Previously we focused on the bohr effect
And we said the bohr effect tells us that the concentration of carbon dioxide and h+ ions in the blood effects
hemoglobins affinity for Oxygen and what the bohr effect ultimately
does is it increases the amount of oxygen that can be absorbed by the
exercising tissue
And it also increases the amount of oxygen that can be absorbed by the blood from the alveoli of our lungs
now another equally important effect is known as the Haldane effect and the held in effect is really the
opposite the reverse of the bohr effect so remember the bohr effect talks about how the
concentration of Co2 and Hydrogen [effect] hemoglobins affinity for oxygen
but what the held in effect does is it takes the opposite perspective it talks about how the
Concentration of Oxygen inside the red blood cell inside our blood actually affects hemoglobins affinity for carbon
[dioxide] and
h+ ions
Now why is the held in effect actually important well as we'll see in just a moment the [howling] effect actually
promotes it
increases the mouth of Carbon dioxide
that can be released by the
exercising tissue to the blood and at the same time it also increases the number of Co2 molecules that can be absorbed by the
Alveoli of the lungs
from [the] blood plasma and to see
What the hell in effect is and how it achieves this let's begin by taking a look at the following diagram
So let's suppose
I'm moving my arm back and forth and as I move [my] arm back and forth the muscle tissue begins to contract and atp
Molecules aren't being produced by those muscle cells
So this is let's suppose that muscle cell and this is the nearby
Capillary that carries the red blood cells now as these cells are
Exercising they require a greater number of Oxygen molecules to produce the atP
And so inside the red blood cells the bohr effect takes place
The it causes hemoglobin to actually unload and release the oxygen which then travels into those
exercising cells
inside the cells in a process called aerobic cellular respiration
We produce the energy
ATp Molecules now these aTp Molecules are used for muscle contraction
[for] the actin contraction
but the Co2
Molecules a byproduct are produced and these cannot be used in any useful way and so the Co2
Molecules are expelled from the cell and they enter the plot of the blood plasma of the capillary the nearby
Capillary now because Carbon dioxide is nonpolar only a very small portion about 5%
Will actually remain dissolved in the blood plasma
The majority of it the rest of it will enter the cytoplasm of the red blood cell
Now once inside the red blood cell what we have to do is we have to convert the carbon dioxide a non-polar
molecule into a polar form namely [the]
Bicarbonate and that's because we want to be able to dissolve the carbon dioxide in the blood
so the majority of the carbon
[dioxide] in the red blood cell will follow this reaction pathway, so a special enzyme. We call carbonic anhydrase
will combine
Carbon dioxide and water to form the carbonic acid Molecule and then the
Carbonic acid being a good acid it will dissociate into h+ ions and the
bicarbonate ions, and this is where the howling effect takes place
so according to the held in effect if we decrease the
[concentration] of Oxygen in the red blood cells so the mouth of Oxygen decreases because it
travels into [the] tissue that exercising tissue and so as this basically
decreases that increases the affinity [of] hemoglobin for the h+ ions
now if we increase
hemoglobins affinity for HP ion's what that means is the
Hemoglobin will begin to bind the h+ ions and so the concentration [of] these free h+ ions
Will begin to decrease because they will begin to bind to the hemoglobin?
Now what will happen as we decrease?
this H+ concentration
Well by lycia clears principle if we decrease the product concentration that will shift the equilibrium
Toward the right side toward the product side and what that means is as
hemoglobin is binding h+ ions we're going to ultimately produce even more of the
Bicarbonate Ions
And it's these bicarbonate ions that are basically the polar form of these co2
Molecules, and so ultimately the [Halden] effect basically
Increases the number of Bicarbonate ions that we can store and dissolve in the blood plasma
Next to the exercising tissue, so once again
the held in effect the fact that as we decrease the
Concentration of Oxygen inside the red blood plot red blood cell as it leaves it enters our tissue cell
that increases hemoglobins affinity to bind h+ ion
So this is what the housing effect tells us and what the hell in effect. Does is it basically?
shifts the equilibrium
To the right side towards the bicarbonate side and that increases the [number] [of] Co2
Molecules in this form that we can store in dissolve in the blood plasma of the nearby
Capillary now we can also represent this effect graphically
So let's take a look at a following graph the y-Axis is basically the Co2
Content in the blood dissolved in the blood and the x-Axis [is] the partial pressure of the carbon dioxide
In that region in the blood now this relatively straight line the black curve basically
Describes how much carbon the young side we can fit we can dissolve
inside the blood at some given partial pressure of Carbon Dioxide
and notice as we
Decrease the
concentration of Oxygen
inside the red blood cell the hell in effect basically
causes A
Leftward shift in this curve, and so the curve moves into the blue position now. Why is that?
