Ch.26 Fluid and Acid - Base Balance
The bicarbonate buffer system is one of the chemical buffer systems of the body. How would the bicarbonate buffer system work if sodium hydroxide were added to a solution? A. A hydrogen on carbonic acid would dissociate and join the hydroxyl group on the base to form water and sodium bicarbonate. B. The hydrogen ion would attach to carbonic acid. C. The hydrogen ion would attach to bicarbonate (HCO3) to form carbonic acid (H2CO3).
A. A hydrogen on carbonic acid would dissociate and join the hydroxyl group on the base to form water and sodium bicarbonate. Yes, a strong base (sodium hydroxide) would be converted to a weak base (sodium bicarbonate).
What type of intravenous infusion would you give to a runner who has collapsed after drinking too much water during the course of her marathon and why? A. A hypertonic saline solution to pull water out of her cells. B. A hypertonic saline solution to cause more water to enter her cells. C. An isotonic saline solution to pull water out of her cells. D. A hypotonic saline solution to pull water out of her cells.
A. A hypertonic saline solution to pull water out of her cells.
Which of the following statements is FALSE regarding water intake and output by the body? A. An increase in fluid taken by mouth would reduce the amount produced by metabolism. B. An increase in the amount of beverages taken by mouth would increase the urine output. C. An irritation to the colon the leads to diarrhea would increase the proportion of water lost through feces. D. The proportion of fluid lost by the body as sweat would increase during exercise.
A. An increase in fluid taken by mouth would reduce the amount produced by metabolism. The water produced by metabolism is a by-product of energy processing. This amount is not dependent on the amount of water taken by mouth.
The respiratory system is one of the three systems that regulate acid-base balance in the body. How does it work to decrease an acidosis? A. Carbonic acid is broken down into water and CO2; the CO2 is then exhaled. B. Carbonic acid converts a strong acid to a weak acid, thus decreasing acidity. C. Carbonic acid is converted to bicarbonate and hydrogen ions. D. Carbonic acid is converted to bicarbonate, which then buffers the acid.
A. Carbonic acid is broken down into water and CO2; the CO2 is then exhaled. Yes, CO2 can be blown off, thus decreasing acidity.
Which of the following statements about fluid movement is NOT correct? A. Exchange between the plasma and the intracellular fluid occurs across the cell membrane. B. Under normal circumstances, lymph vessels help maintain fluid balance, especially between the plasma and the interstitial fluid. C. Exchange between interstitial fluid and intracellular fluid occurs across the plasma membrane. D. Exchanges between plasma and interstitial fluid happen between capillary walls.
A. Exchange between the plasma and the intracellular fluid occurs across the cell membrane. Exchange between the plasma and the intracellular fluid would have to involve exchange through the interstitial fluid.
In a car accident, Jane suffered a chest injury that resulted in impaired breathing and respiratory acidosis. How will her body compensate for this imbalance? A. Kidneys retain bicarbonate ions. B. Kidneys retain hydrogen ions. C. Kidneys eliminate bicarbonate ions. D. Kidneys eliminate carbon dioxide.
A. Kidneys retain bicarbonate ions.
Mr. Heyden's low blood pressure will trigger certain compensatory mechanisms. Which statement below best reflects the changes in hormone levels that will occur? A. Mr. Heyden's ADH, aldosterone, and renin will increase. B. Mr. Heyden's ADH and renin will decrease, and his aldosterone will increase. C. Mr. Heyden's ADH will decrease, his aldosterone will increase, and his renin will be unchanged. D. Mr. Heyden's ADH will increase, and his aldosterone and renin will decrease.
A. Mr. Heyden's ADH, aldosterone, and renin will increase. Elevation of renin, aldosterone, and antidiuretic hormone indicate that Mr. Heyden's body is trying to compensate for his falling blood pressure and blood loss.
Usually the body needs to excrete excess acid. Sometimes, however, the body is in alkalosis. In the collecting duct, there are special cells (type B intercalated cells) whose sole job is to deal with alkalosis. What would you expect these cells to do? A. Secrete bicarbonate ions and reabsorb hydrogen ions. B. Reabsorb both hydrogen ions and bicarbonate ions. C. Secrete both hydrogen ions and bicarbonate ions. D. Secrete hydrogen ions and reabsorb bicarbonate ions
A. Secrete bicarbonate ions and reabsorb hydrogen ions Type B intercalated cells are located in the collecting ducts, where final adjustment of pH occurs. Keep in mind, though, that alkalosis is rare and that most of the time the body needs to get rid of excess acid. So most of the time the activity of type A intercalated cells in the collecting ducts (which secrete H+ and reabsorb HCO3- like PCT cells) predominates.
In a respiratory acidosis the kidney would do which of the following? A. The kidney would reabsorb bicarbonate and secrete hydrogen ions. B. The kidney would increase excretion of both bicarbonate and hydrogen ions. C. The kidney will reabsorb both bicarbonate and hydrogen ions. When it reabsorbs the hydrogen ion, it also generates more bicarbonate ions.
A. The kidney would reabsorb bicarbonate and secrete hydrogen ions. Yes, when the kidney secretes hydrogen ions it also generates a bicarbonate ion, which further aids in decreasing the acidity of the plasma.
