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

Question 1

________ ________ ________ is a function of age, body mass, and body fat.

Answer 1

Total body water

Question 2

Due to their low body fat and bone mass, infants are about ________ water.

Answer 2

73%

Question 3

The body water content of men is about ________, but because women have relatively more body fat and less skeletal muscle than men, theirs is about _________.

Answer 3

60%

50%

Question 4

Body water declines throughout life, ultimately comprising about ________of total body mass in old age.

Answer 4

45%

Question 5

There are two main fluid compartments of the body: The ________ ________ contains slightly less than two-thirds by volume; the remaining third is distributed in the ________ ________.

Answer 5

intracellular compartment

extracellular fluid

Question 6

There are two subcompartments of the extracellular fluid: ________ ________ and ________ ________.

Answer 6

blood plasma

interstitial fluid

Question 7

________ include most organic molecules, do not dissociate in water, and carry no net electrical charge.

Answer 7

Nonelectrolytes

Question 8

_________ dissociate in water to ions, and include inorganic salts, acids and bases, and some proteins.

Answer 8

Electrolytes

Question 9

Electrolytes have greater ________ ________ because they dissociate in water and contribute at least two particles to solution.

Answer 9

osmotic power

Question 10

The major cation in extracellular fluids is ________, and the major anion is ________; in intracellular fluid the major cation is ________, and the major anion is ________.

Answer 10

sodium
chloride
potassium
phosphate

Question 11

________ are the most abundant solutes in body fluids, but ________ and some ________ account for 60–97% of dissolved solutes.

Answer 11

Electrolytes
proteins
nonelectrolytes

Question 12

Anything that changes solute concentration in any compartment leads to ________ ________ ________.

Answer 12

net water flows

Question 13

Substances must pass through both the ________ and ________ ________ in order to reach the ________ ________, and exchanges between these compartments occur almost continuously, leading to compensatory shifts from one compartment to another.

Answer 13

plasma
interstitial fluid
intracellular fluid

Question 14

Nearly protein-free plasma is forced out of the blood by ________ ________, and almost completely reabsorbed due to ________ ________ ________ of plasma proteins.

Answer 14

hydrostatic pressure
colloid osmotic (oncotic) pressure

Question 15

Movement of water between the interstitial fluid and intracellular fluid involves substantial two-way ________ ________ that is equal in both directions.

Answer 15

osmotic flow

Question 16

Ion fluxes between the interstitial and intracellular compartments are restricted; but movement of ________, ________, and ________ typically occur in one direction.

Answer 16

nutrients
respiratory gases
wastes

Question 17

For the body to remain properly hydrated, ________ ________ must equal ________ ________.

Answer 17

water intake

water output

Question 18

Most water enters the body through ________ ________ and ________, but is also produced by ________ ________.

Answer 18

ingested liquids
food
cellular metabolism

Question 19

Water output is due to ________ ________ from lungs and skin, ________, ________, and ________.

Answer 19

evaporative loss (insensible water loss)
sweating
defecation
urination

Question 20

The thirst mechanism is triggered by a decrease in ________ ________, which results in a dry mouth and excites the ________ ________ ________.

Answer 20

plasma osmolarity

hypothalamic thirst center

Question 21

Thirst is quenched as the ________ of the mouth is moistened, and continues with ________ of the stomach and intestines, resulting in ________ of the hypothalamic thirst center.

Answer 21

mucosa
distention
inhibition

Question 22

Drinking is necessary because there is ________ water loss due to the ________ water losses.

Answer 22

obligatory

insensible

Question 23

Beyond obligatory water losses, ________ concentration and ________ of urine depend on fluid intake.

Answer 23

solute

volume

Question 24

Beyond obligatory water losses, solute concentration and volume of urine depend on ________ ________.

Answer 24

fluid intake

Question 25

The amount of water reabsorbed in the renal collecting ducts is proportional to ________ ________.

Answer 25

ADH release

Question 26

When ADH levels are ________, most water in the collecting ducts is not reabsorbed, resulting in large quantities of _________ urine.

Answer 26

low | dilute

Question 27

When ADH levels are ________, filtered water is reabsorbed, resulting in a lower volume of ________ urine.

Answer 27

high | concentrated

Question 28

ADH secretion is promoted or inhibited by the ________ in response to changes in solute concentration of ________ ________, large changes in ________ ________ or ________, or ________ ________.

Answer 28

hypothalamus extracellular fluid blood volume or pressure vascular baroreceptors

Question 29

________ occurs when water output exceeds water intake, and may lead to weight loss, fever, mental confusion, or hypovolemic shock.

Answer 29

Dehydration

Question 30

________ ________ is a result of renal insufficiency, or intake of an excessive amount of water very quickly.

Answer 30

Hypotonic hydration

Question 31

________ is the accumulation of fluid in the interstitial space, which may impair tissue function.

Answer 31

Edema

Question 32

________ is the most important cation in regulation of fluid and electrolyte balance in the body due to its abundance and osmotic pressure.

