physiology- resp ventilation & gas exchange Flashcards
Pulmonary Minute Ventilation
total volume of air entering and leaving respiratory system per min
Alveolar Ventilation
volume of air exchanged between the atmosphere and alveoli per min
Respiratory Diseases
• Two main classifications
- obstructive
- restrictive
obstructive
decreased air flow during expiration
airway narrowing
increased airway resistance
example asthma , chronic bronchitis
restrictive
reduced compliance , lung volume
scar tissue forming
fibrosis
example : pulmonary fiborsis
asthma what happens
it causes
symptoms
when bronchi are hyper sensitive to dust , pollutants ect
chronic inflammation which leads to excess production of mucous and airway narrowing
breathlessness , tightness in chest , coughing
asthma caused by
- alleregns
- smoking , airborne pollutants
- changes in air temp and pressure
- excersize
- anxiety , emotional distress
asthma treatment
bronchodilators , anti - inflammatory , 02
chronic bronchitis
what
symptoms
inflammation of airway walls
excessive mucous production
airway narrowing and coughing
chronic bronchitis : caused by
bacterial and viral infections
smoking
airborne pollutant
Pulmonary fibrosis
what happens when you have it
↓ elasticity
↓ compliance of lungs and chest wall
↑work of breathing
pulmonary fibrosis
caused by
inflammation
scar tissue formation
NEW LECTURE : GAS EXCHANGE
……..
what is partial pressures of gases
the pressure exerted by a individual gas in a mixture
Partial pressure of a gas depends on:
fractional component of gas
total pressure of gas mixture
Composition of Air
79% nitrogen
21% oxygen
trace amounts of c02 , helium , argon
water % depends of humidity
Ficks law - rate of diffusion
Vgas= A/T x D⋅(ΔP)
Vgas= A/T x D⋅(ΔP)
D∝ S / square root of MW
Vgas= rate of diffusion A= surface area T=thickness D= diffusion constant ΔP=pressure difference
S= gas solubility 24:1 MW= molecular weight 44:32
surface area
increases during excersize… more pulmonary capillaries open and aveoli expands
50-100cm in lung
Equilibration rates
02 and c02 rates
at rest
during intense excersiz
- 02 and c02 equilibrate at similar rates
- blood spends 0.75 secs in a capillary
- 0.25 secs
Diffusion process affected by:
excersize
thickening of blood gas barrier
Pulmonary Oedema
what is it
what does it do
-fluid accumlation in alveoli and /or interstitial fluid
- impairs diffusion
- leakage in unprotected capillaries
- increased work of breathing (decrease in lung compliance)
- artierol blood : lower P02 , higher PC02
Pulmonary Oedema
caused by
treatment
increased capillary pressure and reduced atmospheric pressure
Administering oxygen and diuretics
