2 Respiration Ventilation: Movement of air into and out of lungs External respiration: Gas exchange between air in lungs and bloodTransport of oxygen and carbon dioxide in the bloodInternal respiration: Gas exchange between the blood and tissuesCellular Respiration: The use of O2 to produce ATP via Glycolysis, TCA cycle, & ETS
3 Respiratory System Functions Gas exchange: Oxygen enters blood and carbon dioxide leavesRegulation of blood pH: Altered by changing blood carbon dioxide levels Carbonic acid Buffer systemSound production: Movement of air past vocal folds makes sound and speechOlfaction: Smell occurs when airborne molecules drawn into nasal cavityThermoregulation: Heating and cooling of bodyProtection: Against microorganisms by preventing entry and removing them
4 Respiratory System Divisions Upper tractNose, pharynx and associated structures, Larynx.Lower tracttrachea, bronchi, lungs
7 Nose and Pharynx Nose Pharynx External nose Nasal cavity FunctionsPassageway for airCleans the airHumidifies, warms airSmellAlong with paranasal sinuses are resonating chambers for speechPharynxCommon opening for digestive and respiratory systemsSkull-C6Three regionsNasopharynxOropharynxLaryngopharynx
8 Larynx Functions Maintain an open passageway for air movement Epiglottis and vestibular folds prevent swallowed material from moving into larynxVocal folds are primary source of sound production
10 Trachea Windpipe Divides to form Insert Fig 23.5 all but b Rt , Lt Primary bronchiCarina: Cough reflexInsert Fig 23.5 all but b
11 Tracheobronchial Tree Non-Acinus -Conducting zoneTrachea to terminal bronchioles which is ciliated for removal of debris, mucus linedPassageway for air movement controlled by smooth muscle at end of terminal bronchiolesCartilage holds tube system open and smooth muscle controls tube diameterAcinus Portion - Respiratory zoneRespiratory bronchioles to alveoliSite for gas exchange Area the size of a football field
15 Lungs Two lungs: Principal organs of respiration Divisions Right lung: Three lobes, shorter, broader, and has a greater volume.Left lung: Two lobes, is longer and narrower than the right lungDivisionsLobes, bronchopulmonary segments, lobules
16 LungsThe only point of attachment for each lung is at the hilum, or root, on the medial side. This is where the bronchi, blood vessels, lymphatics, and nerves enter the lungs.Each lung is enclosed by a double-layered serous membrane, called the pleura. The visceral pleura is firmly attached to the surface of the lung. At the hilum, the visceral pleura is continuous with the parietal pleura that lines the wall of the thorax. The small space between the visceral and parietal pleurae is the pleural cavity. It contains a thin film of serous fluid that is produced by the pleura. The fluid acts as a lubricant to reduce friction as the two layers slide against each other, and it helps to hold the two layers together as the lungs inflate and deflate.
19 Pleura Pleural fluid produced by pleural membranes Acts as lubricant Helps hold parietal and visceral pleural membranes together
20 Pressure – Volume Relationships As vol. , pressure As vol. , pressure This is given by Boyle’s Law which says:P1V1 = P2V2Why does this occur?Remember, pressure equals force/areaP = Force/AreaSo, in this equation as A gets larger P must get smaller.
22 VentilationMovement of air into and out of lungs via negative pressure pump mechanismAir moves from area of higher pressure outside the lung to area of lower pressure created in the thorax and lungs by diaphramPressure is inversely related to volume in that as pressure goes down lung volume goes up
23 InspirationBegins with the contraction of the diaphragm and the external intercostalsThis causes thoracic volume to Which causes lung volume to Which causes lung pressure to Now Palv is <Patm so air will flow down its pressure gradient and enter the lungs.Inspiration ends when Palv=Patm
24 Inspiration Active process involving the diaphragm and intercostal muscles
25 3 Muscle Groups of Inhalation Diaphragm:contraction draws air into lungs75% of normal air movementExternal intracostal muscles:assist inhalation25% of normal air movementAccessory muscles assist in elevating ribs:sternocleidomastoidserratus anteriorpectoralis minorscalene muscles
26 Quiet expiration is a passive process that is due to the elasticity of the lungs. Forced expiration is an active process due to contraction of oblique and transverse abdominus muscles, internal intercostals, and the latissimus dorsi.Expiration
27 Expiration Usually passive Can become active Using internal intercoastal andabdominalmuscles
29 Changing Alveolar Volume Lung recoilCauses alveoli to collapse resulting fromElastic recoil and surface tension : PneumothoraxSurfactant: Reduces tendency of lungs to collapsePleural pressureNegative pressure can cause alveoli to expandPneumothorax is an opening between pleural cavity and air that causes a loss of pleural pressure
30 Compliance Measure of the ease with which lungs and thorax expand The greater the compliance, the easier it is for a change in pressure to cause expansionA lower-than-normal compliance means the lungs and thorax are harder to expandConditions that decrease compliancePulmonary fibrosisPulmonary edemaRespiratory distress syndrome.
