Acid-Base, Fluid and Electrolytes
When bicarbonate ion diffuses out of red blood cells into plasma, it is usually exchanged with anion
Chloride
Hormonal control of urinary excretion primarily affects
DCTs and collecting ducts
A decrease in angiotensin II leads to
decreased blood volume due to increased GFR
H+ ion
has special significance because of the narrow ranges that it must be maintained in order to be comptible with living systems
Respiratory alkalosis is caused by
hyperventilation
Direction of bicarbonate secretion diffusion
is reversed in pancreatic epthelial cells
Metabolic Intermediate by-products
lactic acid, pyruvic acid, acetoacetic acid
Acid
lower pH of 7
Any acid-base imbalance not attributable to CO2 is classified as
metabolic, metabolic production of acids, or loss of bases
Pure water
neutral
Acid-Base regulation
primarily controlled by regulation of H+ ions in the body fluids especially extracellular fluids
Food Products
sauerkraut and yogurt
The primary intracellular ions are
sodium and chloride
Bicarbonate and H+ are balanced
there is no net change in the amount of bicarbonate in blood loss of ghastric or pancreatic juice can change that balance
Normal ratio of HCO3- to H2CO3
20:1
The ratio of bicarbonate ions to carbonic acid molecule in extracellular fluid is normally about
20:1
pH range compatible with life
6.7 - 7.9
Blood pH
7.35 - 7.45
pH of blood is
7.45
What is the renal mechanism to correct for respiratory alkalosis
B type intercalated cells in the DCT and cortical CD will increase bicarbonate secretion and H+ reabsorption
Aerobic Respiration
CO2 diffuses into the bloodstream where the reaction occurs in red blood cells
Sources of bicarbonate ions
CO2 diffusion into red blood cells, parietal cell secretion of the gastric mucosa
H2CO3 is source of
H+ ions in the body
The addition of a strong acid to the extracellular fluid would result in the increased formation of
H2CO3
The pH of blood varies directly with
HCO3
Extracellular fluids are
High in sodium and low in potassium
In humans, the thirst center is located in the
Hypothalamus
Which is an effect of increased levels of parathyroid hormone
Increased absorption of calcium ions from the gastrointestinal tract, increased reabosrption of calcium ions by renal tubule cells, increased release of calcium ions from mineral salts in bone matrix, increased release of phosphate ions from mineral salts in bone matrix
The longer the ____, the greater an animal's capacity to conserve water and to concentrate the solutes excreted in the urine
Loop of Henle
OH-
a base
Acidosis
a decrease in the normal 20:1 base to acid ratio, an increase in the number of hydrogen ions, a decrease in the number of bicarbonate ions, caused by too much acid or too little base
An acid may be defined as
a donor of hydrogen
Water ionizes to
a limited extent to form equal amounts of H+ ions and OH- ions
Acids
a proton (H+) donor molecules which dissociate in solution to release H+
Bases
a proton H+ acceptro molecules capable of accepting a hydrogen ion
Alkalosis
a relative increase in bicarbonate
Acidosis
a relative increase in hydrogen ions
A pH of 6.5 is said to be
acid
Levels of potassium ions in the extracellular fluid are regulated primarily by
aldosterone
Levels of sodium ions in the extracellular fluid are regulated primarily by
aldosterone
If the blood is acidic, what would occur
ammonia would not secrete by the cells of the kidney tubules, rate of breathing would decrease, sodium ions would not be taken up by the kidneys, hydrogen ions would not be excreted by the kidneys
Hyperkapnia
an accumulation of carbon dioxide in extracellular fluids
H+
an acid
Alkalosis
an increase of base to acid ratio, an increase in the amount of bicarbonate, a decrease in the number of hydrogen ions, caused by base excess or acid deficit
Hyperventilation is a result of
anxiety, emotional disturbances, fever, salicylate poisoning, assisted respiration, high altitude
Why are levels of bicarbonate ion higher in arterial blood than in venous blood
because more bicarbonate ions are used up in venous blood to buffer hydrogen ions
The term alkaline reserve is used to describe the ___ buffer system
bicarbonate
Cannont help protect against PH changes caused by respiratory problems in which there is an excess or shortage of carbon dioxide
bicarbonate ion/carbonic acid buffers
Physiologically important bases
bicarbonate, biphosphate
In an attempt to compensate for plasma acidosis
breathing rate and depth will increase
Physiologically important acids
carbonic acid, phosphoric acid, pyruvic acid and lactic acid
Respiratory Acidosis
caused by hyperkapnia due to hypoventilation characterized by a pH decrease and an increase in PCO2
Bicarbonate Secretion
cells of the gastric mucosa secrete H+ ions into the lumen of the stomach in exchange for the diffusion of bicarbonate ions into blood
Sources of hydrogen ions
cellular metabolism, food products, medications, metabolic intermediate by products
The chief extracellular anion is
chloride
