Physiology Electrolytes Answer Key

MATCHING. Choose the item in column 2 that best matches each item in column 1. Match the following: 1) Dissociate into ions in water. A) Electrolytes Answer: A B) Interstitial 2) Do not dissociate in solution. Answer: E 3) The main fluid compartment outside the cells. Answer: C C) Extracellular D) Intracellular E) Nonelectrolytes 4) The main fluid compartment located within the cell. Answer: D 5) Fluid in the spaces between cells. Answer: B Match the following: 6) Magnesium excess. A) Hyperkalemia Answer: D B) Hypocalcemia 7) Calcium depletion. Answer: B 8) Sodium excess. C) Hypernatremia D) Hypermagnesemia Answer: C 9) Potassium excess. E) Hyponatremia Answer: A 10) Sodium depletion. Answer: E 1 Match the following: 11) An atypical accumulation of fluid in the interstitial space. Answer: E 12) Fluid loss, either the loss of water or the loss of water and solutes together. Answer: D 13) A disorder entailing deficient aldosterone production by the adrenal cortex. A) Hyponatremia B) Addison's disease C) Aldosterone D) Dehydration E) Edema Answer: B 14) Regulates sodium ion concentrations in the extracellular fluid. Answer: C 15) A condition due to excessive water intake that results in net osmosis into tissue cells. This leads to severe metabolic disturbances. Answer: A Match the electrolyte composition for the following: 16) The concentration of sodium ions is highest in ________. Answer: C 17) The concentration of potassium ions is highest in ________. A) Intracellular fluid B) Interstitial fluid C) Blood plasma Answer: A 18) The concentration of phosphate ions is highest in ________. Answer: A 19) The concentration of bicarbonate ions is highest in ________. Answer: B 20) The concentration of protein anions is highest in ________. Answer: A 2 Match the following: 21) Possibly caused by severe diarrhea or untreated diabetes mellitus. Answer: C A) Metabolic alkalosis B) Respiratory alkalosis 22) Possibly occurring with emphysema, extreme obesity, or narcotic overdose. Answer: D C) Metabolic acidosis D) Respiratory acidosis 23) Possibly caused by asthma, pneumonia, or a severe panic attack. Answer: B 24) Possibly caused by vomiting, use of diuretics, or use of antacids. Answer: A TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 25) Adipose tissue is one of the most hydrated of all tissues in the human body. Answer: True False 26) The most abundant cation in intracellular fluid is sodium. Answer: True False 27) Electrolytes determine most of the chemical and physical reactions of body fluids. Answer: True False 28) Solutes, regardless of size, are able to move freely between compartments because water carries them along the osmotic gradients. Answer: True False 29) The thirst center in the brain is located in the hypothalamus. Answer: True False 30) Dehydration can be caused by endocrine disturbances such as diabetes mellitus or diabetes insipidus. Answer: True False 31) It is impossible to overhydrate because people need as much water as they can drink to carry out ordinary body functions. Answer: True False 32) Water imbalance, in which output exceeds intake, causing an imbalance in body fluids, is termed dehydration. Answer: True False 33) Salts are lost from the body in perspiration and urine only. Answer: True False 3 34) Excessive loss of water from the extracellular fluid (ECF) leads to a rise in osmotic pressure in the ECF which causes cells to shrink as water leaves by osmosis. Answer: True False 35) Although the sodium content of the body may be altered, its concentration in the ECF remains relatively stable because of immediate adjustments in water volume. Answer: True False 36) Sodium is pivotal to fluid and electrolyte balance and to the homeostasis of all body systems. Answer: True False 37) When aldosterone release is inhibited, sodium reabsorption cannot occur beyond the distal convoluted tubule. Answer: True False 38) Aldosterone stimulates the reabsorption of sodium while enhancing potassium secretion. Answer: True False 39) Some potassium ions are reabsorbed from the kidney filtrate via type A intercalated cells, a unique population of collecting duct cells. Answer: True False 40) Aldosterone is secreted in response to low extracellular potassium. Answer: True False 41) To remain properly hydrated, water intake must equal water output. Answer: True False 42) The main way the kidney regulates potassium ions is to excrete them. Answer: True False 43) Obligatory water loss occurs because humans always take in more fluids through eating and drinking than they need to maintain water balance. Answer: True False 44) Premenstrual edema may be due to enhanced reabsorption of sodium chloride. Answer: True False 45) Heavy consumption of salt substitutes high in potassium can present a serious clinical problem when aldosterone release is not normal. Answer: True False 46) Insensible water loss