity 3. Opens into larynx and esophagus 4. Divided into three regions: a. Nasopharynx b. Oropharynx c. Laryngopharynx Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 8 Larynx Larynx 1. Commonly called the voice box 2. Passageway for air between pharynx and trachea 5. Formed by nine pieces of cartilage 6. 2 pairs of ligaments that make up false and true vocal cords Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 9 Ventilation, cont. Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 10 Trachea Trachea 1. Commonly called the windpipe 2. Tube extends from larynx to mediastinum 3. Divides into right and left bronchi 4. 15-20 C-shaped pieces of hyaline cartilage a. Hold the trachea open Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 11 Bronchi Bronchi and Bronchial Tree 1. Trachea divides into right and left primary bronchi 2. Enters the lungs forms the bronchial tree 3. Primary bronchi divide to form secondary (lobar) bronchi a. Branch into tertiary (segmental) bronchi 4. Branching continues: finally giving rise to bronchioles Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 12 Bronchioles • Terminal bronchioles: branch into smaller respiratory bronchioles a. Lead into microscopic alveolar ducts • Terminate in clusters of tiny air sacs: alveoli • Alveolar ducts and alveoli permits rapid diffusion of oxygen and carbon dioxide a. Exchange of gases between the air in the lungs and blood in capillaries • Occurs across walls of alveolar ducts and alveoli Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 13 Lungs Lungs 1. Occupy most of space in thoracic cavity 2. Soft and spongy a. Mostly air spaces surrounded by alveolar cells and elastic connective tissue 3. Separated by mediastinum, which contains the heart 4. Rests on the diaphragm Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 14 Lungs 1. Right lung: shorter, broader, greater volume than left lung a. Divided into three lobes (superior, middle, and inferior) by two fissures 2. Left lung: longer and narrower than right lung a. Cardiac notch: indentation on medial surface • For apex of heart b. Divided into two lobes by a single fissure Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 15 Lungs Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 16 Pleura • Pleura: double-layered serous membrane that encloses the lungs a. Visceral pleura: firmly attached to surface of lung b. Parietal pleura: lines the wall of the thorax • Pleural cavity: small space between the visceral and parietal pleura a. Contains a thin film of serous fluid • Acts as a lubricant – Reduces friction as the two layers slide against each other Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 17 The Lungs and Pleura Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 18 Ventilation 1. Pulmonary ventilation: breathing 2. Air flows because of pressure differences between atmosphere and gases inside the lungs 3. Normal respiratory rate: 12-20 breaths per minute 4. Consists of one inhalation and one exhalation 5. Amount of air that is exchanged during one cycle a. Varies with age, sex, size, physical condition Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 19 Inhalation Inhalation 1. Process of taking air into the lungs 2. Diaphragm: dome-shaped muscle a. Separates thoracic cavity from abdominal cavity b. Contraction causes diaphragm to drop • Increases the size of the thoracic cavity – Air flows from outside the body into the lungs Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 20 Exhalation Exhalation 1. Process of letting air out of the lungs 2. Diaphragm relaxes: thoracic cavity decreases to its normal size a. Air now flows from within the lungs to the outside of the body until the two pressures are equal Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 21 Ventilation External Respiration 1. Exchange of oxygen and carbon dioxide a. Between the lungs and blood 2. Oxygen diffuses from alveoli of the lungs into the blood (capillaries) 3. Carbon dioxide diffuses from the blood into the alveoli Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 22 Ventilation Internal Respiration 1. Exchange of gases between the tissue cells and the blood 2. Oxygen is given off to the cells 3. Carbon dioxide is picked up by the blood a. Transported as a waste product to the lungs Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 23 Regulation of Respiration Chemoreceptors 1. Chemoreceptors in the medulla a. Sensitive to changes in carbon dioxide concentrations b. Not sensitive to changes in oxygen levels c. If carbon dioxide increases: • Stimulate respiratory center to increase rate and depth of breathing – Decrease concentrations back to normal levels Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 24 Regulation of Respiration Stimulus from Higher Brain Centers 1. Impulses from higher brain centers a. May override respiratory center temporarily b. Example: voluntarily holding your breath • • Can do so for only a limited time When carbon dioxide levels reach a critical point – Impulses from higher brain centers are ignored: respiratory center resumes regular breathing Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 25 Regulation of Respiration, cont. Nonrespiratory Air Movements 1. Reflexes that clear air passages 2. Sneezing and coughing 3. Sighing 4. Hiccuping 5. Crying 6. Laughing 7. Yawning Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc. 26 Deviated septum Constant rubbing/wiping of the nose or injury to the nose can cause a deviated septum. 27 Epistaxis Nosebleeds are common and can be idiopathic, cold/allergy related or due to nasal dryness. 28 Pleurisy Also known as pleuritis-an inflammation of the pleura, the lining of the pleural cavity surrounding the lungs. Infection most common cause. Main symptom is sharp or stabbing pain in the chest that gets worse with deep breathing, coughing or sneezing. 29 Pleural Effusion • Fluid in the thoracic cavity between the visceral and parietal pleura. 30 Rhinits Inflammation of the nasal mucosa. Caused by virus, bacteria & allergens. 31 COPD • • • • One of the most common lung diseases 2 types: chronic bronchitis & emphysema May have both-No cure! Causes: Smoking #1. Exposure to gas, fumes, smoke & pollution • Symptoms: Develop slowly a.Cough with mucus b.Shortness of breath (dyspnea) that gets worse with mild activity c. Fatigue d.Frequent respiratory infections e.Wheezing 32 Tuberculosis 1. TB 2. Caused by Mycobacterium tuberculosis 3. Can lie dormant in body for years 4. May have positive TB skin test but never develop disease 5. Increased chance to become active TB when immune system not functioning properly 6. Preventative antibiotics for 6 months 33 Pertussis Whooping cough, a highly contagious bacterial infection of the pharynx, larynx & trachea. Explosive coughing spasms ending in “whooping” sound. Immunization given to protect. Passed from adults whose immunity worn off. 34 Pneumothorax Accumulation of air in the pleural cavity Collapse of the alveoli is known as a collapsed lung or atelectasis. 35 36