Which of the following is true of a patient with arterial blood pH of 7.6? A. The patient has alkalosis and is out of the normal homeostatic range. B. The patient has alkalosis but is in the normal homeostatic range. C. The patient has acidosis but is in the normal range. D. The patient has acidosis and is outside of the normal homeostatic range.
A. The patient has alkalosis and is out of the normal homeostatic range. The normal pH range of arterial blood is 7.4 to 7.45. A higher pH is a sign of alkalosis.
Which of the following is not a hormone involved in water or electrolyte balance? A. thyroxine B. aldosterone C. antidiuretic hormone D. atrial natriuretic peptide
A. Thyroxine Thyroxine is a thyroid hormone that regulates metabolic activities and is not involved in water and electrolyte balance.
The term hypotonic hydration refers to ________. A. a condition that may result from renal insufficiency or drinking excessive amounts of water. B. the feeling one might have after profuse sweating with exertion. C. the unpleasant feeling people have after drinking too much liquor. D. a condition that is caused by high levels of sodium in the extracellular fluid compartment.
A. a condition that may result from renal insufficiency or drinking excessive amounts of water
Which of the following is most likely to trigger the release of renin? A. a drop in blood pressure. B. an increase in blood pressure. C. an increase in aldosterone production. D. an increase in water reabsorption
A. a drop in blood pressure When baroreceptors in the heart and blood vessels sense a drop in blood pressure, they trigger juxtaglomerular cells of the kidney to release renin.
Which of the following is NOT a likely source of hydrogen ions in blood plasma? A. aerobic metabolism of glucose. B. metabolism of proteins containing phosphorus. C. anaerobic metabolism of glucose. D. metabolism of fats.
A. aerobic metabolism of glucose
Suppose the extracellular fluid (ECF) osmolality becomes too high. What hormone would most likely be released to correct this situation? A. antidiuretic hormone (ADH) B. aldosterone C. parathyroid hormone (PTH) D. angiotensin II
A. antidiuretic hormone (ADH) High osmolality in extracellular tissue indicates a drop in blood pressure and loss of fluid volume. The hypothalamus monitors ECF osmolality and, if high, triggers the posterior pituitary to release ADH. ADH acts on the kidneys to correct this by reclaiming more water from kidney filtrate.
Increasing levels of which of the following would result in a decrease in reabsorption in the collecting ducts in the kidneys? A. atrial natriuretic peptide B. aldosterone C. antidiuretic hormone (ADH) D. angiotensin II
A. atrial natriuretic peptide Atrial natriuretic peptide (ANP) is released by certain cells of the heart atria when they are stretched by the effects of elevated blood pressure. The hormone targets the collecting ducts, blocking reabsorption.
If the thyroid and parathyroid glands are surgically removed, which of the following would go out of balance without replacement therapy? A. calcium ion levels B. sodium ion levels C. potassium ion levels D. anion levels
A. calcium ion levels
Which of the following is not an electrolyte? A. carbohydrate B. salt C. base D. acid
A. carbohydrate Excellent! Carbohydrates are held together by covalent bonds, whereas electrolytes are held together by ionic bonds.
For bulk flow across capillary walls, ________. A. hydrostatic pressure of blood forces nearly protein-free plasma out of the blood into the interstitial space. B. hydrostatic pressure of the interstitial space returns fluid to the capillary. C. fluid runs into lymphatic capillaries that empty into the interstitial space. D. osmotic pressure of plasma proteins pulls fluid from the capillary into the interstitial space.
A. hydrostatic pressure of blood forces nearly protein-free plasma out of the blood into the interstitial space
Choose the appropriate term to fill in the sentence: When Mrs. M ate, her intestinal contents became more concentrated than her blood. This means her intestinal contents were __________ to her blood and her blood was __________ to her intestinal contents. A. hyperosmotic; hyposmotic. B. hyposmotic; hyposmotic. C. hyperosmotic; hyperosmotic. D. hyposmotic; hyperosmotic
A. hyperosmotic; hyposmotic You are right. A compartment with a higher solute concentration is said to be hyperosmotic to a less concentrated compartment. The less concentrated compartment is therefore hyposmotic to the more concentrated compartment.
What results from increased levels of aldosterone? A. Increased Na+ reabsorption B. increased Ca2+ reabsorption C. increased K+ reabsorption D. decreased Na+ reabsorption
A. increased Na+ reabsorption Na+ reabsorption is increased by aldosterone, which leads to reabsorption of more water and an increase in blood pressure.
Which of the following is NOT a risk factor for dehydration? A. increased muscle mass B. vomiting C. inefficient kidneys D. a high rate of insensible water loss
A. increased muscle mass Aerobic metabolism of glucose in muscle tissue would actually generate water for the body.
An illness causes Doug to experience severe diarrhea and an accompanying loss of bicarbonate-rich secretions. How can this metabolic acidosis be compensated? A. increased respiratory rate and depth B. enhanced sodium ion loss in urine C. increased renin secretion D. hypoventilation
A. increased respiratory rate and depth
In the case of edema, excess fluid is held in which fluid compartment(s)? A. interstitial fluid B. intracellular fluid and interstitial fluid C. blood plasma D. intracellular fluid
A. interstitial fluid
The most important renal mechanism for regulating acid-base balance of the blood involves __________. A. maintaining HCO3 - balance. B.maintaining water balance. C. maintaining CO2 balance D. maintaining phosphate balance
A. maintaining HCO3 - balance Excretion of bicarbonate is a long-term mechanism that the kidneys contribute to acid-base regulation.
