BGYC33/CC4 Respiratory System Study Guide, Lectures 9-15 (2013)
Lecture 9: Pulmonary Mechanics
The Respiratory Tract
Blood Flow to the Lungs
Thoracic Cavity and Respiratory Muscles
Diaphragm; Intercostal Muscles; Abdominal Muscles; Chest Wall; Phrenic Nerve
Parietal Pleura; Visceral Pleura; Pleural Space
Atmospheric Pressure (P )atmlveolar Pressure (P );alvtrapleural Pressure (P ) ip
Important Pressure Differences
P atm PalvDriving force for air flow in and out of the lungs
P alv =ipranspulmonary Pressure (drives lung expansion)
Damage to the Pleura / Pleural Space
Air Flow In and Out of the Lungs
Lung Compliance 2
1) Transpulmonary pressure is:
a) P - P and the driving force for airflow in and out of the lungs.
b) Patm- Pipnd the driving force for lung expansion.
*c) Palv aip the driving force for lung expansion.
d) Palv ipd the driving force for airflow in and out of the lungs.
e) Palv ipd increased by a pneumothorax.
2) In the diagram below, Palvlative to Patm(the upper trace) decreases in the part of the curve
labeled “A” because the “X”; while lung pressure decreases in area labeled “E” because “Y”.
a) X = lung volume decreases; Y = the number of molecules of air in the lungs decreases.
b) X = diaphragm contracts; Y = the number of molecules of air in the lungs decreases.
c) X = lung volume decreases; Y = the number of molecules of air in the lungs increases.
*d) X = lungs expand; Y = the number of molecules of air in the lungs decreases.
e) X = lung volume increases; Y = the diaphragm relaxes.
C D E
3) During inspiration, transpulmonary pressure because the decrease
in is greater than the decrease in .
*a) Increases; intrapleural pressure; alveolar pressure.
b) Decreases; intrapleural pressure; alveolar pressure.
c) Increases; alveolar pressure; intrapleural pressure.
d) Decreases; alveolar pressure; intrapleural pressure.
e) Increases; atmospheric pressure; intrapleural pressure. 3
Lecture 10: Pulmonary Mechanics and Spirometry
Air Flow In and Out of the Lungs
Ideal Gas Law
Air Flow = (P - P ) / R
P alvends on Lung Volume and the Number of Moles of Gas in the Lungs
Inspiration: Changes in Pressure, Volume and the # Moles of Gas
Expiration: Changes in Pressure, Volume and the # Moles of Gas
Pressure Volume Changes during Inspiration
Surface Tension of a Liquid
Pressures in Large and Small Alveoli
Bronchiole Smooth Muscle
Tidal Volume (V T)
Inspiratory Reserve Volume (IRV)
Expiratory Reserve Volume (ERV)
Functional Residual Capacity
Total Lung Capacity
1) The following values were obtained using the inert gas technique. Use these volume to calculate
the volume of the lung at the time the test began. Do not worry about units.
Concentration of He in the spirometer before the test begins: 20
Concentration of He in the spirometer at the end of the test: 10
Volume of the spirometer: 100
e) 1000 4
2) Based on the following diagram, what are the following lung volumes? Note the maximum value
on the Y-axis is 5 700.
a) VT = 500 ml; IRV = 3 500 ml; ERV = 1000 ml; RV = 1200 ml
b) VT = 500 ml; IRV = 3 500 ml; ERV = 2200 ml; RV = 1200 ml
c) VT = 1000 ml; IRV = 3 000 ml; ERV = 1000 ml; RV = 2200 ml
d) VT = 500 ml; IRV = 3 000 ml; ERV = 1000 ml; RV = 1200 ml
e) VT = 500 ml; IRV = 3 000 ml; ERV = 2200 ml; RV = 1200 ml
3) Consider the following three patients and their FEV1 and FVC values. Based on these numbers
which patient is normal and which patient has an obstructive or restrictive lung disease?
