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A&PII -Ch 22
Respiratory System
| Question | Answer |
|---|---|
| breathing; consists of inspiration and expiration | pulmonary ventilation |
| period when air flows into lungs | inspiration |
| period when gases exit lungs | expiration |
| respiratory pressures are always described __ __ atmospheric pressure | relative to |
| pressure exerted by air/gases surrounding body | atmospheric pressure (Patm) |
| at __ __ Patm is 760 mm Hg | sea level |
| atmospheric pressure at sea level can be expressed in __ __ 760 mm Hg = 1 atm | atmospheric units |
| an atmospheric pressure of -4 mm Hg means that pressure in that area is __ __ atmospheric pressure by 44 mm Hg | lower than |
| positive respiratory pressure is __ __ atmospheric pressure | higher than |
| is equal to atmospheric pressure | zero respiratory pressure |
| pressure in alveoli; rises & falls with phases of breathing, but always eventually equalizes with atmospheric pressure | intrapulmonary pressure (Ppul) |
| pressure in plural cavity; fluctuates with breathing phases but is always about 4 mm Hg less than Ppul | intraplueral pressure (Pip) |
| Pip is always __ relative to Ppul | negative |
| lung's natural tendency to __ always assume smallest possible size | recoil |
| molecules of fluid lining alveoli tract __ each other & this produces surface tension | attract |
| constantly acts to draw alveoli to smallest possible dimension | surface tension of alveolar fluid |
| opposed by natural elasticity of chest wall | lung-collapsing forces |
| force that tends to pull thorax outward & to enlarge lungs | natural elasticity of chest wall |
| secures parietal & visceral pleurae together | pleural fluid |
| pleurae slide from side to side easily, but remain closely __ | apposed |
| separating the pleurae requires __ force | extreme |
| net result of dynamic interplay btwn forces of pleurae is a(n) __ __ | negative Pip |
| amount of pleural fluid in pleural cavity must remain __ in order for negative Pip to be maintained | minimal |
| pleural fluid is actively pumped out of pleural cavity into __ continuously | lymphatics |
| if pleural fluid wasn't pump out continuously it would accumulate in intrapleural space producing __ __ in pleural cavity | positive pressure |
| any condition that __ Pip with intrapulmonary pressure causes immediate lungs collapse | equalizes |
| difference btwn intrapulmonary & intrapleural pressures (Ppul - Pip) | transpulmonary pressure |
| transpulmonary pressure keeps __ __ of lungs open or keeps them from collapsing | air spaces |
| determines size of lungs at any given time | size of transpulmonary pressure |
| the __ the transpulmonary pressure, the larger the lungs | greater |
| lung collapse; occurs when a bronchiole becomes plugged | atelectasis |
| when a bronchiole becomes plugged its __ __ then absorb all of their air & collapse | associated alveoli |
| atelectasis can also occur when air eneter plueral cavity through | chest wound |
| presence of air i pleural cavity is referred to as | pneumothorax |
| pneumothorax is __ by drawing air out of intrapleural space with chest tubes, which allows pleurae to heal & lung to reinflate & resume normal function | reversed |
| because of this one lung can collapse without interfering with function of the other lung | lungs are in separate cavities |
| pulmonary ventilation, consisting of inspiration & expiration, is a(n) __ __ that depends on volume change in thoaric cavity | mechanical process |
| as a rule __ __ lead to pressure changes | volume changes |
| as a rule __ __ lead to flow of gases to equalize pressure | pressure changes |
| relationship btwn __ & __ of a gas is given by Boyle's law | pressure; volume |
| states that when temperature is constant, pressure of a gas varies inversely with its volume | Boyle's law |
| formula; at constant temperature, pressure of a gas varies inversely with its volume | P1V1 = P2V2 |
| gases always __ their container | fill |
| in large container, molecules in given amount of gas will be __ __ & pressure will be low | far apart |
| in smaller container, gas molecules will be forced __ __ & pressure will be higher | closer together |
| described as a gas-filled box with a single entrance at top (tubelike tranchea) | thoracic cavity |
| volume of thoracic cavity is __ | changeable |
| volume of thoracic cavity can be increased by enlarging all of its dimension, thereby | decreasing gas pressure inside |
| drop in pressure within thoracic cavity causes | air to rush in from atmosphere |
| gases always __ __ their pressure gradients | flow down |
| diaphragm & external intercostal muscles | inspiratory muscles |
| during normal __ __ the inspiratory muscles are activated | quiet inspiration |
| when diaphragm contracts, it moves inferiorly & flattens out; as result __ __ of thoracic cavity increases | superior-inferior dimension |
| works through action of diaphragm & intercostal muscles | quiet inspiration |
| __ __ external intercostal muscles lifts rib cage & pulls sternum superiorly | contraction of |
| because ribs curve downward as well as forward around chest wall, broadest lateral & anteroposterior dimensions of rib cage are normally directed __ __ | obliquely downward |
| when ribs are raised & drawn together, they swing outward, expanding __ of thorax both laterally & in anteroposterior plane | diameter |
| action of diaphragm & external intercostal muscles expand thoracic dimensions only a few __ along each plane, enough to increase thoracic volume by almost 500 ml | millimeters |
| usual amount of air that enters lungs during normal quiet inspiration | 500 ml |
| far more important of inspiratory muscles in producing volume changes that lead to normal quiet inspiration | the diaphragm |
| as thoracic dimensions increase __ __, the lungs are stretched and intrapulmonary volume increases | during inspiration |
| inspiratory muscles contract--> thoracic cavity volume increases --> lungs are stretched & intrapulmonary volume increases --> intrapulmonary pressure drops to -1mm Hg --> air flows into lungs down pressure gradient until intrapulmonary pressure is zero | sequence of inspiration |
| inspiratory muscles relax --> thoracic cavity volume decreases --> elastic lungs recoil passively & intrapulmonary volume decreases --> intrapulmonary pressure rises to +1 mm Hg --> air flows out of lungs down its pressure gradient until Pip is zero | sequence of expiration |
| anytime intrapulmonary pressure is less than atmospheric pressure | air rushes into lungs along pressure gradient |
| inspiration ends when | Ppul = Patm |
| during __ inspiration that occur during vigorous exercise & in some COPDs thoracic volume is further increased by activity of accessory muscles | deep/forced |
| scalenes & sternocleidomastoid muscles of neck & pectoralis minor of chest __ __ even more than occurs during quiet inspiration | raise chest |
| back extends as thoracic curvature is __ by erector spinae muscles during quiet inspiration | straightened |
| in healthy individuals it is a passive process that depends more on lung elasticity than on muscle contraction | quiet expiration |
| during quiet expiration, as inspiratory muscles relax & resume their __ __, the rib cage descends & lungs recoil | resting length |
| both thoracic & intrapulmonary volumes decrease | during quiet expiration |
| volume decreasing during quiet expiration __ the alveoli & Ppul rises to about 1mm Hg above atmospheric pressure | compresses |
| when Ppul > Patm the pressure gradient __ __ to flow out of the lungs | forces gases |
| active process produced by contraction of abdominal wall muscles, primarily the oblique & transverse muscles | forced expiration |
| contraction of abdominal walls muscles during forced expiration increases the __ pressure, which forced abdominal organs superiorly against diaphragm | intra-abdominal |
| contraction of abdominal walls muscles during forced expiration __ the rib cage | depresses |
| internal intercostal muscles also help to depress the rib cage & | decrease thoracic volume |
| control of accessory muscles of expiration is important when __ __ of air flow from lungs is desired | precise regulation |
| inspiratory muscles consume energy to | enlarge the thorax |
| major nonelastic source of resistance to gas flow is __ encountered in the respiratory passageways | friction/drag |
| factors determining gas flow in respiratory passages & blood flow in cardiovascular system are | equivalent |
| amount of gas flowing into & out of the alveoli is directly proportional to (triangle)P, which is the difference in pressure/pressure gradient between | external atmosphere & alveoli |
| very small difference in pressure produce __ __ in volume of gas flow | large changes |
| during normal quiet breathing is 2 mm Hg/less; is sufficient to move 500 ml of air in/out of lungs with each breath | average pressure gradient |
| gas flow changes __, gas flow decreases as resistance increases | inversely |
| resistance in respiratory tree is determine mostly by the diameters of __ __ | conducting tubes |
| as a rule, airway resistance is insignificant because airway diameter in 1st part of conducting zone are huge, relative to | low viscosity of air |
| as a rule, airway resistance is insignificant because as airways get progressively smaller, there are progressively more branches; as result, although individual bronchioles are tiny there are enormous number of them in parallel, so | total cross-sectional area is huge |
| greatest resistance to gas flow occurs in | medium-sized bronchi |
| at terminal bronchioles, gas flow stops & __ takes over as main force driving gas movement, so resistance is no longer an issue | diffusion |
| local accumulations of mucus, infectious material, or solid tumors | important source of airway resistance in those with respiratory disease |
| whenever airway resistance rises, breathing movements become __ __ | more strenuous |
| when bronchioles are severely constricted/obstructed even most magnificent respiratory efforts cannot __ __ to life-sustaining levels | restore ventilation |