Increased levels of which of the following stimulates the thirst mechanism driving increased water intake? A. osmolality of extracellular fluid. B. aldosterone. C. glucose concentration. D. antidiuretic hormone (ADH).
A. osmolality of extracellular fluid Increasing osmolality of ECF stimulates the hypothalamic thirst center by both increasing dry mouth and directly activating osmoreceptors in the hypothalamus.
What is the most significant direct effect of aldosterone release? A. reabsorption of sodium in kidney tubules. B. rapid drop in blood pressure. C. activation of angiotensinogen into angiotensin I. D. stimulate renin production via juxtaglomerular cells of the kidneys.
A. reabsorption of sodium in kidney tubules Aldosterone causes the reabsorption of sodium, and because water follows salt, water is also reabsorbed, increasing blood pressure and volume.
ECF osmolality is primarily dependent on __________. A. relative quantities of sodium and water. B. blood pressure. C. sodium content of the body only. D. water content of the body only
A. relative quantities of sodium and water ECF osmolality is primarily a measure of the concentration of sodium per kilogram of water. This concentration depends on both water and sodium levels, and a disruption of either affects osmolality.
Of the three buffering mechanisms in the body, which is the strongest? A. renal system B. chemical buffer system C. respiratory system
A. renal system Yes, although slow, the renal system is the strongest buffering system in the body. By altering the reabsorption and excretion of hydrogen ions and bicarbonate ions, the kidneys control the pH of body fluids.
Which acid-base imbalance would be caused by over accumulation of CO2 in the blood? A. respiratory acidosis B. metabolic acidosis C. respiratory alkalosis D. metabolic alkalosis
A. respiratory acidosis Respiratory acidosis occurs during periods of hypoventilation. This allows CO2 to build up in the lungs, lowering blood pH and increasing PCO2.
Nancy is experiencing an acute panic attack. While hyperventilating, she remembers to open a paper bag and breathe into it. What is Nancy trying to prevent? A. respiratory alkalosis B. respiratory acidosis C. metabolic acidosis D. metabolic alkalosis
A. respiratory alkalosis
Which of the following would likely be increased by the release of atrial natriuretic peptide (ANP)? A. water excretion by the kidneys. B. antidiuretic hormone (ADH) production. C. aldosterone production. D. blood pressure
A. water excretion by the kidneys ANP inhibits reabsorption in the kidney tubules, which then results in an increase in water excretion. ANP also directly inhibits the release of ADH, renin, and aldosterone.
How many hydrogen ions must be secreted into the filtrate in order to reabsorb one bicarbonate? A. 0 B. 1 C. 2 D. 3
B. 1 For each hydrogen ion secreted, one bicarbonate ion is consumed in the filtrate and converted to carbon dioxide. Carbon dioxide can cross the apical membrane by simple diffusion.
How do physiological buffer systems differ from chemical buffer systems? A. Physiological buffer systems use different compounds than those used by chemical buffer systems. B. Chemical buffer systems convert strong acids or bases into weak acids or bases, while physiological buffer systems remove acids and bases from the body. C. Physiological buffer systems regulate the pH within specific organs, while chemical buffer systems regulate body fluid pH. D. Physiological buffer systems operate faster than chemical buffers, but they are less powerful.
B. Chemical buffer systems convert strong acids or bases into weak acids or bases, while physiological buffer systems remove acids and bases from the body.
Which of these combinations of values would help you determine if your patient was suffering from metabolic acidosis? A. Increased PC02 levels in the blood and decreased pH . B. Decreased blood HCO3- levels and decreased pH . C. Decreased PC02 levels in the blood and increased pH levels . D. Increased blood HCO3- levels and decreased pH.
B. Decreased blood HCO3- levels and decreased pH If the problem is not respiratory, then often carbon dioxide levels are normal. If the kidneys are excreting too much HCO3-, then your pH will decrease.
Which of the following statements is true regarding fluid shifts? A. There are always more positive electrolytes than negative in a solution; it is therefore impossible to follow fluid shifts. B. Electrolytes have greater osmotic power than nonelectrolytes and therefore have the greatest ability to cause fluid shifts. C. Electrolytes are not as important as proteins in regulating fluid shifts in the body. D. Nonelectrolytes are the controlling factor in directing fluid shifts.
B. Electrolytes have greater osmotic power than nonelectrolytes and therefore have the greatest ability to cause fluid shifts.
Mr. Heyden's blood K+ levels are high. Which of the following best explains his high K+ levels? A. Mr. Heyden's increased secretion of ADH will cause his K+ levels to increase. B. Mr. Heyden's damaged kidneys can no longer adequately remove K+ from his blood. C. The loss of Mr. Heyden's spleen means that his aged and fragile erythrocytes are not being removed, and so are rupturing in his blood vessels and releasing K+. D. Mr. Heyden's increased secretion of aldosterone will cause his K+ levels to increase.
