Lab unit 17-18 Flashcards
Respiratory system is composed of
nasal passages, the Larynx, the Trachea, Bronchi, and Alveoli, the Thoracic cage, and the respiratory muscles of the thoracic cage.
Only part of the system that actually take part in transfer of oxygen
Lung and vascular spaces into the blood
dead space
Together with the unused alveoli of the lungs at low respiratory rate.
two physiologically active gases
Oxygen and carbon dioxide
Proper SI unit of Gas pressure
Pascals,
But expressed in mmHg
Atmospheric pressure/ barometric pressure
Increases with proximity to the earth’s centre
partial pressure
Dalton’s law of partial pressure
the product of barometric pressure and gas fraction (%)
barometric pressure (mmHg) x gas fraction (% into decimals)
Volume of gas
Inverse with pressure (Boyle’s law)
Direct with temperature (Charles’ Law)
STPD
Standard temperature and pressure Dry
BTPS
body temperature and pressure saturated
Relative humidity
The amount of water vapour present in a given volume of air
Relative to the maximum amount of water vapour which could be in that volume before it is saturated
x 100%
Corrections of gas volumes from ATPS to STPD
made when we need to know the amount or number of gas molecules,
Vital Capacity (VC)
greatest volume of gas that can be expelled by voluntary effort after maximal inspiration
Vital capacity = inspiratory capacity + ERV
Inspiratory Capacity (IC)
maximal volume of gas that can be inspired form the resting end-end expiratory position
Expiratory Reserve Volume (ERV)
maximal volume that can be exhaled from the resting end-expiratory position
Vital capacity = inspiratory capacity + ERV
Functional Residual Capacity (FRC)
volume of gas remaining in the lungs at the end of a quiet exhalation
= ERV + Residual volume
Residual Volume (RV)
volume of gas remaining in the lungs after forced expiration
Total lung capacity (TLC)
Volume of gas in the lungs at the time of maximal inspiration
= Inspiratory capacity + expiratory capacity + residual volume
Residual volume - Total lung Capacity ratio ( RV/TLC) x 100
Expresses the percentage of the total lung capacity occupied by residual volume. no more than 20-30%
Tidal Volume (Vt)
Volume of gas inspired or expired with each breath at rest or during any stated activity
Minute Ventilation (Ve)
volume of gas either inspired or expired per minute at rest or during any state activity
Tidal volume x number of breaths per min
Maximal breathing capacity (MBC)
Usually estimated from a 12 second period of hyperventilation at rest and is expressed as a volume per minute by x 12 sec value by 5
Forced expiratory Volume in One second
Volume of air expired during the first 1.0 second of a forced vital capacity maneuver
equipment
Respirometer
