Lesson 14

ajv09c's version from 2015-04-30 01:10

Section 1

Question Answer
respiration refers totwo integrated processes; external and internal respiration
external respirationincludes all processes involved in exchanging o2 and co2 with the environment
internal respirationresult of cellular respiration; involves the uptake of o2 and production of co2 within individual cells
three processes of external respirationpulmonary ventilation (breathing); gas diffusion across membranes and capillaries; transport of o2 and co2
transport of 02 and co2 happensbetween alveolar capillaries and capillary beds in other tissues
hypoxia low tissue oxygen levles
anoxiacomplete lack of oxygen

Section 2

Question Answer
pulmonary ventilationthe physical movement of air in and out of respiratory tract; provides alveolar ventilation air movement into/out of alveoli
atmospheric pressureweight of air compresses our bodies and everything around us; has several important physiological effects
boyles lawdefines the relationship between gas pressure and volume P=1/V
in a contained gasexternal pressure forces molecules closer together; movement of gas molecules exerts pressure on container
if you decrease the volume of the containercollisions occur more often per unit of time; increases the pressure of the gas
if you increase the volume of the containerfewer collision occur per unit of time; takes longer time for gas to travel from wall to wall; result is decrease is pressure

Section 3

Question Answer
pressure and airflow to the lungsair flows from higher pressure to area of lower pressure
pulmonary ventilation causes volume changes that create changes in pressure
volume of thoracic cavity changes with expansion or contraction of deaphragm or rib cage
a respiratory cycle consists ofan inspiration (inhalation) an expiration (exhalation)
as the rib cage is elevatedthe diaphragm is depressed, the volume of the thoracic cavity increases; pressure within track cavity decreases and air flows to lungs
as rib cage returns to original positiondiaphragm relaxes; volume of thoracic cavity decreases; pressure increases and air exits lungs
pressure change during inhalation and exhalation can be measured inside or outside of lungs
normal atmospheric pressure 1atm= 760 mm Hg

Section 4

Question Answer
intrapulmonary pressure akaintra alveolar pressure
intrapulmonary pressure is relative toatmospheric pressure
in relaxed breathing the difference between atmospheric pressure and intrapulmonary pressure is small; about -1mmHg on inhalation or +1 mmHg on exhalation
maximum intrapulmonary pressuremaximum straining, dangerous, can increase range -30to +100 mmHg
intrapleural pressurepressure in space between parietal and visceral pleura
average intrapleural pressure-4 mmHg
maximum intrapleural pressure-18 mmHg during powerful inhalation
intrapleural pressure remains belowatmospheric pressure throughout respiratory cycle
pneumothoraxallows air into pleural cavity; breaks fluid bond between the pleurae
atelecatasiscollapsed lung; result of pneumothorax

Section 5

Question Answer
most important respiratory musclesthe diaphragm; external intercostal muscles or the ribs; accessory respiratory muscles
diaphragmused during normal breathing
external intercostal muscles of the ribsused during normal breathing
accessory respiratory musclesused during fast breathing, activated when respiration increases significantly
mechanics of breathing (inhalation)always active
mechanics of breathing exhalationpassive; relies on relaxation of inhalation muscles; recoil of lungs and thoracic cavity; active ; uses muscles during forceful exhalation
elastic reboundrecoil of lungs and thoracic cavity
diaphragm contraction draws75% of normal air movement
external intercostal muscles assistinhalation; 25% of normal air movement
which accessory muscles assist in elevating ribs during fast breathingsternocleidomastoid; serratus anterior; pectoralis minor; scalene muscles
muscles used in exhalationinternal intercostal muscles; transversus thoracis muscles; abdominal muscles
internal intercostal and transversus thoracis muscles do whatdepress the ribs
abdominal muscles docompress the abdomen; force diaphragm upward

Section 6

Question Answer
compliancean indicator of expandability
low compliance requiresgreater force to fill lungs
high compliance requiresless force to fill lungs
factors that affect complianceconnective tissue structure of lungs; level of surfactant production; mobility of thoracic cage
connective tissue structure of the lungs disorderemphysema; alveolar tissue damage causes high compliance
level of surfactant production disorderrespiratory distress syndrome; causes low compliance
mobility of the thoracic cage disorderarhtritis/ skeletal disorders reduce compliance

Section 7

Question Answer
modes of breathingmodes classified by pattern of muscle activity; quiet breathing and forced breathing
eupneaquiet breathing
quiet breathing involves actiive inhalation and passive exhalation
daphragmatic breathingdeep breathing; form of quiet breathing; dominate by diaphragm
costal breathingshallow breathing; form of quiet breathing; dominated by rib cage movements
hyperpneaforced breathing
forced breathing involvesactive inhalation and exhalation; assisted by accessory muscles; maximum levels occur in exhastion