| at any __ __, the molecules of liquid are more strongly attracted to each other than to gas molecules | gas-liquid boundary |
| unequal attraction, at gas-liquid boundary, that produces a state of tension at liquid surface | surface tension |
| surface tension draws liquid molecules closer together & reduces their contact with __ gas molecules | dissimilar |
| surface tension __ any force that tends to increase surface are of the liquid | resists |
| water is composed of __ __ molecules | highly polar |
| water has a very __ surface tension | high |
| as the major component of the liquid film that coats the alveolar walls, water is always acting to __ __ to their smallest possible size | reduce alveoli |
| if the liquid film that coats the alveolar walls were __ __ the alveoli would collapse between breaths | pure water |
| secretion produced by certain cells of alveoli that reduces surface tension of water molecules, thus preventing collapse of the alveoli after each expiration | surfactant |
| surfactant is a(n) __ __ of lipids & proteins produced by type II alveolar cells | detergent-like complex |
| surfactant decreases __ of water molecules | cohesiveness |
| surfactant reduces surface tension of alveolar fluid, so __ __ is needed to overcome those forces to expand lungs & discourage alveolar collapse | less energy |
| breaths that are deeper than normal stimulate type II cells to | secrete more surfactant |
| when __ __ surfactant is present, surface tension forces can collapse alveoli | too little |
| condition peculiar to premature babies; inadequate pulmonary surfactant is produced due to prematurity often they are unable to keep alveoli inflated btwn breaths | infant respiratory distress syndrome (IRDS) |
| treated by spraying natural/synthetic surfactant into newborn's respiratory passageways | IRDS |
| device that maintain positive airway pressure throughout respiratory cycle, for premature babies, are often used to | keep alveoli open between breaths |
| many IRDS survivors suffer from chronic lung disease during childhood and beyond; believed to be result from inflammatory injury to respiratory zone structure caused by mechanical ventilation of premature's delicate lungs | bronchopulmonary dysplasia |
| measure of change in lung volume that occurs with given change in transpulmonary pressure; or, distensibility/stretchiness of healthy lungs is referred to as | lung compliance (CL) |
| the more a lung expands for a given rise in transpulmonary pressure, the __ its compliance | greater |
| the higher the lung compliance, the easier it is to __ __ at any given transpulmonary pressure | expand lungs |
| lung compliance is determined by __ of the lung tissue | distensibility |
| lung compliance is determined by __ surface tension | alveolar |
| lung distensibility is __ | high |
| alveolar surface tension is __ __ by surfactant | kept low |
| because of high lung distensibility & low alveolar surface tension, lungs of healthy people tend to have __ __ __, which favors efficient ventilation | high lung compliance |
| lung compliance is diminished by decrease in __ __ of lungs | natural resilience |
| chronic inflammation or infection can cause __ __ tissue to replace normal lung tissue | nonelastic scar |
| nonelastic scar tissue that replaces normal lung tissue | fibrosis |
| decrease in production of surfactant can decrease | compliance of thoracic wall |
| factors that decrease compliance of thoracic wall __ expansion of lungs | hinder |
| total compliance of respiratory system is comprised of | lung compliance & thoracic wall compliance |
| deformities of thorax, ossification of costal cartilages, & paralysis of intercostal muscles all reduce __ __ __ by hindering thoracic expansion | total respiratory compliance |
| combinations of respiratory volumes that are measured to gain information about a person's respiratory status | respiratory capacities |
| air moving into & out of the lungs with each breath; about 500 ml | tidal volume (TV) |
| amount of air that can be inspired forcibly beyond the tidal volume; 2100-3200 ml | inspiratory reserve volume (IRV) |
| amount of air (normally 1000-1200 ml) that can be evacuated from the lungs after a tidal expiration | expiratory reserve volume (ERV) |
| 1200 ml of air that remains in the lungs, which helps to keep alveoli patent & prevent lung collapse | residual volume (RV) |
| include inspiratory capacity, functional residual capacity, vital capacity, & total lung capacity; always consist of 2< lung volumes | respiratory capacities |
| total amount of air that can be inspired after a tidal expiration; sum of TV & IRV | inspiratory capacity (IC) |
| represent amount of air remaining in lungs after tidal expiration & is combined RV & ERV | functional residual capacity |
| volume of air that can be expelled from lungs by forcible expiration after deepest inspiration; total exchangeable air | vital capacity (VC) |
| sum of all lung volumes & is normally around 6000 ml | total lung capacity (TLC) |
| lung volumes & capacities, with exception of __ __, tend to be smaller in women than in men | tidal volume |
| volume of conducting zone conduits; typically amounts to about 150 ml | anatomical dead space |
| anatomical dead space volume in healthy young adult is equal to 1 ml per pound of | ideal body weight |
| if TV is 500 ml, only 350 ml of it is involved in alveolar ventilation, leaving 150 ml of tidal breath | in anatomical dead space |
| alveoli cease to act in gas exchange due to alveolar collapse or obstruction by mucus creates | alveolar dead space |
| alveolar dead space is added to anatomical dead space, and sum of nonuseful volumes is referred to as | total dead space |
| original instrument for measuring the volume of air entering and leaving the lungs | spirometer |
| spirometer is most useful in evaluating losses in respiratory function & following course of certain __ __ | respiratory diseases |
| involves increased airway resistance | obstructive pulmonary disease |
| involves reduction in total lung capacity resulting from structural or functional changes in lungs | restrictive pulmonary disorders |
| increases in TLC, FRC, & RV may occur as a result of __ of lungs in obstructive disease | hyperinflation |
| VC, TLC, FRC, & RV are __ in restrictive pulmonary disorders which limit lung expansion | reduced |
| total amount of gas that flows into or out of respiratory tract in 1 minute | minute ventilation |
| during normal quiet breathing the minute ventilation in healthy people is about | 6 L/min |
| during vigorous exercise minute ventilation may reach | 200 L/min |
| measures amount of gas expelled when subject takes deep breath & then forcefully exhales maximally and as rapidly as possible | forced vital capacity (FVC) |
| determined amount of air expelled during specific time intervals of FVC test | forced expiratory volume (FEV) |
| healthy lungs can __ about 80% of FVC within 1 second | exhale |
| better index of respiratory efficiency; measures volume of fresh air that flows in and out of alveoli | alveolar ventilation rate (AVR) |
| takes into account volume of air wasted in dead space & measures flow of fresh gases in/out of alveoli during particular time interval | AVR |
| formula for AVR | frequency x (TV - dead space) |
| in healthy people AVR is usually about 12 breaths per minute times the difference of 500-150 ml per breath, or | 4200 ml/min |
| because anatomical dead space is constant, increasing volume of each inspiration enhances AVR and gas exchange more than | raising respiratory rate |
| AVR drops dramatically during rapid shallow breathing because most of inspired air | never reaches exchange sites |
| as tidal volume approaches the dead space value, __ __ approaches zero regardless of how fast a person is breathing | effective ventilation |
| result from reflex activity, but some are voluntary; processes other than breathing that move air into/out of lungs; may modify normal respiratory rhythm | nonrespiratory air movements |
| states that total pressure exerted by mixture of gases is sum of pressures exerted independently by each gas in mixture; pressure exerted by each gas is directly proportional to percentage of that gas in gas mixture | Dalton's law of partial pressures |
| pressure exerted by each gas | partial pressure |
| make up about 79% of air | nitrogen |
| 78.6% x 760 mm Hg, or 597 mm Hg | partial pressure of nitrogen (Pn2) |
| 20.9% x 760 mm Hg) 159 mm Hg | partial pressure of oxygen (Po2) |
| contribute about 99% of total atmospheric pressure | nitrogen & oxygen together |
| contains nitrogen, oxygen, 0.04% carbon dioxide, up to 0.5% water vapor, & insignificant amounts of inert gases | air |
| at high altitudes, partial pressures __ in direct proportion to decrease in atmospheric pressure | decline |
| atmosphere is less influenced by gravity | high altitudes |
| atmospheric pressure increase by 1 atm (760 mm Hg) for each 33 ft of | descent below sea level |
| when gas is in contact with a liquid that gas will dissolve in the liquid in proportion to its partial pressure | Henry's law |
| according to Henry's law the greater the concentration of particular gas in gas phase, the more & faster that gas will go into | solution in the liquid |
| at __, the gas partial pressures in two phases are the same | equilibrium |
| if partial pressure of gas later becomes greater in liquid than in adjacent gas phase, some of dissolved gas molecules will | reenter gaseous phase |
| how much of a gas that will dissolve in liquid at any given partial pressure depends on __ of gas in the liquid and on __ of liquid | solubility; temperature |
| is most soluble gas in air | carbon dioxide |
| only 1/20 as soluble in air as carbon dioxide | oxygen |
| only half as soluble in air as oxygen | nitrogen |
| at a given partial pressure much more CO2 than O2 | dissolves in water |
| at a given partial pressure practically no N2 | goes into solution |
| effect of increasing liquid's temperature is to | decrease gas solubility |
