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Acid and Base Balance
Test 3
108
Physiology
Graduate
07/20/2011

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Term
Compared with other ions, the concentration of __ in body fluids is usually kept at a very low level and is regulated with extreme precision.
Definition
H+
Term
The concentration of what ion is essential to the activity of almost all enzymes in the body
Definition
H+
Term
Substances that release H+ ion in solution
Definition
Acids
Term
Give 2 examples of acids
Definition
HCl-
Carbonic Acid (H2CO3)
Term
Ions that can accept an H+ ion in solution
Definition
Base
Term
Give an example of a base.
Definition
Bicarbonate (HCO3)
Term
Some proteins can function as a base because some of the amino acids are __ charged and readily accept H+ (hemoglobin)
Definition
Negatively
Term
What is another term that is synonymously used with BASE
Definition
Alkali
Term
A molecule formed by the combination of one or more alkaline metals (Na, K, Li) with a hydroxyl ion (OH-)
Definition
Alkali
Term
The base portion reacts quickly with __ to remove it from solution
Definition
H+
Term
Excess removal of H+ from body fluids
Definition
Alkalosis
Term
Excess addition of H+ to body fluids
Definition
Acidosi
Term
This ion readily accepts an H+ to have H2O
Definition
OH-
Term
Name 4 causes to gain of H+
Definition
1. Generation of hydrogen ions from CO2
2. Production of nonvolatile acids from the metabolism of proteins and other organic molecules
3. Gain of H+ ions due to loss of bicarbonate in diarrhea of other nongastric GI fluids
4. Gain of H+ ions due to loss of bicarbonate in the urine
Term
Name 4 causes to loss of H+
Definition
1. Utilization of H+ ions in the metabolism of various organic anions
2. Loss of H+ ions in vomit
3. Loss of H+ ions in the urine
4. Hyperventilation
Term
Name the 3 primary systems that regulate the H+ concentration of body fluids to prevent acidosis or alkalosis
Definition
1. Chemical acid-base buffer system
2. Respiratory Regulation of Acid-Base Balance
3. Renal Conrol of Acid-Base Balance
Term
This system reacts within seconds to minimize changes in H+ concentration.
Definition
Chemical acid-base buffer system
Term
This system does not eliminate H+ from or add to the body, but only keep them tied up until balance can be re-established.
Definition
Chemical acid-base buffer system
Term
Any substance that can reversibly bind to H+
Definition
Buffer
Term
When H+ concentration increases, __ H+ bind to the buffer as long as the buffer is available.
Definition
More
Term
When the H+ concentration __, H+ is released from the buffer.
Definition
Decreases
Term
This system helps to account for daily changes in H+ production with digestion or metabolism
Definition
Chemical acid-base buffer system
Term
The major buffering system of ECF
Definition
Bicarbonate Buffer System
Term
The major ICF and renal tubular buffering system
Definition
Phosphate Buffer System
Term
The most plentiful buffer in the body because of high concentrations, especially in cells
Definition
Protein Buffer System
Term
When a strong base is added (NaOH), the incresed OH- if buffered by H2CO3 and forms what?
Definition
Additional HCO3-
Term
This buffer system consists of a water solution with a weak acid (H2CO3) and a bicarbonate salt (such as NaHCO3)
Definition
Bicarbonate Buffer System

CO2 + H2O <-> H2CO3 <-> HCO3 + H+
Term
When a strong acid is added (HCl-), the increased H+ is buffered by ___ and forms __, driving the equation to the left. This __ the production of CO2 and H20. The excess CO2 stimulates respiration, which eliminates the CO2 from the ECF.
Definition
Bicarbonate
H2CO3
Increases
Term
H2CO3
Definition
Carbonic Acid
Term
When additional HCO3- is formed, the resultant decrease in H2CO3 drives the equation to the right and ___ CO2 to form additional H2CO3.
