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97 Cards in this Set
- Front
- Back
Respiratory Zone |
Site of gas exchange; Includes respiratory bronchioles, alveolar ducts, and alveoli (300 million alveoli account for most of lungs volume and are main site for gas exchange) |
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Conducting Zone |
Conduits in gas exchange sites; Includes all other respiratory sturctures |
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Respiratory Muscles |
Diaphragm and other muscles that promote ventilation |
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Nose |
Provides airway; Moistens and warms entering air; Filters inspired air; Serves as a resonating chamber for speech; Houses olfactory receptors; External nose and nasal cavity regions |
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Philtrum (Nose) |
Shallow vertical groove inferior to apex |
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Nostrils (Nares) |
Bounded laterally by alae |
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Nasal Cavity |
In and posterior to external nose; Divided by midline nasal septum; Posterior nasal apertures (choanae) open into nasal pharynx; Roof is ethmoid and sphenoid bones; Floor is hard and soft palates |
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Respiratory Mucosa |
In nasal cavity; Pseudostratified ciliated columnar epithelium; Mucous and serous secretions contain lysozyme and defensins; Cilia move contaminated mucus to throat; Inspired air warmed by plexuses of capillaries/veins; Sensory nerve endings trigger sneezing |
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Nasal Conchae |
Superior, middle, and inferior ones; Protrude from lateral walls in nasal cavity; Increase mucosal area; Enhance air turbulence |
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Functions of Nasal Mucosa and Conchae |
During inhalation they filter, heat, and moisten air; During exhalation they reclaim heat and moisture |
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Paranasal Sinuses |
In frontal, sphenoid, ethmoid, and maxillary bones; Lighten the skull and help to warm and moisten air |
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Pharynx |
Muscular tube that connects to nasal cavity and mouth superiorly, larynx and esophagus inferiorly; From base of skull to level of sixth cervical vertebra |
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Larynx |
Attaches to hyoid bone and opens into laryngopharynx; Continuous with trachea; Functions - provides patent airway, routes air and food into proper channels, voice production |
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Larynx Cartilages |
Hyaline cartilage except for epiglottis; Thyroid cartilage with laryngeal prominence (Adam's apple); Ring shaped cricoid cartilage; Paired arytenoid, cuneiform, and comiculate cartilages |
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Epiglottis |
Elastic cartilage - covers laryngeal inlet during swallowing |
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Vocal Ligaments |
Attach the arytenoid cartilages to thyroid cartilage; Contain elastic fibers; Form core of vocal folds - opening between them is glottis, folds vibrate to produce sound as air rushes up from the lungs |
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Trachea |
Windpipe - from larynx to mediastnum; Wall composed of three layers - mucosa, submucosa, and adventitia |
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Mucosa |
Wall layer of trachea; Ciliated pseudostratified epithelium with goblet cells |
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Submucosa |
Wall layer of trachea; Connective tissue with seromucous glands |
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Adventitia |
Outermost wall layer of trachea; connective tissue that encases the C shaped rings of hyaline cartilage |
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Trachealis Muscle |
Connects posterior parts of cartilage rings; Contracts during coughing to expel mucus |
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Carina |
Last tracheal cartilage; Point where trachea branches into two bronchi |
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Bronchi and Subdivisions |
AIr passages undergo 23 orders of branching; Branching patter called bronchial tree |
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Conducting Zone Structures |
Trachea to right and left primary bronchi; Each main bronchus enters the hilum of one lung - right main bronchus is wider, shorter, more vertical than left; Each primary bronchus branches into secondary bronchi, each secondary bronchus supplies one lobe and branches into tertiary bronchi (segmental bronchi divide repeatedly; Bronchioles less than 1 mm in diameter; Terminal bronchioles are smallest, less than .5 mm in diameter |
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Structural Changes of Bronchi though Bronchioles |
Cartilage rings give way to plates, cartilage is absent from bronchioles; Epithelium changes from pseudostratified columnar to cuboidal epithelium - cilia and goblet cells become sparse; Relative amount of smooth muscle increases |
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Respiratory Membrane |
