respiratory II lab
What causes intrapulmonary pressure (Ppul) to fall below atmospheric pressure (Patm)?
An increase in the volume of the thoracic cavity during inspiration.
Assuming an anatomical dead space of 150 ml, what would be the alveolar ventilation rate (AVR) for the same adult male (see Part A)?
3500 ml/minute Recall that the alveolar ventilation rate (AVR) is measured by subtracting the anatomical dead space from the tidal volume, and then multiplying by the breathing rate. So in this example, (500 ml - 150 ml) X 10 breaths/min = 3500 ml/minute.
What is the minute ventilation of an average adult male at rest breathing at a rate of 10 breaths per minute?
5000 milliliters per minute -The minute ventilation is calculated by multiplying the breaths per minute by the tidal volume, so in this case, 10 breaths/minute x 500 ml/breath = 5000 ml/minute.
Which ONE of the following statements about gas pressures at high altitude is TRUE? Atmospheric pressure is lower at high altitude. At high elevations there are more oxygen molecules available in the atmospheric air. The percentage of oxygen in the air is decreased at high altitude. PO2 (partial pressure of oxygen) is higher (at high altitude) than at sea level.
Atmospheric pressure is lower at high altitude.
What is TRUE about contraction of the diaphragm?
Contraction moves the muscle inferiorly and increases the volume of the thoracic cavity.
Which phrase describes compliance?
How easy it is to expand the lungs
What is Dalton's Law?
In a mixture of gases, the total pressure equals the sum of the partial pressures exerted by each gas.
What is TRUE about internal respiration?
In the tissues, oxygen flows from the blood into the tissues and carbon dioxide flows from the tissue cells into the blood. it occurs in the tissues
What is TRUE about external respiration?
It occurs in the lungs. During external respiration, oxygen moves from the alveolar air spaces into the blood, and carbon dioxide leaves the blood and enters the alveoli where it can be exhaled.
If one lung collapses due to pneumothorax, does the second lung collapse also, and why or why not?
No, only one lung collapses because each lung is surrounded by its own pleural cavity and pleural membranes.
Which of the following pressure relationships best illustrates when inspiration will occur?
Ppul < Patm
What happens to Ppul (relative to Patm) during expiration (exhalation)?
Ppul becomes greater than Patm, so air flows out of the lungs
Which of the following statements is TRUE?
Quiet expiration is due to relaxation of the diaphragm and external intercostal muscles.
What is Henry's Law?
The amount of gas which dissolves in a liquid is proportional to the partial pressure of the gas and the solubility of the gas.
What is Boyle's law?
The pressure of a gas is inversely proportional to the volume of its container.
According to this spirographic record, what is the total volume of exchangeable air for a normal male (i.e. the amount of air that can be drawn into the lungs after a forced exhalation)?
The total volume of exchangeable air (vital capacity) for a normal male is the amount of air that can be drawn into the lungs after a forced exhalation and, in this case, is 4800 milliliters.
What is the difference between Total Lung Capacity (TLC) and Vital Capacity (VC)?
Total lung capacity includes residual volume; vital capacity does not include residual volume.
What is pneumothorax?
When air enters the pleural cavity.
With each breath, a certain amount of air remains in the respiratory passageways and doesn't reach the alveoli to participate in gas exchange. The volume of air that remains in the air passageways is called the
anatomical dead space
While minute ventilation values provide a rough yardstick for assessing respiratory efficiency, the alveolar ventilation rate (AVR) is a better index of effective ventilation because it takes into consideration the volume of air wasted in the anatomical dead space, and measures the flow of fresh air in and out of the alveoli during a particular time interval.
breaths/minute X (tidal volume - anatomical dead space)
The minute ventilation is
calculated by multiplying the rate of respiration by tidal volume (TV).
Which muscles increase the volume of the thoracic cavity when they contract?
diaphragm and external intercostal muscles
During an allergic reaction which of the following would improve airflow through lung passageways (bronchioles)?
epinephrine -Recall that epinephrine works on beta 2 receptors that relax smooth muscle.
All of the following increase lung compliance EXCEPT:
fibrosis, or increased connective tissue in the walls of the lung tissue.
Which muscles are involved in forced expiration?
internal intercostal muscles and abdominal muscles
Which of the following pressures must remain negative to prevent lung collapse?
intrapleural pressure
Which pressure is the result of the natural tendency of the lungs to decrease their size (because of elasticity) and the opposing tendency of the thoracic wall to pull outward and enlarge the lungs?
intrapleural pressure
Which of the following pressures rises and falls with the phases of breathing but equalizes with atmospheric pressure in between each breath?
intrapulmonary pressure -Intrapulmonary pressure rises when the thorax volume is reduced (during exhalation) and drops when the thorax volume rises (during inhalation). When there is no change in thorax volume (i.e. in between each breath), intrapulmonary pressure equalizes with the atmospheric pressure.
If type II alveolar cells do not secrete surfactant,
lung compliance is low.
When smooth muscle in the wall of the bronchioles contract
resistance of the airways increases and airflow decreases.
The transpulmonary pressure is the difference between the intrapulmonary pressure and intrapleural pressure (Ppul - Pip). If the transpulmonary pressure equals zero, what will happen to the lung?
the lungs will collapse
What determines how much oxygen can dissolve in the blood?
the partial pressure of oxygen and how soluble oxygen is in blood
What is the driving force for the movement of air into the lungs?
the pressure gradient
Which of the following describes the volume of air exhaled during passive breathing?
tidal volume
Which volumes are combined to determine the inspiratory capacity?
tidal volume (TV) and inspiratory reserve volume (IRV)
