resp physio 2 Flashcards
define tidal volume
Amount of air you move into & out of your lungs during rest
not forced
define forced vital capacity
Maximum volume of air into & out of your lungs in a single respiratory cycle
define inspiratory reserve volume
the air that can be forcibly inhaled after inspiration of normal tidal volume
define expiratory reserve volume
Additional air that can be forcible exhaled after expiration of a tidal volume
how do you calculate forced vital capacity?
Inspiratory reserve capacity + tidal volume + expiratory reserve volume
define residual volume
Volume of air that remains in the lungs even after maximal exhalation
what is FEV1/FVC?
a ratio of Forced Expiratory Volume in 1 sec & Forced Vital Capacity
what values are normal for FEV1/FVC?
70-80%
what effect does asthma have on FEV1/FVC?
decreases it
what generates the pressure differences for breathing?
respiratory muscles
how does FEV1/FVC change in restrictive lung disorders?
FEV1 is reduced in proportion to loss of lung volume (FVC) so no change in ratio.
These two values are reduced by about 20- 30% the normal value.
how does FEV1/FVC change in obstructive lung disorders?
o FEV1 is lowered due to obstruction while FVC does not decrease much. So, the ratio is decreased
what occurs in restrictive lung disease?
harder to fully expand airways due to damage to lung tissue
what occurs in obstructive lung disease?
narrowing of airways
what are the two main muscles involved in quiet respiration?
diaphragm
external intercostals
what movements do the external intercostals carry out?
o Pump-handle movements: anterior end of each rib elevated
o Bucket handle: diameter of chest increases by rib on either side
why is expiration in quiet breathing passive?
elastic recoil of the lungs
what muscles are involved in forced inspiration?
Diaphragm, external intercostal muscles; accessory muscles (E.g. Pectoralis major; minor, Serratus anterior)
what muscles are involved in forced expiration?
Involves accessory respiratory muscles (E.g. Anterior abdominal muscles; quadratus lumborum).
what is alveolar ventilation?
portion of total ventilation that reaches alveoli
what is the anatomical dead space?
air that is inhaled but isn’t used in gas exchange
found in the mouth, pharynx, trachea and bronchi up the terminal bronchioles
how much is anatomical dead space?
150ml
what is alveolar dead space and what causes it?
dead space due to age/disease (e.g. in alveoli with insufficient blood supply)
in healthy individuals, how much is the alveolar dead space?
5ml