31 Alveolar Membrane Surfactant and water layer Alveolar wall- Simple squamous epithelium3) Basement membrane of alveolar wall4) Interstitial space5) Capillary wall- Simple squamous epithelium6) Basement membrane of cap wall.
33 The factors that effect rate of gas exchange Partial pressure gradients of O2 and CO2Surface area of alveolar membraneThickness of capillary-alveolar membraneVentilation- perfusion mismatch
34 Pulmonary Volumes Tidal volume Inspiratory reserve volume Volume of air inspired or expired during a normal inspiration or expirationInspiratory reserve volumeAmount of air inspired forcefully after inspiration of normal tidal volumeExpiratory reserve volumeAmount of air forcefully expired after expiration of normal tidal volumeResidual volumeVolume of air remaining in respiratory passages and lungs after the most forceful expiration
35 Pulmonary Capacities Inspiratory capacity Functional residual capacity Tidal volume plus inspiratory reserve volumeFunctional residual capacityExpiratory reserve volume plus the residual volumeVital capacitySum of inspiratory reserve volume, tidal volume, and expiratory reserve volumeTotal lung capacitySum of inspiratory and expiratory reserve volumes plus the tidal volume and residual volume
36 Pulmonary CapacitiesInspiratory capacity is the total amt of air that can be inspired after a tidal expiration:IC = TV + IRVFunctional residual capacity is the amt of air in the lungs after a tidal expiration:FRC = ERV + RVVital capacity is the total amt of exchangeable air:VC = TV+IRV+ERVTotal lung capacity is the sum of all lung volumes and is normally around 6L in males:TLC = VC + RV
39 Minute and Alveolar Ventilation Minute ventilation: Total amount of air moved into and out of respiratory system per minuteRespiratory rate or frequency: Number of breaths taken per minuteAnatomic dead space: Part of respiratory system where gas exchange does not take placeAlveolar ventilation: How much air per minute enters the parts of the respiratory system in which gas exchange takes place
40 Physical Principles of Gas Exchange Partial pressureThe pressure exerted by each type of gas in a mixtureDalton’s lawWater vapor pressureDiffusion of gases through liquidsConcentration of a gas in a liquid is determined by its partial pressure and its solubility coefficientHenry’s law
41 Physical Principles of Gas Exchange Diffusion of gases through the respiratory membraneDepends on membrane’s thickness, the diffusion coefficient of gas, surface areas of membrane, partial pressure of gases in alveoli and bloodRelationship between ventilation and pulmonary capillary flowIncreased ventilation or increased pulmonary capillary blood flow increases gas exchangePhysiologic shunt is deoxygenated blood returning from lungs
42 Oxygen and Carbon Dioxide Diffusion Gradients Moves from alveoli into blood. Blood is almost completely saturated with oxygen when it leaves the capillaryP02 in blood decreases because of mixing with deoxygenated bloodOxygen moves from tissue capillaries into the tissuesCarbon dioxideMoves from tissues into tissue capillariesMoves from pulmonary capillaries into the alveoli.
46 Hemoglobin and 02 Transport 280 million hemoglobin/ RBC.Each hemoglobin has 4 polypeptide chains and 4 hemes.Each heme has 1 atom iron that can combine with 1 molecule 02.