B. Mr. Heyden's damaged kidneys can no longer adequately remove K+ from his blood. The kidneys' main role in K+ regulation is to remove excess K+.
Which of the following chemicals should be added to the solution at (b) in order to create a buffered solution that will resist pH change? A. additional H2CO3 B. Na2CO3 C. water D. HCl
B. Na2CO3 The addition of CO3−2 to the solution, along with the HCO−3 that is already present, will produce a buffer solution that will resist pH change. Buffers are solutions containing an acid and its conjugate base (which has one less hydrogen).
What is the most likely explanation for the increased concentration of Mrs. M's blood? A. Solutes have moved from her intestinal contents into her blood. B. Water has moved from her blood into her intestinal contents, leaving solutes behind. C. Water has moved from her intestinal contents into her blood. D. Body cells have added water to her blood.
B. Water has moved from her blood into her intestinal contents, leaving solutes behind. Good. Abnormal lab values indicate a problem. In this case, the fact that ALL of the values are abnormal suggests that the underlying problem is loss of water from the blood.
Which of the following would NOT be associated with a rise in K+ concentration in the extracellular fluid (ECF)? A. release of aldosterone B. a drop in Na+ reabsorption C. stimulation of the adrenal cortex D. a rise in K+ excretion
B. a drop in Na+ reabsorption Rising levels of K+ directly influence the adrenal cortex. The subsequent release of aldosterone leads to both increased loss of K+ in the urine and increased reabsorption of Na+.
Respiratory acidosis can occur when ________. A. the kidneys secrete hydrogen ions. B. a person's breathing is shallow due to obstruction. C. a person consumes excessive amounts of antacids. D. a runner has completed a very long marathon
B. a person's breathing is shallow due to obstruction
Which hormone results in increased blood sodium levels? A. ADH B. aldosterone C. progesterone D. PTH
B. aldosterone Aldosterone increases Na+ reabsorption.
What hormone reduces blood pressure and blood volume by inhibiting nearly all events that promote vasoconstriction and sodium ion and water retention? A. aldosterone B. atrial natriuretic peptide (ANP) C. antidiuretic hormone (ADH) D. thyroxine
B. atrial natriuretic peptide (ANP)
The most important force causing net outward water flow across capillary walls is ________. A. osmotic pressure of plasma proteins. B. hydrostatic pressure of capillary blood. C. hydrostatic pressure of interstitial fluid. D. intracellular hydrostatic pressure.
B. hydrostatic pressure of capillary blood
Which of the following would NOT be expected to lead to edema? A. inflammation B. hyponatremia C. incompetent venous valves D. hypoproteinemia
B. hyponatremia Hyponatremia is low levels of sodium in the blood. This can lead to dehydration, not edema.
After completing a marathon on a particularly warm day, Dave consumes four liters of water. Soon after, he begins to feel nauseous and starts vomiting. What is likely happening to Dave? A. dehydration. B. hyponatremia; very low extracellular sodium ion concentration. C. obligatory water loss. D. hypoproteinemia; unusually low levels of plasma proteins
B. hyponatremia; very low extracellular sodium ion concentration
Which of the following conditions promotes edema? A. diabetes mellitus. B. hypoproteinemia C. hemorrhage. D. hyponatremia
B. hypoproteinemia Low protein levels in the blood, which can be caused by conditions such as liver failure, will lower its osmolality, resulting in fluid loss from the plasma to the extracellular fluid.
What might be a sign that the renin-angiotensin-aldosterone mechanism is NOT producing enough aldosterone? A. increased blood pressure. B. increased excretion of water and NaCl in urine. C. increased antidiuretic hormone (ADH) production. D. increased blood volume
B. increased excretion of water and NaCl in urine Aldosterone is primarily responsible for triggering reabsorption of water and NaCl.
Which of the following is NOT a trigger for juxtaglomerular granular cells to release renin? A. decreased stretch of the granular cells of the afferent arterioles. B. increased extracellular fluid water levels. C. decreased filtrate NaCl concentration. D. sympathetic stimulation
B. increased extracellular fluid water levels
The regulation of potassium balance ________. A. is not linked to sodium balance. B. involves aldosterone-induced secretion of potassium. C. is accomplished mainly by hepatic mechanisms. D. includes renal secretion, but never absorption
B. involves aldosterone-induced secretion of potassium
Blood analysis indicates a low pH, and the patient is breathing rapidly. Given your knowledge of acid-base balance, which of the following is most likely? A. respiratory acidosis B. metabolic acidosis C. respiratory alkalosis D. metabolic alkalosis
B. metabolic acidosis
Starvation would cause which of the following acid-base conditions? Also, determine what type of compensation (metabolic or respiratory) there would be. A. respiratory alkalosis with metabolic compensation. B. metabolic acidosis with respiratory compensation. C. respiratory acidosis with metabolic compensation. D. metabolic alkalosis with respiratory compensation.
