respiratory quiz Flashcards
Forced expiratory volume (FEV)
- a test which limits the time a subject has to expel vital capacity air.
- Normal 97% in 3 sec
- Reduced in restrictive pulmonary diseases.
Maximal voluntary ventilation (MVV)
- measures both volume and flow rates to assess overall pulmonary ventilation function
- pt inspires and expires and deeply and fast as possible while tidal volume and RR are measured
- look at average volume/respiratory cycle.
- tends to be reduced in both restrictive and obstructive diseases
spirometer
the instrument used to measure breath
spirogram
the record of volume change versus time of breath
tidal volume
- the volume of air inspired or expired during a single normal breath
- ~500mL at rest
Inspiratory reserve volume (IRV)
- the volume of air that can be maximally inhaled after tidal inspiration
- resting IRV is male: 3300mL
- Female: 1900mL
- IRV decreases with
- increased age
- decreased compliance
Expiratory reserve volume (ERV)
- the volume of air that can be maximally expired after tidal expiration
- males: 1000mL
- Females: 700mL
- ERV decreases with
- increased age
- decreased lung elasticity
Residual volume (RV)
- the volume of gas remaining in the lungs at the end of maximal expiration
- does not change with exercise
- Male: 1200ml
- Female: 1100ml
- Residual increases with
- increased age
Inspiratory capacity (IC) =
Tidal Volume (TV) + inspiratory reserve volume (IRV)
Expiratory capacity (EC) =
Tidal volume (TV) + expiratory reserve volume (ERV)
Functional residual capacity (FRC) =
expiratory reserve volume + residual volume
ERV + RV
Vital capacity (VC) =
- inspiratory reserve volume + Tidal volume + expiratory reserve volume
- IRV + TV + ERV
- Sum of the three primary lung volumes
- Vital capacity decreases with
- age
- restrictive disorders
Total lung capacity (TLC) =
inspiratory reserve volume + tidal volume + expiratory reserve volume + residual volume
IRV + TV + ERV + RV
Influencing factors on the rate of diffusion
- partial pressure - directly
- surface area - directly
- thickness of the membrane - indiretly
- solubility of gas - direclty
- CO2 is 20x more soluble than O2
Alveolar ventilation of the lungs
Ideal ratio vs. Real ratio
Why?
- Ideal is 1:1
- Real is 0.8-0.9:1
- Regional airflow assumes all parts of the lungs are equally ventilated and perfused.
- Reality is the base has greater alvealar ventilation due to a number of factors
Influencing Factors for ventilation-perfusion ratios: air flow to the base
- Larger transpulmonary pressure across the lung base
- Increased airway resistance in the upper passages
- Alveolar O2 and CO2 levels
- High CO2 cause decreased blood flow (high levels cause vasoconstriction and low blood flow)
- High O2 cause the greates blood flow (high levels cause vasodilation and increased blood flow)
- Gravity
- Upright position keeps a larger percentage of blood in the lung base
Boyle’s Law
PV = K
Dalton’s law
Pressure = P1 + P2 + P3 + etc
Muscles of inspiration
external intercostals, diaphragm
Muscles of expiration
- Normal expiration = relaxation of inspiratory muscles
- Forced expiration = internal intercostals and rectus abdominus
Compliance is
- CL = V/P
- the measurement of lung distensibility or the ease of stretching
- NOTE: compliance refers ONLY to INSPIRATION!
Compliance curve shows
- the ease of inflatability against averages
- steep slope = easily inflatable
- flat slope = difficult to inflate
Calculation for the transpulmonary pressure
P(Transpulmonary) = P(alveolar) - P(interplural)
Calculation for pulmonary ventilation
Pulmonary ventilation = TV x RR
Calculation for alveolar ventilation
Alveolar ventilation = (TV - ADS) x RR
Gas exhange is _______ during inspiration and expiration
constant
It takes _____ to replace all the air in the alveolus
90 seconds
Calculating O2 carrying capacity
Carrying capacity = gm Hb/dl x 1.34 ml O2/gm Hb
ex: Carrying capacity = 15 g/dl x 1.34 ml O2/gm Hb
= 20.1 ml O2/dl
or 20 vol%
The body requires what rate of blood flow for delivery of sufficient oxygen?
5 Liters
The most powerful chemical influence on the regulation of alveolar ventilation is
PCO2 in the systemic arterial blood
The greates partial pressure of carbon dioxide is in the
intracellular fluid
According to the dissociation curve, oxyhemoglobin saturation is effected PCO2, pH, H+, and Temp in the following manner.
- PCO2 : directly
- pH :indirectly (increase = decrease O2)
- H+: directly
- Temp: directly
The Hering-Breuer reflex…
prevents overstretch by inhibiting further inspiration
The Bohr Effect states
as H+ is loaded onto Hb, O2 is bumped off
The Haldane effect states
An increase in CO2 production causes the Hb to accept more CO2
thus limiting the amount of free CO2 in blood circulation
The distribution of CO2 in circulation is
- 10% Dissolved in blood
- 20% in Carbaminohemoglobin
- 70% in Bicarbonate
The distribution of O2 in the blood
- 1.5% dissolved in the blood
- 98.5% bound in oxyhemoglobin