47 Hemoglobin Hemoglobin production controlled by erythropoietin. Production stimulated by P02 delivery to kidneys.Loading/unloading depends:P02 of environment.Affinity between hemoglobin and 02.
48 Hemoglobin and Oxygen Transport Oxygen is transported by hemoglobin (98.5%) and is dissolved in plasma (1.5%)Oxygen-hemoglobin dissociation curve shows that hemoglobin is almost completely saturated when P02 is 80 mm Hg or above. At lower partial pressures, the hemoglobin releases oxygen.A shift of the curve to the left because of an increase in pH, a decrease in carbon dioxide, or a decrease in temperature results in an increase in the ability of hemoglobin to hold oxygen
49 Hemoglobin and Oxygen Transport A shift of the curve to the right because of a decrease in pH, an increase in carbon dioxide, or an increase in temperature results in a decrease in the ability of hemoglobin to hold oxygenThe substance 2.3-bisphosphoglycerate increases the ability of hemoglobin to release oxygenFetal hemoglobin has a higher affinity for oxygen than does maternal
55 Transport of Carbon Dioxide Carbon dioxide is transported as bicarbonate ions (70%) in combination with blood proteins (23%) and in solution with plasma (7%)Hemoglobin that has released oxygen binds more readily to carbon dioxide than hemoglobin that has oxygen bound to it (Haldane effect)In tissue capillaries, carbon dioxide combines with water inside RBCs to form carbonic acid which dissociates to form bicarbonate ions and hydrogen ions
56 Transport of Carbon Dioxide In lung capillaries, bicarbonate ions and hydrogen ions move into RBCs and chloride ions move out. Bicarbonate ions combine with hydrogen ions to form carbonic acid. The carbonic acid is converted to carbon dioxide and water. The carbon dioxide diffuses out of the RBCs.Increased plasma carbon dioxide lowers blood pH. The respiratory system regulates blood pH by regulating plasma carbon dioxide levels
58 Respiratory Areas in Brainstem Medullary respiratory centerDorsal groups stimulate the diaphragmVentral groups stimulate the intercostal and abdominal musclesPontine (pneumotaxic) respiratory groupInvolved with switching between inspiration and expiration
60 Rhythmic Ventilation Starting inspiration Increasing inspiration Medullary respiratory center neurons are continuously activeCenter receives stimulation from receptors and simulation from parts of brain concerned with voluntary respiratory movements and emotionCombined input from all sources causes action potentials to stimulate respiratory musclesIncreasing inspirationMore and more neurons are activatedStopping inspirationNeurons stimulating also responsible for stopping inspiration and receive input from pontine group and stretch receptors in lungs. Inhibitory neurons activated and relaxation of respiratory muscles results in expiration.
61 Modification of Ventilation Chemical controlCarbon dioxide is major regulatorIncrease or decrease in pH can stimulate chemo- sensitive area, causing a greater rate and depth of respirationOxygen levels in blood affect respiration when a 50% or greater decrease from normal levels existsCerebral and limbic systemRespiration can be voluntarily controlled and modified by emotions
64 Herring-Breuer Reflex Limits the degree of inspiration and prevents overinflation of the lungsInfantsReflex plays a role in regulating basic rhythm of breathing and preventing overinflation of lungsAdultsReflex important only when tidal volume large as in exercise
65 Ventilation in Exercise Ventilation increases abruptlyAt onset of exerciseMovement of limbs has strong influenceLearned componentVentilation increases graduallyAfter immediate increase, gradual increase occurs (4-6 minutes)Anaerobic threshold is highest level of exercise without causing significant change in blood pHIf exceeded, lactic acid produced by skeletal muscles
66 Effects of AgingVital capacity and maximum minute ventilation decreaseResidual volume and dead space increaseAbility to remove mucus from respiratory passageways decreasesGas exchange across respiratory membrane is reduced.
67 Ventilation PatternsEupnea - Normal, quiet breathingDyspnea - Difficult breathingApnea - absence of breathingTachypnea - Rapid breathing rateBradypnea - Slow breathingHyperpnea - Deep breathingHypopnea - Shallow breathingHyperventilation - Rapid, deep breathingCheyne-Stokes breathing - periods of apnea interspersed with hyperpnea