Respiratory Physiology, Waters and Leffler Flashcards
Total Lung Capacity Equals…
Vital Capacity + Residual Volume
-Normal: 6-7 L
Vital Capacity Equals…
Tidal volume + Inspiratory Reserve Volume + Expiratory Reserve Volume
-Normal: 3-5 L
Functional Residual Capacity Equals…
Expiratory Reserve Volume + Reserve Volume
- Amount of air in lungs after a NORMAL expiration
- Normally 2.5 L
Residual Volume Equals…
- Amount of air in lungs after a MAXIMAL expiration
- Normally 1000 L
Effect of Obstructive Lung Disease on FEV1
-FEV1 is decreased
Effect of Restrictive Lung Disease on FEV1
- FEV1/FVC ratio is normal
- FVC is decreased
What determines air movement into and out of lungs?
Trans-respiratory system pressure
P(alveolar) - P(atmospheric)
Transpulmonary Pressure
P(Alveolar) - P(intrapleural)
Inspiratory Muscles
Diaphragm Accessory Muscles (Scalene, Sternocleidomastoid)
Expiratory Muscles
Abdominal Muscles (Rectus Abdominis, Obliques) Internal Intercostal Muscles
Compliance Equals…
(Change in Pressure)/(Change in Volume)
- SLOPE of a Pressure-volume curve
- Measure of DISTENSIBILITY of lungs
- Normal: 0.2 L/cmH2O
Methemoglobin
- Oxidized form of Hb; Fe3+
- DOES NOT bind O2
Fetal Hemoglobin (HbF)
- higher affinity for O2 than normal hemoglobin
- has alpha2gamma2 subunits instead
Factors which cause the Hb Saturation Curve to shift to the RIGHT (DECREASE AFFINITY FOR O2, facilitate unloading)
- Increased PCO2
- Decreased pH (acidosis)
- Increased Temperature (Metabolism)
- Increased 2,3 DPG (RBC metabolism)
Factors which cause the Hb Saturation Curve to shift to the LEFT (INCREASE AFFINITY FOR O2, facilitate loading)
- Decreased PCO2
- Increased pH (alkalosis)
- Decreased Temperature (Metabolism)
- Presence of Fetal Hemoglobin
- Decreased 2,3 DPG
Bohr Effect
- As H+ binds to hemoglobin, O2 binds less strongly; this shifts the O2 saturation curve to the right, facilitating unloading of O2.
- Occurs in venous blood
Haldane Effect
- Deoxygenation of the blood leads to an increased ability for the blood’s ability to carry CO2.
- Decreases in O2 facilitate H+ binding to hemoglobin; this results in a “left shift” in the position of the CO2 curve, this increasing the ability to remove CO2.
Medullary Control of Breathing
Central Respiratory Center (DRG, VRG)
- Drives inspiration and expiration
- Establishes and Maintains Rhythmicity
- NORMALLY, not active
- DRIVEN BY pH!!!
Pontine Respiratory Contorl Centers
- Apneustic Center
- Pneumotaxic Center
Apneustic Center
- Stimulates inspiration
- produces a deep and prolonged inspiratory gasp
Pneumotaxic Center
- Inhibits inspiration
- Regulates inspiratory volume and respiratory rate
Peripheral Chemoreceptors
- Aortic Bodies (efferent via Vagus Nerve)
- Carotid Bodies (efferent via Glossopharyngeal N.)
- Respond to low PaO2, stimulating inspiration
