7PharynxMuscular tubeExtends vertically from back of the soft palate to superior aspect of the esophagusAllows air to flow in and out of the respiratory tract and food to pass into the digestive tract
8LarynxJoins the pharynx with the tracheaConsists of the thyroid and cricoid cartilage, glottic opening, vocal cords, cricothyroid membrane.
9Trachea:10 to 12 centimeter long tube that connects the larynx to the two mainstem bronchi.Lined with respiratory epithelium containing cilia and mucous producing cells.Mucous traps particles that the upper airway did not filter.Cilia move the trapped particles up into the mouth where it is expelled or swallowed.
10Bronchi:At the carina bifurcates into the right a left mainstem bronchi.AlveoliBronchioles divide into the alveolar ducts and terminates into the alveoliComprise the key functional unit of the respiratory systemContain an alveolar membrane that is only 2 cells thickMost CO2 and O2 exchange takes placeBecome thinner as they expandSurface area totals more than 20 square meters, enough to cover half a tennis courtThe hollow structure resists collapse due to the presence of a surfactant, a chemical that decreases their surface tension and makes it easier for them to expand.Carina
12AtelectasisAveolar collapseLung ParenchymaParenchyma: Principal or essential parts of an organOrganized into the lobesRight lung has three lobes where as the left lung has only two as it shares thoracic space with the heart.
13PleuraMembranous connective tissue that covers the lungsVisceral: Envelopes the lungs and does not contain nerve tissueParietal: Lines the Thoracic cavity and contains nerve fibers
14RESPIRATION AND VENTILATION Ventilation: The mechanical process that moves air into and out of the lungsPulmonary or external respiration: AlveoliCellular or internal respiration occurs in the peripheral capillaries It is the exchange of respiratory gases between the RBCs and various body tissuesCellular respiration in the peripheral tissue produces CO2 which is picked up by the blood in the capillaries and transports it as bicarbonate ions through the venous system to the lungs.
15RESPIRATORY CYCLENothing within the lung parenchyma makes it contract or expandVentilation depends upon changes of pressure within the thoracic cavityBegins when the lungs have achieved a normal expiration and the pressure inside the thoracic cavity is equal to the atmospheric pressureRespiratory centers in the brain communicate with the diaphragm by way of the phrenic nerve, signaling it to contract. This initiates the respiratory cycleThen……….
16Thorax increases; pressure within decreases; becomes lower than atmospheric pressure; with the negative pressure, air rushes in; the alveoli inflate with the lungs, becoming thinner allowing oxygen and CO2 to diffuse across their membranes.When the pressure in the thoracic cavity is again that of the atmospheric pressure, the alveoli are maximally inflated.
17Pulmonary expansion stimulates microscopic stretch receptors in the bronchi and bronchioles that signal the respiratory center by way of the vegus nerve to inhibit respiration and the influx of air stops.At the end of respiration:Respiratory muscles relaxSize of the chest cavity decreasesElastic lungs recoil forcing air out of the lungs (expiration)
18Expiration is passiveRespiration is active process using energy
19Use of Accessory muscles: Strap muscles of the neck, and abdominal muscles to augment efforts to expand the thoracic cavity
20Pulmonary Circulation During each cardiac cycle, the heart pumps just as much blood to the lungs as it does to the peripheral tissues.Bronchial arteries that branch from the aorta supply most of their blood.Bronchial veins return blood from the lungs to the superior vena cava.
21Hypoventilation: Reduction in breathing rate and depth
22Pneumothorax: Air or gas in the pleural cavity Hemothorax: Accumulation of blood or fluid containing blood in the pleural cavityPulmonary embolism: Blood clot that travels to the pulmonary circulation and hinders oxygenation of blood
23Hypoxic DriveThe body constantly monitors the PaO2 and the pH.COPDChronically elevated PaCO2Body no longer uses PaCO2 levels to stimulate breathingHypoxic drive increases respiratory stimulation when PaO2 level falls and inhibits respiratory stimulation when PaO2 levels increase.
24Hypoxemia: Decreases partial pressure of oxygen in the blood
25Respiratory Acidosis: Retention of CO2 can result from impaired ventilation due to problems occurring in either the lungs or in the respiratory center of the brain.Respiratory Alkalosis results from increased respiration and excessive elimination of CO2.