Well, let's suppose that this is [the] partial pressure of Carbon Dioxide
inside the exercising tissue
And so we draw a [straight] line going
Upward now in this [particular] case this line basically did not take into consideration
the held in effect and according to this line
We can only fit this amount of co2 inside our blood
But if we do take the [housing] effect into consideration because we do decrease the oxygen content in our blood
Next to the exercising tissue that shifts the curve this way to the left and so the new y coordinate is
This value here [and] notice that what that means is as the oxygen decreases
We can actually store even more carbon dioxide
Inside our blood
Because of what we discussed just a moment ago
So we see that a drop in the oxygen in the red blood cells next to the exercising tissue actually
causes a leftward shift in the curve which means more carbon dioxide
Can ultimately be stored inside the blood and so the tissues will release?
More of [the] carbon [dioxide] because we can fit more of it into that blood plasma
Now we can also use the held in effect to basically describe how the alveoli of the lungs are able to absorb more
more Carbon dioxide
From the blood plasma so the car of the housing effect can also be used to explain how oxygen
concentration affects carbon dioxide unloading into the alveoli of along
so let's take a look at the following diagram so as always we have the red blood cell and this is the
alveolus of our lung
Now what's happening inside our lungs well inside our lungs the oxygen is moving down its
concentration gradient
From the alveolus and into the red blood cell now by the Haldane effect so again we have this
Haldane effect taking place
and
By this howling effect because we increase the concentration
Of oxygen inside our red blood cell we decrease
hemoglobins ability to bind Carbon dioxide and h+ ions
So as oh to binds to hemoglobin it basically decreases
Hemoglobins affinity for h+ in co2 so these two molecules are now released now as we release carbon
dioxide the Carbon dioxide
will begin to dissolve and eventually will leave the red blood cell and into the alveolus now the
Hemoglobin also releases the h+ ions which bind onto the hemoglobin in this area?
What happens to the h+ ions is they essentially?
recombine with the bicarbonate ions that came from the blood plasma
Remember these bicarbonate ions dissolve into the blood plasma at the same time we have the [C]
The Chloride ions going into the red blood cell that's known as the chloride shift and in here the opposite takes place
These basically move into the cell chloride ions leave the cell and this
Recombines with the h+ to reform the carbonic acid and then that basically breaks down into carbon dioxide
and the carbon dioxide
then leaves the cell and
It enters the alveolus and so we see that the held in effect basically promotes
the amount of Co2 that can be absorbed by the
alveolus
so the red blood cells [near] lungs filled with oxygen [the] rise in oxygen causes them to bind to
hemoglobin which in turn decreases
hemoglobins affinity for carbon dioxide and h+ ions and this stimulates
the unloading of Co2 and h+ ions
From the hemoglobin and eventually from the lungs and it enters the alveolus
And then we expel it in the process of exhalation now
We can also look at this graphically, but now we're going to see a rightward shift and not a leftward shift
So once again the y-Axis is the content of Co2 in the blood
the
X-Axis is the partial pressure of that co2 and now the partial pressure of Co2 will be smaller than in this case
So we're going to be farther to the left side along the curve because in the lungs we have a lower Co2
concentration than in the tissues and so now we're somewhere here now an
Increase in the oxygen content in our red blood cell next to the lungs
Means we have a rightward shift in our curve
So the black curve now shifts this way and what that means is before
this is how much Co2
Was actually stored in the blood but now this is how much Co2 can be stored in the blood so we have
less Co2
That can be stored and dissolved in the blood now if we can dissolve Co2 in the blood
where can the Co2 go well the only place it can actually go is into the
Alveoli of the lungs, and that's exactly what happens as it moves into the Alveoli
We have the pressure difference that expels that co2 to the outside environment
And this is what the haldane effect is the [Halden] affect promotes the release
of co2 from the tissues to [the] blood and also promotes the release of
Co2 from the blood and to the Alveoli of the lungs