Acid-base (physiology) Flashcards
What is pH?
The negative log of hydrogen ion concentration.
pH of the human body
7.35-7.45
Why is pH important? (3)
It is NB bcs it affects:
- Oxygen delivery to tissues.
- Protein structure
- Enzymatic reactions
What is an acid according to arrhenius theory? (2)
-It is a compound that increases the concentration of hydrogen ions when added to water.
-These hydrogen ions form hydronium ions when they combine with the water molecule.
What is a base according to arrhenius theory?
-It is a compound that increases the concentration of hydroxide ions when added to water.
What is the problem with the arrhenius theory?
Does not explain how Flouride ion(F-) and nitrite(NO2-) can make basic solutions when they do not have hydroxide ions.
What is a base and an acid according to bronsted-lowry theory?
An acid is a proton donor, a base is a proton acceptor.
What is the diff btwn strong acids and weak acids?
Strong acids completely dissociate while weak acids incompletely dissociate.
What is a buffer?
It is a solution that can resist pH changes upon addition of an acidic or basic component.
What condition has to be met in order for a buffer to perform its function?
The buffer must consist of a weak conjugate acid-base pair.
How does the buffer resist pH changes?
The weak acids/bases partially dissociate in solution to neutralise excess hydrogen or hydroxide ions.
Do acidic foods cause a change in pH?
No they don’t
Explain the three mechanisms in which the pH in bodyfluids is regulated.
•The chemical acid-base buffer of the body fluids.
•The respiratory center, which regulates the removal of CO2.
•The kidneys, which can either excrete an acidic or basic urine.
Explain the three lines of defence when hydrogen concentration changes. (3)
- The buffer system tries to resist this change, note that it does not add nor remove hydrogen ions from the body.
- The respiratory center regulates the capacity of blood buffer system by removing CO2.
- The kidneys can eliminate the excess acid or base from the body.
Two ingredients of the bicarbonate buffer system
A weak acid
Bicarbonate salt