Statics Flashcards
how to calculate the alveolar ventilation amount?
tidal volume-dead space volume…then times respiratory rate
what is the anatomical dead space volume usually equal to?
150 ml
what is the normal volume of inspiration?
500 ml
what is another dead space that can occur? how much of this do we see in normal people?
alveolar dead space…not receiving ventilation or perfusion…from like a PE
in normal person this is like nothing
do small bubbles usually empty into big bubbles or big bubbles empty into small? why?
small into big due to surface tension
what does pulmonary surfactant actually cause in terms of surface tension?
it causes the surface tension of the alveoli to drop and therefore not empty contents into larger space and essentially collapse
what is the molecule in surfactant that really causes the lowering of the ST?
phosphatyidlycholine
what are the roles of SP-B and SP-C?
they are hydrophobic proteins that add phosphatidylcholine to the alveolar surface
when alveoli collapse, what happens to the pressure required to open the lungs?
the collapsed alveoli require higher pressures to open them
will an obstructive lung disease fall above or below the normal line on a pressure/volume compliance curve?
above…because the lung is much more compliant but less elastance
will a restrictive lung disease like fibrosis fall above or below the normal line on a pressure/volume compliance curve?
below…because the lung is not very compliant and has very high elastance
what is the total compliance of the chest equal to?
lung compliance plus chest wall compliance
name two common changes of chest wall compliance and what effect on compliance do these have?
obesity and MSK disorders affecting rib cage mobility