. um thick air blood barrier; Alveolar and capillary walls and their fused basement membranes; Scattered type II cuboidal cells secrete surfactant and antimicrobial proteins |
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Alveolar Walls |
Single layer of squamous epithelium |
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Alveoli |
Surrounded by fine elastic fibers; Contain open pores - connect adjacent alveoli, allow air pressure throughout lung to be equalized; House alveolar macrophages that keep alveolar surfaces sterile |
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Lungs |
Left lung is smaller, separated into two lobes by oblique fissure; Right lung has three lobes separated by oblique and horizontal fissures; Bronchopulmonary segments (10 right, 8-9 left); Lobules are smallest subdivisions, served by bronchioles and their branches |
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Blood Supply |
Pulmonary circulation (low pressure, high volume); Pulmonary arteries deliver systemic venous blood - branch profusely, along with bronchi and feed into the pulmonary capillary networks; Pulmonary veins carry oxygenated blood from respiratory zones to heart |
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Pleurae |
Thin, double layered serosa; Parietal pleura on thoracic wall and superior face of diaphragm; Visceral pleura on external lung surface; Pleural fluid fills the slitlike pleural cavity - provides lubrication and surface tension |
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Inspiration |
Gases flow into lungs; Active process; Inspiratory muscles contract; Thoracic vol. increases; Lungs stretch, intrapulmonary vol. increases; P pul pressure drops (to -1 mm Hg); Air flows into lungs down its pressure gradient until P pul = P atm |
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Expiration |
Gases exit lungs; Quiet expiration normally passive process; Inspiratory muscles relax; Thoracic cavity vol. decreases; Elastic lungs recoil and P pul decreases; P pul rises to +1 mm Hg; Air flows out of lungs down it pressure gradient until P pul = 0 |
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Atmospheric Pressure (P atm) |
Pressure exerted by air surrounding the body; 760 mm Hg at sea level |
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Respiratory Pressures |
Described relative to P atm; Negative respiratory pressure is less than P atm, positive is greater than P atm; 0 respiratory pressure = P atm |
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Intrapulmonary Pressure (P pul) |
Intra-alveolar; Pressure in the alveoli; Fluctuates with breathing; Always eventually equalizes with P atm |
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Intrapleural Pressure (P ip) |
Pressure in pleural cavity; Fluctuates with breathing; Always negative pressure (less than P atm and P pul); Negative P ip caused by opposing forces, two inward forces promote lung collapse - elastic recoil of lungs decreases lung size and surface tension of alveolar fluid reduces alveolar size; One outward force enlarges lungs - elasticity of chest wall pulls thorax outward |
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Pressure Relationships |
If P ip = P pul, lungs collapse |
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Transpulmonary Pressure |
P pul - P ip; Keeps the airways open; The greater the transpulmonary pressure, the larger th lungs |
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Atelectasis |
Lung collapse; Caused by plugged bronchioles (collapse of alveoli) or a wound that admits air into pleural cavity (pneumothorax) |
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Pulmonary Ventilaation |
Inspiration and expiration; Mechanical processes that depend on volume changes in thoracic cavity; Volume changes lead to pressure changes, pressure changes lead to gas flow that equalizes pressure |
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Forced Expiration |
Active process, uses abdominal and internal intercostal muscles |
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Physical Factors of Pulmonary Ventilation |
Airway resistance; Alveolar surface tension; Lung compliance |
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Airway Resistance |
F = ^P/R; ^P is pressure gradient between atmosphere and alveoli (2 mm Hg or less during normal breathing); Gas flow changes inversely with R; Insignificant (large airway diameters, progressive branching of airways); R disappears at terminal bronchioles where diffusion drives gas movement; As R increases, breathing movements become more strenuous |
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Constriction/Obstruction of Bronchioles |
Can prevent life sustaining ventilation; Can occur during acute asthma attacks and stop ventilation |
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Friction |
Major nonelastic source of resistance |
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Epinephrine |
Dilates bronchioles and reduces air resistance |
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Alveolar Surface Tension |
Attracts liquid molecules to one another at a gas liquid interface; Resists any force that tends to increase surface area of liquid |
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Surfactant |
