Acids and Bases Flashcards
contains only a single proton; not orbited by any electron; smallest ionic particle
Hydrogen ion (H+)
normal H+ concentration in the extracellular fluid (ECF)
38 to 42 nM/L
another term for H+ concentration that is generally used nowadays
pH
introduced in order to simplify the mathematical handling of large numbers
pH scale
An ___ in H+ ion concentration ____ the pH (acidosis) and a ____ in H+
concentration ___ the pH (alkalosis).
increase, decreases;
reduction, increases
the pH of the ECF of a healthy person and its range
7.40- pH
range: 7.38 and 7.42
indirect method of determining pH
Henderson-Hasselbalch equation
In Henderson-Hasselbalch equation, to determine the pH of a fluid, the concentration of ____ and the ____ dissolved in the fluid are measured
bicarbonate ions (𝐻𝐶𝑂3
−); 𝐶𝑂2
pH of plasma is determined by using an instrument called
pH meter
Normal acid-base ratio
1:20
is an indirect measurement of H+ concentration and it
reflects the balance of 𝐶𝑂2 and 𝐻𝐶𝑂3 −.
pH of arterial blood
two types of acids are produced in the body
- Volatile acids
- Non-volatile acids.
acids derived from 𝐶𝑂2
Volatile acids
Large quantity of 𝐶𝑂2 is produced during the
metabolism of ___ and ___
carbohydrates, lipids
acids that are produced during the metabolism of other nutritive substances
such as proteins.
Non-volatile acids
These acids are real threat to the acid-base status of the body
Non-volatile acids
sulfuric acid is produced during the metabolism of sulfur containing amino acids such as (2)
cysteine and metheonine
hydrochloric acid is produced during the metabolism of (3)
lysine, arginine and histidine
Three mechanisms to regulate acid-base status
Acid-base buffer system
Respiratory mechanism
Renal mechanism
compensatory mechanisms which binds free H+
Acid-base buffer system
Compensatory Mechanisms which eliminates 𝐶𝑂2
Respiratory mechanism
Compensatory Mechanisms which excretes H+ and conserves the bases (HCO3 –).
Renal mechanism
Which compensatory mechanism is the fastest one and readjusts the pH within seconds
acid-base buffer system
Which compensatory mechanism
readjusts the pH within minutes
respiratory mechanism
Which compensatory mechanism is slower and takes few hours to few days to bring the pH back to normal; most powerful mechanism
renal mechanism
acid-base buffer system is the combination of a ______
and a ______
weak acid (protonated substance);
base – the salt (unprotonated substance).
is the one, which acts immediately to prevent the changes in pH.
Buffer system
maintains pH by binding with free H+.
Buffer system
three types of buffer systems
Bicarbonate buffer system
Phosphate buffer system
Protein buffer system.
This buffer system is present in ECF (plasma)
Bicarbonate buffer system
It consists of the protonated
substance, carbonic acid (H2CO3) which is a weak acid and the unprotonated substance, HCO3 –, which is a weak base. HCO3 – is in the form of salt
Bicarbonate buffer system
prevents the fall of pH in a fluid to which a strong acid like
hydrochloric acid (HCl) is added
Bicarbonate buffer system
also prevents the increase in pH in a fluid to which a strong
base like sodium hydroxide (NaOH) is added.
Bicarbonate buffer system
Bicarbonate buffer system:
a weak base and it prevents the increase in pH by the strong NaOH.
NaHCO3
____ is a very weak base, its association with H+ is poor
sodium bicarbonate
This buffer system is not powerful like the other buffer systems because of the
large difference between the pH of ECF (7.4) and the pK of ___
bicarbonate buffer system (6.1)
this buffer system plays an important role in maintaining the pH of body fluids than the other buffer systems
Bicarbonate buffer system
concentration of two components (H𝐶𝑂3 – and 𝐶𝑂2) of this buffer system is regulated separately by two different mechanisms.
Bicarbonate buffer system
These two regulatory mechanisms from Bicarbonate buffer system operate constantly and simultaneously, making this system more effective
Concentration of H𝐶𝑂3-
concentration of 𝐶𝑂2
Which organ regukates the mechanism?
