acid base balance

Question 1

ACIDITY AND ALKALINITY

Answer 1

The acidity or alkalinity of a solution is determined by its
hydrogen ion (H+) concentration.
◼ An increase in the hydrogen ion concentration makes a
solution more acidic. A decrease in the hydrogen ion
concentration makes the solution more alkaline.
◼ The degree of acidity or alkalinity of a solution can also be
expressed in a negative logarithm of hydrogen ion
concentration known as the pH scale.

Question 2

pH BALANCE

Answer 2

A 7.5 on the pH scale is considered neutral.
◼ Acidity (a high hydrogen ion concentration) is a pH below 7.5
◼ Alkalinity (a low hydrogen ion concentration) is a pH above 7.5
◼ A pH balance between 7.35 and 7.45 (slightly acidic) is considered
normal for the human body (blood).

Question 3

CELLULAR METABOLISM

Answer 3

Aerobic Metabolism – This occurs in an environment where a cell
is adequately perfused. It receives oxygen, glucose, and other
nutrients from the arterial system and uses them to form
adenosine triphosphate (ATP), the fuel for all of the energy related
functions of the cell. Aerobic metabolism is highly efficient,
resulting in a minimal excretion of lactic acid and CO2
, the
byproducts of metabolism.

Question 4

Lactic Acid & CO2

Answer 4

The excretion of lactic acid and CO2
, the
byproducts of metabolism, decrease the overall pH of blood
because both of these substances are extremely acidic.
Remember, the acidity or alkalinity of a solution is determined by
its hydrogen ion (H+) concentration, and there are six (6)
hydrogen ions in every molecule of lactic acid.

Question 5

Carbon Dioxide

Answer 5

CO2

Question 6

▪ Lactic Acid

Answer 6

C3H6O3

Question 7

THE BUFFER SYSTEMS

Answer 7

In order to maintain a balanced pH the body must continually
excrete or retain hydrogen ions.
◼ The transportation, elimination, or retention of hydrogen ions is
done by 3 inter-related mechanisms:
1. The Carbonic Acid-bicarbonate Buffering System
2. The Protein Buffering System
3. The Renal System

Question 8

THE CARBONIC – BICARBONIC BUFFER SYSTEM

Answer 8

This is the fastest and most effective of the buffer systems.

◼ The two components of this buffer system are always present in
the bloodstream, constantly attempting to maintain a balanced
pH.
◼ CARBONIC ACID = H2CO3
◼ BICARBONATE = HCO3
-

Question 9

THE CARBONIC – BICARBONIC BUFFER SYSTEM

Answer 9

Carbonic acid is formed when the carbon dioxide (CO2
) excreted
by the cells combines with water (H2O) in the bloodstream. It is a
‘weak’ acid which can be safely transported inside the
bloodstream.
CO2 + H2O = H2CO3
CARBONIC

Question 10

THE CARBONIC – BICARBONIC BUFFER SYSTEM

Answer 10

Carbonic acid is formed when the carbon dioxide (CO2
) excreted
by the cells combines with water (H2O) for transport in the
bloodstream.
CO2
+ H2O = H2CO3
◼ Carbonic acid can then be safely transported in abundance to the
respiratory system, where it is broken down: carbon dioxide is
excreted by the lungs, and most of the water is retained in the
bloodstream.
H2CO3
= CO2 [excreted by lungs] + H2O [retained]

Question 11

THE CARBONIC – BICARBONIC BUFFER SYSTEM

Answer 11

Carbonic acid can also be broken down in the kidney in a manner
which allows for the kidney to maintain a homeostatic pH balance.
◼ In the kidney carbonic acid (H2CO3
) is broken down into
bicarbonate (HCO3
-
) and hydrogen ions (H+).