Trachte: Gas Transport Flashcards
What are the two forms that oxygen can exist in in the blood?
Dissolved
Associated w/ Hb
How much Oxygen is dissolved in the blood at PO2 of 100 mmHg?
.3 ml/dl blood
What determines the amount of oxygen that is dissolved in the blood?
It is PROPORTIONAL to the partial pressure (.003 ml/mmHg/dL)
How much oxygen is dissolved at PO2 of 200 mmHg?
.6 ml
How much oxygen is dissolved at PO2 of 50 mmHg?
1/2 (.3)
How much oxygen is associated w/ Hb at PO2 of 100 mmHg?
20 ml/dL of blood
What is the relationship between oxygen and Hb association?
Sigmoidal so it is NOT direct
How much oxygen is associated with Hb at PO2 of 40 mmHg (venous blood)?
15 ml/dl (75% Hb saturation)
How much oxygen is associated with Hb at 200 mm HG? At pure oxygen 760 mmHg?
20 ml/dl
20 ml/dl
Can’t get more than 100% saturation!!
What is the maximal amount of oxygen that binds to Hb?
1.39 ml/g
What is the normal Hb level in the blood?
15 g/100 ml
What is the maximal oxygen binding to Hb?
20 ml/ 100 ml of blood
What is oxygen saturation?
Amount combined w/ Hb/maximal oxygen capacity of hemoglobin
What is normal oxygen saturation for arterial blood?
95%
What is normal oxygen saturation for venous blood?
75%
What affect does anemia have on hemoglobin?
It lowers Hb to 9 g/100 ml of blood so the O2 capacity will be redued to 13 ml O2/100 ml of blood instead of 15
Does anemia impact PO2? Why?
The amount of oxygen dissolved in plasma is NOT determined by Hb so NO
Does anemia impact O2 saturation?
NO–this just tells you whether the RBC are saturated or not (you can have fewer there and they can still all be saturated)
Does anemia impact O2 capacity?
YES!
With fewer RBC you can’t deliver as much O2
How does Hb appear when it is reduced and how does this cause cyanosis?
It’s purple
Hypoxia (low O2)–> reduced form–> causes cyanosis
What shifts the O2 dissociation curve to the right?
Less affinity for oxygen
What reduces the affinity of oxygen to Hb?
LOW pH
Increased CO2
Increased temprature
Increased 2,3 diphosphoglycerate
Does CO have a greater affinity for Hb than O2? What can this do?
YES–> this can tie up all the Hb
240x as much
How do you tx someone with CO poisoning?
Put them in a hyperbaric chamber and increase pressure by 3 atm up to 2200 mmHG to get enough O2 to dissolve in plasma.
How id CO2 transported in the blood?
Dissolved
Bicarbonate
Carbamino compounds
What percent of CO2 is transported dissolved in the blood?
10%
.067 x 40 = 2.67 ml CO2/dl
What is the predominate form of CO2 in the blood?
Bicarbonate
25 mep/L
What does CA do?
Catalyzes CO2 and water into H2CO3> H and HCO2
What happens to bicarb and H that are made in the RBC? What happens to Cl?
It diffuses OUT of the RBC
H stays IN
Cl is ATTRACTED INTO the RBC
Why is deoxygenated Hb a better carrier of CO2?
Acidification
Does oxygenated or deoxygenated Hb carry CO2 better?
Deoxygenated
What are carbamino compounds? This accounts for what percent of CO2 transport in the blood?
CO2 can bind to Hb
5%
How does the CO2 dissociation curve differ from the O2 dissociation curve?
Much more LINEAR and much STEEPER
Can the blood carry more CO2 or O2?
CO2
How does O2 saturation affect the CO2 dissociation curve?
Shifts it to the RIGHT
What controls bicarb levels?
Kidneys
What controls PCO2 levels?
Lungs
What is respiratory acidosis?
RETENTION of CO2
What are typical causes of respiratory acidosis?
Hypoventilation
Ventilation perfusion mismatch
What is respiratory alkalosis?
excessive EXHALATION of CO2
What causes respiratory alkalosis?
Exposure to high altitude
What is metabolic acidosis?
Decreased bicarb
What causes metabolic acidosis?
Acid in blood (diabetes mellitus)
What is metabolic alkalosis?
Increased concentration of bicarb
What causes metabolic alkalosis?
vomiting
How does O2 diffuse into the tissues?
From CAPILLARIES
What are diffusion distances in skeletal muscle?
100 u
What is the PO2 of muscle?
LOW 1-3 mmHg
What helps to keep the PO2 in muscle uniform?
myoglobin
What cause hypoxia/ decreased O2 delivery?
Low arterial PO2
Anemia
Tissue blood flow disruption (embolism, thrombus)
Poison
