Oxygenation -
Respiration
Exchange of O2 and CO2 during cellular metabolism
Diffusion Environmental O2 exchanged for CO2 via alveolar capillary membrane
Perfusion Ability of cardiovascular system to pump oxygenated blood to the tissues and
return deoxygenated blood to the lungs via pulmonary circulation
Ventilation Process of moving O2 in & CO2 out of the lungs through pressure changes
Transport Ability of hemoglobin to carry oxygen (combined w/ perfusion & ventilation)
Work of Breathing (WOB)
Effort required to expand and contract the lungs
Inspiration Process of drawing air into the lungs
● Diaphragm & external intercostal muscles contract
● Expands the chest cavity = Reducing lung pressure
● Pressure difference = Air into lungs
Expiration Process of expelling air out from the lungs
● Diaphragm & intercostal muscles relax
● Decreased chest cavity = Increase lung pressure
● Pressure difference = Air out of the lungs
Lung Change in lung volume per unit change in transpulmonary pressure
Compliance ● AKA, "stretchability" or distensibility of lung tissues
● High = Lungs expand easily with less pressure
● Low = Require more pressure to achieve the regular expansion
Airway Change in transpulmonary pressure required to produce a unit flow of gas
Resistance through airways of lung
● AKA, resistance to airflow within the respiratory airways
● Influenced by airway diameter, air passage length, & air viscosity
● High Resist = Harder for air to flow in/out of the lungs
Surfactant Chemical substance, ↓ surface tension in alveoli & ↑ lung compliance
● Improves lung expansion during inspiration
● Without surfactant, alveoli would collapse after each breath (atelectasis)
Atelectasis Complete or partial collapse of a lung or lobe
Total Lung Capacity (TLC)
, Max amount of air the lungs can hold
Tidal Vol. Amount of air that is inhaled or exhaled during a normal, relaxed breath
(TV) ● Represents regular, resting breathing cycle
● Ensures continuous gas exchange (O2 in & CO2 out) without extra
effort
Residual Vol. Amount of air that remains in the lungs even after a forceful exhalation
(RV) ● Remaining air prevents the lungs from collapsing by maintaining
alveolar structure
● Ensures that gas exchange continues between breaths
Forced Vital Total volume of air that can be forcibly exhaled after taking a full inhalation
Capacity ● Used in pulmonary function testing
(FVC) ● Measured using spirometer
Pulmonary Moves blood (Hgb carries O2) to & from alveolar capillary membrane for gas
Circulation exchange
Regulation of Respiration
Neural ● CNS = Controls the respiratory rate, depth, & rhythm
Regulation ● Cerebral Cortex = Regulates voluntary control of respiration
Chemical Normal Lung Function -
Regulation ● Changes in CO2, O2 and pH
Chronic Obstructive Pulmonary Disease (COPD) -
● ↑ levels of CO2
● Expected O2 saturation is 88%-92%
● Work closely with respiratory therapists with patients with COPD
Physical Factors (Etiology) Affecting Oxygenation
Physiological ● Decreased O2 carrying capacity
Factors ● Hypovolemia
● Decreased inspired oxygen concentration
● Increased metabolic rate
Conditions ● Pregnancy
Affecting ● Obesity
Chest Wall ● Neuromuscular disease
Movement ● Musculoskeletal abnormalities
● CNS alterations
Respiration
Exchange of O2 and CO2 during cellular metabolism
Diffusion Environmental O2 exchanged for CO2 via alveolar capillary membrane
Perfusion Ability of cardiovascular system to pump oxygenated blood to the tissues and
return deoxygenated blood to the lungs via pulmonary circulation
Ventilation Process of moving O2 in & CO2 out of the lungs through pressure changes
Transport Ability of hemoglobin to carry oxygen (combined w/ perfusion & ventilation)
Work of Breathing (WOB)
Effort required to expand and contract the lungs
Inspiration Process of drawing air into the lungs
● Diaphragm & external intercostal muscles contract
● Expands the chest cavity = Reducing lung pressure
● Pressure difference = Air into lungs
Expiration Process of expelling air out from the lungs
● Diaphragm & intercostal muscles relax
● Decreased chest cavity = Increase lung pressure
● Pressure difference = Air out of the lungs
Lung Change in lung volume per unit change in transpulmonary pressure
Compliance ● AKA, "stretchability" or distensibility of lung tissues
● High = Lungs expand easily with less pressure
● Low = Require more pressure to achieve the regular expansion
Airway Change in transpulmonary pressure required to produce a unit flow of gas
Resistance through airways of lung
● AKA, resistance to airflow within the respiratory airways
● Influenced by airway diameter, air passage length, & air viscosity
● High Resist = Harder for air to flow in/out of the lungs
Surfactant Chemical substance, ↓ surface tension in alveoli & ↑ lung compliance
● Improves lung expansion during inspiration
● Without surfactant, alveoli would collapse after each breath (atelectasis)
Atelectasis Complete or partial collapse of a lung or lobe
Total Lung Capacity (TLC)
, Max amount of air the lungs can hold
Tidal Vol. Amount of air that is inhaled or exhaled during a normal, relaxed breath
(TV) ● Represents regular, resting breathing cycle
● Ensures continuous gas exchange (O2 in & CO2 out) without extra
effort
Residual Vol. Amount of air that remains in the lungs even after a forceful exhalation
(RV) ● Remaining air prevents the lungs from collapsing by maintaining
alveolar structure
● Ensures that gas exchange continues between breaths
Forced Vital Total volume of air that can be forcibly exhaled after taking a full inhalation
Capacity ● Used in pulmonary function testing
(FVC) ● Measured using spirometer
Pulmonary Moves blood (Hgb carries O2) to & from alveolar capillary membrane for gas
Circulation exchange
Regulation of Respiration
Neural ● CNS = Controls the respiratory rate, depth, & rhythm
Regulation ● Cerebral Cortex = Regulates voluntary control of respiration
Chemical Normal Lung Function -
Regulation ● Changes in CO2, O2 and pH
Chronic Obstructive Pulmonary Disease (COPD) -
● ↑ levels of CO2
● Expected O2 saturation is 88%-92%
● Work closely with respiratory therapists with patients with COPD
Physical Factors (Etiology) Affecting Oxygenation
Physiological ● Decreased O2 carrying capacity
Factors ● Hypovolemia
● Decreased inspired oxygen concentration
● Increased metabolic rate
Conditions ● Pregnancy
Affecting ● Obesity
Chest Wall ● Neuromuscular disease
Movement ● Musculoskeletal abnormalities
● CNS alterations