| provide clinical applications of Henry's law; contain O2 gas at pressures higher than 1 atm & are used to force greater-than-normal amount of O2 into blood of patients suffering from carbon monoxide poisoning or tissue damage following radiation therapy | hyperbaric oxygen chambers |
| used to treat individuals with gas gangrene, because anaerobic bacteria causing infection cannot live in presence of high O2 levels | hyperbaric therapy |
| scuba diving provides another illustration of Henry's law - if divers rise rapidly from depths, dissolved nitrogen forms bubbles in their blood causing | "the bends" |
| develops rapidly when Po2 is greater than 2.5-3 atm; excessively high concentrations generate huge amounts of harmful free radicals, resulting in profound CNS disturbances, coma, & death | oxygen toxicity |
| difference in atmospheric & alveoli gases reflect effects of __ __, O2 diffusing from alveoli to pulmonary blood & CO2 diffusing in opposite direction, occurring in the lungs | gas exchange |
| difference in atmospheric & alveoli gases reflect effects of __ of air by conducting passages | humidification |
| difference in atmospheric & alveoli gases reflect effects of the __ __ alveolar gas that occurs with each breath | mixing of |
| because only 500 ml of air is inspired with each tidal inspiration, gas in alveoli is actually a mixture of newly inspired gases and | gases remaining in respiratory passageways between breaths |
| alveolar partial pressures of O2 & CO2 are easily changed by increasing breathing __ & __ | depth; rate |
| high AVR bring more O2 into the alveoli, increasing alveolar Po2, and rapidly | eliminating CO2 from the lungs |
| during __ __ dark red blood flowing through pulmonary circuit is transformed into scarlet river that is returned to heart for distribution by systemic arteries to all body tissues | external respiration |
| color change of blood during pulmonary gas exchange is due to O2 __ & __ to hemoglobin in RBCs | uptake; binding |
| partial pressure __ & gas __ influence movement of oxygen & carbon dioxide across respiratory membrane | gradients; solubilities |
| matching of __ ventilation & __ blood perfusion influence movement of oxygen & carbon dioxide across respiratory membrane | alveolar; pulmonary |
| __ characteristics of respiratory membrane influence movement of oxygen & carbon dioxide across respiratory membrane | structural |
| drive diffusion of gases across respiratory membrane | partial pressure gradients of O2 & CO2 |
| exists across respiratory membrane because the Po2 of deoxygenated blood in pulmonary arteries is only 40 mm Hg opposed to Po2 of approx. 104 mm Hg in alveoli | steep oxygen partial pressure gradient |
| because of steep oxygen partial pressure gradient O2 __ __ from alveoli into pulmonary capillary blood | diffuses rapidly |
| Po2 of 104 mm Hg on both side of respiratory membrane usually occurs in 0.25 seconds | equilibrium |
| blood can flow through __ __ three times as quickly and still be adequately oxygenated | pulmonary capillaries |
| CO2 diffuses in __ __ than O2 along a much gentler partial pressure gradient of 5 mm Hg until equilibrium occurs at 40 mm Hg | opposite direction |
| equal amounts of CO2 & O2 are exchanged, even with O2 having steeper pressure gradient, because CO2 is 20x more soluble in | plasma & alveolar fluid |
| amount of gas reaching alveoli | ventilation |
| blood flow in pulmonary capillaries | perfusion |
| for gas exchange to be __ there must be a coupling between ventilation & perfusion | efficient |
| when alveoli ventilation is inadequate terminal arterioles constrict & blood is __ to respiratory areas where Po2 is high & O2 pickup may be more efficient | redirected |
| in alveoli where ventilation is __, pulmonary arterioles dilate increasing blood flow into the associated pulmonary capillaries | maximal |
| __ mechanisms controlling pulmonary vascular muscle is the opposite of mechanism controlling most arterioles in systemic circulation | autoregulatory |
| as result of changing diameter of local bronchioles and arterioles, alveolar ventilation & pulmonary perfusion are __ | synchronized |
| changes in alveolar Po2 affect diameter of __ | arterioles |
| changes in alveolar Pco2 cause changes in diameters of | bronchioles |
| bronchioles servicing areas where alveolar CO2 levels are high __ allowing CO2 to be eliminated from body more rapidly | dilate |
| results in low O2 & high CO2 levels in alveoli | poor alveolar ventilation |
| when there is poor alveolar ventilation, arterioles constrict & airways dilate, bringing blood flow & air flow into closer | physiological match |
| high Po2 & low Pco2 in alveoli cause bronchioles serving alveoli to constrict, and promote __ __ __ to pulmonary capillaries | flushing of blood |
| homeostatic mechanisms that provide appropriate conditions for efficient gas exchange never completely balance ventilation & perfusion because gravity causes __ __ in blood & air flow in lungs | regional variations |
| homeostatic mechanisms that provide appropriate conditions for efficient gas exchange never completely balance ventilation & perfusion because occasionally alveolar duct plugged with mucus creates __ __ | unventilated areas |
| homeostatic mechanisms that provide appropriate conditions for efficient gas exchange never completely balance ventilation & perfusion because of __ of blood from bronchial veins | shunting |
| in healthy lungs, __ __ is only 0.5-1 micrometer thick, and gas exchange is usually very efficient | respiratory membrane |
| __ __ of respiratory membrane increases dramatically is lungs become waterlogged & edematous, as in pneumonia or left heart failure | effective thickness |
| greater the surface are of respiratory membrane, the __ __ can diffuse across it in a given period of time | more gas |
| alveolar surface area actually functioning in gas exchange is drastically reduced; walls of adajacent alveoli break down & alveolar chambers become larger in | emphysema |
| factors promoting gas exchanges btwn systemic capillaries & tissue cells are essentially | identical to those acting in lungs |
| Po2 in tissues is always lower than that in systemic arterial blood, therefore | O2 moves rapidly from blood into tissues until equilibrium is reached |
| venous blood draining to tissue capillary beds & returning to heart has | Po2 of 40 mm Hg & Pco2 of 45 mm Hg |
| gas exchanges that occur btwn blood & alveoli & btwn blood & tissue cells take place by __ __ driven by partial pressure gradient of O2 & CO2 that exists on opposite sides of exchange membranes | simple diffusion |
| molecular oxygen is carried to blood bound to | hemoglobin within RBCs |
| molecular oxygen is carried to blood | dissolved in plasma |
| composed of 4 polypeptide chains, each bound to an iron-containing heme group | hemoglobin (Hb) |
| because the __ __ bind oxygen each hemoglobin molecule can combine with 4 molecules of O2, & oxygen loading is rapid & reversible | iron atoms |
| hemoglobin-oxygen combination | oxyhemoglobin HbO2 |
| hemoglobin that has released oxygen | reduced hemoglobin/deoxyhemoglobin (HHb) |
| when all 4 heme groups are bound to O2 a hemoglobin molecule is said to be | fully saturated |
| when 1, 2, or 3 oxygen molecules are bound, hemoglobin is | partially saturated |
| binding strength | affinity |
| the affinity of hemoglobin for oxygen changes with extent of __ __, and both loading & unloading of oxygen are very efficient | oxygen saturation |
| rate at which Hb reversibly binds/releases O2 is __ __ Po2, temperature, & blood concentration of BPG | regulated by |
| relationship between degree of hemoglobin saturation & Po2 of blood is not linear because affinity of hemoglobin for O2 changes with | O2 binding |
| S-shaped curve has steep slope for Po2 values between 10-50 mm Hg and then flattens out between 70-100 mm Hg | oxygen-hemoglobin dissociation curve |
| Under __ __ conditions aterial blood hemoglobin is 98% saturated and 100 ml of systemic aterial blood contains about 20 ml of O2 (20 vol %) | normal resting |
| Po2 measurements indicate only the amount of O2 dissolved in __, not the amount bound to hemoglobin | plasma |
| Po2 values are a(n) __ __ of lung function | good index |
| when arterial Po2 is significantly less than alveolar Po2 some degree of __ __ exists | respiratory impairment |
| as arterial blood flows through systemic capillaries, about 5 ml of O2 per 100 ml of blood is released, yielding an Hb saturation of 75% and O2 content of 15 vol % in | venous blood |
| nearly complete saturation of Hb in arterial blood explains why breathing deeply increases | both alveolar & arterial blood Po2 |
| nearly complete saturation of Hb in arterial blood explains why breathing deeply causes very little increase in | O2 saturation of hemoglobin |
| Po2 measurements indicate only the amount of __ __ in plasma | O2 dissolved |
| oxygen-hemoglobin dissociation curve reveals Hb is __ __ saturated at a Po2 of 70 mm Hg & further increases in Po2 produce only small increases in __ __ | almost completely; O2 binding |
| oxygen-hemoglobin dissociation curve reveals most O2 unloading occurs on | steep portion of curve |
| adaptive value of oxygen-hemoglobin dissociation curve is that O2 loading & delivery to tissues can still be adequate when | Po2 of inspired air is well below its usual levels |
| Po2 of inspired air is well below its usual levels in those people | at higher altitudes & with cardiopulmonary disease |
| small drop in Po2 will cause large increase in __ in oxygen-hemoglobin dissociation curve | unloading |
| normally only 20-25% of bound oxygen is unloaded during on __ __ | systemic circuit |
| substantial amounts of O2 are __ __ in venous blood, even though only 20-25% of bound oxygen is unloaded during 1 systemic circuit | still available |
| amounts of O2 are still available in venous blood, even though only 20-25% of bound oxygen is unloaded during 1 systemic circuit | venous reserve |
| if O2 drops to very low levels in tissues, such as during vigorous exercise, much more O2 will dissociate from hemoglobin to be used by tissue cells without any | increase in respiratory rate or cardiac output |
