Carbonic Equation and Acid/Base balance

[emt217]

Any good reviews, animations, etc. For some reason, I just can't seem to get this in my head.

I'm pretty sure of 2 things:

1) excessive CO2 retention is respiratory acidosis

2) excess release of CO2 is respiratory alkalosis

I've gone over it a million times, it just isnt sinking in. i don't wanna memorize it, i want to

LEARN it.

ANY help would be much much appreciated

[mobey]

Honestly I could type it all out and risk confusing you further.

I suggest going to o2demand.com

On the right hand side of the screen there is an icon for lecture video's. There is great lectures on gas tensions, V/Q, acid/base and more.

Good luck!

(BTW understand the Ph scale before you even try this stuff)

[chbare]

This is exactly why I advocate for a year of A&P as a prerequisite for paramedic student candidates. Good question to ask however.

Your basic theory is correct. However, I suspect you have confusion understanding how CO2 relates to acid/base balance. Obviously, acidosis is actually the concentration of hydrogen ions (H+), so the obvious question is how does CO2 equal H+ or acidosis?

To understand this, you first need to understand how the body transports CO2. The body transports CO2 in three ways.

1) CO2 dissolved in the plasma: Approx 6-10% of CO2 is transported as dissolved CO2 in plasma.

2) Attached to hemoglobin: Approx 20-30% of CO2 is transported attached to hemoglobin in the RBC.

3)As bicarbonate: Approx 60-70% of CO2 is transported as bicarbonate.

So, it is safe to say that most of the CO2 in our body is transported as bicarbonate (HCO3-). However, this still does not explain the CO2 to H+ relation.

Let's explain how this occurs. When CO2 combines with water H2O, the substance carbonic acid is formed (H2CO3). Carbonic acid; however, is very unstable and quickly splits into a hydrogen ion and bicarbonate ion. So the formula looks like this:

CO2 + H2O = H2CO3 ---> H+ & HCO3-

Of course, when this reaches the alveoli of the lung, this process is reversed, and CO2 is released via exhalation. I hope this helps explain these concepts.

Additional concepts to know include the role of carbonic anhydrase. While these reactions can occur in plasma, most of this actually occurs in the RBC. Carbonic anhydrase is present in the RBC and allows these reactions to occur much faster than within the plasma. Now, throw in the chloride shift, and you will be an expert.

Clear as mud?

Take care,

chbare.

[emt217]

This is exactly why I advocate for a year of A&P as a prerequisite for paramedic student candidates. Good question to ask however.

Your basic theory is correct. However, I suspect you have confusion understanding how CO2 relates to acid/base balance. Obviously, acidosis is actually the concentration of hydrogen ions (H+), so the obvious question is how does CO2 equal H+ or acidosis?

To understand this, you first need to understand how the body transports CO2. The body transports CO2 in three ways.

1) CO2 dissolved in the plasma: Approx 6-10% of CO2 is transported as dissolved CO2 in plasma.

2) Attached to hemoglobin: Approx 20-30% of CO2 is transported attached to hemoglobin in the RBC.

3)As bicarbonate: Approx 60-70% of CO2 is transported as bicarbonate.

So, it is safe to say that most of the CO2 in our body is transported as bicarbonate (HCO3-). However, this still does not explain the CO2 to H+ relation.

Let's explain how this occurs. When CO2 combines with water H2O, the substance carbonic acid is formed (H2CO3). Carbonic acid; however, is very unstable and quickly splits into a hydrogen ion and bicarbonate ion. So the formula looks like this:

CO2 + H2O = H2CO3 ---> H+ & HCO3-

Of course, when this reaches the alveoli of the lung, this process is reversed, and CO2 is released via exhalation. I hope this helps explain these concepts.

Additional concepts to know include the role of carbonic anhydrase. While these reactions can occur in plasma, most of this actually occurs in the RBC. Carbonic anhydrase is present in the RBC and allows these reactions to occur much faster than within the plasma. Now, throw in the chloride shift, and you will be an expert.

Clear as mud?

Take care,

chbare.

Actually, this helps quite a lot! We are taking a full A&P course in parallel, and to be honest, I'm jumping

ahead a little. I just want this sooooo bad that i'm willing to put in as much time as it takes to understand

all the concepts. Our instructor went through the atomic and molecular levels rather quick. Most of the

other students just memorize and move on. Maybe I'm odd, but i want to understand what's

going on. I'm not a memory person. If I can see how it works, and comprehend the mechanics involved, it

sticks with me. Again, thanks CH, I appreciate it!

edited to add: I do have an understanding of the pH scale, and the hydrogen/hydroxide difference. The equations were getting me. Been around 18 yrs since i had algebra/calculus, so i'm a little rusty. Gonna do a quick math review.