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97 Cards in this Set
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- Back
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Pulmonary respiration
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-ventilation
-exchange of O2 and CO2 in lungs |
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cellular respiration
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O2 utilization and CO2 production by the tissues
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purpose of respiratory system during exercise
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-gas exchange between environment and body
-regulation of acid-base balance during exercise |
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function of the lung
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-means of gas exchange between external environment and body
-ventilation -diffusion |
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means of gas exchange between external environment and body
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-replacing O2
-removing CO2 -regulation of acid-base balance |
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Pulmonary respiration
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-ventilation
-exchange of O2 and CO2 in lungs |
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cellular respiration
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O2 utilization and CO2 production by the tissues
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purpose of respiratory system during exercise
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-gas exchange between environment and body
-regulation of acid-base balance during exercise |
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function of the lung
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-means of gas exchange between external environment and body
-ventilation -diffusion |
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means of gas exchange between external environment and body
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-replacing O2
-removing CO2 -regulation of acid-base balance |
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ventilation
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mechanical process of moving air into and out of lungs
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diffusion
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random movement of molecule from an area of high concentration to an area of low concentration
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structure of respiratory system
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organs
diaphragm lungs enclosed by membranes called pleura |
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organs of respiratory system
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-nose and nasal cavities
-pharynx and larynx -trachea and bronchial tree -lungs (alveoli- site of gas exchange) |
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diaphragm of respiratory system
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major muscle of inspiration
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lungs enclosed by membranes (pleura)
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-visceral pleura
-parietal pleura -intrapleural space |
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visceral pleura
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on outer surface of lung
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parietal pleura
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lines thoracic wall
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intrapleural space
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intrapleural pressure lower than atmospheric (prevents collapse of alveoli)
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conducting zone
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-conducts air to RESPIRATORY zone
-humidifies warms and filters air |
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conducting zone components
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-trachea
-bronchial tree -bronchioles |
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respiratory zone
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-exchange of gases
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respiratory zone components
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-respiratory bronchioles
-alveolar sacs (surfactant prevents alveolar collapse) |
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mechanics of breathing
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-movement of air occurs via bulk flow
-inspiration -expiration |
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mechanics of breathing: movement of air occurs via bulk flow
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movement of molecules due to pressure difference
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mechanics of breathing: inspiration
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-diaphragm pushes downward, ribs lift outward
-volume of lungs increases -intrapulmonary pressure lowered |
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mechanics of breathing: expiration
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-diaphragm relaxes, ribs pulled downward
-volume of lungs decreases -intrapulmonary pressure raised |
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respiratory muscles at exercise:
do respiratory muscles fatigue during exercise |
-historically believed they dont
-currently they do fatigue during exercise (prolonged >120 minutes; high intensity 90-100% VO2max) |
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respiratory muscles at exercise:
do respiratory muscles adapt to training |
YES
-increased oxidative capacity improves respiratory muscle endurance -reduced work of breathing |
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airway resistance:
airflow |
depends on:
-pressure difference between 2 ends of airway -resistance of airway airflow= (p1-p2)/resistance |
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airway resistance
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depends on diameter
-chronic obstructive lung disease -asthma and exercise-induced asthma |
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Asthma results in
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bronchospasm
-narrowing of airways 1. increased work of breathing 2. shortness of breath (dyspnea) -many potential causes |
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exercise-induced asthma
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-during or immediately following exercise
-may impair exercise performance |
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chronic obstructive lung disease (COPD)
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-increased airway resistance (due to constant airway narrowing)