Definition
Decreases
Term
When there is a net result of low CO2, this inhibits respiration and CO2 respiration. The rise in HCO3- that occurs is compensated for by increased what?
Definition
Renal excretion of HCO3-
Term
HCO3-
Definition
Bicarbonate
Term
Increase H2CO3 =
Definition
Increase CO2 + H2O
Term
Decreased H2CO3 =
Definition
Increased HCO3- + H+
Term
What is the equation for the Bicarbonate Buffer System
Definition
CO2 + H2O <-> H2CO3 <-> HCO3 + H+
Term
What is the equation for the Phosphate Buffer System
Definition
H2PO4 <-> HPO4 + H+
Term
With this buffer system, the intracellular pH changes approximately in proportion to ECF pH because rapid diffusion of CO2 across the cell membranes
Definition
Protein Buffer System
Term
In RBCs, what is the more important buffer?
Definition
Hgb
Term
What is the equation of the Protein Buffer System in RBCs
Definition
H+ + HgB <-> HHgB
Term
Do the buffer systems usually work together or separate?
Definition
Simultaneously
Term
When there is a change in ECF H+, the balance of all the systems changes at the same time
Definition
Isohydric Principle
Term
Regulates the removal of CO2, and therefore H2CO3, from the ECF
Definition
Respiratory Center
Term
This system acts within a few minutes to eliminate CO2, and therefore carbonic acid, from the body
Definition
Respiratory Regulation of Acid-Base Balance
Term
Ventilation rate can be altered by changes in __ and/or __ concentration
Definition
PCO2 and/or H+
Term
Decreased CO2 = __ H+ = __ pH
Definition
Decreases
Increases
Term
Name 2 causes of decreased PCO2
Definition
1. Decreased rate of cellular metabolism (metabolic CO2 formation)
2. PCO2 can also be decreased with increased ventilation
Term
Decreased H+ inhibites what
Definition
Ventilation rate
Term
Increased CO2 = __ H+ = __ pH
Definition
Increases
Decreases
Term
Name 2 causes for increased PCO2
Definition
1. Increase in the rate of cellular metabolism (metabolic CO2 formation)
2. Decreased ventilation
Term
Increased H+ stimulates what?
Definition
Ventilation rate
Term
The Respiratoy Regulation of Acid-Base Balance is a negative feedback loop. So if you have an increased H+ = __ alveolar ventilation = __ PCO2 = __ H+
Definition
Increase
Decrease
Decrease
Term
Can excrete either acid or alkaline urine and adjust the ECF H+ concentration toward normal = Eliminate excess acid or base from the body
Definition
Kidneys
Term
This system is slower to respond. Take a period of hours to days. It is a very powerful regulator of the acid-base system.
Definition
Renal Control of Acid-Base Balance
Term
Under normal circumstances, the kidneys filter 4320 mEq of __ per day.
Definition
Bicarbonate
Term
Almost all of ___ filtered is reabsorbed from the tubules in order to conserve the primary buffering system of the ECF
Definition
Bicarbonate
Term
In order for bicarbonate to be reabsorbed, it must first react with __ to form __. Therefore, an equivalent amount of __ must be secreted into the tubules to reabsorb the filtered bicarbonate.
Definition
H+
H2CO3
H+
Term
If there is excess H+ secreted what happens to it?
Definition
It is excreted in the urine
Term
When there is alkalosis, the kidneys fail to reabsorb all the filtered bicarbonate, thereby __ the excretion of bicarbonate.
Definition
Increasing
Term
When there is alkalosis, the loss of bicarb translates into an inability to buffer __ in the ECF, so the effect is the same as adding _ to the ECF.
Definition
H+
H+
Term
When there is alkalosis, the removal of bicarbonate raises the ECF H+ back toward __
Definition
Normal
Term
When there is acidosis the kidneys do not excrete bicarbonate in the urine but reabsorb all the filtered bicarbonate, which is added back to the ECF. This reduced __ back toward __
Definition
H+
Normal
Term
Name the 3 fundamental mechanisms of renal regulation of acid-base balance.
