Acid Base Balance Flashcards
Acids are sometimes referred to as
Proton donors
Defined as any compound, which can release hydrogen ions in solution.
Acids
A compounds that are only partially ionized in solution
Weak acids and bases
Compound that ionizes completely in solution to form hydrogen ions and a base.
Strong acids
An ion or a molecule that can accept an hydrogen
Bases
Bases can be referred to as
Proton acceptors
A compound that limits the change in hydrogen ion concentration when hydrogen ions are added or removed from the solution
Buffers
All buffers are in fact
Weak acids or bases
Immediately combine with acid or base to prevent excessive changes in hydrogen concentration
Chemical acid base buffer system
Buffers in plasma
Bicarbonate buffer
Phosphate buffer
Protein buffer
Buffers in the RBC
Bicarbonate buffer
Phosphate buffer
Hemoglobin buffer
Responsible for 60% of the buffering capacity of blood
Hemoglobin buffer
Responsible for 60% of the buffering capacity of blood
Hemoglobin buffer
Has the strongest affinity for both Co2 and Hydrogen
Deoxygenated hemoglobin
Buffering effect of deoxygenated hemoglobin. Is strongest in the
Tissue
CO2 that binds directly with hemoglobin combines reversibly with terminal amine groups on the hemoglobin molecule to form
Carbaminohaemoglobin
In the tissues, dissolved CO2 passes into the red blood cell down its concentration gradient where it combines with water to form
Carbonic acid
To form carbonic acid, this reaction is catalyzed by th enzyme
Carbonic anhydrase
Chief buffer for fixed, nonvolatile acids
Bicarbonate buffer system
Alkali reserve of the body
Sodium bicarbonate
Sodium bicarbonate deficiency
Metabolic acidosis
Excess sodium bicarbonate
Metabolic alkalosis
Important in buffering acids in the distal tubules of the kidney
Phosphate buffer system
Hemoglobin buffer system
Carbon dioxide + hemoglobin or water
Carbonic acid
Hemoglobin buffer system
CO2 + amine groups of hemoglobin
Carbaminohaemoglobin
Hemoglobin buffer system
CO2 + water = carbonic acid
Catalyze by?
Carbonic anhydrase
Hemoglobin buffer system
In tissue, carbonic acid dissociates to
Bicarbonate
Hydrogen ions
Hemoglobin buffer system
Bicarbonate goes to
Plasma in exchange for cholride
Hemoglobin buffer system
In tissue
Hydrogen ions to become
HHb
Hemoglobin buffer system
In lungs
Hydrogen ions + haemoglobin and bicarbonate
CO2
The second line of defense, which regulates the removal of carbon dioxide from the extracellular fluid
Respiratory mechanism
Slow acting
Can completely restore acid base balance
Most powerful of the acid base regulatory systems
Renal mechanism
Renal mechanism regulates primarily ___________ level in the blood
Sodium bocarbonate
Main site of bicarbonate reabsorption accounting for 75-90% of the filtered load
Proximal convoluted tubule
Proximal convoluted tubule
Bicarbonate is reabsorb with?
Sodium
Proximal convoluted tubule
H+ enters the tubule via
Secretion and not filtered at bowmans capsule
Proximal convoluted tubule
Excrete H+ into the tubular fluid by
Sodium hydrogen counter transport
Remaining 10-25% of bicarbonate is reabsorbed
Distal convoluted tubule
Distal convoluted tubule
Secretes H+ by
Primary active transport
Distal convoluted tubule
Where H+ is transported directly by a specific protein, a?
Hydrogen transporting ATPase
Distal convoluted tubule
The energy required for pumping the H+ is derived from the breakdown of ATP to
Adenosine diphosphate
Distal convoluted tubule
Anion that is filtered and not reabsorbed
Phosphate
Distal convoluted tubule
Formed in cells lining tubule from amino acids through deamination
Ammonia
State of excess H+
Acidosis
Results when the blood pH is less than 7.35
Acidemia
A state of excess HCO3
Alkalosis
Results when the blood pH is greater than 7.45
Alkalemia
Occurs from pathological conditions that damage the respiratory centers or that decrease the ability of the lungs to eliminate CO2
Respiratory acidosis
Due to hypoventilation and consequential increased in pCO2
Respiratory acidosis
Due to hyperventilation and consequential decreased in pCO2
Respiratory alkalosis
Eg of respiratory alkalosis
Hysteria
Early stage of salicylate poisoning
Injudicious of repirators
Due to decrease in bicarbonate fraction
Metabolic acidosis
Type of acidosis results from a defect in renal secretion of H+ or in reabsorption of HCO3 or both
Renal tubular acidosis
Most frequent cause of metabolic acidosis.
Diarrhea
Eg of metabolic acidosis
Vomiting of intestinal content
DM
Ingestion of acids
Chronic Renal Failure
Due to increase in bicarbonate fraction
There is excess retention of HCO3 or loss of H+ from the body
Metabolic alkalosis
Eg metabolic alkalosis
Diuretics
Aldosterone
Vomiting of gastric contrnts
Alkaline drugs
