Respiratory system 5 Flashcards
What is the equation for respiratory minute volume
Ve = VT x f
Respiratory minute volume = tidal volume x respiratory rate
What is dead space (VD)
The inhaled air that never gets to the alveoli (about 150ml)
What is alveolar ventilation (VA)
The amount of air that gets into the alveoli
What is the formula for Alveolar ventilation (VA)
VA = (VT - VD) x f
Alveolar ventilation = (Tidal volume - dead space) x respiratory rate
What can VT and f be summised by
VT - breathing strength
f - breathing speed
What does Dalton’s law say
Each individual gas exerts its own pressure - partial pressure
What is the aim of gas exchange
Move gas back and forth between alveoli and capillaries - Oxygen into capillaries - Carbon dioxide into alveoli to be exhaled
What does Fick’s law of diffusion say
Gases move across the membrane through diffusion
What determines the rate of diffusion
Surface area
Thickness
Pressure difference
What is the equation for Fick’s law
F = A/T x D x (P1 - P2) F = flux (amount flowing) D = diffusion constant
Describe the diffusion constant (D)
Depends on gas solubility and molecular weight - On a per-molecule basis
What is emphysema
Disease of dilation of alveolar spaces and destruction of walls - greatly reduces oxygen exchange
What is pulmonary fibrosis
Thickening and scarring of alveolar membranes - chronic inflammation or exposure to industrial chemicals
What does the partial pressure of O2 depend on (PAO2)
Partial Pressure of oxygen
Alveolar ventilation
Oxygen consumption (blood oxygen)
What does partial pressure of CO2 depend on (PACO2)
Partial pressure of CO2
Alveolar ventilation
Carbon dioxide production