Definition
1. Tubular secretion of H+
2. Tubular reabsorption of HCO3-
3. Production of new HCO3-
Term
80-90% of H+ is secreted in the __ __, secreted by sodium-hydrogen counter-transport (early tubular segments) and hydrogen-transporting ATPase (late distal and collecting tubules)
Definition
Proximal Tubules
Term
80-90% of HCO3- reabsorption occurs where?
Definition
in the proximal tubules
Term
HCO3- combines with the secreted H+ to form ___, which dissociates into CO2 and H2O. The CO2 diffuses into the tubular cell. It combines with H2O to form __, which dissociates into HCO3- and H+
Definition
H2CO3
H2CO3
Term
H+ can be secreted again and the new HCO3- diffuses into the renal intersitium (reabsorption). The movement of HCO3- into the interstitium is facilitated by a ____ co-transport in the proximal tubules, and ___ in the late segments of the prox tubule, thick ascending loop of henle, and collecting tubules and ducts.
Definition
Na-HCO3
Cl-HCO3
Term
The net result for tubular reabsorption of HCO3- is that for every H+ secreted into the tubular lumen, a __ enters the blood.
Definition
HCO3-
Term
When H+ is secreted in excess of filtered bicarbonate, the majority of it must be buffered for what?
Definition
Excretion in the urine
Term
Excess H+ can be buffered by _ to form __ and excreted as a sodium salt.
Definition
HPO4
H2PO4
Term
The key buffer in tubular fluid, because most filtered phosphates are reabsorbed.
Definition
Ammonia
Term
Whenever a secreted H+ combines with a buffe other than HCO3-, the net affect ist he addition of 1 new __ to the blood
Definition
HCO3-
Term
For each NH4 excreted, a new __ is generated and added to the blood.
Definition
HCO3-
Term
A decreased acidity in the blood pH >7.45 caused by excessive ventilation by the lungs.
Definition
Respiratory Alkalosis
Term
How common is respiratory alkalosis?
Definition
Rare because of physical pathological conditions
Term
This can occur when a person ascends to high altitude. Low CO2 content stimulates respiration, which causes loss of CO2.
Definition
Respiratory Alkalosis
Term
Name 2 compensatory responses of Respiratory Alkalosis
Definition
1. Chemical Buffers of the body fluids
2. Kidneys increase HCO3 excretion (so that CO2 production will increase)
Term
A condition in which there is decreased respiration that causes an increase in blood CO2 and decreased pH.
Definition
Respiratory Acidosis
Term
Respiratory acidosis causes and increase in __ and __ concentrations
Definition
H2CO3
H+
Term
Can occur from pathological conditions that damage the respiratory centers or that decrease the ability of the lung to eliminate CO2.
Definition
Respiratory Acidosis
Term
Can damage to the medulla cause respiratory acidosis?
Definition
Yes
Term
Obstruction of passageways of the respiratory tract, pneumnia, emphysema, decreased pulmonary membrane surface area, or any other factors that interfere with gas exchange between blood and alveolar sac can cause what?
Definition
Respiratory Acidosis
Term
Na 2 compensatory techniques for respiratory acidosis.
Definition
1. Buffers of the body fluids
2. Kidneys (increase production of HCO3)
Term
A condition that occurs when the body produces too much acid or when the kidneys are not removing enough acid from the body.
Definition
Metabolic Acidosis
Term
This refers to all other types of acidosis that are not cause by ecess CO2 in the body fluids
Definition
Metabolic Acidosis
Term
Name 4 typical causes of metabolic acidosis.
Definition
1. Failure of kidneys to excrete metabolic acids normally found in body
2. Formation of excess metabolic acids in the body
3. Addition of metabolic acids to the body by ingestion or infusion of acids
4. Loss of base from body fluids
Term
How might you have a loss of base from body fluids?
