Question 1

Water loss can occur from each,except one.Which is the exception?

Accepted Answer

Water is liberated in the process of metabolism and becomes available for hydration of the cells and tissues of the body.Metabolism of fat produces approximately twice as much water as does the metabolism of protein or carbohydrate.Metabolism of fat supplies about 300 to 350 mL/day.

Question 2

Dissolved substances that freely cross cellular membranes are:

Accepted Answer

Dissolved substances called solutes freely cross cellular membranes.Glucose,amino acids,and oxygen are examples of solutions.Osmoreceptors are neurons in the hypothalamus that register thirst when stimulated and increase release of antidiuretic hormone (ADH)from the pituitary gland.Renin is a hormone that leads to increased release of the hormone aldosterone by the adrenal cortex.This release of aldosterone ultimately results in an increase in blood pressure.Cations are positively charged ions related to electrolytes and the body's hydration status.

Question 3

Calcium and magnesium are among the nutrients added to sports drinks to restore fluid balance during exercise because these minerals are not readily available in a well-balanced diet.

Accepted Answer

The statement is correct,but the reason is not correct.It is true that calcium and magnesium are among nutrients added to sports drinks; however,there is no advantage to obtaining these minerals in this manner because they are readily available in a well-balanced diet.Other nutrients added to sports drinks,with the goal of optimizing athletic performance,include carbohydrates,electrolytes,and sometimes vitamins or other nutrients,such as protein or amino acids.Endurance athletes can benefit from a sports beverage containing carbohydrates,electrolytes,and protein,but sports drinks offer little to no advantage over plain water for most people.Note that some sources state that calcium added to sports drinks lessens the erosive potential of these acidic beverages.

Question 4

Cellular edema is present during hypernatremia because when sodium losses exceed water losses,sodium moves from the extracellular fluid (ECF)to the intracellular fluid (ICF),and water enters the ICF.

Accepted Answer

The statement is not correct,but the reason is correct.During hyponatremia,or low serum sodium level,cellular edema is present.The reason portion of the question provides a concise explanation.The detailed mechanism involves fluid retention during hyponatremia because sodium losses exceed water losses.This leads to a greater concentration of water than sodium,which decreases the extracellular fluid concentration (ECF).As a result,sodium moves from the ECF to the ICF and water enters the ICF.These events result in cellular edema (retention of fluids).The cause and mechanisms of hypernatremia (elevated serum sodium level)are reversed.Note that peripheral edema and cellular edema are not the same condition.

Question 5

Each is a classic sign of fluid volume deficit (FVD)except one.Which one is the exception?

Accepted Answer

Pale yellow or almost colorless urine indicates adequate hydration.Dark yellow urine with strong odor,advancing to painful urination,are advancing signs of inadequate water intake and dehydration.A diminished salivary flow is also associated with inadequate fluid intake.Treatment of FVD involves replacing lost fluid.For mild FVD,oral fluids are likely sufficient.Intravenous solutions are needed with significant FVD.

Question 6

Post-meal coffee or tea should be consumed 2 hours after eating because caffeine decreases iron absorption.

Accepted Answer

The statement is correct,but the reason is not correct.Polyphenols,not caffeine,in tea and coffee decrease iron absorption.No decrease in absorption occurs when the tea or coffee is consumed 1 hour before or 2 hours after a meal.

Question 7

Sodium deficiency can lead to an increased salivary flow rate.High levels of sodium (greater than 2 g/day)cause calcium retention in the kidneys.

Accepted Answer

Both statements are false.Sodium deficiency can lead to a decreased salivary flow because the body reverts to processes designed to conserve fluid.Conversely,high levels of sodium cause calcium loss in the urine.Dental hygienists should routinely examine their patients for fluid volume deficit (FVD)and fluid volume excess (FVE)and stress the importance of appropriate sodium intake.

Question 8

Excess water is eliminated by the kidneys because antidiuretic hormone (ADH)secretion is increased when osmoreceptors detect excess water.

Accepted Answer

The statement is correct,but the reason is not correct.Excess water is eliminated by the kidneys because ADH secretion is decreased when osmoreceptors detect excess water.ADH originates in the pituitary gland and is involved in the regulation of fluid levels.As in this question,during times of excess water,ADH is decreased causing increased urinary output.Conversely,if osmoreceptors detect a water deficit,ADH stimulation is increased.This causes the body to retain fluid by decreasing urinary output.

Question 9

A person with a large amount of fat has a higher percentage of total body water than average because adipose tissue absorbs and retains water.

Accepted Answer

Neither the statement nor the reason is correct.Adipose tissue contains less water than muscle.Thus,a person with a large amount of fat has a lower percentage of total body water.Similarly,women's bodies,with inherently larger fat stores,contain less water than do men's bodies,which have a higher percentage of lean muscle tissue.

Question 10

Approximately 25% of reputable producers of bottled water use groundwater as their water source.Plain tap water is the most natural source of fluids.