B. metabolic acidosis with respiratory compensation Yes, this is known as a ketosis (due to the breakdown of fat for metabolism), and the respiratory system would increase respiration to compensate for the excess hydrogen ions.
A patient is breathing slowly, and blood pH analysis indicates an abnormally high value. What is the likely diagnosis? A. respiratory alkalosis B. metabolic alkalosis C. respiratory acidosis D. metabolic acidosis
B. metabolic alkalosis
Vomiting will cause which type of acid-base disturbance? A. metabolic acidosis B. metabolic alkalosis C. respiratory alkalosis D. respiratory acidosis
B. metabolic alkalosis Yes, loss of HCL acid from the stomach would cause a metabolic alkalosis.
A friend has acid indigestion after eating a big meal. Which of the following would act as a buffer and help ease his pain? A. pure water, with a pH of 7. B. milk of magnesia, with a pH of 10. C. cola, with a pH of 3. D. black coffee, with a pH of 5.
B. milk of magnesia, with a pH of 10 Excellent! Excess acid can be buffered by the addition of an alkaline or base.
Insufficient parathyroid hormone production in the body could result in ________. A. muscle weakness B. muscle twitching C. cardiac arrhythmia D. kidney stones
B. muscle twitching
Which of the following is NOT a chemical buffer system? A. bicarbonate B. nitrogen C. protein D. phosphate
B. nitrogen
Atrial natriuretic peptide (ANP) is a hormone that is made in the atria of the heart. The influence of this hormone is to ________. A. prevent pH changes caused by organic acids. B. reduce blood pressure and blood volume by inhibiting sodium and water retention. C. enhance atrial contractions. D. activate the renin-angiotensin mechanism
B. reduce blood pressure and blood volume by inhibiting sodium and water retention
Emphysema can lead to which acid/base disturbance? What would be the compensation? A. respiratory acidosis; hyperventilation. B. respiratory acidosis; kidneys will retain more HCO3 − and excrete H+. C. respiratory alkalosis; kidneys will retain more H+ and excrete HCO3 − . D. metabolic acidosis; hypoventilation by the lungs.
B. respiratory acidosis; kidneys will retain more HCO3 − and excrete H+ Yes, a patient with emphysema would retain CO2, leading to a respiratory acidosis. The kidneys would compensate by retaining HCO3 − and excreting H+.
Severe anxiety would cause which type of acid-base disturbance? What would be the compensation? A. respiratory alkalosis; kidneys would retain HCO3. B. respiratory alkalosis; kidneys would excrete HCO3. C. metabolic alkalosis; hypoventilation by the lungs. D. respiratory acidosis; kidneys would excrete HCO3.
B. respiratory alkalosis; kidneys would excrete HCO3 Yes, during hyperventilation caused by severe anxiety, carbonic acid is excreted from the lungs in the form of CO2, thus causing an alkalosis. Kidneys would compensate by excreting HCO3.
The maintenance of the proper pH of the body fluids may be the result of ________. A. the active secretion of OH- into the filtrate by the kidney tubule cells. B. the control of respiratory ventilation. C. the operation of the various buffer systems in the stomach. D. control of the acids produced in the stomach
B. the control of respiratory ventilation
Falling arterial blood pressure promotes ________. A. enhanced sodium ion loss in urine. B. vasoconstriction. C. enhanced water loss in urine. D. vasodilation
B. vasoconstriction
This chemical equation shows the reaction of a strong acid and weak base in the bicarbonate buffer system. Provide the products of the following reaction. A. NaH2PO4 + NaCl B. NaHCO3 + H2O C. H2CO3 + NaCl D. NaOH + NaH2PO4
C. H2CO3 + NaCl HCl is a strong acid and will completely dissociate in water, as will the salt NaHCO3. The bicarbonate ion will bond to the free hydrogen ion forming carbonic acid, while the remaining ions will form aqueous salt (NaCl).
What is the most abundant intracellular cation? A. HPO42− B. Na+ C. K+ D. Cl−
C. K+ K+ is the most abundant cation in the intracellular fluid.
Which of the following describes the distribution of sodium and potassium between cells and body fluids? A. Na+ mainly in the cells, K+ in the body fluids. B. equal amounts of each ion in the cells and body fluids. C. K+ mainly in the cells, Na+ in the body fluids. D. little of either in the cells, but large amounts of each in the body fluids.
C. K+ mainly in the cells, Na+ in the body fluids
Which organs are most important for the long-term regulation of acid-base homeostasis? A. gastrointestinal tract organs B. cardiovascular organs C. kidneys D. lungs
C. Kidneys The kidneys regulate pH over long-term time periods.
Which of the following substances is a key component of the major buffer system in extracellular fluids? A. protein B. NaOH C. NaHCO3 D. NaH2PO4
C. NaHCO3 The bicarbonate buffer system is the only important ECF buffer and consists of a solution of carbonic acid (H2CO3) and its salt, sodium bicarbonate (NaHCO3, a weak base).