Definition
Diarrhea - intestinal contents
Term
Name 5 common conditions that cause metabolic acidosis.
Definition
1. Diarrhea
2. Vomiting of intestinal contents
3. Diabetes mellitus
4. Ingestion of acids
5. Chronic renal failure
Term
Name 2 compensatory responses for metabolic acidosis
Definition
1. Buffers of the body fluids
2. Kidneys increase production of HCO3
Term
Caused by excess retention of HCO3 or loss of H+ from the body.
Definition
Metabolic alkalosis
Term
Metabolic acidosis is not neary as common as __ but more common than ___
Definition
Metabolic acidosis
Respiratory alkalosis
Term
Name 4 common causes of metabolic alkalosis
Definition
1. Administration of diuretics
2. Excess aldosterone
3. Vomiting of gastric contents
4. Ingestion of alkaline drugs
Term
What is the best treatment for alkalosis or acidosis?
Definition
Correct the condition that caused the abnormality
Term
How might you neutralize excess acid?
Definition
Large amounts of sodium bicarbonate can be ingested by mouth or administered IV
Term
How might you treat alkalosis?
Definition
Ammonium chloride can be administered by mout. It is converted by the liver into urea which liberates HCl
Term
Can result in a patient with acute HCO3 loss from the GI tract because of diarrhea who also has emphysema
Definition
Mixed acidosis
Term
Respiratory compensation in primary metabolic conditions is ___hours
Definition
6-12
Term
Metabolic compensation in primary respiratory conditions is __ days
Definition
3-5
Term
Failure of the kidneys to reabsorb glucose. Person will present with normal blood glucose, but high levels of glucose in the urine. Must be ruled out before making a diagnosis of diabetes mellitus.
Definition
Renal Glycosuria
Term
Failure of the kidneys to reabsorb amino acids. Fairly rare and apparently has no major clinical significance. Would result in high lvels of cystine, Glycine, etc in the urine
Definition
Aminoaciduria
Term
Failure of the kidneys to reabsorb phosphate. No immediate clinical significant of low phosphate in the blood. Long term low levels can cause diminished calcification of the bones which may lead to a type of rickets.
Definition
Renal Hypophosphatemia
Term
Failure of the tubules to secrete hydrogen ions. As a result, large amounts of sodium bicarbonate are continuously lost in the urine. Causes a continuous state of metabolic acidosis. Can be hereditary or the result of tubular damage.
Definition
Renal Tubular Acidosis
Term
Failure of the kidneys to respond to antidiuretic hormone. Can lead to large quantities of dilute urine to be excreted. As long as the person is supplied plenty of water this can be a non-issue, but the person is at risk for dehydration if not properly managed
Definition
Nephrogenic Diabetes Insipidus
Term
A generalized reabsorptive detect of the renal tubules
Definition
Fanconi's Syndrome
Term
Usually associated with increased urinary excretion of virtually all amino acids, glucose, and phosphate. Severe causes involve the inability to reabsorb sodium bicarb, increased excretion of potassium and or calcium, and nephrogenic diabetes insipidus.
Definition
Fanconi's Syndrome
Term
Can be caused by hereditary defects or injury from toxins
Definition
Fanconi's Syndrome
Term
Characterized by decreased sodium, chloride, and potassium reabsorption in the loops of henle.
Definition
Bartter's Syndrome
Term
An autosomal recessive disorder caused by impaired function of membrane channels (cotransporters, potassium channels, chloride channels)
Definition
Bartter's Syndrome
Term
This Syndrome leads to increased excretion of Na, H2O, Cl, K, and Ca by the kidneys. Salt and water loss lead to volume depletion, resulting in activation of renin-angiotensin-aldosterone system. Stimulates K and H+ secretion in the tubules, and leads to hypokalemia and metabolic alkalosis.
Definition
Bartter's Syndrome
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