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
How is oxygen and carbon dioxide transferred in the blood?
Hemoglobin
What do oxygen and hemoglobin create when combined?
Oxyhemoglobin
T/F
The amount of oxygen present in the blood depends on the amount of hemoglobin in the blood
True
T/F
As soon as oxyhemoglobin is produced, the blood is ready to take on more oxygen
True
What are the 2 forms that oxygen travels in?
-dissolved oxygen in plasma
-oxyhemoglobin (carries the majority of oxygen transported in the blood)
How many oxygen does one hemoglobin carry? Why?
4 hemoglobin
Because there are 4 heme groups within the one red blood cell
What acts as a “oxygen sponge”?
Hemoglobin molecule
Because the red blood cells contain hemoglobin molecules, how much oxygen can they carry?
20ml of dissolved O2 per 100ml of blood
Carbon dioxide + hemoglobin
Carbamiohemoglobin
Generates the basic rhythm of the respiratory cycle
Medullary rhythmicity center
What percent of CO2 dissolved in plasma and is transported as a solute?
10%
What percent of blood CO2 combines with NH2 (amine) groups of hemoglobin and other proteins to form carbaminohemoglobin?
20%
T/F
CO2 association with Hb is accelerated by an increase in blood PCO2 therefore more CO2 in blood means more carbaminohemoglobin
True
What happens when carbon dioxide adds with hemoglobin?
-Carbaminhemoglobin is formed
-this allows for more carbon dioxide to enter the
What percent of CO2 is carried in plasma as bicarbonate ions?
70%
T/F
Venous blood has more CO2
True
HbCO2
Carbaminohemoglobin
HCO3
Bicarbonate
Why does pulmonary gas exchange occur?
Blood returns from the body with a higher concentration of CO2 than the CO2 in the alveoli (CO2 is higher in blood than alveoli) and the CO2 move out of the blood and into the alveoli
Exchange of gases in tissues takes place between arterial blood flowing through tissue capillaries and cells
Systemic gas exchange
Oxyhemoglobin transfers back to hemoglobin and oxygen, so the oxygen can go to the cells
Oxyhemoglobin dissociation
T/F
CO2 exchange takes place in the opposite direction from oxygen exchange in systemic gas exchange
True
Why do cells have a high amount of CO2 inside them?
Due to cells activities (catabolism)
Since there is a decrease in O2 and an increase in CO2 in the capillaries traveling from the cells, what two reactions appear?
- O2 dissociation because we need more O2 in the cells -> HbO2 = Hb + O2
- CO2 association with Hb to form carbaminohemoglobin because we have too much CO2 in the red blood cells
Blood carried away from the heart
Arterial
Blood carried to the heart
Venous