Accepted Answer

The first statement is false; the second is true.Although the bottled water market has been increasing,as a result of environmental concerns and the revelation that approximately 75% of reputable producers of bottle water use groundwater (same source as the public water supply)or tap water,the rate of increase has declined.Environmental concerns include the energy required to produce plastic,non-biodegradable bottles,the bisphenol A content of bottles,and the marketing and shipping costs.

Question 11

Water losses result in increased kidney output because increased kidney function stimulates thirst and encourages fluid intake.

Accepted Answer

Neither the statement nor the reason is correct.Water losses result in decreased kidney output as a means of conserving the body's fluid content.Although it is true that water losses result in stimulation of water intake,this is not a result of increased kidney function.

Question 12

Loss of 1 lb of body weight during exercise means that at least 2 cups of water have been lost.High-protein diets during exercise retain more water than do diets high in fruits and vegetables.

Accepted Answer

The first statement is true; the second is false.High-protein diets,such as those in which fruit and vegetable intake is minimal,require larger amounts of water to eliminate higher levels of urinary waste products.Thus,patients on high-protein diets need to increase fluid consumption with water being the preferred beverage.The dental hygienist can suggest adding slices of lemon,lime,or watermelon to make water more enticing.An important caveat is that the addition of citrus lowers the pH of water,making a beverage of neutral pH more acidic.

Question 13

High pH levels of sports and energy drinks resulting from hydrochloric acid content causes irreversible damage to teeth in just 5 days.Energy drinks cause twice as much damage to teeth as sports drinks do.

Accepted Answer

The first statement is false; the second is true.Sports and energy drinks contain citric,not hydrochloric,acid.Low pH levels indicate high acidity; high pH levels indicate alkalinity (base).The remainder of both statements accurately describes these products.

Question 14

Equalization of solute concentration of intracellular fluids (ICFs)and extracellular fluids (ECFs)is accomplished by:

Accepted Answer

Osmotic pressure within the body equalizes the solute concentration of ICFs and ECFs by shifting small amounts of water in the direction of higher concentration solute.Semipermeable membranes separate one fluid compartment from another.Hydration and perspiration are important elements of fluid balance.

Question 15

During heat exhaustion,a sodium deficit results in hyponatremia.Early symptoms include nausea,abdominal cramps,headache,hyperactivity,and excessive talking.

Accepted Answer

The first statement is true; the second is false.During heat exhaustion,hyperactivity and excessive talking are not symptoms.Instead,patients are lethargic and may lapse into coma.Note that symptoms are the result of cellular edema,which is not the same as peripheral edema.The distinction is that with cellular edema,water is primarily retained within cells rather than in the interstitial compartment as occurs in peripheral edema.

Question 16

Each interferes with zinc absorption,except one.Which is the exception?

Accepted Answer

Bioavailability of zinc varies widely.Absorption can be inhibited by calcium,fiber,phosphate salts,and phytate (a plant fiber).Higher quality protein improves zinc absorption.In developing countries,severe zinc deprivation has been related to excessive consumption of inhibitors,which adversely affect zinc absorption,rather than inadequate zinc intake.

Question 17

The approximately 75% to 80% of sodium that is consumed from processed foods can be reduced by using sea salt because the natural ingredients of sea salt provide more flavor,less sodium,and more minerals than table salt do.

Accepted Answer

Neither the statement nor the reason is correct.Most consumers believe that sea salt is lower in sodium than regular salt; however,this is solely due to marketing sea salt as "natural." Sea salt provides miniscule trace elements with no known health benefits and similar taste intensity.A concern of dietitians,sea salt is not fortified with iodine,a nutrient important in thyroid health,especially during pregnancy.The 75% to 80% attributed to sodium consumption from processed foods includes foods prepared in restaurants and fast food establishments.

Question 18

The RDA for iron is higher in premenopausal women than for men or postmenopausal women because of the blood loss during menstruation.

Accepted Answer

Both the statement and the reason are correct and related.The Institute of Medicine (IOM)recommends 18 mg of iron per day for women 19 to 50 years old,8 mg/day for women 51 years old and older and men 19 years old and older.Note that during the reproductive phase of a woman's life,iron loss is at least twice that of a man or of a postmenopausal woman.

Question 19

The body's hydration status depends on an electrolyte balance of equal concentrations of solutes to kilocalories.Electrolytes are important in water balance and acid-base (pH)balance.

Accepted Answer

The first statement is false; the second is true.The body's hydration status depends on an electrolyte balance of equal concentrations of cations to anions.Sodium and potassium are the major cations while chloride and phosphate are the major anions.Solutes are substances that create a solution when dissolved in a solvent such as sugar dissolved in water.Note that solvents are involved in hydration via osmosis and cellular permeability.

Question 20

Each describes the physiologic roles of water,except one.Which is the exception?

Accepted Answer

Water regulates body temperature by evaporating,not pooling,as perspiration from skin.Similarly,water regulates temperature by evaporating as vapor from the mouth and nose.

Quiz 12: Water and Minerals Required for Oral Soft Tissues and Salivary Glands