Answer 32

Sodium

Question 33

Because all body fluids are in ________ _______, any change in sodium levels causes a ________ ________ in water, affecting plasma volume, blood pressure, and intracellular and interstitial fluid volumes.

Answer 33

chemical equilibrium | compensatory shift

Question 34

When ________ secretion is high, nearly all the filtered sodium is reabsorbed in the distal convoluted tubule and the collecting duct.

Answer 34

aldosterone

Question 35

When aldosterone secretion is high, nearly all the filtered sodium is reabsorbed in the ________ ________ ________ and the ________ ________.

Answer 35

distal convoluted tubule | collecting duct

Question 36

The most important trigger for the release of aldosterone is the ________ ________, initiated in response to sympathetic stimulation, decrease in filtrate osmolality, or decreased blood pressure.

Answer 36

renin-angiotensin mechanism

Question 37

________, produced by the renin-angiotensin mechanism, causes the adrenal cortex to release ________, and also directly causes kidney tubules to increase Na+ retention as part of a mechanism regulating systemic blood pressure.

Answer 37

Angiotensin II | aldosterone

Question 38

Angiotensin II, produced by the ________ mechanism, causes the adrenal cortex to release aldosterone, and also directly causes kidney tubules to increase ________ as part of a mechanism regulating ________ ________ ________.

Answer 38

renin-angiotensin Na+ retention systemic blood pressure

Question 39

________ ________ monitor blood volume so that blood pressure remains stable.

Answer 39

Cardiovascular baroreceptors

Question 40

Cardiovascular baroreceptors monitor ________ so that ________ ________ remains stable.

Answer 40

blood volume | blood pressure

Question 41

Atrial natriuretic peptide reduces blood pressure and blood volume by inhibiting release of ADH, renin, and aldosterone, and directly causing vasodilation.

Answer 41

Atrial natriuretic peptide

Question 42

Atrial natriuretic peptide reduces ________ ________ and ________ ________ by inhibiting release of ADH, renin, and aldosterone, and directly causing vasodilation.

Answer 42

blood pressure | blood volume

Question 43

Atrial natriuretic peptide reduces blood pressure and blood volume by inhibiting release of ________, _________, and ________, and directly causing ________.

Answer 43

ADH renin aldosterone vasodilation

Question 44

________ are chemically similar to aldosterone, and enhance reabsorption of salt by the renal tubules.

Answer 44

Estrogens

Question 45

________ enhance tubular reabsorption of sodium, but increase glomerular filtration.

Answer 45

Glucocorticoids

Question 46

________ is critical to the maintenance of the membrane potential of neurons and muscle cells, and is a buffer that compensates for shifts of hydrogen ions in or out of the cell.

Answer 46

Potassium

Question 47

Potassium is critical to the maintenance of the membrane potential of neurons and muscle cells, and is a buffer that compensates for shifts of __________ ________ in or out of the cell.

Answer 47

hydrogen ions

Question 48

Potassium balance is chiefly regulated by renal mechanisms, which control the amount of potassium secreted into the ________.

Answer 48

filtrate

Question 49

________ ________ levels of potassium are the most important factor regulating potassium secretion.

Answer 49

Blood plasma

Question 50

Aldosterone influences potassium secretion, because potassium secretion is simultaneously enhanced when sodium reabsorption increases.

Answer 50

sodium reabsorption

Question 51

Calcium ion levels are closely regulated by ________ ________ and ________; about 98% is reabsorbed.

Answer 51

parathyroid hormone | calcitonin

Question 52

Parathyroid hormone is released when _________ ________ levels decline, and targets the bones, small intestine, and kidneys.

Answer 52

blood calcium

Question 53

________ is an antagonist to parathyroid hormone, and is released when blood calcium rises, targeting bone.

Answer 53

Calcitonin

Question 54

________ is the major anion reabsorbed with sodium, and helps maintain the osmotic pressure of the blood.

Answer 54

Chloride

Question 55

Because of the abundance of _______ bonds in the body’s functional proteins, they are strongly influenced by hydrogen ion concentration

Answer 55

hydrogen

Question 56

When arterial blood pH rises above 7.45, the body is in ________; when arterial pH falls below 7.35, the body is in physiological ________.

Answer 56

alkalosis | acidosis

Question 57

Most hydrogen ions originate as ________, although they can also enter the body via ________.

Answer 57

metabolic by-products | ingested foods

Question 58

A chemical buffer is a system of one or two molecules that acts to resist changes in pH by _________ H+ when the pH drops, or ________ H+ when the pH rises.

Answer 58

binding | releasing

Question 59

The ________ buffer system is the main buffer of the extracellular fluid, and consists of carbonic acid and its salt, sodium bicarbonate.

Answer 59

bicarbonate

Question 60

The bicarbonate buffer system is the main buffer of the extracellular fluid, and consists of ________ ________ and its ________, ________ _________.

