Acid-base imbalances Flashcards
What is the linkage between hydrogen levels and pH?
When the H+ levels are high the pH will decrease
When the H+ levels are low the pH will increase
Alteration in pH below or above 7.35 - 7.45 can cause?
Acidosis - pH below 7.35
Alkalosis - pH above 7.45
What is a common end-product in catabolic processes of nutrients?
Carbonic acid
How is carbonic acid formed?
By reaction of CO2 + H20 —– carbonic anhydrase—-> carbonic acid, H2CO3
- The concentration of CO2 is regulated by the lungs
The H2CO3 can spontaneously dissociate into HCO3- and H+ ions
- The concentration of HCO3- is regulated by the kidneys
CO2 + H20 —– carbonic anhydrase—-> H2CO3 HCO3- + H+
Acid are generally classified into 2 types of acids, which?
Volatile acids
- Weak acids
- Can be eliminated as a gas; CO2
Non-volatile acids
- Strong acids
- Can NOT be eliminated as CO2
What is the principal gas of volatile acids?
Carbonic acid
What is typical for Non-volatile acids?
- Strong acids from metabolism of proteins, carbohydrates and fats
- Can react immediately with plasma buffers (bicarbonate) and form
- Sulfuric acid: Formed from sulphur containing acids as Methionine, Cystine, Cysteine
- Phosphoric acid: Produced from hydrolysis of phosphodiesters
What is typical for bases?
Binding to H+ ions and appear in blood as HCO3-
Formed during intake of feed
What are regulatory mechanisms for acid-base imbalances?
- IC/EC chemical buffers
- Lungs (Resp. adjustment of CO2 concentration)
- Kidneys ( Excretion of acids and regeneration of buffer systems)
Complete restoration of acid-base balance takes how long?
Few hours or even several weeks
How quickly does buffers and respiratory systems act and for prevention of what?
Act within minutes in order to prevent large deviation of H+ ions
What does the Henderson-Hasselbach equation tell?
That the pH of a solution containing buffer systems is termed by the ratio of BASES to ACIDS: HCO3 / H2CO3
What are the Principle buffer systems ?
- Bicarbonate buffers
- Plasma protein buffers
- Phosphate buffers
- Haemoglobin buffers
What are the Major buffer systems in body?
- Blood plasma
- RBC
- Interstitial fluid
- IC fluid
- Mineral matrix of bone
What is the Isohydric principle?
That each base of each buffer pair will bind to H+ ions
As a result, addition of acid or base to a solution containing several buffers will result in a change in the rations of all the buffer pairs
OR
The phenomenon whereby multiple acid/base pairs in solution will be in equilibrium with one another, tied together by their common reagent: the hydrogen ion and hence, the pH of solution. That is, when several buffers are present together in the same solution, they are all exposed to the same hydrogen ion activity.
Which buffer system is the most important in the body?
The bicarbonate buffer system
Which principal buffer system is the most important and contain which buffer pair?
- The bicarbonate buffer system
- Carbonic acid + Bicarbonate buffer pair makes up the system
The respiratory and renal systems also play major roles in acid-base homeostasis by removing CO2 and hydrogen ions, respectively, from the body
Describe the function / process of bicarbonate buffer system
Function both in LUNGS and KIDNEYS.
CO2 + H2O H2CO3
H2CO3 H+ + HCO3-
- The acid in this process = CO2 = carbonic anhydrate = not a true acid
- H2CO3 = carbonic acid = a weak acid that quickly ionizes to form H+ ions and HCO3-
- The carbonic anhydrase enzyme catalyses formation of carbonic acid from CO2 + H2O.
This acid then dissociates and the H+ ions is then mainly buffered by Hb by HCO3- and leaving the RBC to exchange for Cl- ions for entering the plasma.
Why is a part of the Bicarbonate buffering happening by Hb, protein and Phosphate instead?
Since the HCO3- (bicarbonate) itself is unable to buffer the formed H2CO3.
Therefore the rest of the buffering is happening within the RBC by Hb, protein and phosphate
What is a very good intracellular buffer system and why?
Haemoglobin buffer system
Due to its ability to bind to H+ ions and CO2
Which blood type is the best buffer ?
Unsaturated Hb (venous blood) is a better buffer than Hb saturated with O2 (arterial blood) due to the O2 effect on pK
Which buffer systems are good IC systems?
- Phosphate buffer system
- Protein buffer system
- Haemoglobin buffer system