includes water lost in feces. Answer: True False 47) The two hormones responsible for the regulation of calcium are pituitary hormone and calcitonin. Answer: True False 48) Calcitonin targets the bones and causes the release of calcium from storage when serum calcium levels are low. Answer: True False 4 49) The normal pH of blood is 7.35- 7.45. Answer: True False 50) Most acidic substances (hydrogen ions) originate as by- products of cellular metabolism. Answer: True False 51) Weak acids are able to act as chemical buffering systems for the body because they only partially dissociate. Answer: True False 52) The phosphate buffer system is relatively unimportant for buffering blood plasma. Answer: True False 53) The single most important blood buffer system is the bicarbonate buffer system. Answer: True False 54) One of the most powerful and plentiful sources of buffers is the protein buffer system. Answer: True False 55) As ventilation increases and more carbon dioxide is removed from the blood, the hydrogen ion concentration of the blood decreases. Answer: True False 56) Carotid artery and aortic baroreceptors are involved in long term adjustment to total body sodium ion content. Answer: True False 57) Respiratory acidosis results when lungs are obstructed and gas exchange is inefficient. Answer: True False 58) Prolonged hyperventilation can cause alkalosis. Answer: True False 59) Thirst is normally triggered by hypothalamic osmoreceptors sensitive to a 1- 2% increase in plasma osmolality. Answer: True False 60) Blood acidity results in depression of the CNS, whereas blood alkalosis results in overexcitement of the CNS. Answer: True False MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 61) The body's water volume is closely tied to the level of which of the following ions? A) sodium ions B) hydrogen ions C) calcium ions D) potassium ions Answer: A 62) The term hypotonic hydration refers to ________. A) a condition that may result from renal insufficiency or drinking excessive amounts of water B) a condition that is caused by high levels of sodium in the extracellular fluid compartment C) the feeling one might have after profuse sweating with exertion D) the unpleasant feeling people have after drinking too much liquor Answer: A 5 63) When antidiuretic hormone (ADH) levels are low, ________. A) a small volume of concentrated urine is excreted B) nearly all of the filtered water is reabsorbed C) aquaporins are inserted into the collecting duct principal cell apical membranes D) most of the water reaching the collecting ducts is not reabsorbed Answer: D 64) Which of the following hormones is important in the regulation of sodium ion concentrations in the extracellular fluid? A) antidiuretic hormone B) aldosterone C) erythropoietin D) renin Answer: B 65) Atrial natriuretic peptide (ANP) is a hormone that is made in the atria of the heart. The influence of this hormone is to ________. A) enhance atrial contractions B) reduce blood pressure and blood volume by inhibiting sodium and water retention C) prevent pH changes caused by organic acids D) activate the renin- angiotensin mechanism Answer: B 66) Respiratory acidosis can occur when ________. A) a person consumes excessive amounts of antacids B) the kidneys secrete hydrogen ions C) a person's breathing is shallow due to obstruction D) a runner has completed a very long marathon Answer: C 67) Total body water is NOT a function of which of the following? A) amount of water ingested B) amount of body fat C) age D) body mass Answer: A 68) Which of the choices below is NOT an essential role of salts in the body? A) anabolism of lipids B) membrane permeability C) neuromuscular activity D) secretory activity Answer: A 69) Which of the choices below exerts primary control over sodium levels in the body? A) glucocorticoids B) ADH C) aldosterone D) water levels Answer: C 70) The fluid link between the external and internal environment is ________. A) interstitial fluid B) cerebrospinal fluid C) intracellular fluid Answer: D 6 D) plasma 71) 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 eliminate carbon dioxide. B) Kidneys retain bicarbonate ions. C) Kidneys eliminate bicarbonate ions. D) Kidneys retain hydrogen ions. Answer: B 72) Whereas sodium is found mainly in the extracellular fluid, most ________ is found in the intracellular fluid. A) bicarbonate B) chloride C) potassium D) iron Answer: C 73) Which of the following describes the distribution of sodium and potassium between cells and body fluids? A) K+ mainly in the cells, Na+ in the body fluids B) little of either in the cells, but large amounts of each in the body fluids C) Na+ mainly in the cells, K+ in the body fluids D) equal amounts of each ion in the cells and body fluids Answer: A 74) For bulk flow across capillary walls, ________. A) fluid runs into lymphatic capillaries that empty into the interstitial space B) hydrostatic