resp phys 2 Flashcards
what is atmospheric pressure
101 Kpa or 760 mmHg
what is the partial pressure of nitrogen
593
what is the partial pressure of oxygen
159
what is the partial pressure of CO2
0.29
what is Henry’s Law
when a mixture of gasses is in contact with a liquid each will dissolve in proportion with its partial pressure
but the absolute amount of gas dissolved depends on its solubility. only applies to dissolved gas
the total amount of gas is that dissolved plus that chemically bound
what is the water vapour pressure in alveoli
48 mmHg
what is the O2 pressure in alveoli
104 mmHg
how will oedema affect diffusion
increases wall thickness
what is 2-3 bisphosphoglycerate
produced in metabolism
decreases the affinity of haemoglobin for oxygen
also temperature H+ CO2
modifies the 3d structure of Hb
how do you calculate the amount of O2 carried in the blood
total = conc HB x capacity of Hb x percentage saturation +amount dissolved in the plasma
what % of CO2 is carried in the plasma
7-10
what % of CO2 is bound to Hb
10-20 %
what is the Haldane effect
deoxygenation of Hb increases it affinity for CO2 and vice versa in the lungs
what enzyme forms carbonic acid
carbonic anhydrase
what is the Henderson hasslebach eqn
calculates the ph of blood
ph = pk + log (bicarbonate / co2)
where does most gas go in a normal lung
base
because the base changes volume more than the apex - more compliance
partly due to gravity
what do the bronchial arteries supply
lung parenchyma, airways smooth muscles, pulmonary arteries and veins and pleura
also warms inspired air
what is transmural pressure
balance between alveolar pressure and blood pressure
what is the normal distribution of blood flow
apex- low
base- high
blood pressure must be greater than alveolar pressure in order for blood to flow
if capillaries are closed then dead space
what happens in zone 1
cappilaries are closed
what happens in zone 2
cappileries are open in systole but not in diastole
what happens in zone 3
alveolar pressure is lower than arterial and venous pressure
what is the V/q at the base
0.6
more perfusion than ventilation
what is the v/q in the middle
1
what is the v/q at the apex
3 (more ventilation than perfusion)
what is hypoxic vasoconstriction
blood is diverted away from poorly ventilated areas
when does sputum production tend to be worse with COPD
morning
what is wheeze a sign of
obstruction
what defines obstructive airway disease
fev1/fvc
what is pKa
the ph at which 50% is unionised
what do metabolic acid base disturbances affect
the amount of protons and bicarbonate
what do respiratory disturbances affect
amount of CO2
what cells are toll like receptors found on
dendritic cells
also express pattern recognition receptors