Answer 60

carbonic acid salt sodium bicarbonate

Question 61

When a strong acid is added to the solution, ________ ________ is mostly unchanged, but ________ ________ of the salt bind excess H+, forming more carbonic acid.

Answer 61

carbonic acid | bicarbonate ions

Question 62

When a strong base is added to solution, the ________ _________ remains relatively unaffected, but ________ ________ dissociates further, donating more H+ to bind the excess hydroxide.

Answer 62

sodium bicarbonate | carbonic acid

Question 63

Bicarbonate concentration of the extracellular fluid is closely regulated by the ________, and plasma bicarbonate concentrations are controlled by the ________ ________.

Answer 63

kidneys | respiratory system

Question 64

The phosphate buffer system operates in the urine and intracellular fluid similarly to the bicarbonate buffer system: ________ _______ ________is its weak acid, and ________ ________ is its weak base.

Answer 64

Sodium dihydrogen phosphate | monohydrogen phosphate

Question 65

The protein buffer system consists of organic acids containing carboxyl groups that dissociate to ________ H+ when the pH begins to rise, or ________ excess H+ when the pH declines.

Answer 65

release | bind

Question 66

Carbon dioxide from cellular metabolism enters erythrocytes and is converted to bicarbonate ions for transport in the plasma.

Answer 66

Carbon dioxide

Question 67

When ________ occurs, blood pH drops, activating medullary respiratory centers, resulting in increased rate and depth of breathing and increased unloading of CO2 in the lungs.

Answer 67

hypercapnia

Question 68

When blood pH rises, the ________ ________ is depressed, allowing CO2 to accumulate in the blood, lowering pH.

Answer 68

respiratory center

Question 69

Only the ________ can rid the body of acids generated by cellular metabolism, while also regulating blood levels of alkaline substances and renewing chemical buffer components.

Answer 69

kidneys

Question 70

________ _________ can be conserved from filtrate when depleted, and their reabsorption is dependent on H+ secretion.

Answer 70

Bicarbonate ions

Question 71

________ ________ intercalated cells of the renal tubules can synthesize new bicarbonate ions while excreting more hydrogen ions.

Answer 71

Type A

Question 72

Type A intercalated cells of the renal tubules can ________ new bicarbonate ions while ________ more hydrogen ions.

Answer 72

synthesize | excreting

Question 73

________ ________ are weak acids that are excreted and lost in urine, replenishing the alkaline reserve of the blood.

Answer 73

Ammonium ions

Question 74

When the body is in ________, type B intercalated cells excrete bicarbonate, and reclaim hydrogen ions.

Answer 74

alkalosis

Question 75

When the body is in alkalosis, ________ ________ intercalated cells excrete ________, and reclaim ________ ________.

Answer 75

type B bicarbonate hydrogen ions

Question 76

________ ________ is characterized by falling blood pH and rising PCO2, which can result from shallow breathing or some respiratory diseases.

Answer 76

Respiratory acidosis

Question 77

Respiratory acidosis is characterized by falling ________ ________ and rising ________, which can result from shallow breathing or some respiratory diseases.

Answer 77

blood pH | PCO2

Question 78

________ ________ results when carbon dioxide is eliminated from the body faster than it is produced, such as during hyperventilation.

Answer 78

Respiratory alkalosis

Question 79

Respiratory alkalosis results when ________ ________ is eliminated from the body faster than it is produced, such as during hyperventilation.

Answer 79

carbon dioxide

Question 80

________ ________ is characterized by low blood pH and bicarbonate levels, and is due to excessive loss of bicarbonate ions, or ingestion of too much alcohol.

Answer 80

Metabolic acidosis

Question 81

________ ________ is indicated by rising blood pH and bicarbonate levels, and is the result of vomiting or excessive base intake.

Answer 81

Metabolic alkalosis

Question 82

Respiratory rate and depth increase during ________ ________, and decrease during ________ ________.

Answer 82

metabolic acidosis | metabolic alkalosis

Question 83

In renal compensation for ________ __________, blood PCO2 and bicarbonate ion concentrations are high; in ________ _________, blood pH is high, but PCO2 is low.

Answer 83

respiratory acidosis | respiratory alkalosis

Question 84

An embryo and young fetus are more than 90% ________, but as ________ accumulate, the percentage declines to about 70–80% at birth

Answer 84

water | solids

Question 85

At puberty, sex differences in body water content appear as males develop more ________ ________.

Answer 85

skeletal muscle

Question 86

During infancy, problems with fluid, electrolyte, and acid-base balance are common, due to large-scale changes in ________.

Answer 86

PCO2

Question 87

In old age, body water loss is primarily from the ________ ________, due to decline in muscle mass and increase in adipose tissue.

Answer 87

intracellular compartment

Question 88

Increased insensitivity to thirst cues makes the elderly vulnerable to ________, and to ________ or ________ imbalances.

Answer 88

dehydration electrolyte acid-base