After treatment with intravenous fluids, Mrs. M. is feeling better and is able to talk with her doctor. She tells you she has finally agreed to have a colostomy − an operation in which part of her large intestine is removed, leaving an opening on her abdomen (a stoma) where the intestinal contents are emptied into a colostomy bag. She refused this operation for years because her aunt had an ileostomy and struggled with fluid balance and managing her ileostomy bag. In Mrs. M's aunt's ileostomy, all of the large intestine was removed. In Mrs. M's colostomy, only part of the large intestine will be removed. How will water balance be different in patients with an ileostomy versus a colostomy? Choose the best answer. A. They will have the same kind of problems with water balance because both have had part of their intestines removed. B. Patients with a colostomy will have more problems with water balance because they have more intestinal surface to absorb solutes into the blood. C. Patients with an ileostomy will have more problems with water balance because they have less intestinal surface to absorb solutes into the blood.
C. Patients with an ileostomy will have more problems with water balance because they have less intestinal surface to absorb solutes into the blood. Good work. The large intestine absorbs solutes from the intestinal contents into the blood, and water follows the solutes. If the entire large intestine is removed (ileostomy), the discharge into the patient's ostomy bag will contain lots of unabsorbed solutes and water and will be very fluid. If only part of the colon is removed (colostomy), the discharge will be less watery and more like regular stools, because more solutes and water have been absorbed from the intestinal contents into the blood.This means that clients with ileostomies will have a bigger problem remaining hydrated.DID YOU KNOW: The ostomy nurse may be the person who decides where the ostomy opening will be, in consultation with the patient, and marks the patient's skin to direct the surgeon.You have used the concept of osmosis to understand why water moves from the blood into the intestines and back again, how a serious emergency can result from an obstructed bowel, what the likely cause is for a patient's abnormal lab results, and what surgery will cause the most difficulties for the patient. Who knew that one concept could be so useful?
Which of the electrolyte solutes is most responsible for osmotic pressure in body fluids and cells? A. calcium B. potassium C. sodium D. phosphate
C. Sodium Sodium is the most abundant cation in ECF, and the amount of sodium present significantly affects ECF volume and water distribution throughout the body.
Annie has just eaten a large order of heavily salted French fries, some pickled eggs, and some cheese. How will consuming this much salt affect her physiology? A. She will experience hypotension. B. There will be a shift in the pH of her body fluids to the higher side of the pH scale. C. There will be a temporary increase in blood volume. D. It will cause a prolonged increase in the osmolality of the blood.
C. There will be a temporary increase in blood volume.
What accounts for the route through which most fluid is lost in a day? A. sweat B. insensible loss through skin and lungs C. urine D. feces
C. Urine Urine typically accounts for 60% of water lost. This amount is regulated in the nephrons of the kidney.
If a person exercises for a long time, lactic acid will start to build up in his or her muscles. Which of the following would you expect to happen as the lactic acid first starts to be formed? A. More water will move to the muscles to move out the acid. B. More water will move to the muscles to buffer the acid. C. Weak bases in the muscles will act as buffers and resist or minimize any pH change.
C. Weak bases in the muscles will act as buffers and resist or minimize any pH change. Excellent! Bases buffer acids, and acids buffer bases.
An increase in blood CO2 levels leads to __________. A. a decreased respiratory rate B. a decrease in carbonic acid C. a drop in blood pH D. an increase in blood pH
C. a drop in blood pH An increase in CO2 results in the formation of more carbonic acid, which leads to an increase in acidity, or a drop in pH.
The pH of the ECF is maintained in homeostatic balance by which chemical buffer system? A. phosphate B. lipid C. bicarbonate D. protein
C. bicarbonate Although the bicarbonate buffer system helps buffer the ICF, it is the only significant buffer system that maintains ECF pH homeostasis.
What is the primary buffer in the plasma? A. sodium-potassium buffer system. B. phosphate buffer system C.bicarbonate buffer system. D. protein buffer system.
C. bicarbonate buffer system Bicarbonate is the form that CO2 is transported in the blood stream. Using carbonic anhydrase to shift between bicarbonate and carbonic acid, the pH of the blood stream can be quickly regulated.
Which of the following is NOT involved in triggering the thirst mechanism? A. decrease in blood volume. B. dry mouth. C. increase in blood pressure. D. detection of increased osmolality by osmoreceptors.
C. increase in blood pressure An increase in blood pressure would lead to a drop in the hormones and responses that would, in turn, trigger the thirst mechanism.
The majority of the fluid in the body is the __________. A. plasma B. electrolytic fluid C. intracellular fluid D. interstitial fluid
C. intracellular fluid Intracellular fluid makes up about 40% of the body weight and comprises over half of the fluid in the body.
The regulation of sodium ________. A. is due to specific sodium receptors in the hypothalamus. B. involves aldosterone, a hormone that increases sodium excretion in the kidneys C. is linked to blood pressure. D. involves hypothalamic osmoreceptor detection of ion concentration.
C. is linked to blood pressure
The movement of fluids between cellular compartments ________. A. requires active transport. B. always involves filtration. C. is regulated by osmotic and hydrostatic forces. D. requires ATP for the transport to take place.
C. is regulated by osmotic and hydrostatic forces
Angiotensinogen is constantly produced by the __________. A. adrenal cortex. B. atrial cells of the heart. C. liver. D. kidney.
