Respiratory Physiology 2 Flashcards
The total pressure exerted by a picture of gases is the sum of the pressure of each gas with constant temp and volume (PT = P1 + P2)
Dalton’s law of partial pressures
Exchange of gases in the lungs: takes place between alveolar air and blood flowing through lung capillaries
Pulmonary gas exchange
When is inspired air considered to be part of our internal environment?
When it crosses the respiratory membrane
(Pulmonary airways are an extension of the external environment)
PO2
Partial pressure of oxygen
How does oxygen enter the blood?
From alveolar air because the PO2 in alveoli is greater than the PO2 in the blood and the oxygen diffuses to the lower pressure in the blood
PCO2
Partial pressure of Carbon Dioxide
When does the PCO2 move out of the blood and into the alveoli?
Blood returns from the body with a higher concentration of PCO2 than the PCO2 in the alveoli, therefore the level is higher in the blood than the alveoli and the PCO2 transfers out of the blood into the alveoli
What are the 4 factors that determine the amount of oxygen that diffuses into the blood from the alveoli?
-oxygen pressure gradient
-total functional surface area
-respiratory rate per minute X volume
-alveolar ventilation
T/F
According to the oxygen pressure gradient of pulmonary gas exchange, if blood had a really low level of PO2 it would create a larger difference and more O2 would diffuse
True
T/F
Greater surface area means more room for diffusion
True
T/F
Faster deeper breaths increase O2 diffusion
True
The volume of inspired air that actually reaches the alveoli because some air stays in the upper airway
Alveolar ventilation
How can a large volume of gases be transported in the blood?
Immediately upon entering the blood these gases dissolve in the plasma of the blood or combine with other molecules. Now that these gases have dissolved or combined with other molecules the gas concentration in the blood decreases and allows for more gases to enter into the blood
Hb
Hemoglobin
-A reddish protein pigment found only in red blood cells
-composed of 4 polypeptide chains, each with an iron containing heme group
Hemoglobin
What part of the hemoglobin does O2 combine with?
The iron (Fe) group
What part of the hemoglobin does the CO2 combine with?
Can bind to amino acids in the polypeptide chains