-decreased expiratory airflow |
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exercise and chronic obstructive lung disease
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-includes 2 lung diseases
1.chronic bronchitis(excessive mucus blocks airway 2. emphysema (airway collapse and increased resistance increased work of breathing -leads to shortness of breah -may interfere with exercise and activities of daily living |
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expiration at rest
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passive, during exercise expiration active using muscles located in abdominal wall (rectus abdominis and internal oblique)
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diameter of airway
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primary factor contributing to airflow resistance in pulmonary system
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pulmonary venilation
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amount of air moved in or out of lungs per minute (V)
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tidal volume (Vt)
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amount of air moved per breath
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breathing frequency (f)
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number of breaths per minute
V= Vt x f |
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alveolar ventilation (Va)
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volume of air that reaches respiratory zone
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dead-space ventilation (Vd)
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volume of air remaining in conducting airways
V = Va + Vd |
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pulmonary volumes and capacities:
vital capacity (VC) |
max amount of gas that can be expired after min inspiration
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pulmonary volumes and capacities:
residual volume (RV) |
volume of gas remaining in lungs after max expiration
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pulmonary volumes and capacities:
total lung capacity (TLC) |
amount of gas in lungs after max inspiration
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spirometry
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-measurement of pulmonary volumes and rate of expired airflow
-useful for diagnosing lung diseases (chronic obstructive lung disease (COPD) |
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spirometry tests
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-vital capacity(max vol air can be expired after max inspiration)
-forced expiratory volume (FEV1) -FEV1/VC ratio |
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Forced expiratory vol (FEV1)
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volume of air expired in 1 second during max expiration
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FEV1/VC ratio
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>/= 80% is normal
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partial pressure of gases:
dalton's law |
total pressure of gas mix is = to the sum of the pressure that each gas would exert independently
Pair = PO2 + PCO2 + PN2 |
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Diffusion of gases:
fick's law of diffusion |
the rate of gas transfer (V gas) is proportional to the tissue area, the diffusion coefficient of gas and difference in partial pressure of gas on 2 sides of tissue, and inversely proportional to the thickness
Rate of diffusion= (tissue area)/t thickness) x diffusion coeff of gas x (difference of partial pressure) Vgas= A/T x D X (P1-P2) |
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gas moves
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across blood-gas interface in lung due to simple diffusion
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rate of diffusion
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-ficks law
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blood flow to lung:
pulmonary circuit |
-same rate of flow as systemic circuit
-lower pressure |
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blood flow to lung:
when standing during exercise |
most blood flow is at base of lung due to gravitational force
more blood flow to apex |
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spirometry
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-measurement of pulmonary volumes and rate of expired airflow
-useful for diagnosing lung diseases (chronic obstructive lung disease (COPD) |
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spirometry tests
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-vital capacity(max vol air can be expired after max inspiration)
-forced expiratory volume (FEV1) -FEV1/VC ratio |
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Forced expiratory vol (FEV1)
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volume of air expired in 1 second during max expiration
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FEV1/VC ratio
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>/= 80% is normal
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partial pressure of gases:
dalton's law |
total pressure of gas mix is = to the sum of the pressure that each gas would exert independently
Pair = PO2 + PCO2 + PN2 |
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Diffusion of gases:
fick's law of diffusion |
the rate of gas transfer (V gas) is proportional to the tissue area, the diffusion coefficient of gas and difference in partial pressure of gas on 2 sides of tissue, and inversely proportional to the thickness
Rate of diffusion= (tissue area)/t thickness) x diffusion coeff of gas x (difference of partial pressure) Vgas= A/T x D X (P1-P2) |
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gas moves
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across blood-gas interface in lung due to simple diffusion
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rate of diffusion
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-ficks law
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blood flow to lung:
pulmonary circuit |
-same rate of flow as systemic circuit
-lower pressure |
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blood flow to lung:
when standing during exercise |
most blood flow is at base of lung due to gravitational force
more blood flow to apex |
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ventilation-perfusion relationships:
ventilation/perfusion ratio (V/Q) |
indicates matching of blood flow to ventilation (1.0 or slightly > is ideal)
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ventilation-perfusion relationships:
apex of lung |
under perfused
(ratio <1.0) |
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ventilation-perfusion relationships:
base of lung |
overperfused
(ratio >1.0) |
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ventilation-perfusion relationships:
during exercise |
-light exercise improves V/Q ratio
-heavy exercise results in V/Q inequality |
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ventilation-perfusion relationships
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efficient gas exchange between blood and lungs requires proper matching of blood flow to ventilation
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O2 transport in blood:
99% of O2 |
transported bound to hemoglobin(Hb)
-oxyhemoglobin: Hb bound to O2 -deoxyhemoglobin: Hb not bound to O2 |
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O2 transport in blood:
amount of O2 that can be transported per unit volume of blood- |
dependent of Hb concentration
-each gram of Hb can transport 1.34 ml O2 |
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O2 transport in blood:
oxygen content of blood |
100% Hb saturation
-males-150g Hb/L blood x 1.34ml O2/gHb = 200 ml O2/L blood -females 130 g 174 ml |
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oxyhemoglobin dissociation curve
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deoxyhemoglobin + O2 <-> oxyhemoglobin
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oxyhemoglobin dissociation curve:
direction of reaction |
depends on:
-PO2 of blood -affinity between Hb and O2 |
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oxyhemoglobin dissociation curve:
at lung |
high PO2=formation of oxyhemoglobin
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oxyhemoglobin dissociation curve:
at tissue |
low PO2 = release of O2 to tissues
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effect of pH on O2-Hb dissociation curve
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-decreased pH lowers Hb-O2 affinity
-results in 'rightward' shift of curve (favors 'offloading' of O2 to tissues) |
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effect of temperature on O2-Hb dissociation curve
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-increased blood temp lowers Hb-O2 affinity
-results in 'right' shift of curve |
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effect of 2-3 DPG on O2-Hb dissociation curve
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-byproduct of RBC glycolysis
-may result in 'rightward' shift of curve 1.during altitude exposure 2. not a major cause of rightward shift during exercise |
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O2 transport in muscle
-myoglobin (Mb) |
-shuttles O2 from cell membrane to mitochondria
-has higher affinity for O2 then hemoglobin even at low PO2 allows Mb to store O2 (O2 reserve for muscle) |
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CO2 transport in blood
-at tissue -at lung |
-dissolved in plasma(10%)
-bound to Hb (20%) -bicarbonate (70%) H+binds to Hb; HCO3- diffuses out of RBC into plasma; Cl- diffuses into RBC (chloride shift) O2 binds to Hb (drives off H+); reaction reverses to release CO2 |
CO2 + H20 --carbonic anhydrase--> H2CO3 -->H+ + HCO3-
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O2 hemoglobin dissociation curve
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effect of partial pressure of O2 on combo of O2 with hemoglobin illustrated by S-curve
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ventilation and acid base balance
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pulmonary ventilation removes H+ from blood by HCO3- reaction
-increased vent results in CO2 exhalation(reduced PCO2 and H- [ ], pH increases) -decreased buildup of CO2 (increases PCO2 and H- [ ], pH decrease) |
<----------------------------------lung
CO2 + H2O <-carbonic anhydrase-> H2CO3 <-> H+ + HCO3- muscle------------------------> |
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rest-to-work transitions
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at onset of constant-load submaximal exercise
-initially ventilation increases rapidly (then slower rise toward steady state) -PO2 and PCO2 relatively unchanged (slight decrease in PO2 and increase in PCO2) |
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prolonged submaximal exercise in hot/humid environment
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-ventilation tends to drift upward (increased blood temperature affects respiratory control center)
-little change in PCO2 (higher ventilation not due to increased PCO2 |
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incremental exercise in untrained subject
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ventilation
-linear increase up to 50-75% VO2max -exponential increase beyond this point -ventilatory threshold (Tvent)-inflection point where Ve increases exponentially PO2 -maintained within 10-12 mmHg of resting value |
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incremental exercise in elite athlete
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ventilation
-tvent occurs at higher % VO2max PO2 -decrease 30-40 mmHg at near maximal work (hypoxemia) -due to: 1.ventilation/perfusion mismatch 2.short RBC transit time in pulmonary capillary due to high cardiac output |
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control of ventilation at rest:
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-inspiration and expiration produced by contraction and relaxation of diaphragm
-controlled by somatic motor neurons in spinal cord (controlled by respiratory control center in medulla oblongata) |
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respiratory control center
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-stimulus for inspiration comes from four respiratory rhythm centers
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respiratory control center
1.medulla: |
prebotzinger complex and retrotrapezodial nucleus
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respiratory control center
2.pons: |
pneumotaxic center and caudal pons
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respiratory control center:
group pacemaker hypothesis |
suggests regulation of breathing under redundant control
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input to respiratory control center:
humoral chemoreceptors |
-central chemore
1.in medulla 2. PCO2 and H+ [ ] in cerebrospinal fluid -peripheral chem 1.aortic and carotid bodies 2.PO2, PCO2, H+, and K+ in blood |
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input to respiratory control center:
neural input |
from motor complex and skeletal muscle mechanoreceptors
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ventilatory control during exercise:
submaximal exercise |
-primary drive (higher brain centers-central command)
-'fine tuned' by: 1.humoral chemore 2.neural feedback from muscle |
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input to respiratory control center:
heavy exercise |
alinear rise in Ve
-increasing blood H+ (from lactic acid) stimulates carotid bodies -also K+, body temp and blood catecholamines may contribute |
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