Detergent like lipid and protein complex produced by type II alveolar cells; Reduces surface tension of alveolar collapse; Insufficient quantity in premature infants causes infant respiratory distress syndrome |
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Lung Compliance |
Measure of change in lung volume that occurs with a given change in transpulmonary pressure; Normally high due to distensibility of lung tissue and alveolar surface tension; Diminished by nonelastic scar tissue (fibrosis), reduced production of surfactant, and decreased flexibility of thoracic cage |
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Imbalances that Reduce Lung Compliance |
Deformities of thorax; Ossification of costal cartilage; Paralysis of intercostal muscles |
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Respiratory Volumes |
Used to assess a person's respiratory status |
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Tidal Volume (TV |
Amount of air inhaled or exhaled with each breath under resting conditions |
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Inspiratory Reserve Volume (IRV) |
Amount of air that can be forcefully inhaled after a normal tidal volume inhalation |
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Expiratory Reserve Volume |
Amount of air that can be forcefully exhaled after a normal tidal volume exhalation |
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Residual Volume |
Amount of air remaining in the lungs after a forced exhalation |
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Total Lung Capacity (TLC) |
Max amount of air contained in lungs after a max inspiratory action; TLC = TV + IRV + ERV + RV |
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Vital Capacity (VC) |
Max amount of air that can be expired after a max inspiratory effort; VC = TV + IRV + ERV |
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Inspiratory Capacity (IC) |
Max amount of air that can be inspired after a normal expiration; IC = TV + IRV |
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Functional Residual Capacity (FRC) |
Volume of air remaining in lungs after a normal tidal volume expiration; FRC = ERV + RV |
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Spirometer |
Instrument used to measure respiratory volumes and capacities; Can distinguish between Obstructive Pulmonary DIsease and Restrictive Disorders |
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Obstructive Pulmonary Disease |
Increased airway resistance (ex: bronchitis) |
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Restrictive Disorders |
Reduction in total lung capacity due to structural or functional lung changes (fibrosis or TB) |
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Partial Pressure Gradient (O2 in Lungs) |
Venous blood Po2 = 40 mm Hg; Alveolar Po2 = 104 mm Hg (O2 partial pressures reach equilibrium of 104 mm Hg in .25 seconds) |
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Partial Pressure Gradient (CO2 in Lungs) |
Pco2 in lungs less steep than O2; Venous blood Pco2 = 45 mm Hg; Alveloar Pco2 = 40 mm Hg; CO2 is 20 times more soluble in plasma than oxygen; Co2 diffuses in equal amount with oxygen |
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Respiratory Membranes |
.5 to 1 um thick; Large total surface area (40 times that of one's skin); Thicken if lungs become waterlogged and edematous and gas exchange become inadequate; Reduction in surface area with emphysema, when walls of adjacent alveoli break down |
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Internal Respiration |
Capillary gas exchange in body tissues; Partial pressures and diffusion gradients are reversed compared to external respiration; Po2 in tissue is always lower than in systemic arterial blood |
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Oxygen Transport |
Molecular O2 is carried in blood - 1.5% dissolved in plasma, 98.5% loosely bound to each Fe of Hb in RBCs, 4 O2 per Hb |
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Oxyhemoglobin (HbO2) |
Hemoglobin - Oxygen combination
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Reduced Hemoglobin (HHb) |
Hemoglobin that has released O2 |
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O2 Loading/Unloading |
Facilitated by change in shape of Hb - as O2 binds, Hb affinity for O2 increases, as O2 is released, Hb affinity for O2 decreases; Fully saturated if all four heme groups carry O2; Partially saturate when one to three hemes carry O2; Only 20 - 25% of bound O2 is unloaded during 1 systemic circulation |
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Po2 Influence on Hb Saturation |
In arterial blood, Po2 = 100 mm Hg; Contains 20 ml oxygen per 100 ml blood (20 vol %); Hb is 99% saturated; Further increases in Po2 produce minimal increases in O2 binding |
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Drop of O2 Levels in Tissues |
More oxygen dissociates from Hb and is used by cells; Respiratory rate of cardiac output need not increase |
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Other Factors Influencing Hb Saturation |
Increases in temp., H+, Pco2, and BPG - modify structure of Hb and decrease affinity for O2, occur in systemic capillaries, enhance O2 unloading, shift O2 Hb dissociation curve to right; Decreases in these factors shift curve to left |