Section 8

Question Answer
gas exchangeoccurs between blood and alveolar air; across the respiratory membrane
gas exchange depends on partial pressures of the gases; diffusion of molecules between gas and liquid
diffusion occurs in response toconcentration gradients
composition of airNitrogen N2 78.6%; oxygen o2 about 20.9%; water vapor (h2o) about .5%; carbon dioxide co2 about .04%
daltons laweach gas contributes to the total pressure in proportion to its number of molecules
partial pressurethe pressure contributed by each gas in the atmosphere all add up to 760mmHg
henry's law gas/liquidwhen gas under pressure comes in contact with liquid, gas dissolves in liquid until equilibrium is reached
henry's at any given temperatureamount of a gas in solution is proportional to partial pressure of that gas
henry's law actual amount of gas in solutionactual amount of gain solution at given partial pressure and temperature depends on the solubility of that gain that particular liquid
partial pressures in pulmonary vein plasma after gas exchange at alveoliPco2= 40mmHg Po2= 100mmHg Pn2= 573mmHg
what determines different partial pressures and solubilitiesdirection and rate of diffusion of gases across the respiratory membrane
four most common methods of reporting gas pressuresmillimeters of mercury; torr; centimeters of water; pounds per square inch
five reasons for efficiency of gas exchangesubstantial differences in partial pressure across the respiratory membrane; distances involved in gas exchange are short; o2 and co2 are lipid soluble; total surface area is large; blood flow and airflow are coordinated

Section 9

Question Answer
blood arriving in pulmonary arteries has what partial pressureslow Po2 (40mmHg); high Pco2 (45mmHg)
concentration gradient of blood arriving at pulmonary arteries causeso2 to enter blood (since Po2 of alveolus is 100mmHg) co2 to leave blood (since Pco2 is 40mmHg)
rapid exchange allows blood and alveolar air to reach equilibrium
in systemic circuit oxygenated blood mixes with deoxygenated blood from colducting passageways; lowers the Po2 of blood entering systemic circuit to about 95mmHg
partial pressures of interstitial fluidPo2=40mmHg Pco2=45mmHg
concentration gradient in peripheral capillaries isopposite of lungs co2 diffuses into blood (since Pco2 is 40mmHg) o2 diffuses out of blood (since Po2 is 95mmHg)
blood plasma cannot transport enougho2 or co2 to meet physiological needs
red blood cells transport o2 to and co2 from peripheral tissues
red blood cells removeo2 and co2 from plasma, allowing gases to diffuse into blood
o2 binds to iron ions in hemoglobin (Hb) molecules
when o2 blinds to hemoglobin it createsoxyhemoglobin (HbO2) in a reversible reaction
each rbc has ? hb molecules280 million
each hb molecule binds ? o2four
number of o2 molecules in a single rbc1.1billion
hemoglobin saturationthe percentage of heme units in a hemoglobin molecule that contain bound oxygen
environmental factors affecting hemoglobinPo2 of blood, blood pH, temperature, metabolic activity within RBC's

Section 10

Question Answer
oxygen hemoglobin saturation curvea graph relating the saturation of hemoglobin to partial pressure of oxygen
higher Po2 results in greater Hb saturation
curve rather than a straight line becauseHb changes shape each time a molecule of o2 is bound; each o2 makes next o2 binding easier; allows Hb to bind o2 when o2 levels are low
even at low Po2 (60mmHg)Hb is still about 90% saturated
oxygen reserves- amount of o2 released depends oninterstitial Po2 at tissue; o2 diffuses from peripheral capillaries (high Po2) into interstitial fluid (low o2); allows for up to 3/4 to be reserved by RBCs
Carbon Monoxidebinds strongly to Hb; takes place of o2; results in carbon monoxide poisoning
oxygen-hemoglobin saturation curve is standardized for normal blood pH7.4, 37C
when pH drops or temperature risesmore oxygen is released; curve shifts right
when pH rises or temperature dropsless oxygen is released; curve shifts left
bohr effectresult of pH on hemoglobin-saturation curve; caused by co2
bohr effect- co2 diffuses intoRBC; enzyme (carbonic anhydrase) catalyzes reaction with H2O; produces carbonic acid
carbonic acid dissociates intohydrogen ion and bicarbonate ion
hydrogen ions diffuseout of RBC; lowering pH
as temperature increase hemoglobinreleases more oxygen
as temperature decrease hemoglobinreleases less oxygen
temperature effects are significant only in active tissues that are generating large amounts of heat (active skeletal muscles)
when temp increases ox hb curve shiftsright, more oxygen is released
when temp decreases ox hb curve shifts left, less oxygen is released