If lactic acid is injected iv, then plasma bicarbonate ion levels will immediately
decrease
If plasma (aldosterone) increases, Na+ excretion will ___
decrease
Drinking plain water after excessive sweating leads to
dehydration of cells
Derangements of hydrogen and bicarbonate concentrations in body fluids are common in
disease processes
Decreased gas exchange between pulmonary capillaries and air sacs of lungs
emphysema, bronchitis, pulmonary edema
ADH saves water by
enhancing passive movement of water out of the collecting ducts
The carboxyl group of an amino acid acts as a buffer for
excess hydroxide ions
Hypernatremia can be defined as
excessive retention of plasma sodium
pH Scale
expresses hydrogen ion concentration in water solutions
Plasma is considered to be
extracellular
7.0 is the normal pH of the
fluid within a typical cell
Base
higher pH of 7
Which 2 ions is acid-base balance is concerned with
hydrogen and bicarbonate
What are enzymes, hormones and ion distribution affected by
hydrogen ion concentrations maintenance of an acceptable pH range in the extracellular fluids is accomplished by three mechanisms, chemical buffers, respiratory regulation and renal regulation
What ion imbalance problem might develop
hypokalemia, the reabsorption of H+ is via an H+/K+ antiport so K+ will be hypersecreted
The area taht stimulates teh conscious desire to drink water is .located in the
hypothalamus
As dehydration increases, the release of ADH from the posterior pituitary will
increase
Parathyroid hormone acts to
increase plasma calcium levels
Which of the following would you expect to see in response to an extracellular fluid calcium ion level of 5.7 mEq/liter
increased secretion of CT
What is a function of atrial natriuretic peptide
it acts to decrease aldosterone release from the adrenal cortex, increase urine output, decreases ADH release
Hemoglobin picks up a hydrogen ion when
it releases oxygen to tissues
Unregulated diabetes mellitus causes
ketoacidosis
Hyperventilation
leads to eliminating excessive amounts of carbon dioxide, increased loss of CO2 from the lungs at a rate faster than it is produced, decrease in hydrogen ions
How low of a pH is fetal
less than 7.0
The plasma protein concentration of a patient with untreated glomerulonephritis would be expected to be
less than normal
Medications
may stimulate HCl production by parietal cells of the stomach
Which of the following depends on the presence of electrolytes
membrane polarity, neuromuscular excitability, maintenance of osmotic relations between cells and ECF
In studies of fluid balance, the term water intoxication refers to
movement of water from interstitial fluid due to osmotic gradients created by ion loss
The primary determinant of body fluid volume is the
number of sodium and chloride ions lost from the kidney
Respiratory Acidosis can be the result of
obstruction of air passages, decreased respiration, decreased gas exchange between pulmoanry capillaires and air sacs of lungs, collapse of lung
Metabolic Acidosis
occurs when there is a decrease in the normal 20:1 ratio, decrease in blood pH and bicarbonate level, excessibe H+ or decreased HCO3
Cellular metabolism
of carbohydrates release CO2 as a waste product, aerobic respiration
The thirst center is stimulated by
osmoreceptros in the hypothalamus, baroreceptros, dry mouth and angiotensin II
The primary means of water movement between fluid compartments is
osmosis
The chief intracellular anion is
phosphate
The chief intracellular cation is
potassium
Chemical Buffers
react very rapidly (less than a second)
Respiratory regulation
reacts rapidly (seconds to minutes)
Renal regulation
reacts slowly (minutes to hours)
Excessive intake or drinking of water normally leads to
reduced ADH secretion
Holding your breath for an extended period of time results in
respiratory acidosis
Kidneys compensate by
retaining hydrogen ions, increasing bicarbonate excretion
A stron acid plus a weak base yields a
salt puls a weak acid
Parietal Cell Secretion
secrete hydrogen ions into the lumen of the stomach
Decreased Respiration
shallow, slow breathing
Decreased CO2 in the lungs will eventually
slow the rate of breathing, will permit a normal amount of CO2 to be retained in the lung
The chief extracellular cation is
sodium
The cation that is necessary for generation and conduction of action potentials and that contributes nearly half of the osmotic pressure of extracellular fluid is
sodium ion
The stimulus for release of ANP is
stretching of the atrial wall
H+ ions are secreted into t
the blood and bicarbonate ions diffuse into pancreatic juice
Bicarbonate ions diffuse into
the bloodstream to maintain electrical neutrality in the parietal cell in pancreatic epithelial cells the direction of ion movement is reversed
The direction of water movement between fluid compartments is determined by
the concentration of solutes
Protein anions are most abundant in
the cytosol
Women generally have a lower amount of total body water than men because
they have a higher body temperature
Bicarbonate ion acts as a
weak base