| temperature, blood pH, Pco2, & amount of BPG in blood all __ __ saturation at a given Po2 | influence hemoglobin |
| binds reversibly with hemoglobin; produced by RBCs as they break down glucose by glycolysis | 2,3-bisphosphoglycerate (BPG) |
| anaerobic process of glucose breakdown | glycolysis |
| temperature, blood pH, Pco2, & amount of BPG in blood influence __ __ by modifying three-dimensional structure, thereby changing its affinity for O2 | Hb saturation |
| increase in temperature, Pco2, H+, or BPG levels in blood decreases Hb's affinity for O2 enhancing | oxygen unloading from blood |
| decrease in temperature, blood pH, Pco2, & amount of BPG in blood increases __ __ for oxygen, decreasing oxygen unloading | hemoglobin's affinity |
| decrease in temperature, blood pH, Pco2, & amount of BPG in blood shift oxygen-hemoglobin dissociation curve to the __ | left |
| increase in temperature, blood pH, Pco2, & amount of BPG in blood shift oxygen-hemoglobin dissociation curve to the __ | right |
| temperature, blood pH, Pco2, & amount of BPG in blood all tend to be at __ __ in systemic capillaries where oxygen unloading is goal | highest levels |
| as cells metabolize glucose & use O2 they release CO2, which increases Pco2 & H+ levels in | capillary blood |
| declining blood pH | acidosis |
| declining blood pH & increasing Pco2 weaken | Hb-O2 bond |
| effect by which increase of CO2 in blood & decrease in pH results in reduction of affinity of hemoglobin for oxygen | Bohr effect |
| rise in temperature affects hemoglobin's affinity for O2 both directly & indirectly via its influence on | RBC metabolism & BPG synthesis |
| temperature, blood pH, Pco2, & amount of BPG in blood all see to it that Hb unloads much more O2 in vicinity of | hard-working tissue cells |
| condition in which inadequate oxygen is available to tissues | hypoxia |
| hypoxia is observed more easily in __ people because their skin & mucosa take on a bluish cast with Hb saturation falls below 75% | fair-skinned |
| in __ people, when Hb saturation falls below 75% this color change (cyanosis) can only be observed in their mucosae & nail beds | dark-skinned |
| reflects poor O2 delivery resulting from too few RBCs or from RBCs that contain abnormal/too little Hb | anemic hypoxia |
| results when blood circulation is impaired/blocked; CHF may cause this body-wide, whereas emboli/thrombi block O2 delivery only to tissues distal to obstruction | ischemic/stagnant hypoxia |
| occurs when body cells are unable to use O2 even though adequate amounts are delivered; this is consequence of metabolic poisons, such as cyanide | histotoxic hypoxia |
| indicated by reduced arterial Po2; possible causes include disordered/abnormal ventilation-perfusion coupling, pulmonary diseases that impair ventilation, & breathing air containing scant amounts of O2 | hypoxemic hypoxia |
| unique type of hypoxemic hypoxia, leading cause of death from fire; does not produce characteristic signs of hypoxia, instead victim is confused & has throbbing headache | carbon monoxide poisoning |
| cyanosis & resulting respiratory distress | characteristic signs of hypoxia |
| patients with __ __ are given hyperbaric therapy or 100% O2 until it has been cleared from body | CO poisoning |
| normally active body cells produce about 200ml of __ exactly the amount excreted by lungs | CO2/minute |
| blood transports CO2 from tissue cells to lungs via dissolved __ | plasma |
| blood transports CO2 from tissue cells to lungs __ __ to hemoglobin | chemically bound |
| when blood transports CO2 from tissue cells to lungs chemically bound to hemoglobin in RBCs as | RBCs as carbaminohemoglobin |
| when carbon dioxide binds to hemoglobin, thus lowering hemoglobin's affinity for oxygen via the Bohr Effect | carbaminohemoglobin |
| creation reaction to carbaminohemoglobin is rapid & does not require a(n) __ | catalyst |
| CO2 transport in RBCs foes not compete with oxyhemoglobin transport because CO2 binds directly to | amino acids of globin |
| CO2 loading/unloading to & from Hb are directly influenced by | Pco2 & degree of Hb oxygenation |
| CO2 __ __ from hemoglobin in lungs, where Pco2 of alveolar air is lower than that in blood | rapidly dissociates |
| CO2 in unloaded in __, where Pco2 is higher than that in blood | tissues |
| deoxygenated hemoglobin combines __ __ with CO2 than does oxygenated hemoglobin | more readily |
| blood transports CO2 from tissue cells to lungs as __ __ in plasma | bicarbonate ion |
| when dissolved CO2 diffused into RBCs it combines with water forming __ __ | carbonic acid (H2CO3) |
| carbonic acid (H2CO3) is unstable & __ into hydrogen ions & bicarbonate ions | dissociates |
| enzyme that facilitates combination of carbon dioxide with water to form carbonic acid, reversibly catalyzing the conversion of water & CO2 to to carbonic acid | carbonic anhydrase |
| dissociation of carbon acid into hydrogen & bicarbonate ions is thousands of times __ in RBCs because they contain carbonic anhydrase | faster |
| CO2 unloading __ O2 release | enhances |
| because of __ __ of Hb, the liberated H+ causes little change in pH under resting conditions | buffering effect |
| once generated HCO3- __ __ from RBCs into plasma, where it is carried to lungs | moves quickly |
| process which occurs in cardiovascular system & refers to exchange (facilitated diffusion) of bicarbonate (HCO3-) & chloride (Cl-) across membrane of RBCs | chloride shift |
| chloride shift is also called | Hamburger shift |
| in the lungs chloride shift is __ | reversed |
| as blood moves through pulmonary capillaries its Pco2 declines from 45 mm Hg to 40 mm Hg; CO2 must 1st be freed from its __ __ | bicarbonate housing |
| once freed from its bicarbonate housing HCO3- reenters RBCs and binds with H+ to form carbonic acid, which is then split by carbonic anhydrase to release | CO2 & water |
| amount of CO2 transported in blood is __ __ by degree of oxygenation of blood | markedly affected |
| lower the Po2 & lower extent of Hb saturation with oxygen, the more | CO2 can be carried in blood |
| Haldane effect reflects greater ability of __ __ to form carbaminohemoglobin & to buffer H+ by combining with it; as CO2 enters systemic bloodstream it causes Bohr effect | reduced hemoglobin |
| deoxygenation of the blood increases its ability to carry carbon dioxide & combine with Hb | Haldane effect |
| Haldane effect encourages CO2 exchange in | tissues & lungs |
| part of blood's carbonic acid-bicarbonate buffer system | alkaline reserve |
| typically the H+ released during __ __ __ is buffered by Hb or other proteins within RBCs or plasma | carbonic acid dissociation |
| during carbonic acid dissociation, the HCO3- generated in RBCs __ __ __, where it acts as alkaline reserve | diffuses into plasma |
| chemical system that helps maintain pH homeostasis of the blood | carbonic acid–bicarbonate buffer system |
| carbonic acid–bicarbonate buffer system is very important in __ __ in blood pH | resisting shifts |
| if hydrogen ion concentration in blood begins to rise, __ __ is removed by combining with HCO3- to form carbonic acid | excess H+ |
| if H+ concentration __ __ desirable levels in blood, carbonic acid dissociates, releasing H+ & lowering blood pH again | drops below |
| changes in respiratory rate/depth can produce dramatic changes in __ __ by altering amount of carbonic acid in blood | blood pH |
| slow, shallow breathing allows CO2 __ __ in blood, increasing carbonic acid levels & decreasing blood pH | to accumulate |
| rapid, deep breathing quickly flushes CO2 out of blood, __ carbonic acid levels & increasing blood pH | reducing |
| respiratory ventilation ca provide __ __ to adjust blood pH & Pco2 when it is disturbed by metabolic factors | fast-acting system |
| play major role in acid-base balance of blood | respiratory adjustments |
| located dorsally near toot of cranial nerve IX | dorsal respiratory group (DRG) |
| network of neurons that extends in ventral brain stem from spinal cord to pons-medulla junction | ventral respiratory group (VRG) |
| clustered neurons in areas of medulla oblongata that are critically important in respiration | DRG & VRG |
| VRG appears to be __ & __ center | rhythm-generating; integrative |
| VRG contains groups of neurons that fire during inspiration & others that fire during expiration in __ __ | mutual inhibition |
| when inspiratory neurons fire in VRG a burst of impulse travels along __ __to excite diaphragm | phrenic nerves |
| when inspiratory neurons fire in VRG a burst of impulse travels along __ __to excite external intercostal muscles | intercostal nerves |
| when VRG's __ __ fire the output stops & expiration occurs passively as inspiratory muscles relax & recoil | expiratory neurons |
| cyclic on/off activity of inspiratory & expiratory neurons repeats continuously & produces | respiratory rate of 12-15 breaths/min |
| cyclic on/off activity of inspiratory & expiratory neurons repeats continuously & inspiratory phase lasts about __ __ followed by expiratory phase lasting about __ __ | 2 seconds; 3 seconds |
| normal respiratory rate and rhythm | eupnea |
| during __ __, VRG networks generate gasping | severe hypoxia |
| respiration __ __ when certain cluster of VRG neurons in completely suppressed, as by an overdose of morphine/alcohol | stops completely |
| in almost all mammals, DRG __ __ from peripheral stretch & chemoreceptors & communicates this info to VRG | integrates input |
| influence & modify activity of medullary neurons | pontine respiratory centers |
| pontine centers appears to __ __ transitions from inspiration to expiration & vice versa | smooth out |
| when lesions are made in pontine respiratory centers' superior region inspirations become __ __ | very prolonged |
| lower pons appears to promote inspiration by stimulation of the I neurons in the medulla oblongata providing a constant stimulus | apneustic breathing |
| formerly called pneumatic center; transmit impulses to VRG of medulla; input modifies & fine-tunes breathing rhythms generated by VRG during certain activities | pontine respiratory group |