pressure of the interstitial space returns fluid to the capillary C) hydrostatic pressure of blood forces nearly protein- free plasma out of the blood into the interstitial space D) osmotic pressure of plasma proteins pulls fluid from the capillary into the interstitial space Answer: C 75) The single most important factor influencing potassium ion secretion is ________. A) potassium ion concentration in extracellular fluid B) the pH of the intracellular fluid C) intracellular sodium levels D) the potassium ion content in the renal tubule cells Answer: A 76) Amphoteric molecules _______. A) can function as acids at low pH B) trigger pH imbalances and must be neutralized by buffers C) can function as bases at high pH D) can function as an acid or a base depending on the pH Answer: D 77) A falling blood pH and a rising partial pressure of carbon dioxide due to pneumonia or emphysema indicates ________. A) respiratory acidosis B) metabolic alkalosis C) metabolic acidosis D) respiratory alkalosis Answer: A 78) The movement of fluids between cellular compartments ________. A) is regulated by osmotic and hydrostatic forces B) requires active transport C) requires ATP for the transport to take place D) always involves filtration Answer: A 7 79) What hormone reduces blood pressure and blood volume by inhibiting nearly all events that promote vasoconstriction and sodium ion and water retention? A) atrial natriuretic peptide (ANP) B) aldosterone C) antidiuretic hormone (ADH) D) thyroxine Answer: A 80) When a strong acid such as HCl is added to the carbonic acid buffer system, _________. A) more carbonic acid is formed B) carbonic acid is converted into bicarbonate C) hydrochloric acid is neutralized by sodium hydroxide D) the blood plasma pH is reduced Answer: A 81) Which of the following is NOT a chemical buffer system? A) protein B) nitrogen C) bicarbonate D) phosphate Answer: B 82) Which of the following is NOT a trigger for juxtaglomerular granular cells to release renin? A) sympathetic stimulation B) increased extracellular fluid water levels C) decreased stretch of the granular cells of the afferent arterioles D) decreased filtrate NaCl concentration Answer: B 83) 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) Nonelectrolytes are the controlling factor in directing fluid shifts. D) Electrolytes are not as important as proteins in regulating fluid shifts in the body. Answer: B 84) Which of the following would describe nonelectrolytes? A) inorganic acids C) inorganic salts B) organic bases D) polar covalent compounds Answer: D 85) 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) control of the acids produced in the stomach C) the operation of the various buffer systems in the stomach D) the control of respiratory ventilation Answer: D 8 86) Which of the following is NOT a disorder of water balance? A) edema or tissue swelling, which is usually due to an increased capillary hydrostatic pressure B) excess water in interstitial spaces due to a low level of plasma proteins C) excessive hydration due to excess atrial natriuretic peptide (ANP) secretion D) hypotonic hydration, in which sodium content is normal but water content is high Answer: C 87) The regulation of sodium ________. A) is linked to blood pressure B) involves aldosterone, a hormone that increases sodium excretion in the kidneys C) involves hypothalamic osmoreceptor detection of ion concentration D) is due to specific sodium receptors in the hypothalamus Answer: A 88) 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) metabolic acidosis B) respiratory alkalosis C) metabolic alkalosis D) respiratory acidosis Answer: A 89) 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 Answer: B 90) Which of the following is NOT a likely source of hydrogen ions in blood plasma? A) anaerobic metabolism of glucose B) aerobic metabolism of glucose C) metabolism of proteins containing phosphorus D) metabolism of fats Answer: B 91) 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 temporary increase in blood volume. C) There will be a shift in the pH of her body fluids to the higher side of the pH scale. D) It will cause a prolonged increase in the osmolality of the blood. Answer: B 92) The most important force causing net outward water flow across capillary walls is ________. A) intracellular hydrostatic pressure B) osmotic pressure of plasma proteins C) hydrostatic pressure of interstitial fluid D) hydrostatic pressure of capillary blood Answer: D 93) 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) Glutamine is metabolized by deamination, oxidation, and acidification. B) Bicarbonate ions are reclaimed by tubular reabsorption. C) Ammonium ions are excreted in urine. D) Buffered hydrogen ions are excreted in urine. Answer: B 9 94) The regulation of potassium balance ________. A) is not linked to sodium balance B) is accomplished mainly by hepatic mechanisms C) involves