Acids, Bases and Buffers

00:01 The types of acids that you could get. So, these are where, what type of acid it might be.

00:08 First you have Volatile acids.

00:11 Volatile acids are primarily carbon dioxide.

00:14 So, you don’t always think of carbon dioxide as an acid but it really is.

00:19 It fits in to the carbonic and hydrase equation and if you have CO2 plus water, forms carbonic acid and then, will this associate into hydrogen ion and a bicarb. That process is acidic.

00:38 So, carbon dioxide in this case is acting like an acid.

00:43 Non- volatile acids, these are stabler but these are harder for the body to deal with.

00:49 A volatile acid is easy for the body to deal with. You just blow off CO2.

00:55 But a Non- volatile acid has to be not only taking care of but usually at the level of the kidney.

01:02 We have things like sulfuric acid, phosphoric acid and you even have some organic acids associated with different types of amino acids.

01:13 You have a very small amounts of bases that are added to the system.

01:17 This is mainly from your gastrointestinal tract.

01:21 You do have buffers. Buffers are going to be very important.

01:27 You can hold on to a hydrogen ion or release it as a buffer.

01:32 So it really acts to stabilize the pH in a narrower range.

01:38 Our big buffers that we use in the body; the first one is bicarbonate.

01:43 And bicarbonates going to be circulating around the blood, it’s going to bind majority of the hydrogen ions.

01:50 but we also do have some non- bicarb base buffers.

01:53 Things like phosphates, things like proteins these can also buffer hydrogen ions.

02:00 Probably, not as important as bicarb but it’s part of the overall buffering process.

02:07 And so, we need to discuss them.

02:09 Some cells we utilize by certain buffering techniques or types more than others.

02:18 So, let’s just go through a couple example pH changes.

02:22 This way we can get a better insight into how the pH will change when you add an acid or add a base.

02:31 So, let’s first add an acid.

02:33 So let’s say we add a certain amount of an acid to a beaker.

02:37 Then we wait until that particular beaker equilibrates.

02:43 In this case, you’ll see that there are more hydrogen ions around which will decrease the pH.

02:50 In our example here of the acid that was added, we lowered pH by 0,03.

02:57 It doesn’t seem like a big pH change, right? 0,03 it’s not even 1 right? But think arterial blood needs to have a pH at 7,4 plus or minus (±) 0,05.

03:13 So a 0,3 change could take it out of homeostatic normal.

03:20 If we add now a base, rather than an acid, we put it in to our beaker, we sit in let it equilibrate and we have an end solution.

03:31 We take the pH of that and we maybe give a ph change of an increase of 3.

03:38 Again, it doesn’t seem like a much to have a 0,3 increase.

03:42 But again, that can take you out of your homeostatic normal.

03:46 And therefore, you would be in an alkalimic condition.

03:52 So, whether you add an acid or add a base, you have to think about how that is going to change your pH.

04:01 What acids could we add? Well, you could add a volatile one like CO2.

04:07 You can add a non- volatile one like something like a sulfuric acid or from uric acid.

04:13 But if you want to do something like add a base, therefore it’s probably coming from the GI tract but it’s gonna be something with an OH kind of group attached to it.