| pontine respiratory centers receive input from brain centers & from various sensory receptor in __ | periphery |
| pacemaker-like activity has been demonstrated in certain VRG neurons, but suppressing their activity | does not abolish breathing |
| normal respiratory rhythm is a result of __ __ of interconnected neuronal networks in medulla | reciprocal inhibition |
| determined by how actively respiratory center stimulates motor neurons serving respiratory muscles | inspiratory depth |
| determined by how long inspiratory center is active or how quickly it is switched off | respiratory rate |
| can be modified in response to changing body demands | depth & rate of breathing |
| respiratory centers in medulla and pons are sensitive to | excitatory & inhibitory stimuli |
| receptor sensitive to various chemicals in solution | chemoreceptors |
| chemoreceptors located throughout brain stem, including ventrolateral medulla | central chemoreceptors |
| chemoreceptors found in aortic arch & carotid arteries | peripheral chemoreceptors |
| most potent and most closely controlled chemical influencing respiration | CO2 |
| normally arterial Pco2 is __ | 40 mm Hg |
| arterial Pco2 is maintained +/-3 mm Hg of normal level by homeostatic mechanism mediated by effect that | rising CO2 levels have on central chemoreceptors of brain stem |
| high carbon dioxide levels in the blood that accumulates in the brain | hypercapnia |
| as CO2 is accumulated in brain it is __ to form carbonic acid | hydrated |
| as carbon acid dissociates, when CO2 accumulates in brain, H+ is __ and pH __ | liberated; drops |
| when CO2 accumulates in brain, after carbon acid dissociates and H+ is liberated, H+ excites central chemoreceptors which | make abundant synapses with respiratory regulatory centers |
| when H+ excites central chemoreceptors depth & rate of breathing __ __ | are increased |
| enhanced alveolar ventilation, when H+ excites central chemoreceptors, quickly flushes | CO2 out of body, increasing blood pH |
| elevation of only 5 mm Hg in arterial Pco2 results in | doubling of alveolar ventilation |
| when Po2 & pH are __ __ the response to elevated Pco2 is even greater | below normal |
| increased ventilation is normally __ ending when homeostatic blood Pco2 levels are restored | self-limiting |
| even though rising blood CO2 levels act as initial stimulus for increased ventilation, it is rising levels of H+ generated within brain that | prod central chemoreceptors into increased activity |
| __ readily diffuses across blood-brain barrier between brain & blood, but __ does not | CO2; H+ |
| control of breathing during rest is aimed primarily at __ __ concentration in the brain | regulating H+ |
| headaches, shortness of breath, nausea, & dizziness due to being at higher elevations, going above 8000ft above sea level rapidly | acute mountain sickness (AMS) |
| lethal pulmonary & cerebral edema may occur in __ __ of AMS | severe cases |
| body begins to make respiratory & hematopoietic adjustments via adaptive response | acclimatization |
| increase in depth & rate of breathing that is in excess of body's need for removal of CO2 | hyperventilation |
| low CO2 levels in the blood | hypocapnia |
| when a person hyperventilates (involuntarily) & becomes dizzy/faints, this is due to hypocapnia causing cerebral blood vessels to __ reducing brain perfusion & producing cerebral ischemia | constrict |
| symptoms of hyperventilation, such as tingling & tetany in hands/face, is caused by blood Ca2+ levels __ as pH rises | falling |
| when Pco2 is abnormally low, respiration is __ & becomes slow & shallow | inhibited |
| blood O2 content rarely drops much __ __ of normal during regular breath-holding, because as Po2 drops, __ rises enough to make breathing unavoidable | below 60%; Pco2 |
| strenuous hyperventilation can lower Pco2 so much that a lag period occurs before it rebounds enough to | stimulate respiration again |
| cells sensitive to arterial O2 levels are found in __ chemoreceptors | peripheral |
| receptor in aortic arch sensitive to changing oxygen, carbon dioxide, & pH levels of the blood | aortic bodies |
| receptor in the common carotid artery sensitive to changing oxygen, carbon dioxide, and pH levels of the blood | carotid bodies |
| aortic bodies & carotid bodies are considered | peripheral chemoreceptors |
| cells sensitive to arterial O2 levels in carotid bodies are | main oxygen sensors |
| under normal conditions effect of __ __ on ventilation is slight & mostly limited to enhancing sensitivity of peripheral receptors to increased Pco2 | declining Po2 |
| arterial Po2 must __ __ to at least 60 mm Hg before O2 levels become major stimulus for increased ventilation | drop substantially |
| when brain stem centers begin to suffer from O2 starvation, depressing their activity, when | arterial blood falls below 60 mm Hg |
| once arterial blood falls below 60 mm Hg peripheral chemoreceptors become excited & stimulate respiratory centers to | increase ventilation, even if Pco2 is normal |
| peripheral chemoreceptors system can __ __ when alveolar O2 levels are low even though brain stem centers are depressed by hypoxia | maintain ventilation |
| changes in arterial pH can modify respiratory rate & rhythm even when | CO2 & O2 levels are normal |
| because little H+ diffuses from blood into brain, direct effect of arterial H+ concentration on central chemoreceptors is insignificant compared to | effect of H+ generated by elevations in Pco2 |
| increased ventilation that occurs in response to __ __ __ is mediated through peripheral chemoreceptors | falling arterial pH |
| as arterial pH declines respiratory system controls attempt to __ & raise the pH by __ CO2 & carbonic acid from the blood by increasing respiratory rate & depth | compensate; eliminating |
| body's need to rid itself of CO2 is __ __ __ for breathing, in a healthy person | most important stimulus |
| low Pco2 levels __ respiration | depress |
| as CO2 is hydrated in brain tissue, liberated H+ acts directly on central chemoreceptors, causing __ __ in breathing rate & depth | reflexive increase |
| low Po2 __ Pco2 effects | augments |
| high Po2 levels diminish effectiveness of __ __ | CO2 stimulation |
| both hypocapnia & increase in blood pH __ __ | inhibit respiration |
| changes in arterial pH resulting from CO2 retention/metabolic factors __ __ through peripheral chemoreceptors to promote changes in ventilation, which in turn modify arterial Pco2 & pH | act indirectly |
| acting through hypothalamus & rest of limbic system, strong emotions & pain send signals to respiratory centers, modifying | respiratory rate & depth |
| sudden chilling of body can cause __ of breathing | cessation |
| during voluntary control, __ __ cortex send signals to motor neurons that stimulate respiratory muscles, bypassing medullary centers | cerebral motor |
| when lung receptors respond to irritants they communicate with respiratory centers via | vagal nerve afferents |
| visceral pleurae & conducting passages in lungs contain numerous stretch receptors that are vigorously stimulated when | lungs are inflated |
| stretch receptors in visceral pleurae & conducting passages in lungs signal the medullary respiratory centers via afferent fibers of __ __ | vagus nerves |
| reflex that limits excessive expansion and contraction of the chest during respiration prior to sending impulses to the brain via the vagus nerve | inflation/Hering-Breuer reflex |
| inflation/Hering-Breuer reflex is thought to be more a(n) __ __ than normal regulatory mechanism | protective response |
| increase in ventilation in response to metabolic need (e.g., during exercise) | hyperpnea |
| working muscles consume tremendous amounts of O2 & produce large amounts of CO2, so ventilation can increase __ during vigorous exercise | 10-to-20-fold |
| hyperpnea is an increase in ventilation in | response to metabolic needs |
| respiratory changes in hyperpnea do not lead to __ __ in blood O2 & CO2 levels | significant changes |
| hyperventilation is characterized by | low Pco2 & alkalosis |
| aterial Pco2 & Po2 levels __ __ during exercise | remain constant |
| abrupt increase in ventilation occurring as exercise begins reflect __ stimuli | psychological |
| abrupt increase in ventilation occurring as exercise begins reflect simultaneous __ __ activation of skeletal muscles & respiratory centers | cortical motor |
| abrupt increase in ventilation occurring as exercise begins reflect excitatory impulses reaching respiratory centers from __ in moving muscles, tendons, & joints | proprioreceptors |
| rise in lactic acid levels that contributes to __ __ during exercise is not result of inadequate respiratory function | O2 deficit |
| rise in lactic acid levels that contributes to O2 deficit during exercise reflects __ __ limitation or inability of skeletal muscles to further increase their oxygen consumption | cardiac output |
| collective term for progressive, obstructive respiratory disorders | chronic obstructive pulmonary disease (COPD) |
| includes emphysema, chronic bronchitisollective term for progressive, obstructive respiratory disorders | COPD |
| __ __ __ of COPD is irreversible decrease in ability to force air out of lungs | key physiological feature |
| more than 80% of patient with COPD have | history of smoking |
| difficult or labored breathing; "air hunger" | dyspnea |
| common feature of COPDs is that dyspnea occurs and | gets progressively more severe |
| common feature of COPDs is coughing and frequent __ __ which occur commonly | respiratory infections |
| most COPD victims develop __ __ manifested as hypoventilation, respiratory acidosis, & hypoxemia | respiratory failure |
| decrease in depth & rate of breathing; characterized by an increase in blood CO2 | hypoventilation |
| hypoventilation is insufficient ventilation in relation to __ __ causing CO2 retention | metabolic needs |
| pathological accumulation of air in tissues or organs; distinguished by permanent enlargement of alveoli, accompanied by destruction of alveolar walls | emphysema |