Patient 1: FEV 1 4.0; FVC = 5.0
Patient 2: FEV 1 1.5; FVC = 3.0
Patient 3: FEV 1 2.9; FVC = 3.0
a) Patient 1 = normal; Patient 2 = restrictive disease; Patient 3 = obstructive disease.
b) Patient 1 = restrictive disease; Patient 2 = normal; Patient 3 = obstructive disease.
c) Patient 1 = normal; Patient 2 = obstructive disease; Patient 3 = restrictive disease.
d) Patient 1 = obstructive disease; Patient 2 = restrictive disease; Patient 3 = normal.
e) Patient 1 = restrictive disease; Patient 2 = obstructive disease; Patient 3 = normal. 5
Lecture 11: Alveolar Ventilation and Blood Gases
Pulmonary Function Tests
Restrictive Lung Disease
Obstructive Lung Disease
Forced Vital Capacity (FVC)
Forced Expiratory Volume (FEV)
FVC and FEV du1ing Obstructive and Restrictive Lung Disease
The Inert Gas (Helium Dilution) Technique
The Inert Gas Technique Reviewed
Minute Ventilation (V I)
Breathing Frequency (f R )
Tidal Volume (V T)
Alveolar Ventilation (VA )
Dead Space Ventilation (DSV)
Increasing Breathing Frequency and Tidal Volume
Calculating Alveolar Ventilation
The Assumptions and Approximations
Measuring Alveolar Ventilation using Exhaled and Arterial CO L2vels
Partial Pressure of Gases
Composition of Air; Atmospheric Pressure; Relative Humidity 6
1) Which of the following is a reason for using the following equation to measure alveolar
V A = (VCO X2K) / P aCO 2
a) Anatomical dead space volume (K) is relatively easy to estimate.
b) PA CO 2 P aCO 2
c) Arterial pCO 2s easily calculated from the Henderson-Hasselbach equation once arterial pH is
measured (which is easy to do)
d) PaO 2s easy to measure.
2) How many of the following 6 statements are false?
1) PCO 2 in blood entering the systemic veins is less than or equal to tCO 2 in the tissue cells.
2) PO 2in blood leaving the pulmonary capillaries is equal to theOP2in blood entering the systemic
3) PO 2in the tissue cells is slightly less than (or at most equal to)O2hin blood leaving the
4) PCO 2 in blood entering the pulmonary capillaries is equal to theCO2 in the alveoli.
5) PO 2in mixed venous blood is equal to PCO 2in arterial blood in the systemic arteries.
6) PO 2in the atmosphere (at sea level) is equal to alveolaO 2
3) Blood with an arterial PCO 2f 45 Torr and an arterial PO 2f 90 Torr is referred to as:
a) Hyperoxic hypercapnic
b) Hyperoxic hypocapnic
c) Hypoxic hypercapnic
d) Hypoxic hypocapnic
e) Hypoxic normocapnic 7
Lecture 12: Alveolar Ventilation and Blood Gases
Partial Pressures of Gases throughout the Circulatory System
Perfusion Limitation of O2Uptake and CO Ex2retion
Eupnea; Hyperpnea; Apnea; Dyspnea
Normoxia; Hyperoxia; Hypoxia
Normocapnia; Hypercapnia; Hypocapnia
Daily Oxygen Consumption
Calculating Daily Oxygen Consumption
Concluding that Dissolved Oxygen can’t Meet Daily Oxygen Demands
Daily Oxygen Consumption Reviewed
Changes in Haemoglobin with Development
Sickle Cell Anaemia
Oxygen and Carbon Dioxide Transport in the Blood
Linking O 2nd CO Tr2nsport
Transport Processes at the Lungs
Transport Processes in the Tissues
The Oxygen Equilibrium (Dissociation) Curve
Units of the X- and Y-Axes
The p50 Value
Left and Right Shifts of the Oxygen Equilibrium Curve
Oxygen Loading and Unloading