C. liver The liver continuously secretes angiotensinogen.
Ingesting too much antacid would cause which of the following acid-base disturbances? A. respiratory alkalosis B. metabolic acidosis C. metabolic alkalosis D. respiratory acidosis
C. metabolic alkalosis Yes, ingestion of an antacid would increase the bicarbonate, causing a metabolic alkalosis.
When a strong acid such as HCl is added to the carbonic acid buffer system, _________. A. carbonic acid is converted into bicarbonate. B. the blood plasma pH is reduced. C. more carbonic acid is formed. D. hydrochloric acid is neutralized by sodium hydroxide
C. more carbonic acid is formed
When antidiuretic hormone (ADH) levels are low, ________. A. aquaporins are inserted into the collecting duct principal cell apical membranes. B. a small volume of concentrated urine is excreted. C. most of the water reaching the collecting ducts is not reabsorbed. D. nearly all of the filtered water is reabsorbed.
C. most of the water reaching the collecting ducts is not reabsorbed
Whereas sodium is found mainly in the extracellular fluid, most ________ is found in the intracellular fluid. A. iron B. chloride C. potassium D. bicarbonate
C. potassium
The single most important factor influencing potassium ion secretion is ________. A. the potassium ion content in the renal tubule cells. B. intracellular sodium levels. C. potassium ion concentration in extracellular fluid. D. the pH of the intracellular fluid
C. potassium ion concentration in extracellular fluid
A patient is admitted to the hospital with the following plasma values: pH = 7.2, pCO2 = 55 mmHg, and HCO3 − = 30 mEq/L. What is the acid base imbalance? A. metabolic alkalosis with respiratory compensation. B. respiratory alkalosis with metabolic compensation. C. respiratory acidosis with metabolic compensation. D. metabolic acidosis with respiratory compensation.
C. respiratory acidosis with metabolic compensation Yes, this is a respiratory acidosis with metabolic compensation. Since pCO2 is above the normal range, it is the cause of the acidosis. HCO3 −− is increased to compensate, which is a metabolic compensation.
The body's water volume is closely tied to the level of which of the following ions? A. potassium ions B. calcium ions C. sodium ions D. hydrogen ions
C. sodium ions
Hypersecretion of aldosterone results in hypokalemia, which causes hyperpolarization of neurons; this in turn results in ______. A. increased speed of sodium-potassium pump activity in order to compensate for the reduced concentration of potassium ions. B. decreased plasma membrane permeability to potassium ions. C. the need for a stronger than normal stimulus in order to trigger an action potential. D. a craving for more salt in the diet
C. the need for a stronger than normal stimulus in order to trigger an action potential To trigger an action potential cells must reach threshold (critical electrical value required to open voltage-gated ion channels). If the membrane potential is hyperpolarized and falls below normal resting membrane potential, more cations must enter the cytoplasm for the cell to reach threshold.
Which of the following does NOT impact how much sodium is reabsorbed? A. aldosterone B. atrial natriuretic peptide C. transport maximum of the renal proximal tubule. E. estrogen
C. transport maximum of the renal proximal tubule The transport maximum only describes the max potential for sodium transport. This transport is regulated by hormones that influence transport, especially beyond the proximal convoluted tubule (PCT).
What percentage of extracellular fluid is accounted for by interstitial fluid and plasma? A. 20% B. 40% C. 80% D. 100%
D. 100% All of the extracellular water in the body is accounted for by interstitial fluid (80%) and plasma (20%).
In a typical day, what amount of water is taken by mouth? A. 250 milliliters B. 750 milliliters C. 1500 milliliters D. 2250 milliliters
D. 2250 milliliters The combined volume of water from food (750 milliliters) and beverages (1500 milliliters) is 2250 milliliters.
When the blood becomes acidic (acidosis) and bicarbonate ions have been depleted, new bicarbonate ions must be generated in the plasma. Which of the following is NOT a means for replenishing bicarbonate ions? A. Ammonium ions are excreted in urine. B. Buffered hydrogen ions are excreted in urine. C. Glutamine is metabolized by deamination, oxidation, and acidification. D. Bicarbonate ions are reclaimed by tubular reabsorption.
D. Bicarbonate ions are reclaimed by tubular reabsorption.
How does carbonic acid alone directly affect the pH of blood? A. Carbonic acid acts as a buffer by binding to a strong acid, producing a weak acid and salt, thus lowering blood pH. B. Carbonic acid is a strong acid that, if added to blood, causes the pH to rise. C. Carbonic acid is a strong acid that dramatically lowers blood pH unless immediately neutralized by a buffer. D. Carbonic acid does not significantly affect blood pH.
D. Carbonic acid does not significantly affect blood pH. The difference between strong acids and weak ones is their ability to dissociate in water. Weak acids such as carbonic acid do not completely dissociate, which limits their effect on pH, whereas strong acids such as HCl completely dissociate
What negatively charged ion is reabsorbed by renal tubules when the blood pH is drawing near its alkaline limit? A. NO2- B. HCO3- C. PO4-3 D. Cl-
D. Cl-
Which of the following would NOT be expected to occur as a result of dehydration? A. shrinkage of body cells B. reduced urine flow C. hypovolemic shock D. edema
D. Edema Edema is tissue swelling that results from an atypical accumulation of fluid in the interstitial space. During dehydration, this fluid would be reduced.