| in emphysema, the lung lose their __ | elasticity |
| loss of elasticity in lungs, accompanying emphysema, has consequence of accessory muscles that must be enlisted to breath causing victims to be __ __ because breathing requires 15-20% of total body energy supply | perpetually exhausted |
| loss of elasticity in lungs, accompanying emphysema, has consequence that when bronchioles open during inspiration they collapse on expiration which causes | trapping of huge volumes of air in alveoli |
| in healthy individuals breathing requires | about 5% of total body energy |
| hyperventilation, in emphysema, leads to development of permanently expanded __ __ and flattens diaphragm, reducing ventilation efficiency | barrel chest |
| loss of elasticity in lungs, accompanying emphysema, has consequence of damage to pulmonary capillaries as alveolar walls disintegrate increases resistance in pulmonary circuit, which forces | right ventricle to overwork & become enlarged |
| emphysema is not only caused by smoking, but also | hereditary factors, such as alpha-1 antitrypsin deficiency |
| inhaled irritants lead to chronic excessive mucus production by mucosa of lower respiratory passageways & to inflammation & fibrosis of that mucosa; these responses obstruct airways & severely impair lung ventilation & gas exchange | chronic bronchitis |
| in chronic bronchitis, pulmonary infections are frequent because bacteria thrive in | stagnant pools of mucus |
| in chronic bronchitis the __ __ __ is usually moderate compared to emphysema suffers | degree of dyspnea |
| cigarette smoking & environmental pollution may __ __ development of chronic bronchitis | contribute to |
| in clinical setting COPD pattern called __ __ is where patients work so hard maintaining adequate ventilation that they lose weight, becoming thin but still having nearly normal blood gases | pink puffer |
| in clinical setting COPD pattern called __ __ is patient commonly of stocky build, who become sufficiently hypoxic that they are obviously cyanotic | blue bloaters |
| hypoxia related to COPD causes constriction of pulmonary blood vessels, which leads to pulmonary hypertension & __ heart failure | right-sided |
| patients who suffer from COPD may present as pink puffer/blue bloater, depending on 3rd factor of | strength of their innate respiratory drive |
| COPD is routinely treated with __ & __ in aerosol form/inhalers | bronchodilators; corticosteroids |
| surgical treatment for COPD in which part of grossly enlarged lungs is removed to give remaining lung tissue room to expand; offers increased exercise capability & higher quality of life, not prolonging life | lung volume reduction surgery |
| COPD patients in __ __ __ are commonly given O2, but it must be administered with care | acute respiratory distress |
| in some COPD patients giving pure O2 can increase __ __ & lower blood pH to life-threatening levels, thought to be sudden loss of hypoxic drive | blood Pco2 |
| proposed chemoreceptor responses to CO2 adapt to chronically high Pco2, leaving only O2 starvation to trigger adequate ventilation | hypoxic drive hypothesis |
| O2 dilates pulmonary arterioles, increasing perfusion & worsening an already poor __ __, in COPD patients | ventilation-perfusion mismatch |
| O2 drives more CO2 off hemoglobin dumping it into alveoli from which it cannot be removed because of __ __ | underlying COPD |
| characterized by episodes of coughing, dyspnea, wheezing & chest tightness, along or in combination | asthma |
| asthma is marked by __ __ followed by symptom-free periods; obstruction is reversible | acute exacerbation |
| in asthma __ __ of airways comes first | active inflammation |
| in asthma, airway inflammation is a(n) __ __ under control of Th2 cells, subset of T lymphocytes | immune response |
| secrete certain interleukins, stimulate production of IgE & recruit inflammatory cells (eosinophils) to site of the asthma | TH2 cells |
| once someone has __ __, inflammation periods even during symptom-free periods & makes airways hypersensitive to almost any irritant | allergic asthma |
| in allergic asthma, once airway walls are __ with inflammatory exudate, effect of bronchospasm is vastly magnified & can dramatically reduce airflow | thickened |
| in order to treat asthma, now the underlying inflammation is treated using __ __ | inhaled corticosteroids |
| new approaches in asthma treatment include limiting airway inflammation with | antileukotrienes & antibodies against the patient's own IgE class of antibodies |
| infectious disease; spread by coughing & primarily enters body in inhaled air | tuberculosis (TB) |
| mycobaterium tuberculosis | TB |
| TB mostly effects lungs but can | spread through lymphatics to affect other organs |
| 25-30% cases of lung cancer; arises in epithelium of bronchi/larger subdivisions & tends to form masses that may hollow out & bleed | squamous cell carcinoma |
| about 40% of cases of lung cancer; originates in peripheral lung areas as solitary nodules that develop from bronchial glands & alveolar cells | adenocarcinoma |
| about 20% of cases of lung cancer; contains round lymphocyte-sized cells that originate in main bronchi & grow aggressively in small grape-like clusters within mediastinum; subsequent metastasis from mediastinum is especially rapid | small cell carcinoma |
| some small cell carcinomas cause problems beyond their effects on lungs because they become __ __ of hormone production | ectopic sites |
| some small cell carcinomas secrete __ or __ | ACTH; ADH |
| small cell carcinomas that secrete ACTH can | lead to Cushing's syndrome |
| small cell carcinomas that secrete ADH can lead to | syndrome of inappropriate ADH secretion (SIADH) |
| with lung cancer, __ __ of diseased lung has the greatest potential for prolonging life & providing a cure | complete removal |
| complete removal of diseased lung is open to few lung cancer patients because the cancer has __ __ before it is discovered | often metastasized |
| in most lung cancer cases radiation therapy & chemotherapy are the __ __, but have low success rates | only options |
| antibodies that target specific growth factors or other molecules required by tumor of that deliver toxic agents directly to the tumor are __ __ on the horizon | new therapies |
| new therapies on the horizon include __ __ to stimulate immune system to fight it | cancer vaccines |
| new therapies on the horizon include various forms of __ __ to replace defective genes that make tumor cells divide continuously | gene therapy |
| because embryos develop in __ __, upper respiratory structures appear first | cephalocaudal direction |
| head-to-tail | cephalocaudal |
| 2 thickened plates of ectoderm present on anterior aspect of head by 4th week of development | olfactory placodes |
| olfactory placodes invaginate to form __ __ that form nasal cavities | olfactory pits |
| olfactory pits then extend posteriorly to connect with __ __, which forma at same time from endodermal germ layer | developing pharynx |
| epithelium of lower respiratory organs develops as outpocketing of __ __, which becomes pharyngeal mucosa | foregut endoderm |
| present by 5th week of development; proximal part of laryngotracheal bud forms __ __ | tracheal lining |
| present by 5th week of development; distal part of laryngotracheal bud splits and forms | mucosae of bronchi & all their subdivisions, including lung alveoli |
| mesoderm covers __ lining & forms walls of respiratory passageways & stroma of lungs during fetal development | endoderm-derived |
| by 28 weeks respiratory system has __ __ to allow baby born prematurely to breathe on its own | developed sufficiently |
| babies born before 28 weeks tend to exhibit infant respiratory distress syndrome resulting from | inadequate surfactant production |
| during fetal life lungs are filled with fluid & all respiratory exchanges are made by | placenta |
| cause circulating blood to largely bypass lungs | vascular shunts |
| at birth, fluid-filled pathway empties and respiratory passageways | fill with air |
| as Pco2 in baby's blood rises, respiratory centers are excited, causing baby to | take its first breath |
| it is nearly __ __ before newborn's lungs are fully inflated | two weeks |
| most common lethal genetic disease in North America, strikes 1/2400 births; causes secretion of abnormally viscous mucus that clogs respiratory passages, providing breading ground for airborne bacteria that predisposes child to respiratory infections | cystic fibrosis (CF) |
| infection of CF victims' lungs with bacterium __ __ trips genetic switch that causes disabled cells to churn our oceans of abnormal mucin, then feeding on stagnant pools of mucus & keep sending signals to cells to make more | Pseudomonas aeruginosa |
| in CF, toxins released by bacteria & local inflammatory reaction set up by immune response both | damage lungs |
| in CF, unable to reach bacteria embedded in mucus, the immune cells begin to __ __ __, turning air sacs into bloated cysts | attack lung tissue |
| only treatment for extensive lung damage from CF is | lung transplant |
| CF also impairs __ __ by clogging ducts that deliver pancreatic enzymes & bile to small intestine & sweat glands produce an extremely salty perspiration | food digestion |
| at the root of CF is a faulty gene that code for | cystic fibrosis transmembrane conductance regulator (CFTR) protein |
| normal CFTR protein works as a membrane channel to control __ flow in/out of cells | Cl- |
| in those with mutated gene, CFTR lacks an essential __ __ & so gets stuck in endoplasmic reticulum, unable to reach membrane & perform normal role | amino acid |
| in those with mutated gene, CFTR consequently allows less Cl- to be secreted and less water flows, resulting in | thick mucus typical of CF |
| mucus-dissolving drugs, clapping chest to loosen thick mucus, & antibiotics to prevent infection are | conventional therapy for CF |
| basic goal of CF research is to restore normal salt/water movements by introducing __ __ genes into respiratory tract mucosa cells | normal CFTR |