aldosterone- induced secretion of potassium D) includes renal secretion, but never absorption Answer: C 95) 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) obligatory water loss B) hypoproteinemia; unusually low levels of plasma proteins C) hyponatremia; very low extracellular sodium ion concentration D) dehydration Answer: C 96) Mary finds that she regularly retains water at a certain point in the menstrual cycle. Which of the following is chemically similar to aldosterone, and like aldosterone, enhances NaCl reabsorption in the renal tubules? A) follicle- stimulating hormone B) progesterone C) luteinizing hormone D) estrogen Answer: D 97) 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 acidosis B) respiratory alkalosis C) metabolic acidosis D) metabolic alkalosis Answer: B 98) If the thyroid and parathyroid glands are surgically removed, which of the following would go out of balance without replacement therapy? A) potassium ion levels B) calcium ion levels C) anion levels D) sodium ion levels Answer: B 99) Insufficient parathyroid hormone production in the body could result in ________. A) kidney stones B) muscle twitching C) muscle weakness D) cardiac arrhythmia Answer: B 100) In the case of edema, excess fluid is held in which fluid compartment(s)? A) blood plasma B) interstitial fluid C) intracellular fluid D) intracellular fluid and interstitial fluid Answer: B 101) Falling arterial blood pressure promotes ________. A) enhanced water loss in urine C) vasodilation B) enhanced sodium ion loss in urine D) vasoconstriction Answer: D 10 102) An illness causes Doug to experience severe diarrhea and an accompanying loss of bicarbonate- rich secretions. How can this metabolic acidosis be compensated? A) hypoventilation B) increased renin secretion C) enhanced sodium ion loss in urine D) increased respiratory rate and depth Answer: D SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 103) What provides the shortest- term mechanism for preventing acid- base imbalances in the body? The longest- term mechanism? Answer: Chemical buffers act within a fraction of a second to resist a pH change. The longest- term mechanism is the kidney system, which ordinarily requires from several hours to a day or more to effect changes in blood pH. 104) What is the effect of acidosis on the body? Of alkalosis? Answer: When the body is in acute acidosis, the nervous system becomes so severely depressed that the person goes into a coma and death soon follows. Alkalosis causes overexcitement of the nervous system. Characteristic signs include muscle tetany, extreme nervousness, and convulsions. Death often results from respiratory arrest. 105) Describe the mechanisms by which the kidneys remove hydrogen ions from the body. Answer: Virtually all of the H+ that leaves the body in urine is secreted into the filtrate. The tubule cells, including collecting ducts, appear to respond directly to the pH of the ECF and to alter their rate of H+ secretion accordingly. The secreted H+ ions are obtained from the dissociation of carbonic acid within the tubule cells. For each H+ ion actively secreted into the tubule lumen, one sodium ion is reabsorbed into the tubule cell from the filtrate, thus maintaining the electrochemical balance. 106) Describe the influence of rising parathyroid hormone (PTH) levels on bone, the small intestine, and the kidneys. Answer: Parathyroid hormone (PTH) activates osteoclasts that break down the bone matrix, resulting in the release of Ca2+ and PO4 3- to the blood. PTH enhances intestinal absorption of Ca2+ indirectly by stimulating the kidneys to transform vitamin D to its active form, which is necessary for calcium absorption by the small intestine. PTH increases the reabsorption of calcium by the renal tubules, which simultaneously decreases phosphate ion reabsorption. 107) When the blood becomes hypertonic (too many solutes) due to dehydration, antidiuretic hormone (ADH) is released. What is the effect of ADH on the kidney tubules? Answer: The release of ADH causes the kidney tubules to reabsorb excess water, resulting in the excretion of concentrated urine. 108) Why would an infant with colic be suffering from respiratory alkalosis? Answer: If the infant is uncomfortable and cries forcefully for long periods of time, this would be similar to hyperventilation. Hyperventilation would cause respiratory alkalosis because the infant is losing carbon dioxide rapidly. 