26MEASURES OF RESPIRATORY FUNCTION Respiratory rate:Adults 12 to 20Children 18 to 24Infants 40 to 60Eupnea: Normal RespirationFever IncreasesEmotion IncreasesPain IncreasesHypoxia IncreasesAcidosis IncreasesStimulant Drugs IncreasesDepressant Drugs DecreasesSleep Decreases
27Total Lung CapacityTotal amount of air contained in the lung at the end of the maximal respiration6LTidal VolumeAverage volume of gas inhaled or exhaled in one respiratory cycle500 mL (5 to 7 cc/kg)Dead Space VolumeThe amount of gas in the tidal volume that remains in the airpassageways unavailable for gas exchange.Anatomic dead space includes the trachea and bronchiPhysiologic dead space from COPD, obstruction or atelactesis150 ml
28Minute VolumeAmount of gas moved in and out of the respiratory tract in one minuteVmin = VT x Respiratory RateAlveolar Minute VolumeAmount of gas that reaches the alveoli for gas exchange in one minuteVA-min = (VT – VD) X Respiratory rate
29RESPIRATORY PROBLEMSDyspnea: An abnormality of breathing rate, pattern, or effortHypoxia: Oxygen deficiencyAnoxia: The absence or near-absence of oxygen
30Modified forms of respiration Coughing: forceful exhalation of a large volume of air form the lungs, expelling foreign materials from the lungsSneezing: Sudden forceful exhalation from the nose. Nasal irritationHiccoughing: Sudden inspiration; caused by spasmodic contraction of the diaphragm with spasmodic closure of the glottis. No physiologic purpose. Occasionally been associated with MI on the inferior (diaphragmatic) surface of the heartSighing: Slow, deep, involuntary inspiration followed by a prolonged expiration; hyperventilates the lungs and reexpands atlectatic alveoli; occurs once a minuteGrunting: Forceful expiration; occurs against a partially closed epiglottis; usually an indication of respiratory distress.
33Pulsus ParadoxusComparison of blood pressure between that ofinspiration and that of exhalationA drop in blood pressure greater than 10 torrDrop in blood pressure during inspirationDrop is due to increased pressure in the thoracic cavity that impairs the inability of theventricles to fill.
34ABNORMAL RESPIRATORY PATTERNS Kusssmaul’s RespirationsDeep, slow or rapid, gasping breathing,Commonly found in diabetic ketoacidosisCheyne-Stokes RespirationsProgressively deeper, faster breathing alternating gradually with shallow, slower breathing.Indicates brain-stem injuryBiot’s RespirationsIrregular pattern of rate and depth with sudden, periodic episodes of apneaIndicates increased intracranial pressure
36Agonal RespirationsShallow, slow, or infrequent breathingIndicates brain anoxia
37Rales: Fine, bubbling sound; on inspiration; fluid in smaller bronchioles Rhonchi; Course, rattling noise on inspiration; associated with inflammation, mucous or fluid in the bronchiolesStridor: Harsh, high-pitched heard on inhalation; laryngeal edema or constrictionSnoring: Partial obstruction of the upper airway by the tongueGurgling: Accumulation of blood, vomitus, or other secretions in the upper airway
38Tension PnuemothoraxAny tear in the lung parenchyma can cause a pneumothorax.Tension: Large pneumothorax that affects other structures in the chestProgressively worsening compliance when baggingDiminished unilateral breath soundsHypoxia with hypotensionDistended neck veinsMarked increase in pressure can prevent ventricles from adequately filling decreasing cardiac outputTracheal deviation
39Tachypnea/BradypneaRespiratory effort: How hard a patient has to work to breatheOrthopnea: Difficulty breathing while lying supine
40HypothermiaCombines the mechanisms of convection, radiation, and evaporationAccounts for a large proportion of the body’s heat lossHeat is transferred to from the lungs to inspired air by convection and radiationEvaporation in the lungs humidifies the inspired air.During expiration, warm humidified air is released into the environment, creating heat loss
41Respiratory ShockRespiratory system is not able to bring oxygen into the alveoli and remove CO2Blood leaves the pulmonary circulation without adequate oxygen and with an excess ofCO2The cells become hypoxic while the bloodstream becomes acidic
42RESPIRATORY CONTROLRespiratory centers within the brainstem control respirationInspiration and expiration occur automatically and are triggered by impulses generated in the respiratory center of the medulla oblongata during normal respirationThe medullary respiratory system contains chemoreceptors that respond to changes in the CO2 and pH levels in the CSFCO2 rapidly diffuses across the blood-brain barrier in to the CSF while H+ and bicarbonate ions do not.
43Two Respiratory Centers in the Pons ApneusticLocated in the lower ponsActs as a shut-off switch to inspirationIf non-functional, prolonged inspiration interrupted by occasional expirationPneumotaxic CenterLocated in the upper ponsModerates the activity of the apneustic center and provide fine tuningMedulla OblongataCO2 receptorsInternal Carotid ArteriesCO2, O2 and B/P receptorsAortaLungsStretch receptors
44PonsModifies rate and depth of breathingMedulla OblongataSets basic rate and depth of breathing