Chapter 13 Flashcards
what are 2 factors the body’s supply of oxygen depends on? *
- concentration of gases in ambient air
2. partial pressure of gases in ambient air
what are the concentration of gases in ambient air at sea level? *
- 93% O2
- 04% N2
- 03% CO2
what is a torr?
pressure of air molecules that raises a column of mercury in a barometer to a height of 760 mm
what is partial pressure?
molecules of each specific gas in a mixture of gases exert their own partial pressure
how do you calculate partial pressure?
partial pressure = percentage concentration of a specific gas / total pressure of gas mixture
what does PAO2 stand for? *
partial pressure of O2 in alveolar chambers
what does PaO2 stand for? *
partial pressure of O2 in arterial blood
what does SaO2% stand for? *
percent saturation of O2 arterial blood with O2
what does PvCO2 stand for? *
partial pressure of CO2 in venous blood
what does a-VO2 diff stand for? *
arterial-mixed venous oxygen differences
what is henry’s law?
mass of a gas that dissolves in a fluid at a given temperature varies in direct proportion to pressure of gas over the liquid
what are 2 factors that govern the rate of gas diffusion into a fluid? *
- pressure differential between gas above the fluid and gas dissolved in fluid
- solubility of gas in the fluid
what does it mean to have a higher total barometric pressure?
more ease of gas moving from high to low
how fast does alveolar gas-blood gas equilibrium occur?
0.25 seconds
what are 2 factors that impair gas transfer capacity at the alveolar-capillary membrane?
- buildup of a pollutant layer that “thickens” the alveolar membrane
- reduction in alveolar surface area
what is the PO2 and PCO2 in active muscles during vigorous exercise?
PO2 falls toward 0 mmHg, making the pressure gradient very large so that O2 is driven into muscles
PCO2 approaches 90 mmHg
why does alveolar ventilation couple tightly to metabolic demand?
to maintain a constant alveolar gas composition constant
what are 2 ways that blood transports oxygen?
- physical solution dissolved in the fluid portion of blood (plasma)
- loose combination with hemoglobin
what are 3 functions of O2 transported in physical solution?
- establishes PO2 of plasma and tissue fluids
- helps regulate breathing, particularly at altitude
- determines O2 loading of hemoglobin in lungs and subsequent release in tissues
what is hemoglobin?
iron-containing globular protein pigment
composed of 4 subunit polypeptide chains
why do men have high Hb concentration levels?
relates to stimulating effects on red blood cell production of testosterone
how many mL of O2 is in 1 gram of Hb?
1.34 mL
what is the gold standard for examining O2 capacity?
Hb mass testing
what is microcytic anemia? *
normal RBC levels but they are smaller cells
what are the effects of iron deficiency anemia on athletes?
significant decrease in iron availability to decrease hemoglobin concentration
reduces the blood O2 carrying capacity
diminishes a person’s ability to sustain mild-intensity aerobic exercise
what is cooperative binding?
the joining of O2 with Hb
what is the relationship between pressure and Hb saturation with O2?
as pressure increases, saturation of Hb with O2 increases
what is the relationship between temperature and Hb saturation with O2?
as temperature increases, saturation of Hb with O2 decreases
what is the optimal temperature for aerobic performance and why?
8-10 degrees
if the blood is cold, hemoglobin can’t leave which hinders performance
what is the relationship between acidity and Hb saturation with O2?
as acidity in blood increases, saturation of Hb with O2 decreases
what is the bohr effect? *
states that any increase in plasma acidity and temperature causes the oxyhemoglobin dissociation curve to shift downward and to the right
indicates that [H+] and CO2 alter hemoglobin’s molecular structure to decrease its O2 binding affinity
what is a-vO2 difference?
the difference between oxygen content of arterial blood and mixed-venous blood
where do red blood cells get its energy?
anaerobic glycolysis, because it has no mitochondria, which produces the compound 2,3-diphosphoglycerate (2,3-DPG)
what happens when 2,3-DPG and Hb bind?
reduces Hb affinity for O2 causing greater O2 release to tissues
what are 3 ways blood carries CO2? *
- physical solution in plasma (7%)
- combined with hemoglobin (carbamino hemoglobin) within red blood cells (23%)
- as plasma bicarbonate (70%)
