Week 1 Flashcards
What is the formula for flow?
• formula for resistance?
F = ∆P/R
R = 8nl/r^4
• ∆P = difference in pressure
• R = resistance
What can be said about the rate of oxygen uptake and oxygen consumption and CO2 production and excretion during steady state?
O2 uptake = O2 consumption
CO2 production = CO2 excretion
What is tidal volume (TV)?
• Functional Residual Capacity (FRC)?
• Residual Volume (RV)?
Tidal volume ~500 mL = volume of a normal breathe
Functional Residual Capcacity (FRC) = volume of air leftover in lungs after a normal breath
Residual Volume (RV) = amount of air left in the lungs after maximum exhalation
What volumes compose:
• Inspiratory Capacity?
• Functional Residual Capacity?
Inspiratory Capacity:
• Tidal Volume + Inspiratory Reserve Volume (the extra air you could inhale above and beyond tidal volume)
Functional Residual Capacity:
• Residual Volume + Expiratory Reserve Volume (the air you could exhale if you pushed as hard has you could)
What volumes compose:
• Vital Capacity?
• Total Lung Capacity?
Vital Capacity:
• Tidal Volume + Inspiratory Reserve Volume + Expiratory Reserve Volume
Total Lung Capacity:
•Inspiratory Reserve Volume + Tidal Volume + Expiratory reserve volume + Residual Volume
T or F: Residual Volume can’t be measured with a spirometer
True
What is the normal FEV1/FVC ratio?
80% which means you exhale most of your breathe in the 1st second
Someone has a FEV1/FVC ratio that is less than 0.7, name 4 diseases they might have?
COPD:
1) Emphysema
2) Chronic Bronchitis
3) Bronchietasis
4) Asthma
Someone has an FEV1/FVC that is greater than 0.8, what are some possible pathologies that could cause this?
Mechanical Breathing Disorders:
• Weakness, Neuromuscular
Interstitial Diseases: • Pulmonary Fibrosis • ARDS • Sarcoidosis • Hypersensitivity Pneumonitis
How can the physiological dead space be measured?
End tidal Pco2 / arterial Pco2
• Less CO2
How would a pulmonary embolus affect alveolar dead space?
It would increase because no blood is supplying that lung tissue
What is the formula for Minute Ventilation?
• Alveolar ventilation?
MINUTE VENTILATION:
Vmv = TV x f
- TV = tidal volume
- f = respiratory rate
ALVEOLAR VENTILATION:
Valv = (TV - dead space)*Respiratory Rate
T or F: if you want to take up a greater amount of O2 increasing breathing rate is the most important factor.
False, Depth of breathing is a more important factor in increasing Alveolar Ventilation
What is the transmural pressure between breaths if the elastic recoil of the lungs is X.
X - the transmural exactly opposes the elastic recoil of the lungs, this keeps the lungs from collapsing
How many cm H2O is equivalent to 760 mmHg?
1033 cmH2O = 760 mmHg
What is the primary driving force of airflow into and out of the lung?
• Pressure Difference between the mouth and Alveoli
What is the formula to calculate Transplural pressure?
Ptp = Palv - Pip
Intrapleural Pressure = Pressure outside the lungs
Alveolar Pressure = Pressure Inside the lungs
What is Ptp (transpleural pressure) between breaths?
Ptp = 0
Name the nerve and muscles responsible for inspiration?
Scalene
Sternocleidomastoids
EXTERNAL INTERCOSTAL MM.
Name the muscles responsible for expiration?
NONE - at rest
During Ex.:
• INTERNAL INTERCOSTALS
• External Obliques
• Transverse abdominus
When is the maximal magnitude of Alveolar pressure achieved in inspiration?
•When is elastic recoil of the lung maxed out?
Palv = most negative 1/2 through inspiration
Elastic Recoil = Maximal at the end of inspiration
What is the difference in response of a compliant lung compared to a non-compliant lung with the same Transpleural pressure?
Compliant Lung will inflate more with the same applied pressure
What is hysteresis?
• explain why we see it?
Hysteresis:
• Asymmetry of pressure-volume curves for inspiration and expiration
• Caused by surface tension that is higher in the closed lung which reduces its compliance
Explain what happens to the following in restrictive disease. • FVC • TLC • RV • FRC
They have difficulty getting air in so all these values are decreased.