Chapter 26: Fluid, Electrolyte, and Acid-Base Balance

Which of the following does NOT impact how much sodium is reabsorbed?

B) transport maximum of the renal proximal tubule

Under normal circumstances, most water is lost in __________.

B) urine

In a given day, what is the typical value for water intake?

C) 2500 ml

PTH (parathyroid hormone) acts on the __________ to __________ Ca2+ reabsorption.

C) DCT; increase

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. HCl + NaHCO3 -->

C) H2CO3 + NaCl

What is the most abundant intracellular anion?

C) HPO4 2-

What is the most abundant intracellular cation?

C) K+

Which of the following is the only logical explanation for why hypocalcemia increases neuromuscular excitability and causes muscle tetany?

C) Low plasma calcium ion concentration increases the permeability of neuron membranes to sodium ions, thereby causing depolarization that in turn increases the likelihood of action potentials being generated. Sodium and calcium are cations, and so loss of positive charge in the extracellular fluid would increase membrane permeability to all cations, including sodium. Recall that the efflux (outward movement) of sodium causes depolarization.

Which chemical buffer system is the only important system in the extracellular fluid (ECF) that resists short-term changes in pH?

C) bicarbonate buffer system

What results from increased levels of aldosterone?

C) increased Na+ reabsorption

The fluid that bathes the cells found in tissues is called __________.

C) interstitial fluid

Which of the following is not a chemical buffer system?

C) nucleic acid

Which of the following is an electrolyte?

C) potassium

What is the most important trigger for aldosterone release?

C) renin-angiotensin-aldosterone mechanism

What is the effect of hyperventilation on pH?

C) respiratory alkalosis

Hypersecretion of aldosterone results in hypokalemia, which causes hyperpolarization of neurons; this in turn results in ______.

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, then more cations must enter the cytoplasm for the cell to reach threshold.

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?

C) weak base

Which of the following creates the greatest osmotic pressure?

D) H3PO4

What is the most common cation found in the interstitial fluid?

D) Na+

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. Which side of the heart failed, and how did this cause edema?

D) The right side of the heart failed, causing edema in her lower extremities. The failure to pump blood around the pulmonary circulation caused pooling of blood in the systemic circulation, leading to edema.

What receptors does the brain use to detect changes in osmolality?

D) osmoreceptors

The fluid link between the external and internal environment is ________.

D) plasma

The single most important factor influencing potassium ion secretion is ________.

D) potassium ion concentration in blood plasma

What is the driving force for water intake?

D) thirst

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. Why did she get these symptoms?

E) The abuse of laxatives and self-induced vomiting caused her to be chronically fluid and electrolyte depleted. She developed a compensatory increased production of aldosterone and ADH.

Which of the following statements is true regarding fluid shifts?

A) Electrolytes have greater osmotic power than nonelectrolytes and therefore have the greatest ability to cause fluid shifts.

The role of ADH is to __________.

A) increase water reabsorption

Which of the following is not a trigger for juxtaglomerular granular cells to release renin?

A) increased extracellular fluid water levels

Where is the majority of water stored in the human body?

A) intracellular fluid (ICF) compartment

Which organs are the ultimate acid-base regulatory organs?

A) kidneys

The most important renal mechanism for regulating acid-base balance of the blood involves __________.

A) maintaining HCO3- balance.

A patient is breathing slowly and blood pH analysis indicates an abnormally high value. What is the likely diagnosis?

A) metabolic alkalosis

Atrial natriuretic peptide is a hormone that is made in the atria of the heart. The influence of this hormone is to ________.

A) reduce blood pressure and blood volume by inhibiting sodium and water retention

A falling blood pH and a rising partial pressure of carbon dioxide due to pneumonia or emphysema indicates ________.

A) respiratory acidosis

Newborn infants have a relatively higher ________ content in their ECF than do adults.

A) sodium

The body's water volume is closely tied to the level of which of the following ions?

A) sodium ions

The maintenance of the proper pH of the body fluids may be the result of ________.

A) the control of respiratory ventilation

Which of the following is NOT a hormone involved in water and electrolyte balance?

A) thyroxine

What accounts for the route through which most fluid is lost in a day?

A) urine

How much water is generated per day from cellular metabolism?

B) 250 ml

Which hormone raises blood calcium levels?

B) PTH

Respiratory acidosis can occur when ________.

B) a person's breathing is shallow due to obstruction

The term alkaline reserve is used to describe the ________ buffer system.

B) bicarbonate

The primary buffer of the extracellular fluid (ECF) is the __________.

B) bicarbonate buffer system

Which of the following is not a method for regulating the hydrogen ion concentration in blood?

B) diet

Which of the following is not a disorder of water balance?

