Respiratory Physiology
Collapse, expand
Lungs tend to _________ and thoracic wall tends to _______________
more 2:1, even 1:1
Normally Transverse diameter of the chest wall is ________ compared to the anteroposterior diameter. However in people with COPD, Transverse diameter of the chest wall is ________ compared to the anteroposterior diameter.
maximum speed of expiration
Peak Expiratory Flow Rate (PEFR)
Restrictive illnesses, in which case all air volumes are reduced.
Reduced residual volume is found with?
The volume of air remaining in the lungs after maximum expiration?
Residual volume
bullae
Sometimes large air-filled sacs called _________ develop in the lungs in people with COPD
forced expiratory volume in 1 second - FEV1
The amount of air you can blow out in one second is called?
chronic bronchitis - chronic cough that produces sputum, which is a result of bronchial inflammation. This condition is frequently seen in people who smoke cigarettes.
A cough that lasts at least 3 months per year for at least 2 consecutive years is called____________. Then explain what causes it.
emphysema (irreversible) and with air trapping (reversible under bronchodilation)
An increased residual volume is typically present with?
■ is the volume of the conducting airways. ■ is normally approximately 150 mL.
Define Anatomic dead space
■ is defined as the volume of the lungs that does not participate in gas exchange. ■ is approximately equal to the anatomic dead space in normal lungs.
Define Pathological dead space
This is a graph of lung volumes in health and in disease, showing the various lung subdivisions. Normal aging results in an increase in functional reserve capacity (FRC) and residual volume (RV) and a normal total lung capacity (TLC) percentage. Obstructive lung diseases cause hyperinflation (increase in RV and FRC) with a relatively normal forced vital capacity (FVC). In severe emphysema, the TLC percentage can exceed 150%, with the RV impinging on the FVC. Restrictive lung diseases exhibit reduced TLC percentage with relative preservation of the RV/TLC percentage in fibrosis, a reduced inspiratory capacity and expiratory reserve volume (ERV) in neuromuscular disease, and severe reduction of the ERV in extreme obesity.
Examine graph and explain?
Forced expiratory volume in 1 second (FEV1) is normally 80% of the forced vital capacity, FEV/FVC 1 = 0.8
FEV1/FVC ratio should normally equal =
The volume of air remaining in the lungs at the end of a normal tidal volume. = (Residual volume + expiratory reserve volume) *Note: Denoted "Functional" because this is the amount of gas remaining in the lungs when the next breath begins; dilutes the incoming Tidal Volume
Functional residual capacity(FRC)
The process of inhalation occurs due to an increase in the lung volume (diaphragm contraction and thoracic wall expansion) which results in a decrease in lung pressure in comparison to the atmosphere; thus, air rushes in the airway.
How does inspiration take place?
is increased alveolar ventilation(rate and depth) with no change in arterial Pco2
Hyperpnea
Pneumothorax. The intrapleural pressure becomes equal to atmospheric pressure. The lungs will collapse (their natural tendency) and the chest wall will spring outward (its natural tendency).
If air is introduced into the intrapleural space what is it called? what will happen to the lungs in this situation?
In obstructive lung disease, such as asthma, FEV1 is reduced more than FVC so that FEV1/FVC is decreased.
In chronic obstructive pulmonary disease (COPD), or just obstructive lung disease, what should we expect for FEV1/FVC ratio. Give an example of this disease.
In restrictive lung disease, such as fibrosis, both FEV1 and FVC are reduced and FEV1/FVC is either normal or is increased
In restrictive lung disease, what should we expect for FEV1/FVC ratio. Give an example of this disease?
The maximum volume of air inhaled after a normal expiration. = (tidal volume + Inspiratory reserve volume).
Inspiratory capacity
maximum volume of gas that can be inspired from the end expiratory position. About 3100 milliliters in the adult male
Inspiratory capacity (IC)
(A) Shows A healthy subject inspires maximally to total lung capacity and then exhales as forcefully and completely as possible into the spirometer. (B) In an obstructive disorder, expiratory flow rate is significantly decreased, and the FEV1/FVC ratio is low. (C)In a restrictive disorder, lung inflation is decreased, resulting in reduced residual volume (RV) and total lung capacity (TLC). Although FVC is decreased, it is important to note that the FEV1/FVC ratio is normal or increased in a restrictive disorder.
Interpret the graph @ Normal, Restrictive and Obstructive
(A) Shows A healthy subject inspires maximally to total lung capacity and then exhales as forcefully and completely as possible into the spirometer. FEV1/FVC = 80%. (B) In an obstructive disorder, expiratory flow rate is significantly decreased, and the FEV1/FVC ratio is low. FEV1/FVC = ~42%. (C)In a restrictive disorder, lung inflation is decreased, resulting in reduced residual volume (RV) and total lung capacity (TLC). Although FVC is decreased, it is important to note that the FEV1/FVC ratio is normal or increased in a restrictive disorder. FEV1/FVC = ~90 %.