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Factors that Increased Hb O2 Release |
As cells metabolize glucose - Pco2 and H= increase in concentration in capillary blood; Heat production increases - increasing temp. decreases Hb affinity for O2 |
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Bohr Effect |
Declining pH weakens Hb O2 bond |
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CO2 Transport |
CO2 transported in blodo in three forms - 7 to 10 % dissolved in plasma, 20% bound to globin of Hb (carbaminohemoglobin), 70% transported as bicarbonate ions (HCO3) in plasma |
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Respiration Control |
Involves neurons in reticular formation of medulla and pons |
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Dorsal Respiratory Group (DRG) |
Near root of cranial nerve IX; Integrates input from peripheral stretch and chemoreceptors |
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Ventral Respiratory Group (VRG) |
Rhythm generating and integrative center; Sets eupnea (12-15 breaths/minute); Inspiratory neurons excite inspiratory muscles and intercostal nerves - autorhythmically seen in pre-Botzinger neurons; Expiratory neurons inhibit the inspiratory neurons |
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Pontine Respiratory Centers |
Influence and modify activity of VRG; Smooth out transition between inspiration between inspiration and expiration and vice versa |
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Genesis of Respiratory Rhythm |
Not well understood; Most widely accepted hypothesis is reciprocal inhibition of two sets of interconnected neuronal networks in medulla sets rhythm. |
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Depth of Breathing |
Determined by how actively the respiratory center stimulates respiratory muscles |
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Rate of Breathing |
Determined by how long the inspiratory center is active |
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Influence of Pco2 |
If Pco2 level rise (hpyercapnia, CO2 accumulates in brain; CO2 is hydrated - resulting carbonic acid dissociates releasing H+; H+ stimulates central chemoreceptors of brain stem; Chemoreceptors synapse with respiratory regulatory centers, increasing depth and rate of breathing |
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Hyperventiliation |
Increased depth and rate of breathing that exceeds body's need to remove CO2; Cause CO2 levels to decline (hypocapnia); May cause cerebral vasoconstriction and cerebral ischemia |
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Apnea |
Period of breathing cessation that occurs when Pco2 is abnormally low |
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Influence of Po2 |
Peripheral chemoreceptors in aortic and carotid bodies are O2 sensors - when excited, they cause increased ventilation; Substantial drops in aterial Po2 must occur in order to stimulate increased ventilation |
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Influence of Arterial pH |
Can modify respiratory rat and rhythm even if CO2 and O2 levels are normal; Decreased pH may reflect CO2 retention, accumulation of lactic acid, excess ketone bodies in patients with diabetes melitus; Respiratory system controls will attempt to raise pH by increasing respiratory rate and depth |
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Chemical Factors Summary |
Rising CO2 levels are most powerful respiratory stimulant; Normally blood Po2 affects breathing only indirectly by influencing peripheral chemoreceptor sensitivity to changes in Pco2; When arterial Po2 falls below below 60 mm Hg, it become major stimulus for respiration (via peripheral chemoreceptors); Changes in arterial pH resulting from CO2 retention or metabolic factors act indirectly though the peripheral chemoreceptors |
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Hypothalamic Controls |
Act through limbic system to modify rate and depth of respiration |
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Rise in Body Temp. |
Acts to increase respiratory rate |
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Cortical Controls |
Direct signals from the cerebral motor cortex that bypass medullary controls (like voluntary breath holding) |
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Chronic Obstructive Pulmonary Disease (COPD) |
Exemplified by chronic bronchitis and emphysema; Irreversible decrease in ability to force air out of lungs |
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Athsma |
Characterized by coughing, dyspnea, wheezing, chest tightness; Active inflammation of airways precedes bronchospasms; Inflammation is immune response caused by releases of interleukin, lgE production, and recruitment of inflammatory cells; Airways thickened with inflammatory exudate magnify effect of bronchospasms |
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Tuberculosis |
Infectious disease; Symptoms include fever, night sweats, weight loss, racking cough, spitting up blood; Treatment entails 12 month course of antibiotics |
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Mycobacterium tuberculosis |
Bacterium that causes Tuberculosis |