Oxygen Transport: Lecture 1 Flashcards
When in the 4 steps of external respiration is O2 and CO2 being transported?
- Step 3: blood transport
What are the 2 methods of gas transport in the blood for OXYGEN?
- Physically dissolved
- Bound to hemoglobin
What are the 3 methods of gas transport in the blood for Carbon Dioxide?
- Physically dissolved
- Bound to hemoglobin
- As bicarbonate (HCO3)
What is blood doping?
inject “hemoglobin” to have more O2 transport capabilities
What is the percent that oxygen can be carried by physically dissolved?
1.5
What is the percent that oxygen can bound to hemoglobin?
98.5
What is the percent that carbon dioxide can be carried by physically dissolved?
5-10
What is the percent that carbon dioxide can be bound to hemoglobin?
5-10
What is the percent that carbon dioxide can be carried by bicarbonate?
80-90
What is oxyhemogloin?
this is when haemoglobin combines with oxygen
True or False
A small percentage of oxygen is dissolved in the plasma
True
When the partial pressure of oxygen is high, what is happening to oxygen?
oxygen will bind to hemoglobin
When the partial pressure of oxygen is low, what is happening to oxygen?
Oxygen will “unbind” from hemoglobin
At the lung levels is there a tendency for oxygen and hemoglobin to combine?
yes
At the tissue levels is there a tendency for oxygen and hemoglobin to dissociate?
yes
What is the average amount of oxygen we need in the blood per minute for basal function?
250ml O2/min
1 single hemoglobin is composed of what?
- 4 heme groups/molecule
- 4 globin subunits/molecules
- 4 O2 molecules
How many O2 molecules can bind one hemoglobin molecue?
4, one per heme group
where is hemoglobin found?
in the red blood cells
Does Oxyhemoglobin have any pressure?
NAURR
For 1 gram of hemoglobin how many ml of O2 can it bind?
1.34 ml/g of O2
What is the general concentration of hemoglobin in the blood?
15g/100ml of blood
What 2 factors determines O2 carrying capacity?
- Total amount of Hb
- PO2 (alveolar and arterial)
if you have emphysema, or any obstructive lung disorder than your PO2 in the arterial blood is going to be a little bit lower, because of what?
because less oxygen is getting across in the first place
What is the relationship that is being measured on an oxygen hemoglobin dissociation curve?
PO2 of the arterial blood and the % of Hb saturation
At the sight of gas exchange what is the arterial PO2 of the blood? (at the lungs)
100 mmhg
At the sight right after gas exchange at the tissues what is the arterial PO2 of the blood? (veinous circulation)
40 mmhg
True or False
The percent of oxyHb is high where the partial pressure of oxygen is high? (lungs)
True
True or False
The percent of oxyHb is low where the partial pressure of oxygen is low? (tissue)
True
What is a scenario where oxygen does not have enough time to bind to Hb?
- really heavy exercise
- diffusion limitation
What is the Bohr effect?
when the oxygen hemoglobin dissociation curve is shifter to the right, aka favouring dissociation
What are the causes of the Bohr effect?
- Higher temperature
- BPG 2-3
True or False
The partial pressure of oxygen is the main facto determining the percentage of Hb saturation
True
On the oxygen hemoglobin dissociation curve what does the plateau/flat part represent?
- lungs
- where PO2 is high
On the oxygen hemoglobin dissociation curve what does the steep part represent?
- tissue
- where PO2 is low
When does the affinity of O2 to Hb drop?
approx 60 mmhg
True or False
Hb is responsible for 98% of O2 transport from the lungs to the tissue
True
Can we have a slightly lower PO2 and be fully oxygenated from an O2- Hb saturation point of view?
Yes, the buffer period greater than 60
Why would breathing too much oxygen be hurtful?
- having chronic high levels of oxygen can lead to oxidative stress in the blood vessels
True or False
If we are already normally saturated with 98,99% saturation, breathing supplemental pure oxygen is not going to increase your oxygen saturation
True, because oxygen will follow concentration gradients but we cannot double the amount of Hb saturation
As we go higher in altitude what is happening to our oxygen saturation? is it getting higher or lower?
Lower, the percent oxygen saturation falls
At what altitude can we be almost fully saturated? (highest altitude to be fully saturated)
approx 20,000
if we go from 22,000-25,000, what would happen to our oxygen saturation?
almost cut in half
Somebody with anemia will have less of what?
Hb
Will the O2 dissociation curve for individuals with anemia look the same compared to a healthy individual?
yes, because their Hb will be fully saturated they just happened to have less Hb
Will the amount of O2 in the blood be the same, lower or higher for an individual with anemia compared to a healthy individual?
lower, because there is less Hb available
What are 3 physiological factors that can change the O2 dissociation curve?
- High arterial PCO2
- High acidity/decrease in pH in the blood
- Increased temperatures
When would we see a rightward shift in the dissociation curve?
during exercise, all of the physiological factors would be occurring
The Bohr effect is when we have what?
- increased PCO2
- increased acidity
- Increased temperatures
True or False
The Bohr effect promotes the unloading of oxygen
True