Interpret the graphs A, B and C
forced vital capacity - FVC
The total amount you can blow out in one breath called
is the volume of air inspired or expired with each normal breath; it amounts to about 500 milliliters in the adult male
Tidal volume (TV)
maximum volume of gas that the lungs (and airways) can contain. (tidal volume + Inspiratory reserve volume
Total lung capacity(TLC)
-Residual volume (RV) -Expiratory reserve volume (ERV) -Tidal volume (TV) -Inspiratory reserve volume (IRV)
What are the four standard lung volumes (which are not subdivided)
Any volume summed with residual volume: residual volume(RV), Total lung capacity(TLC), Functional residual capacity(FRC).
What can you not measure for volumes in the lung?
-----Using Bohrs formula •VD = physiologic dead space (mL) •VT = tidal volume (mL) •PACO2 = PCO2 of alveolar gas (mm Hg) = PCO2 of arterial blood •PECO2 = PCO2 of expired air (mm Hg) VD = VT x [(PACO2 x PECO2)/ACO2] ----the equation states that physiologic dead space is tidal volume multiplied by a fraction(the fraction represents the dilution of alveolar PCO2 by dead-space air,which does not participate in gas exchange and does not therefore contribute CO2 to expired air)
What equation do you use to measure physiological dead space ? And theoretically what does this equation state?
Lung volume decrease by half
What happens to lung volume if one lung is removed from a patient?
-prevents total collapse of alveoli. If alveoli collapsed, it will never be able to expand again. - ensures continues blood-gas exchange -keeps the content of alveolar gas constant(buffers)
What is the importance of residual volume?
• Helium dilution: an indirect method for determining residual lung volume. which includes: Functional residual capacity(FRC), and total lung capacity (TLC). V1 = original volume of helium C1 = original concentration of helium V2 = Container + Lungs C2 = Final concentration of helium V2 = [V1 (C1- C2)]/C2 functional residual capacity (FRC) = V2 -V1
What method is used in this picture? explain what it is measuring? And identify it's equation?
in normal lung physiological dead space is approximately equal to the anatomic dead space
When physiological dead space is equal to anatomical dead space this is indicative of?
lung diseases, in which there are ventilation/perfusion (V/Q) defects.
When physiological dead space is greater than anatomical dead space this is indicative of?
-Functional residual capacity (FRC)= RV + ERV -Vital capacity (VC) = TV + IRV + ERV -Inspiratory capacity (IC) =TV + IRV -Total lung capacity (TLC) = TV + IRV + ERV + RV
Which four standard lung capacities, which consists of two or more standard lung volumes in combination. As well their equations?
The answer is E. Residual volume (RV) cannot be measured by spirometry. Therefore, any lung volume or capacity that includes the RV cannot be measured by spirometry. Measurements that include RV are functional residual capacity (FRC) and total lung capacity (TLC). Vital capacity (VC) does not include RV and is, therefore, measurable by spirometry. Physiologic dead space is not measurable by spirometry and requires sampling of arterial PCO2 and expired CO2.
Which of the following lung volumes or capacities can be measured by spirometry? (A) Functional residual capacity (FRC) (B) Physiologic dead space (C) Residual volume (RV) (D) Total lung capacity (TLC) (E) Vital capacity (VC)
Simple answer: is because the RV increase. Long answer: Static hyperinflation (⇧RV) is caused by a decrease in elasticity of the lung due to emphysema(obstruction). Chronic obstructive pulmonary disease (COPD) is characterized by reduced expiratory airflows as measured by a reduced ratio of the forced expiratory volume in 1 second (FEV1) to the forced vital capacity (FVC).
Why does the total lung capacity increase in obstructive lung disease?
Alveolar dead space
alveoli that cease to act in gas exchange due to collapse or obstruction-- only in pathological conditions
is the maximum extra volume of air that can be expired by forceful expiration after the end of a normal tidal expiration; this normally amounts to about 1200 milliliter
expiratory reserve volume
Obstructive lung diseases
hyperinflation (increase in residual volume[RV]and Functional residual capacity[FRC]) with a relatively normal forced vital capacity (FVC) will cause.
is increased alveolar ventilation(rate and depth) and decrease in arterial Pco2
hyperventilation
is the amount of air that enters the lungs each minute ex: (500 × 14 = 7,000 mL/min or 7 L/min).
minute ventilation
is the volume of air remaining in the lungs after the most forceful expiration; this volume averages about 1200 milliliters
residual volume (RV)
maximum volume of gas that can be exchanged in a single breath= (expiratory reserve volume+ tidal volume+ + inspiratory reserve volume)
vital capacity (VC)