Concentration of H𝐶𝑂3 is regulated by ___
concentration of 𝐶𝑂3 is regulated by ___
Concentration of H𝐶𝑂3- kidney
concentration of 𝐶𝑂3- respiratory system
Phosphate buffer system is composed of: (2)
- weak acid, the dihydrogen phosphate (H2PO4 – protonated
substance) in the form of sodium dihydrogen phosphate (NaH2PO4) - the base, hydrogen phosphate (HPO4 – unprotonated substance) in the form of disodium hydrogen phosphate (Na2HPO4).
This buffer system is useful in the intracellular fluid (ICF), in red blood cells or other cells.
Phosphate buffer system
When a strong acid like hydrochloric acid is mixed with a fluid containing phosphate
buffer, _____ is formed.
sodium dihydrogen phosphate (NaH2PO4 – weak acid)
If a strong base such as sodium hydroxide (NaOH) is added to the fluid containing
phosphate buffer, a weak base called _____ is formed.
disodium hydrogen phosphate (Na2HPO4)
is more powerful than bicarbonate buffer system as it has a
pK of ___, which is close to the pH of the body fluids
Phosphate buffer system ;6.8
bffer system that is useful in tubular fluids of kidneys
Phosphate buffer system
In the red blood cells, the ___ ion concentration is higher than the sodium ion concentration.
potassium
elements of phosphate buffer inside the red blood cells are in the form of ___ and ___
potassium dihydrogen phosphate (KH2PO4); dipotassium hydrogen phosphate (K2HPO4).
this buffer systems are present in the blood; both in the plasma and erythrocytes.
Protein buffer systems
Elements of proteins, which form the weak acids in the plasma are: (3)
a. C-terminal carboxyl group, N-terminal amino group and side-chain carboxyl group of glutamic acid
b. Side-chain amino group of lysine
c. Imidazole group of histidine.
These buffer systems are more powerful because of their high concentration in plasma and because of their pK being very close to 7.4.
Protein buffer systems (plasma)
is the most effective protein buffer and the major buffer in blood.
Hemoglobin
Due to
its high concentration than the plasma proteins, ___ has about six times more buffering capacity than the plasma proteins.
hemoglobin
The ___ hemoglobin is a more powerful buffer than ___ hemoglobin because of the higher pK.
deoxygenated; oxygenated
When a hemoglobin molecule becomes ___ in the capillaries, it easily binds with H+, which are released when ____ enters the capillaries.
deoxygenated; CO2
This organ plays an important role in the maintenance of acid-base balance by removing ___
which is produced during various metabolic activities in the body.
Lungs; CO2
CO2 combines with water to form ___
carbonic acid
Since carbonic acid is unstable, it splits into ___ and ___
H+ and 𝐻𝐶𝑂3-
CO2 is blown off by ___
ventilation.
When metabolic activities increase, more amount
of ___ is produced in the tissues and the concentration of H+ ___
CO2; increases
Increased ___ concentration increases the pulmonary ventilation (hyperventilation) by acting through the ____.
H+; chemoreceptors
Due to ___, the excess of CO2 is removed from the body.
hyperventilation
Kidney maintains the acid-base balance of the body by the secretion of ___ and by the
retention of ____.
H+; HCO3
Disturbances of Acid and Bases Status (2)
Acidosis
Alkalosis
is the reduction in pH (increase in H + concentration) below normal range.
Acidosis
Acidosis is produced by (2)
- Increase in partial pressure of CO2 in the body fluids particularly in arterial blood
- Decrease in HCO3 – concentration
is the increase in pH (decrease in H+ concentration) above the normal range
Alkalosis
Alkalosis is produced by: (2)
- Decrease in partial pressure of CO2 in the arterial blood
- Increase in HCO3 – concentration.
Since the partial pressure of CO2 (pCO2) in arterial blood is controlled by lungs, the
acid-base disturbances produced by the change in arterial pCO2 are called the ____
respiratory disturbances.
disturbances in acid-base status produced by the change in HCO3 – concentration are generally called the ___
metabolic disturbances.
the acid-base disturbances are (4)
- Respiratory acidosis
- Respiratory alkalosis
- Metabolic acidosis
- Metabolic alkalosis.