| basic goal of CF research is to restore normal salt/water movements by prodding another __ __ to take over duties of transporting Cl- | channel protein |
| basic goal of CF research is to restore normal salt/water movements by developing techniques to free CFTR protein | from the endoplasmic reticulum |
| CF antiinflammatory agent being tested is fatty acid found in fish oils | docosahexaenoic acid (DHA) |
| simple approach to CF treatment is inhaling | hypertonic saline droplets |
| respiratory rate is __ in newborns (40-80 respirations/minute) | highest |
| at 5 years of age respirations are | around 25/minute |
| in adults respirations are | between 12-18/minute |
| at birth only about 1/6 of the final number of | alveoli are present |
| in infants the ribs take a nearly | horizontal course |
| infants relay almost entirely on __ __ __ to increase thoracic volume for inspiration | descent of diaphragm |
| by 2 years of age ribs are positioned __ __, and adult form of breathing is established | obliquely |
| most respiratory problems are result of __ __, such as viral/bacterial infections or obstruction of trachea by piece of food | external factors |
| __ __ respiratory diseases at present at COPD, asthma, lung cancer, & multidrug-resistant TB | most problematic |
| maximum amount of O2 we can use during aerobic metabolism Vo2max declines about 9% per decade in __ __ beginning in their mid-20s | inactive people |
| as we age, thoracic wall becomes __ __ & lungs gradually lose their elasticity | more rigid |
| vital capacity declines about 1/3 by | age of 70 |
| many old people become hypoxic __ __ | during sleep |
| many old people __ __ __ sleep apnea | tend to exhibit |
| temporary cessation of breathing during sleep | sleep apnea |
| functional residual capacity is | volume of air in lungs after normal tidal expiration |
| inspiratory rate is | volume that can be forced in after a tidal inhalation |
| tidal volume is | about 500 ml |
| total lung capacity is | about 6000 ml in an average male |
| vital capacity is | maximum volume of air that can be exhaled after maximum inhalation |
| pulmonary ventilation is | movement of air into and out of the lungs so that gases are continuously changed and refreshed |
| transport of oxygen from lungs to body cells and carbon dioxide from tissue cells to lungs | transport of respiratory gasses |
| internal respiration is | movement of oxygen from the blood to tissue cells and of carbon dioxide from tissue cells to blood |
| external respiration is | movement of oxygen from the lungs to the blood and of carbon dioxide from the blood to the lungs |
| respiratory zone is | actual site of gas exchange |
| conducting zone is | fairly rigid conduits for air to reach the gas exchange sites |
| pressure and volume have an inverse relationship. Inspiration increases lung volume by enlarging all of its dimensions; lowers gas pressure inside lungs | Boyle's law |
| each gas in a mixture has a partial pressure that is proportional to the percentage of that gas in the gas mixture; therefore, if the pp of oxygen is higher in the blood than in the cells, it will diffuse from the blood into the cells | Dalton's law |
| when a mixture of gases is in contact with a liquid, each gas will dissolve in the liquid in proportion to its partial pressure; this affects the movement of oxygen gas from the lungs into fluids in the tissues | Henry's law |
| nasal cavity | secretes mucus and antibacterial enzymes; traps dust, bacteria, and warms air during inspiration |
| pharynx | commonly called the throat; air leaves the nose and enters here en route to the lungs |
| larynx | contains vocal cords that produce speech; called the voice box |
| trachea | descends from the larynx as a single tube reinforced with cartilage rings before it divides to go to each lung |
| bronchi | major branches of the cartilage-reinforced tube that go to each lung |
| alveoli | terminal branches of the lungs where respiratory gas exchange occurs |
| chronic bronchitis | inhaled irritants lead to chronic excessive mucus production by the mucosa of the lower respiratory passageways and to inflammation and fibrosis of that mucosa |
| emphysema | permanent enlargement of the alveoli, accompanied by deterioration of the alveolar walls |
| asthma | characterized by episodes of coughing, dyspnea, wheezing, and chest tightness; airways become hypersensitive to irritants due to inflammation |
| lung cancer | associated with cigarette smoking; constant irritation of cilia are overwhelmed and eventually stop functioning; mutations occur in cells causing uncontrolled growth |
| Air moves into the lungs because gas pressure in lungs becomes | lower than outside pressure as diaphragm contracts |
| Boyle's Law states that volume changes lead to __ __ | pressure change |
| alveolar ventilation rate is movement of air | into and out of alveoli during particular time |
| formula for alveolar ventilation rate is | breaths per minute × (TV - Dead space) |
| hemoglobin has a tendency to release oxygen where | pH is more acidic |
| Bohr effect helps unload O2 when | pH is more alkaline |
| in the alveoli, the partial pressure of oxygen is | about 104 mm Hg |
| partial pressure of O2 in alveoli is is about 35% less than | that of atmospheric PO2 |
| most of the CO2 transported by blood is | converted to bicarbonate ions and transported in plasma |
| elastic cartilage that shields the opening to the larynx during swallowing is | epiglottis |
| pulmonary ventilation is the | movement of air into/out of lungs |
| pseudostratified columnar epithelium | tissue lines the trachea |
| cilia of pseudostratified columnar epithelium in trachea | move mucus to pharynx |
| respiratory structure with the smallest diameter | bronchiole |
| involuntary hyperventilation during an anxiety attack can cause person to become faint because of | lowered CO2 levels in blood & consequent constriction of cerebral blood vessels |
| lowered CO2 levels in the blood cause cerebral blood vessels to __, reducing brain perfusion & causing ischemia | constrict |
| gases that has no effect in blood until hyperbaric conditions occur (SCUBA diving staying down too long at great depths), when a condition ""rapture of the deep"" occurs, producing narcotic-like effect, as gas interacts with other blood chemicals | nitrogen |
| nitrogen makes up about 79% of atmospheric gas and has __ __ at normal atmospheric pressures | no effect |
| __ __ for extended periods of time result in nitrogen narcosis, or "rapture of the deep" | hyperbaric conditions |
| hyperpnea is | increase in depth and force of breathing that occurs during vigorous exercise |
| approximately 20% of CO2 is transported in the blood | as carbaminohemoglobin |
| inspiratory center in the medulla generates the __ __ __ | basic respiratory rhythm |
| walls of the conducting zone are too thick to | allow gas exchange |
| example of an enzyme located in lung capillary membrane that acts on material in blood is | angiotensin converting enzyme |
| airway resistance is insignificant in relationship to gas flow because | airways branch more as they get smaller, resulting in a huge total cross-sectional area |
| transpulmonary pressure is difference between __ &__ pressure | intrapulmonary; intrapleural |
| increase in lung compliance __ __ lead to a decrease in the total respiratory compliance | would not |
| non-respiratory movement that ventilates all of the alveoli | yawning |
| breathing excessively high concentrations of oxygen for a long period of time would lead to | CNS disturbances and could lead to death |
| non-respiratory movements caused by irritation of diaphragm | hiccups |
| dorsal respiratory group is | located dorsally at the root of cranial nerve IX |
| stimulating the contraction of the diaphragm | function of the ventral respiratory group |
| external respiration refers to gas exchange between | blood and alveoli |
| if intrapulmonary pressure & intrapleural pressure equalize | atelectasis will occur |
| most prevalent gas in the __ is nitrogen | atmosphere |
| transpulmonary air pressure is greatest at | start of expiration |
| without the secretions of __ __ __ __, the lungs would collapse between breaths | type II alveolar cells |
| during fetal life lungs are filled with fluid & all __ __ are made by the placenta | respiratory exchanges |
| respiratory rate is __ in newborns & __ until adulthood | highest; decreases |
| increase in temperature of the blood will decrease __ __ for O2 | Hb affinity |
| most carbon dioxide (about 70%) is transported as | bicarbonate ions in plasma |
| increase in CO2 in blood will cause a(n) __ __ in H+ concentration (drop in pH) | slight increase |
| external ventilation is | not involved in respiration |
| vibrissae are | hairs within the nasal cavity that filter coarse particles, such as pollen and dust, from inspired air |
| inflammation of the nasal mucosa accompanied by excessive mucus production, nasal congestion, and postnasal drip | rhinitis |
| nasopharynx, oropharynx, laryngopharynx | regions of the pharynx, from superior to inferior |
| epiglottis is | covered by a mucosa containing taste buds, and keeps food out of the lower respiratory passages |
| bronchial, or respiratory, tree branches | approximately 23 times within the lungs |
| stroma is | elastic connective tissue found within the lungs |
| hypoxia that occurs when body cells are unable to use O2 even though adequate amounts are delivered (this type of hypoxia is usually the consequence of metabolic poisons, such as cyanide) | histotoxic hypoxia |
| organ system that carries out gas exchange; includes the nose, pharynx, larynx, trachea, bronchi, lungs | respiratory system |
| to supply body w/oxygen & dispose of carbon dioxide | major function of respiratory system |
| processes involved in supplying the body with oxygen and disposing of carbon dioxide | respiration |
| breathing; consists of inspiration and expiration; movement of air into & out of lungs so that gases are continuously changed & refreshed | pulmonary ventilation |
