PHGY 3 Flashcards
What is the primary function of the respiratory system?
external respiration
as branching airways get smaller surface area gets …
as branching airways get smaller surface area gets larger
what is the equation for flow
delta pressure / resistance = flow
What is the driving force of air flow?
pressure
- flows from high pressure to low pressure
Which respiratory pressure is negative?
Pleural pressure bc pushes against atmosphere
What units are used for respiration?
mmHg - for partial pressure of gases when discussing diffusion
cmH2O - when discussing bulk flow
What is the equation for alveolar pressure?
Lung recoil pressure (Pi) + Pleural Pressure (PPL) = Alveolar Pressure
Define: Compliance
Compliance: the ability of the lung to stretch so at functional residual capacity, it is easy to move air in or out of the lungs
- is the slope of a pressure-volume curve
Low compliance = more pressure is required to move air in or out
What is the name of the equation used to determined resistance?
Poiseuille’s Law
R^4 ontop so radius is biggest factor
What kind of NS activity promotes bonchocontriction
parasympathetic
What is the most important factor for determining % Hb
PO2
What relationship does the oxygen dissociation curve describe
- Oxygen dissociation curve = describes the relationship btwn PO2 and % Hb saturation
What is the significiance of the Plateau Portion of the O2-Hb Curve
○ Represents the PO2 range found in the pulmonary capillaries where the Hb is collecting O2
○ The low slope of this part of the curve also ensures that even of there was a drop in PO2 to 60, Hb would still be 90% saturated
What is the Significance of Steep Portion of the O2-Hb Curve
○ Corresponds to the range of PO2 that is found in the systemic capillaries
○ The steep portion of the curve allows for larger amounts of O2 dissociation for small decreases in PO2
What is the Haldane effect?
○ This is called the Haldane effect and leads to more oxygen unloading that a decrease in PO2 alone could accomplish
