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The Respiratory System. Structures. Function of the Respiratory System. Filters, warms, and humidifies the air we breathe Ensures that oxygen is supplied TO… …and carbon dioxide is removed FROM… the body’s cells Influences speech production Makes olfaction possible. Structures.
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The Respiratory System Structures
Function of the Respiratory System • Filters, warms, and humidifies the air we breathe • Ensures that oxygen is supplied TO… …and carbon dioxide is removed FROM… the body’s cells • Influences speech production • Makes olfaction possible
Structures Divided into Upper & LowerRespiratory Tracts Contains Respiratory mucosa: • Specialized mucous membrane that lines the respiratory tract • Secretes MUCUS • air purification mechanism. • traps irritants such as dust and pollen • Cilia on mucosal cells beat upward, moving mucus to pharynx for removal.
Histology: PseudostratifiedCiliated Columnar Epithelium with Goblet Cells (secrete mucus)
UPPER RESPIRATORY TRACT • Nose • Nasal cavity • Pharynx • Naso- • Oro- • Laryngo- • Larynx • Mouth • Eustachian tubes
Nose • Air enters through external nares(nostrils) • Nasal septum separates interior of nose into two cavities (composed of ethmoid, quadrangular cartilage, vomer bone) • Nose warms and moistens inhaled air, contains organs of smell
Nasal Cavity • Lined by bone, mucous membrane • Ethmoid • Maxilla • Nasal bones • Warms, moistens, cleans air • Cilia trap microorganisms, materials digestive system • Turbinates/conchae direct air to olfactory gland
Sinuses • Frontal, maxillary, sphenoidal, ethmoidalsinuses drain into the nose • Provide resonance for speech • Can become inflamed (sinusitis)
Pharynx 1. Nasopharynx • Mucous-secreting • Eustachian tubes • Adenoids 2. Oropharynx • Digestive component • Tonsils 3. Laryngopharynx larynx Laryngopharynx
Larynx (voice box) • Composed mainly of cartilage • Bound by ligaments and muscles • Contains vocal cords that stretch across from arytenoid to cricoid cartilages • Changes in tension changes pitch • Superior/anterior to larynx= epiglottis (closes off larynx during swallowing) • Anterior larynx=thyroid cartilage • (largest, contains Adam’s apple) • Inferior larynx=cricoid cartilage • Hyoid bone located here
Pathology of the Larynx Vascular polyp w/ varices Laryngocele Leukoplakia & underlying carcinoma
LOWER RESPIRATORY TRACT • Located within the thoracic cavity • Includes the • Trachea • Bronchi • Lungs • Bronchioles • Alveolar ducts • Alveolar sacs • Alveoli
Trachea • 4 ½ inches long, from larynx to bronchi • Held open by 15-20 C-shaped cartilaginous rings • Posterior muscle • Obstruction can cause death w/in minutes • Ciliated to move mucus out - Smoking affects these 1 - Vocal cords2 - Thyroid cartilage3 - Cricoid cartilage4 - Tracheal cartileges5 - Balloon cuff
Remainder of Lower Respiratory Tract • R & L bronchi • Contain cartilage, smooth muscle • R is wider, shorter, more vertical • Divide into secondary and tertiary bronchi • Bronchioles (terminal and respiratory) • Lungs (alveolar ducts and sacs)
Bronchi Bronchioles Lungs • Terminal bronchioles can dilate, constrict • Respiratory bronchioles split into • 2-11 alveolar ducts each • 5-6 alveolar sacs each (look like bunches of grapes)
Alveolar Ducts Alveolar Sacs Alveoli • Alveolar sacs are microscopic and come in clusters • Made up of alveoli: • site of gas exchange b/w air and blood • Coated with surfactant (reduces surface tension, prevents them from collapsing)
General Structure/Location of the Lungs • Lungs: R—3 lobes, L—2 lobes (divide into lobules) • Apex: under clavicle • Base: above diaphragm • Heart in cardiac notch
Lobes and Lobules • Functional and structural: • Conducting portion • Terminal bronchioles • Clara cells – remove toxins • Type 1 alveolar cells – gas exchange • Type II alveolar cells – secrete surfactant • Surfactant – reduces surface tension of lungs, allows easier expansion; prevents collapse of alveoli • Respiratory portion • Gas exchange occurs here
More on Lung Structure • Pleura: thin, moist, slippery (serous) membrane • Visceral pleura: covers the outer surface of the lungs • Parietal pleura: lines the inner surface of the rib cage • Produces pleural fluid-intrapleural space must remain moist Pathology: Pleurisy (pleuritis) – painful inflammation of the pleura
Collapsed Lung • A.k.a. = pneumothorax • Caused when atmospheric pressure enters the thoracic cavity • Normally a partial vacuum between ribcage and lungs • Trauma introduces air, which removes “suction” that keeps lungs inflated Repaired by: chest tube