Which of the following is true of electrolytes? A. They are produced from water. B. They are held together by covalent bonds. C. They do not dissolve in water. D. They are ionic compounds.
D. They are ionic compounds. Excellent! Electrolytes dissociate, or come apart, in water, releasing ions, which have electrical charges—hence the term "electrolyte."
In order to buffer a strong acid into a weak acid, which has a less dramatic effect on pH, what chemical should be used as the buffer? A. water B. a weak acid C. salt D. a weak base
D. a weak base Weak bases have an affinity for hydrogen ions in water and, by binding them, reduce their effects on pH.
Which of the choices below exerts primary control over sodium levels in the body? A. water levels b. glucocorticoids c. ADH d. aldosterone
D. aldosterone
Which of the choices below is NOT an essential role of salts in the body? A. neuromuscular activity B. secretory activity C. membrane permeability D. anabolism of lipids
D. anabolism of lipids
What type of water imbalance increases the amount of fluid in both cells and tissue? A. Inflammation B. dehydration C. edema D. hypotonic hydration
D. hypotonic hydration Hypotonic hydration occurs when extracellular fluid becomes so hypotonic (dilute) that water is pulled into the cells. Excess water is present in cells and extracellular compartments.
What is a likely result of rapidly consuming excessive quantities of electrolytes? A. decreased sensation of thirst B. decreased blood pressure C. increased aldosterone production D. increased blood pressure
D. increased blood pressure Increased electrolyte levels increase ECF osmolality, which then triggers an increase in blood volume via osmosis and, therefore, an increase in blood pressure.
Which age group most commonly has fluid, electrolyte, and acid-base balance issues? A. growing children B. the elderly C. young adults D. infants
D. infants Several factors work together to cause myriad problems in infants.
Which of the following does NOT serve as a source of acids in the body? A. fat metabolism B. aerobic breakdown of glucose C. CO2 in the blood D. ingesting of bicarbonate
D. ingesting of bicarbonate
In which compartment of the body is the majority of water stored? A. extracellular fluid (ECF) compartment. B. interstitial fluid (IF) C. plasma D. intracellular fluid (ICF) compartment
D. intracellular fluid (ICF) compartment The intracellular fluid (ICF) compartment holds about 62.5% of the body's water, or 40% of the body's total weight, making it the largest of the three compartments.
A patient is admitted to the hospital with the following plasma values: pH = 7.2, pCO2 = 25 mmHg, and HCO3 − = 18 mEq/L. What is the acid base imbalance? A. metabolic acidosis with no compensation. B. metabolic alkalosis with respiratory compensation. C. respiratory acidosis with metabolic compensation. D. metabolic acidosis with respiratory compensation.
D. metabolic acidosis with respiratory compensation Yes, the low bicarbonate indicates this is a metabolic acidosis. Since CO2 is below the normal range, this indicates there is a respiratory compensation.
Diarrhea can lead to which acid/base disturbance? Assuming compensation, would it be a metabolic or respiratory compensation? A. metabolic alkalosis with respiratory compensation. B. respiratory alkalosis with metabolic compensation. C. respiratory acidosis with metabolic compensation. D. metabolic acidosis with respiratory compensation.
D. metabolic acidosis with respiratory compensation Yes, with the loss of bicarbonate ions, this is a metabolic acidosis. If compensated, it would be a respiratory compensation.
Which of the following blood workups would most likely demonstrate metabolic acidosis? A. pH: 7.33; PCO2: 50 mmHg; HCO3 -: 30 mEq/L. B. pH: 7.50; PCO2: 50 mmHg; HCO3 -: 30 mEq/L. C. pH: 7.55; PCO2: 30 mmHg; HCO3 -: 20 mEq/L. D. pH: 7.33; PCO2: 30 mmHg; HCO3 -: 20 mEq/L.
D. pH: 7.33; PCO2: 30 mmHg; HCO3 -: 20 mEq/L The pH indicates acidosis, but the PCO2 is low. The cause is not likely to be respiratory acidosis. The HCO3 - concentration indicates that the cause here would be metabolic acidosis.
A falling blood pH and a rising partial pressure of carbon dioxide due to pneumonia or emphysema indicates ________. A. metabolic alkalosis B. metabolic acidosis C. respiratory alkalosis D. respiratory acidosis
D. respiratory acidosis
A patient is admitted to the hospital with the following plasma values: pH = 7.5, pCO2 = 45 mmHg, and HCO3 − = 30 mEq/L. What is the acid-base imbalance? A. respiratory alkalosis with metabolic compensation. B. respiratory acidosis with metabolic compensation. C. metabolic alkalosis with respiratory compensation. D. metabolic alkalosis with no compensation.
metabolic alkalosis with no compensation Yes, since HCO3¯ is 30 (above the normal range of 22 to 26 mEq/L), this is definitely a metabolic alkalosis. There is no respiratory compensation since CO2 is within the normal range
