Respiration Flashcards
Where does gas exchange occur?
in the alveolar air sacs
What is the efficiency of gas dependent on?
ventilation
What does cyclical breathing do?
cause movements alternately inflate and deflate the alveolar sacs
What does inspiration provide?
the alveoli with some fresh atmospheric air
What does expiration provide?
removes some of the stale air, which has reduced oxygen and increased carbon dioxide concentration
What is spirometry?
the method of choice for a fast and reliable screening of patients with chronic obstructive pulmonary disease COPD
What is COPD
12th leading cause of death worldwide and 5th leading cause in the western countires
85-90 percent caused by smoking- tobacco
How can the important aspects of lung function be determined?
- measuring airflow and the corresponding changes in lung volume
What can airflow be directly measured from?
with a pneumotachometer
-the flow head type used in the experiment is the lily type
What did the lily flow head do?
measures the difference in pressure either side of mesh membrane with known resistance.
What does the transducer do?
- converts the pressure signal into changing voltage.
What does the resistance do?
gives rise to small pressure difference proportional to flow rate.
What is the volume calculated as?
integral flow
What is a complication when measuring the volume?
caused by the difference in air temperature between the spirometer rod (at ambient temp) and the air air exhaled from the lungs (body temp)
What happens with the volume of gas when warming?
it expands so therefore the air volume expired from the lungs will be slightly greater than that inspired- thus a volume trace as calculated by integration flow drifts in the expiratory direction
How would you reduce the drift of flow of air?
BTPS factor-
What does spirometry allow?>
many components of pulmonary function to eb seen, measured and caluclated.
What does respiration consist of ?
a repeated cycle of inspiration followed by expiration
What is the tidal volume?(vT)
when during the respiratory cycle a specific volume of air is drawn into and then expired from the lungs.
is the volume breathed in each breath
What is the breathing frequency(f) in normal ventilation>
approx 15 respiratory cycles per minute
-this value varies with the level of activity.
What is the expired minute volume?
the product of f(frequency) and Vt(tidal volume)
the amount of air exhaled in one minute of breathing
What is residual volume?
the amount of air left in the lungs after full expiration
-cannot be measured by spirometry
What is tidal volume ?
normal breath (500ml)
What is inspiratory reserve volume ? (IRV)
3100ml - the amount of air that can be inspired forcibly beyond the tidal volume
What is expiratory reserve volume ? (ERV)
1200ml- amount of air that can be expired/exhaled forcibly beyond the tidal volume (after a normal expiration)
What is vital capacity (VC)?
4800ml- biggest possible breath- the measure of the maximum volume of gas in the respiratory system that can be exchanged
What is residual volume?
1200ml-air that cannot be expelled
What is total lung capacity (TLC)?
is a measure of the volume of gas in the respiratory system at the end of a maximal inspiration
What is capacity?
the sum of at least 2 volumes
What is FEV1?- forced expired volume
provides a measure of the resistance of the airways to flow
-amount of air you can force from your lungs in one second.
-Measured during spirometry test
known as a pulmonary function test, which involves forcefully breathing out into a mouthpiece connected to a spirometer machine.
