Chapter 24 Flashcards
Dalton’s Law of Partial Pressures - R
Total pressure exerted by a mixture of gases is the sum of the pressures exerted by each gas
Henry’s Law
When a mixture of gases is in contact with a liquid, each gas will dissolve in the liquid in proportion to its partial pressure
what regulates the rate of loading and unloading of O2
Po2
Temperature
Blood pH
Pco2
factors that influence external respiration
Partial pressure gradients and gas solubilities
Ventilation-perfusion coupling
what type of process is external respiration?
a passive process
drop in Pco2 levels
hypocapnia
rise in Pco2 levels
hypercapnia
centers that control the depth and rate of breathing
Pontine Respiratory Center
Medullary Respiratory Center
Apnea
a complete stop in breathing
3 ways that CO2 is transported in the blood
dissolved in plasma
bound to hemoglobin
as bicarbonate ions
the weakening of the Hb-oxygen bond caused by a decline in pH - R
Bohr effect
how much more soluble if CO2 in water compared to O2?
20x
respiratory and hematopoietic adjustments to altitude
Acclimatization
above what altitude does acute mountain sickness occur?
8000 feet
symptoms of altitude sickness
Headaches, shortness of breath, nausea, and dizziness
function of the Hering-Breuer Reflex
to prevent over inflation of the lungs
how does the Hering-Breuer Reflex work?
Stretch receptors in the pleurae and airways are stimulated by lung inflation
Inhibitory signals to the medullary respiratory centers end inhalation and allow expiration to occur
effect of a decrease in pH on ventilation
increased pulmonary ventilation
effect of an increase in pH on ventilation
decreased pulmonary ventilation
Haldane effect
The amount of CO2 transported is affected by the Po2
what is the direction of the diffusion of gases at capillaries in the tissues?
oxygen out of blood
CO2 into blood
dominant method of CO2 transport
dissolved in plasma as bicarbonate ions
Forces that maintain the negative pressure in Pip
- elasticity of the lungs
- surface tension in alveoli
- chest wall pulling action
what level of pH will will make oxygenated hemoglobin release oxygen more readily?
decreased
what will holding breath for 60 sec do?
increase alveolar pCO2
where is partial pressure of CO2 higher than oxygen?
blood leaving right ventricle
chloride ions moving into or out of the red blood cell
chloride shift
the most important stimulus for breathing
body’s need to rid itself of CO2
when CO2 is accumulated in the blood the pH is…?
decreased
how is most oxygen transported?
by iron in Hb
what does alveolar gas have a higher concentration of
CO2
bohr effect
low pH decreases the affinity of hemoglobin for oxygen
what PCO2 increased the affinity of hemoglobin for oxygen?
low PCO2
where is carbonic anhydrase loacted?
inside red blood cells
hypocapnia
drop in Pco2 levels
hypercapnia
rise in Pco2 levels
a complete stop in breathing
Apnea
how much oxygen is unloaded?
20-25%
