Respiratory physiology lab Flashcards
Tidal volume
The amount of air inspired or expired during normal, quiet respiration
Inspiratory reserve volume
The amount of air which can be forcefully inspired above and beyond that taken in during a normal inspiration.
Expiratory reserve volume
The maximal amount of air which can be forcefully expired following a normal expiration.
Residual volume
The amount of air which remains trapped in the lungs after a maximal expiratory effort
Total lung capacity
The total amount of air the lungs can contain–the sum of all four volumes.
Vital capacity
The maximal amount of air that can be forcefully expired after a maximum inspiration.
Functional residual capacity
The amount of air remaining in the lungs after a normal expiration
Inspiratory capacity
The maximal amount of air which can be inspired after a normal expiration
How much smaller are volumes or capacities in females compared to males?
20-25% smaller
Capacities
There are 4 capacities that are combinations of two or more volumes
Spirometer
An instrument used to measure respiratory volumes
Respiratory minute volume
You get this value by multiplying tidal volume and respiratory rate per minute
Heymer test of respiratory reserve
In this test the subject takes five deep breaths and then holds their breath as long as possible after the last inspiration. The breath-holding time gives an indication of the person’s functional respiratory reserve and efficiency of their respiratory system. The test is performed 2-3 times and the average is taken.
Normal values for the Heymer test
Normal values for men are 50-70 seconds and for women, 50-60 seconds.
Why are pulmonary measurements important?
Changes is pulmonary measures are caused either by disease or recovery from a disease. For example, the vital capacity is found to decrease in right heart disease. This is due to blood congestion in the lung capillaries, which in turn leads to pulmonary edema and a decrease in VC. As the person recovers, their heart becomes stronger, pulmonary congestion and edema decrease, and the VC increases. The vital capacity also decreases in paralytic polio due to partial paralysis of respiratory muscles, and in various other respiratory diseases
Nonogram
Graph that predicts forced expiratory volume and vital capacity in males or females when given their height and age
How is tidal volume measured?
Tidal volume can be measured by exhaling through a tube connected to a dry gas meter. This meter measures the volume of gas that passes through it (similar to the natural gas meter in your home) and keeps a cumulative total. One can calculate tidal volume by dividing the total air exhaled by the number of breaths made over the collection period.
How is metabolic rate measured?
Metabolic rate (measured in ml O2 consumed/min) can be determined by calculating the difference between in the percentage of O2 in inhaled air (20.95%) and the percentage of O2 in exhaled air (measured by the oxygen analyzer), and then multiplying this percentage difference by the volume of air breathed during a measured time span (measured by the dry gas meter)
The rate of oxygen consumption is equal to (2)
- The rate at which the respiratory exchange surface of the lungs obtains oxygen from the environment
- The rate at which oxygen is extracted from the blood going through the capillaries
How are the 2 factors that influence the rate of oxygen consumption measured?
Both can be calculated by measuring the flow (ml/min) of the medium (air or blood) and multiplying by the amount of oxygen that is extracted per ml of medium that passes the exchange surface.
Minute volume
Flow of air in the respiratory system
Cardiac output
The flow of blood in the circulatory system
Concentrations of oxygen in the inspired air and exhaled air definition
The amounts of oxygen per ml of medium entering and leaving the exchange surfaces in the respiratory system.
Concentrations of oxygen in the systemic arterial blood and the systemic venous blood definition
The amounts of oxygen per ml of medium entering and leaving the exchange surfaces in the circulatory system
Arterial blood oxygen saturation at rest
100%
Venous blood oxygen saturation at rest
60% saturated
How much oxygen can each gram of hemoglobin bind?
1.3 ml of oxygen
Hyperventilation
Fast respiratory rate
Apnea
Temporary cessation of breathing
% of oxygen in exhaled air resting and during exercise
Resting: 18.24%
During exercise: 18.67%
% of oxygen in inhaled air at rest and during exercise
20.94% during both
The total amount of air one’s lungs can possibly hold is divided into which 4 volumes?
- Tidal volume
- Inspiratory reserve volume
- Expiratory reserve volume
- Residual volume
Vo2
Rate of oxygen consumption
Vm
Minute volume
CO
Cardiac output
CO2i
Concentration of oxygen in inspired air
CO2e
Concentration of oxygen in exhaled air
CO2a
Concentration of oxygen in systemic arterial blood
CO2v
Concentration of oxygen in systemic venous blood
PPr
Pulse pressure at rest
PPe
Pulse pressure during exercise
SVr
Stroke volume at rest
SVe
Stroke volume during exercise
What factors operate during exercise to increase the amplitude and rate of breathing?
Skeletal muscle requires more oxygen, so amplitude and rate of breathing increases to compensate due to carbon dioxide concentration
What factors elevate cardiac output during exercise?
Stroke volume and heart rate
How does hyperventilation affect tidal volume and respiratory rate?
Tidal volume decreases, respiratory rate decreases
Does hyperventilation cause shallow breathing?
Breathing is shallow, and apnea can develop depending on the individual.
What mechanism is responsible for the effects of hyperventilation?
Low carbon dioxide levels increases blood pH, so we need to make adjustments to slow down respiration and get to normal pH.
In a closed system, how does hyperventilation change respiratory rate and tidal volume?
Respiratory rate and tidal volume will increase after hyperventilation to get rid of excess carbon dioxide, since carbon dioxide is rebreathing during hyperventilation. Apnea won’t develop in a closed system because respiratory rate and tidal volume won’t decrease.
During rebreathing, what happens to the respiratory rate?
Respiratory rate increases, but the change takes longer to occur since the individual is breathing normally initially.
During mental concentration, how does respiratory rate change?
Respiratory rate decreases- respiratory centers in lower brain centers are partially depressed
How does tidal volume change in response to the change in respiration rate during mental concentration?
Tidal volume increases during concentration due to the slower respiratory rate
During speech, does the respiratory rate change?
Respiratory rate will decrease because you can breathe less frequently while talking- speech is only produced on an exhale.
During speech, does the regularity of breaths change?
Breaths will become irregular, but the degree of irregularity depends on what you are talking about/how you are speaking
What happens to tidal volume after breath holding?
Tidal volume increases
Why is it impossible to hold your breath indefinitely?
Over time you would lose consciousness and start breathing again as it becomes involuntary due to structures in the pons and medulla.
What changes are seen in respiratory rate and tidal volume during obstruction of respiratory passageways?
Tidal volume increases to compensate for less air, respiratory rate decreases because taking deep breaths takes more time.
In what disorders is obstruction of airway passages a problem?
COPD and asthma