| movement of oxygen from lungs to blood & of carbon dioxide from blood to lungs | external respiration |
| transport of oxygen from lungs to tissue cells of body & of carbon dioxide from tissue cells to lungs | transport of respiratory gases |
| transport of respiratory gases accomplished by cardiovascular system using blood as | transporting fluid |
| movement of oxygen from blood to tissue cells & of carbon dioxide from tissue cells to blood | internal respiration |
| pulmonary & external ventilation are the __ __ of the respiratory system | special responsibility |
| respiratory system cannot accomplish primary goal of obtaining oxygen & eliminating carbon dioxide unless these take place | transport of respiratory gases & internal respiration |
| if either respiratory or circulatory systems fail the body's cells begin to die from | oxygen starvation |
| actual use of oxygen & production of carbon dioxide by tissue cells | cellular respiration |
| cellular respiration is the __ of all energy-producing chemical reaction in body | cornerstone |
| nose, nasal cavity, & paranasal sinuses, pharynx, larynx, trachea, bronchi & smaller branches & lungs which contain alveoli compose the __ system | respiratory |
| terminal air sacs of the lungs | alveoli |
| actual site of gas exchange in lungs; composed of respiratory bronchioles, alveolar ducts, & alveoli (all microscopic structures) | respiratory zone |
| nose, nasal cavity, & paranasal sinuses, pharynx, larynx, trachea, bronchi, & lungs; provides fairly rigid conduits for air to reach gas exchange sites | conducting zone |
| cleanse, humidify, & warm incoming air | conducting zone organs |
| although it brings about volume change that promotes ventilation, it is classified as part of the muscular system | diaphragm |
| only externally visible part of respiratory system; provides airway for respiration; moistens & warms entering air; filters & cleans inspired air; serves as resonating chamber for speech; houses olfactory receptors | nose |
| area of nose between eyebrows | root |
| root, bridge, dorsum nasi, & termination in the apex | external nose |
| anterior margin of external nose | dorsum nasi |
| tip of nose | apex |
| inferior to apex; shallow vertical groove | philtrum |
| eternal openings to nose; bound laterally by flared alae | nostrils/nares |
| flared; bounds the nostrils/nares laterally | alae |
| skeletal framework of external nose is fashioned by nasal & frontal bones __ | superiorly |
| skeletal framework of external nose is fashioned by maxillary bones __ | laterally |
| skeletal framework of external nose is fashioned by flexible plates of hyaline cartilage __ | inferiorly |
| bridge of the nose is formed by | nasal bones |
| root of nose is formed by | frontal bones |
| alar & septal cartilages, & lateral processes of septal cartilage provide the skeletal framework for | flexible plates of hyaline cartilage of nose |
| skin covering nose's dorsal & lateral aspects is thin & contains many | sebaceous glands |
| lies internally & posterior to external nose | nasal cavity |
| divides midline of nasal cavity; formed anteriorly by septal cartilage & posteriorly by vomer bones & perpendicular plate of ethmoid bone | nasal septum |
| nasal cavity is continuous posteriorly with nasal portion of pharynx through | posterior nasal apertures |
| posterior nasal apertures are also called | choanae |
| choanae means | funnels |
| roof of nasal cavity is for by __ & __ bones of skull | ethmoid; sphenoid |
| floor of nasal cavity is formed by the __, which separates nasal cavity from oral cavity below | palate |
| anteriorly the palate is supported by palatine bones & processes of maxillary bones, called | hard palate |
| unsupported posterior portion of palate is the muscular | soft palate |
| part of nasal cavity just superior to nostrils; lined with skin containing sebaceous & sweat glands & numerous hair follicles | nasal vestibule |
| hairs of nasal cavity; filter coarse particles from inspired air | vibrissae |
| vibrissae means | to quiver |
| lining slitlike superior region of nasal cavity; smell receptors | olfactory epithelium/mucosa |
| pseudostratified ciliated columnar epithelium containing scattered goblet cells that rest on lamina propria richly supplied with mucous & serous glands | respiratory mucosa |
| mucous cells secrete | mucus |
| serous cells secrete a watery fluid containing | enzymes |
| antibacterial enzyme secreted in mucus of respiratory mucosa | lysozyme |
| respiratory glands secrete about a(n) __ of mucous containing lysozyme | quart/liter |
| lysozyme attacks & destroys bacteria __ | chemically |
| secreted by epithelial cells of respiratory mucosa; natural antibiotics that help get rid of invading microbes | defensins |
| high water content of __ __ acts to humidify inhaled air | mucus film |
| __ __ of respiratory mucosa create gentle current that moves sheets of contaminated mucus posteriorly toward the throat where it is swallowed & digested by stomach juices | ciliated cells |
| nasal mucosa is richly supplied with sensory nerve endings and contact with irritating particles triggers | sneeze reflex |
| forces air outward in violent burst, expelling irritants from the nose | sneeze |
| __ __ of capillaries & thin-walled veins underlie nasal epithelium & warm incoming air as it flows across mucosal surface | rich plexus |
| when inspired air is __ vascular plexus becomes engorged with blood, thereby intensifying air-heating process | cold |
| protrude medially from each lateral wall of nasal cavity; scroll-like mucosa-covered projections are the superior, middle & inferior | nasal conchae |
| groove inferior to each nasal conchae is a(n) | nasal meatus |
| the curved nasal conchae greatly increase mucosal __ __ exposed to air & enhance air turbulence in nasal cavity | surface area |
| gases in inhaled air swirl through the twirls & turns of nasal conchae, but __ __ particles tend to be deflected onto to mucosal surfaces where they become trapped | heavier nongaseous |
| few particles larger than 6 micrometers | make it past nasal cavity |
| not only function during inhalation to filter, heat, & moisten air, but also act during exhalation to reclaim this heat & moisture | nasal conchae & mucosa |
| inhaled air __ conchae | cools |
| during exhalation __ __ precipitate moisture & extract heat from humid air flowing over them | cooled conchae |
| the reclamation processes, by cooled nasal conchae __ amount of moisture & heat lost from body through breathing, helping us survive in dry & cold climates | minimizes |
| mucous-membrane-lined, air-filled cavity | sinus |
| located in frontal, sphenoid, ethmoid, & maxillary bones, nasal cavity surrounded by ring of | paranasal sinuses |
| lighten skull & together with nasal cavity they warm & moisten air | sinuses |
| ultimately flows into nasal cavity, & suctioning effect created by nose blowing helps drain sinuses | mucus produced by sinuses |
| inflammation of nasal mucosa accompanied by excessive mucus production, nasal congestion, & postnasal drip; caused by cold viruses, streptococcal bacteria & various allergens can cause | rhinitis |
| nasal mucosa is __ with that of rest of respiratory tract, explaining typical nose to throat chest progression of colds | continuous |
| because nasal mucosa extends tentacle-like into nasolacrimal ducts & paranasal sinuses, nasal cavity infections often spread to those regions causing | sinusitis |
| when passageways connecting sinuses to nasal cavity are blocked with mucus or infectious material, air in sinus cavities is absorbed, result is a partial vacuum and localized over inflamed areas causing | sinus headache |
| funnel-shaped; connects nasal cavity & mouth superiorly to larynx & esophagus inferiorly; commonly called throat; extends for about 13 cm fro base of skull to level of C6 | pharynx |
| nasopharynx, oropharnyx, & laryngopharynx | divisions of pharynx |
| composed of skeletal muscles throughout its length | muscular pharynx |
| cellular composition of pharynx | varies from one region to another |
| posterior to nasal cavity, inferior to sphenoid bone & superior to level of soft palate; serves only as an air passageway | nasopharnyx |
| contained in nasopharnyx; part of soft palate; moves superiorly in action that closes off nasopharynx & prevents food from entering nasal cavity | uvula |
| nasopharynx is continuous through posterior nasal __ | apertures |
| nasopharynx is made up on pseudostratified ciliated epithelium, which takes over the job of __ __ where the nasal mucosa leaves off | propelling mucus |
| high on posterior wall of nasopharynx; traps & destroys pathogens entering nasopharynx in air | pharyngeal tonsils |
| infected & swollen __ can block air passage in nasopharynx, making it necessary to breath through the mouth; when chronically enlarged both speech & sleep may be distrubed | adenoids |
| drain the middle ear cavities & allow middle ear pressure to equalize with atmospheric pressure; open into lateral walls of nasopharynx | pharyngotympanic (auditory) tubes |
| ridge of pharyngeal mucosa that arches over each of auditory tube openings | tubal tonsils |
| because of __ of tubal tonsils they help protect middle ear against infections likely to spread from nasopharynx | location |
| superoposterior & medial to tubal tonsils; also play protective role | pharyngeal tonsils |
| lies posterior to oral cavity & is continuous with it through isthmus of the fauces; extends inferiorly from level of soft palate to epiglottis; both swallowed food & inhaled air pass through it | oropharynx |
| where nasopharynx blends into oropharyx, epithelium changes from pseudostratified columnar to a more protective | stratified squamous epithelium |
| structural adaptation of oropharynx epithelium accommodates increased friction & greater chemical trauma accompanying | food passage |
| paired; lie embedded in oropharnygeal mucosa of lateral walls of fauces | palatine tonsils |
| cover posterior surface of tongue | lingual tonsil |
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lfrancois
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