Blood Gas transport Flashcards
In the pulmonary capillary the blood PO2 rises close to that in the alveolar air by the time the blood has moved ________ the distance through the capillary
one-third
a person may require _____x the normal amount of oxygen during exercise
20x
The diffusing capacity of oxygen increases ____x during exercise. How?
3x
- there is increased surface area of capillaries participating in diffusion
- There is a more nearly ideal V/Q ratio in the upper parts of the lungs
factors that determine tissue PO2
- Rate of oxygen transport to the tissues
- Rate of oxygen consumption by the tissues
Normal intracellular PO2: range, Mean, and required for normal cellular respiration
Nl Range: 5-40 mmHg
Mean– 23 mmHg
1-3 mm Hg PO2 is required for normal cellular respiration
As oxygen consumption increases the interstitial fluid PO2
decreases
As blood flow increases interstitial PO2
increases
Normal intracellular PCO2
46 mmHg (compared to interstitial of 45 mmHg)
What is the normal PCO2 for arterial blood entering tissues
40 mmHg
What is the normal venous blood PCO2 leaving the tissues
45mmHg
pulmonary capillaries PO2 is ____ than that of Systemic arterial blood. why
higher, because of shunted blood in systemic arterial blood
Factors that determine tissue PO2
- Rate of oxygen transport to the tissues
- Rate of oxygen consumption by the tissues
a decreases in blood flow from normal _____ peripheral tissue CO2
increases
A ___x increase in blood flow from normal decreases peripheral tissue CO2 to almost equal that in arterial blood
6x
Venous blood has an O2 saturation of ___% meaning that oxygen is bound to _____ of the heme groups
75%, 3/4
What is the oxygen saturation of arterial blood
97%
1 gram of hemoglobin can bind ____mL of O2
1.34mL
1 dl of blood carries ____mL of O2
20.1mL
There are ____ grams of Hb/dl blood
15
What is the utilization coefficient? what is the value at rest and during strenuous exercise
- percentage of blood that gives up its oxygen
rest: 5/19.4 = 25%
strenous exercise= 75-80%
_____ ml O2/dl transported to tissues
5
explain hemoglobin as a “Tissue oxygen buffer” system
- In order to release 5 mL of oxygen/dl of blood PO2 must fall to about 40 mmHg and Tissue PO2 cannot rise above this level
- When PO2 is high (pulmonary capillaries), oxygen binds with hemoglobin
- When PO2 is low (tissue capillaries) oxygen is released form hemoglobin
when PO2 is 40 mm Hg then O2 saturation is
75%
things that shift the oxygen-hemoglobin curve to right
- Decrease in pH
- Increase in hydrogen ions
- Increased CO2
- Increased Temperature
- Increased BPG
what is the Bohr effect
- Increase in blood (CO2) and H+ ions
- shifts oxygen-hemoglobin curve to the right
- enhances release of oxygen form the blood tissues
- enhances oxygenation of blood in lungs
- Decrease in blood (CO2) and H+ ions
- Shifts oxygen-hemoglobin curve to left
- Occurs in lungs
When cellular pO2 is more than 1 mmHg,______ becomes the limiting factor on oxygen usage rate by cells
ADP
about 70% of CO2 in blood is transported as ______
carbonic acid
The thin descending loop of Henle is highly permeable to which of the following
a. ) sodium b. ) water c. ) Urea d. ) Amino Acids
B.) water
Aldosterone is an important regulator of sodium reabsorption and potassium secretion; one of its main target is ?
a. ) Podocytes b. ) principle cells c. ) Intercalated cells d. ) Cells of Macula densa
B.) Principle Cells
The macula densa is found in which of the following parts of the renal tubule?
a. ) Proximal convoluted tubule b. ) thin descending limb of Henle c. ) Thick ascending limb of Henle d. ) distal convoluted tubule
D.) Distal convoluted tubule
True or False: Acidosis occurs when the ratio of bicarbonate ion to carbon dioxide in the extracellular fluid decreases. When this change is due to a decrease in bicarbonate ion, it is called respiratory acidoses
False
The volume by which the lungs and thorax increase for each unit of pressure change in the transpulmonary pressure is referred to as
Compliance
during heavy exercise blood flow through the lungs increases 4 to 7 times that at res. this increase is due to which of the following?
A.) increase in the number of open capillaries up to three times normal
B.) Distention of capillaries and doubling in the flow rate
c.) Increase in pulmonary arterial pressure
d.) all the above
E. A and B only
D.) all the above
According to the oxyen-hemoglobin dissociation curve, an increase in blood partial oxygen presuse will have what effects
An increase in bound oxygen
The Va/Q ratio is zero under which of the following conditions?
A.) Va= infinity, but Q=1 B.) Va= infinity, but Q=o C.) Va=0, but perfusion is greater than 0
C.) Va=0, but perfusion is greater than 0
Reduction of blood flow to a portion of the lung has what effect?
Alveolar pCO2 is lowered, resulting in a constriction of the bronchi supplying that portion of the lung
one gram of hemoglobin can bind to how much oxygen?
1.34 mL oxygen
what is the amount of CO2 dissolved in blood at 45mmHg
2.7mL/dl
what is the amount of CO2 dissolved in blood at 40mmHg
2.4 mL/dl
The carbon dioxide that is not dissolved in blood or transported as carbonic acid is transported as
carbamino hemoglobin
What is the initial pressure difference that causes oxygen to diffuse into the pulmonary capillary
PO2 in alveolus (104) - PCO2 in venous blood (40) = 64 mmHg
What is the Haldane effect
binding of oxygen with hemoglobin displaces dioxide from blood:
- binding of oxygen causes hemoglobin to become a stronger acid
- More acidic hemoglobin has less of a tendency to bind with carbon dioxide
- increased acidity of hemoglobin causes it to release hydrogen ions
The ____ effect states that increase in blood carbon dioxide causes oxygen to be displaced form hemoglobin
Bohr
Normal pCO2 of 45 mmHg causes ______ volumes % of CO2 to combine with blood
52 volumes %
Normal pCO2 of 40mmHg causes ______ volumes % of CO2 to combine with blood
48 volumes %
Carbon Monoxide binds _____x stronger than oxygen to hemoglobin
250x
Why is blood bright red in carbon monoxide poisoning
oxygen content of blood is greatly reduced, but PO2 of blood may be normal
