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Respiration – Overall exchange of gases between atmosphere , blood, and cells. General Functions: A. Provides extensive area for gas exchange between air and circulating blood B. Moves air to and from the exchange surfaces of the lungs
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Respiration – Overall exchange of gases between atmosphere , blood, and cells. • General Functions: • A. Provides extensive area for gas exchange between air and circulating blood • B. Moves air to and from the exchange surfaces of the lungs • C. Protects respiratory surfaces from dehydration, temperature changes, or other environmental variations. • D. Defends the respiratory system and other tissues from invasion by pathogens. • E. Produces sounds – speaking, singing, nonverbal communication. • F. Provides olfactory sensations to CNS http://lungdiseases.about.com/library/graphics/basic_lung_anatomy.bmp
II. Processes involved in respiration: A. Pulmonary Ventilation – (Breathing) The physical movement of air into and out of the lungs (more specifically the alveoli) B. External Respiration – Exchange O2 and CO2 between interstitial fluids and the external environment. C. Internal Respiration – Absorption of O2 and release of CO2 by the cells (cellular respiration in the mitochondria) http://www.apparelyzed.com/_images/content/respritory/Respiratory-System.jpg
Organs of respiration: • A. Respiratory Tract – airways that carry air to and from exchange surfaces • 1. Conducting portion – lined with respiratory mucosa, respiratory defense system – sticky mucus, filtration, alveolar macrophages • 2. Respiratory portion – site of gas exchange • B. Upper Respiratory Tract – nose, nasal cavity, paranasal sinuses, pharynx – filter, warm, humidify incoming air and dehumidify and cool outgoing air • 1. Nose • a. External nares - nostrils • b. Nasal Cavity – highly vascularized, divided by nasal septum, as exhale heat is absorbed by blood vessels and moisture condenses which prevents drying http://www.askdrshah.com/images/nasal_polyp.jpg
c. paranasal sinuses – mucous secretions and tears keep surfaces clean and moist, olfactory receptors, nasal conchae cause air to eddy and swirl which traps foreign objects, warms and humidifies air. 2. Pharynx – Chamber shared by digestive and respiratory systems, divided into: a. nasopharynx – superior, pharyngeal tonsil, auditory tubes open into b. oropharynx – between soft palate and base of tongue, palatine tonsils c. laryngopharynx – between hyoid and entrance to the larynx and esophagus, resists abrasion, chemical attack, pathogens (stratified squamous epithelium)
C. Lower Respiratory Tract – larynx, trachea, bronchi, bronchioles, alveoli 1. Larynx – voice box, located at C4 or C5 to C6 a. Glottis – narrow opening to larynx b. Made up of nine cartilages 3 large unpaired: Thyroid (shield-shaped) – largest, hyaline, U-shaped, incomplete posteriorly (Adam’s Apple) Cricoid (ring-shaped) - hyaline Epiglottis – elastic , forms lid over glottis during swallowing 3 paired: Arytenoid, Corniculated (sound), Cunieform http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f25-4_larynx_c.jpg
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c. VOCAL FOLDS (CORDS) – Highly elastic, protected by VESTIBULAR FOLDS (false vocal cords), when air passes over, vibrates to produce sound waves - PHONATION PITCH – Determined by diameter, length (larynx size) and tension (voluntary) ARTICULATION – modifying sounds with pharynx, oral cavity, nasal cavity, sinuses, tongue, lips, cheeks COUGHING REFLEX – Food touches vestibular or vocal cords http://notsosynonymous.tripod.com/images/cords.jpg
2. Trachea – windpipe a. tough, flexible tube, 2.5 cm in diameter and 11 cm long b. located anterior to C6 – T5 c. tracheal cartilages – bound to neighboring cartilage which stiffens to prevent collapse or overexpansion, C- shaped permits posterior trachea to distort for swallowing d. Intubation e. Tracheostomy http://www.aic.cuhk.edu.hk/web8/Hi%20res/Intubation.jpg http://www.sdhct.nhs.uk/patientCare/pil/images/tracheostomy2.jpg
f. The trachea branches into the left and right PRIMARY BRONCHI (sing. Bronchus) g. The primary bronchi enter the lungs http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/1103.jpg
3. Lungs • Divided into lobes which are separated by fissures • Located in pleural cavities separated by the mediastinum, hilus allows access for pulmonary vessels and nerves • Parietal pleura – lines inner surface of thoracic wall • Visceral pleura – covers outer lungs • Both pleura secrete pleural fluid – moist, slippery, provides lubrication • Pleurisy – lack of pleural fluid http://www.yourlunghealth.org/lung_disease/copd/healthy/graphics/pleura.jpg http://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Lungs_diagram_simple.svg/483px-Lungs_diagram_simple.svg.png
C. Comparison of left and right lungs Right lung 3 lobes – superior, middle, inferior Broader and shorter because diaphragm rises to accommodate liver Left lung 2 lobes – superior, inferior Longer Indented at cardiac notch http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f25-12a_gross_anatomy_o_c.jpg
4. Pathway a. Bronchial Tree Trachea Primary Right Bronchus Primary Left Bronchus (Enter the lungs and divide into) Secondary Bronchi – enter each lobe (3 right, 2 left) Which divide into: Tertiary Bronchi Terminal Bronchioles (6500) Respiratory Bronchioles Alveolar sacs http://training.seer.cancer.gov/module_anatomy/images/illu_bronchi_lungs.jpg
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b. Changes in diameter 1. Bronchodilation – Increase in diameter, sympathetic response 2. Bronchoconstriction – Decrease in diameter, parasympathetic, due to allergies, anaphylaxis http://www.asthmameds.ca/images/lungsbig.jpg
5. Microanatomy • Alveolar sacs are connected to multiple alveoli, surrounded by capillaries • Alveolar/capillary membrane is composed of three parts: • *Squamous epithelial cells lining the alveoli • *Endothelial cells lining the capillaries • *Basement membrane • c. Diffusion occurs quickly across due to: • *small total distance separating air from blood • *O2 and CO2 are lipid soluble • d. SURFACTANT – an oily secretion that decreases surface tensionso alveoli don’t collapse. • If not enough is produced, takes a huge amount of effort to inflate the lungs = Respiratory Distress Syndrome http://content.revolutionhealth.com/contentimages/media-medical-hw-h5550999_001.jpg
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