B) excessive hydration due to excess ANP secretion

Which of the following abnormalities would not be observed in a patient who has Addison's disease?

B) hypertension Hypertension (abnormally high blood pressure) is typically caused by restricting blood flow by vasoconstriction or abnormally high fluid volume in the blood. Water balance is regulated by anti-diuretic hormone secreted from the posterior pituitary.

Which of the following is NOT involved in triggering the thirst mechanism?

B) increase in blood pressure

Which of the following is NOT a risk factor for dehydration?

B) increased muscle mass

Problems with fluid, electrolyte, and acid-base balance are particularly common in infants because of their ________.

B) inefficient kidneys

The regulation of potassium balance ________.

B) involves aldosterone-induced secretion of potassium

The body's water volume is closely tied to a powerful water "magnet." What magnet is referred to here?

B) ionic sodium

The movement of fluids between cellular compartments ________.

B) is regulated by osmotic and hydrostatic forces

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?

B) metabolic acidosis

Whereas sodium is found mainly in the extracellular fluid, most ________ is found in the intracellular fluid.

B) potassium

Which buffer system is the most abundant in the body?

B) protein

The most common cause of acid-base imbalance is __________.

B) respiratory acidosis

What is the most common cause of acid-base imbalance?

B) respiratory acidosis

Hypoproteinemia is a condition of unusually low levels of plasma proteins. This problem is often characterized by ________.

B) tissue edema

What type of water imbalance increases the amount of fluid in all compartments?

A) hypotonic hydration

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

After traveling from Los Angeles to Denver, Claire finds she is not feeling well and checks into a clinic for help. What is the diagnosis, and what has caused this problem?

A) Respiratory alkalosis caused by hyperventilation. Claire is experiencing the effect of the high altitude, breathing faster and deeper to raise her oxygen levels in her blood.

Select the person in the following list who would have the highest percentage of water in his or her body.

A) a 6-month-old baby boy

Total body water is not a function of which of the following?

A) amount of water ingested

Which of the following hormones is important in stimulating water conservation in the kidneys?

A) antidiuretic hormone

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

The most important force causing net water flow across capillary walls is ________.

A) hydrostatic pressure of capillary blood

What is the hallmark of hypotonic hydration?

A) hyponatremia

Which of the following would NOT be expected to lead to edema?

A) hyponatremia

Which of the following conditions promotes edema?

A) hypoproteinemia

A patient's anxiety caused her to develop respiratory alkalosis. What breathing technique did the nurse recommend, and why?

C) The nurse instructed the patient to breathe slower and deeper, and to breathe into a paper bag. This will increase the patient's blood level of carbon dioxide by eliminating less carbon dioxide from the lungs, and by breathing in the expired air which has a higher concentration of carbon dioxide. As a result, the blood pH will decrease.

One of the major physiological factors that triggers thirst is ________.

C) a rise in plasma osmolality

Which of the following does NOT serve as a source of acids in the body?

C) aerobic breakdown of glucose

Which of the choices below exerts primary control over sodium levels in the body?

C) aldosterone

Which of the following regulates the secretion of K+ into the filtrate?

C) aldosterone

A decrease in blood CO2 levels leads to __________.

C) an increase in blood pH

What hormone helps to maintain extracellular fluid (ECF) osmolality when concentrations become too high?

C) antidiuretic hormone (ADH)

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?

D) There will be a temporary increase in blood volume.

The term hypotonic hydration refers to ________.

D) a condition that may result from renal insufficiency or drinking extraordinary amounts of water

Which of the following hormones is important in the regulation of sodium ion concentrations in the extracellular fluid?

D) aldosterone

Which of the following does not depend on the presence of electrolytes?

D) amount of body fat

Which of the choices below is not an essential role of salts in the body?

D) anabolism of lipids

A patient is discovered to have a strange craving for iron objects. To try to determine the cause, her physician decides to order tests to determine if this patient might have some type of ______.

D) anemia Anemia is a condition where red blood cells have an abnormally low oxygen carrying capacity. This capacity depends on the iron content within the hemoglobin molecule.

What solute in body fluids determines most of their chemical and physical reactions?

D) electrolytes

Which age group most commonly has fluid, electrolyte, and acid-base balance issues?

D) infants

The regulation of sodium ________.

D) is linked to blood pressure

A patient is admitted to the hospital in complete collapse. His blood pH is 6.8, and his HCO3- is 20 mEq/L. A medical history reveals that this patient is a chronic alcoholic. What diagnosis would you give, and what prognosis?

E) The pH and bicarbonate levels and the history of alcoholism indicate metabolic acidosis. The patient will go into a coma and death soon follows.