109) How does the respiratory system influence the buffer systems of the body? Answer: The respiratory system maintains a constant bicarbonate level in the bloodstream by outgassing carbon dioxide. In the event of a respiratory problem the CO2 to bicarbonate ratio might change, in turn changing buffering effects on pH. 11 110) Identify and describe the operation of the three major chemical buffers of the body. Answer: The bicarbonate buffer system (carbonic acid plus sodium bicarbonate) acts to tie up the hydrogen ions released by a strong acid, thus converting it to a weaker acid, which lowers the pH only slightly. For a strong base, the carbonic acid will be forced to donate more H+ to tie up the OH- released by the base, with the net result of replacement of a strong base by a weak one. The pH rise is very small. The phosphate buffer system, composed of the sodium salts of dihydrogen phosphate and monohydrogen phosphate, acts in a similar fashion to the bicarbonate system. NaH2 PO4 acts as a weak acid; Na2 HPO4 acts as a weak base. Hydrogen ions released by strong acids are tied up in weak acids; strong bases are converted to weak bases. Amino acids of the protein buffer system release H+ when the pH begins to rise by dissociating carboxyl groups, or bind hydrogen ions with amine groups to form NH3 + when the pH falls. 111) List and describe three stimuli that activate the hypothalamic thirst center. Answer: Hypothalamic osmoreceptors detect ECF osmolality through changes in plasma membrane stretch that result from gaining or losing water. Dry mouth resulting from increased blood osmotic pressure and reduced saliva production. A substantial decrease in blood volume or pressure, as in hemorrhage, also triggers the thirst mechanism. ESSAY. Write your answer in the space provided or on a separate sheet of paper. 112) A patient is admitted to the hospital in complete collapse. His blood pH is 6.8, and his HCO3 - is 20 mEq/L. What diagnosis would you give and what prognosis? A medical history reveals that this patient is a chronic alcoholic. Answer: The pH and bicarbonate levels and the history of alcoholism indicate metabolic acidosis. With a pH below 7.0, the patient will go into a coma and death soon follows. 113) A pregnant woman complains to her doctor that her ankles and feet stay swollen all of the time. She is very worried about this. As her doctor, what would you tell her? Answer: She is showing edema, an atypical accumulation of fluid in the spaces between cells (interstitial spaces). This is caused by her pregnancy due to a high blood volume that increases capillary hydrostatic pressure and enhances capillary permeability. She should be monitored for the edema during the pregnancy and her BP for possible pre- eclampsia, and urine should be periodically checked for proteinuria, but the edema should clear up at the end of the pregnancy once both blood volume and uterine pressure on venous return disappear. 114) Helen is a 62- year- old smoker. Her physician has diagnosed her as having emphysema that has caused her to hypoventilate. Surprisingly, when her blood pH is checked, it is 7.40. Why? Answer: Helen is suffering from respiratory acidosis because she is retaining too much carbon dioxide. Her shallow breathing, due to the damage to her lungs from the disease, is the cause. In order to release the carbon dioxide, one must be able to breathe normally (deep breathing would be optimal). However, because this has been a long- term problem, her kidneys have excreted greater amounts of acids while retaining HCO3 - , thus providing renal compensation to her chronic respiratory acidosis. 115) After traveling from Los Angeles to Denver, Claire finds she is not feeling well and checks into a clinic for help. The clinic's diagnosis is respiratory alkalosis. What has caused this problem? Answer: Respiratory alkalosis is always caused by hyperventilation. Claire is experiencing the effect of the high altitude and was overcompensating or trying to do too much the first day in Denver. 12 116) A patient is 72 years old and was admitted to the hospital for severe shortness of breath and edema to her lower extremities. She was diagnosed with heart failure. A symptom of heart failure is generalized edema. Explain the finding of generalized edema in heart failure. Answer: Edema is an atypical accumulation of fluid in the interstitial space, leading to tissue swelling. Heart failure is one cause of edema. 117) A 13- year- old girl is admitted to the psychiatric unit for anorexia. Her body weight is 89 lbs. and height is 64 inches. She admits to frequent self- induced vomiting and abuse of laxatives. She was treated on the medical unit with intravenous fluids. Now that she is on the psychiatric unit she is experiencing fluid retention as evidenced by mild puffiness and bloating. Explain these symptoms. Answer: It is not uncommon for anorexics who are chronically fluid depleted to develop a compensatory increased production of aldosterone, which causes the kidneys to conserve sodium and water. 118) A patient's anxiety caused her to develop respiratory alkalosis. The nurse instructs the patient to take some slow deep breaths. Explain why this would be effective. Answer: Instructing the patient to breathe more slowly will reduce the elimination of CO2 . Breathing into a paper bag will cause retention of CO2 . 13