Water Balance

Adipose tissue is one of the most hydrated of all tissues in the human body.

False

The most abundant cation in intracellular fluid is sodium.

False

Electrolytes determine most of the chemical and physical reactions of the body.

True

Solutes, regardless of size, are able to move freely between compartments because water carries them along the osmotic gradients.

False

The thirst center in the brain is located in the hypothalamus.

True

Dehydration can be caused by endocrine disturbances such as diabetes mellitus or diabetes insipidus.

True

It is impossible to overhydrate because people need as much water as they can drink to carry out ordinary body functions.

False

Water imbalance, in which output exceeds intake, causing an imbalance in body fluids, is termed dehydration.

True

Salts are lost from the body in perspiration, feces, and urine.

True

Hypoproteinemia reflects a condition of unusually high levels of plasma proteins and causes tissue edema.

False

Although the sodium content of the body may be altered, its concentration in the ECF remains stable because of immediate adjustments in water volume.

True

Sodium is pivotal to fluid and electrolyte balance and to the homeostasis of all body systems.

True

When aldosterone release is inhibited, sodium reabsorption cannot occur beyond the collecting tube.

True

Aldosterone stimulates the reabsorption of sodium while enhancing potassium secretion.

True

Pressure diuresis decreases blood volume and blood pressure.

True

Aldosterone is secreted in response to low extracellular potassium.

False

To remain properly hydrated, water intake must equal water output.

True

The main way the kidney regulates potassium ions is to excrete them.

True

Atrial natriuretic peptide reduces blood pressure and blood volume by inhibiting nearly all events that promote vasodilation and potassium and water retention.

False

Premenstrual edema may be due to enhanced reabsorption of sodium chloride.

True

Heavy consumption of salt substitutes high in potassium can present a serious clinical problem when aldosterone release is not normal.

True

Hypercalcemia causes muscle tetany.

False

The two hormones responsible for the regulation of calcium are pituitary hormone and calcitonin.

False

Calcitonin targets the bones and causes the release of calcium from storage when serum levels are low.

False

The normal pH of blood is 7.35-7.45.

True

Most acidic substances (hydrogen ions) originate as by-products of cellular metabolism.

True

Weak acids are able to act as chemical buffering systems for the body because they partially dissociate.

True

The phosphate buffer system is relatively unimportant for buffering blood plasma.

True

The single most important blood buffer system is the bicarbonate buffer system.

True

One of the most powerful and plentiful sources of buffers is the protein buffer system.

True

As ventilation increases and more carbon dioxide is removed from the blood, the hydrogen ion concentration of the blood decreases.

True

Regulation of the acid-base system is accomplished mainly through respiratory control, and the kidneys also play a small role.

False

Severe damage to the respiratory system rarely will result in acid-base imbalances.

False

Respiratory acidosis results when lungs are obstructed and gas exchange is inefficient.

True

Prolonged hyperventilation can cause alkalosis.

True

Thirst is always a reliable indicator of body water need.

False

Blood acidity results in depression of the CNS, whereas blood alkalosis results in overexcitement of the CNS.

True

1) The body’s water volume is closely tied to the level of which of the following ions?
A) calcium ions
B) potassium ions
C) hydrogen ions
D) sodium ions

D

2) The term hypotonic hydration refers to ________.
A) the feeling one might have after a long swim
B) the unpleasant feeling people have after drinking too much liquor
C) a condition that may result from renal insufficiency or drinking extraordinary amounts of water
D) a condition that is caused by high levels of sodium in the extracellular fluid compartment

C

3) Hypoproteinemia is a condition of unusually low levels of plasma proteins. This problem is
often characterized by ________.
A) tissue edema
B) extreme weight loss
C) extreme weight gain
D) nerve damage

A

4) Which of the following hormones is important in the regulation of sodium ion concentrations
in the extracellular fluid?
A) antidiuretic hormone
B) erythropoietin
C) aldosterone
D) renin

C

5) Atrial natriuretic peptide is a hormone that is made in the atria of the heart. The influence of this hormone is to ________.
A) enhance atrial contractions
B) activate the renin-angiotensin mechanism
C) prevent pH changes caused by organic acids
D) reduce blood pressure and blood volume by inhibiting sodium and water retention

D

6) Respiratory acidosis can occur when ________.
A) a person consumes excessive amounts of antacids
B) a person’s breathing is shallow due to obstruction
C) a runner has completed a very long marathon
D) the kidneys secrete hydrogen ions

B

7) Which of the following two organs function as the most important physiological buffer systems?
A) the lungs and the kidneys
B) the adrenal glands and the testes
C) the thyroid gland and the heart
D) the stomach and the liver

A

8) Which of the choices below is not an essential role of salts in the body?
A) neuromuscular activity
B) membrane permeability
C) secretory activity
D) anabolism of proteins

D

9) Which of the choices below exerts primary control over sodium levels in the body?
A) ADH
B) aldosterone
C) water levels
D) glucocorticoids

B

10) The fluid link between the external and internal environment is ________.
A) plasma
B) intracellular fluid
C) interstitial fluid
D) cerebrospinal fluid

A

11) Newborn infants have a relatively higher ________ content in their ECF than do adults.
A) iron
B) sodium
C) magnesium
D) bicarbonate

B

12) Whereas sodium is found mainly in the extracellular fluid, most ________ is found in the intracellular fluid.
A) iron
B) chloride
C) potassium
D) magnesium

C

13) 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) Na+ mainly in the cells, K+ in the body fluids
C) equal amounts of each ion in the cells and body fluids
D) little of either in the cells, but large amounts of each in the body fluids

A

14) Problems with fluid, electrolyte, and acid-base balance are particularly common in infants because of their ________.
A) inefficient kidneys
B) comparatively low metabolic rates
C) low rate of insensible water loss
D) low daily rate of fluid exchange

A

15) The single most important factor influencing potassium ion secretion is ________.
A) the potassium ion content in the renal tubule cells
B) the pH of the ICF
C) intracellular sodium levels
D) potassium ion concentration in blood plasma

D

16) The term alkaline reserve is used to describe the ________ buffer system.
A) phosphate
B) hemoglobin
C) bicarbonate
D) protein

C

17) A falling blood pH and a rising partial pressure of carbon dioxide due to pneumonia or emphysema indicates ________.
A) respiratory acidosis
B) respiratory alkalosis
C) metabolic acidosis
D) metabolic alkalosis

A

18) The movement of fluids between cellular compartments ________.
A) requires active transport
B) is regulated by osmotic and hydrostatic forces
C) requires ATP for the transport to take place
D) involves filtration

B

19) What hormone reduces blood pressure and blood volume by inhibiting nearly all events that promote vasoconstriction and sodium ion and water retention?
A) ADH
B) aldosterone
C) atrial natriuretic peptide
D) thyroxine

C

20) Which of the following is not a method for regulating the hydrogen ion concentration in blood?
A) chemical buffer systems
B) diet
C) respiratory changes
D) renal mechanism

B

21) Which of the following is not a chemical buffer system?
A) bicarbonate
B) phosphate
C) nucleic acid
D) protein

C

22) Extracellular fluid in the human body is composed of all of the following except ________.
A) lymph and interstitial fluid
B) blood plasma
C) cerebrospinal fluid
D) glucose

D

23) Which of the following statements is true regarding fluid shifts?
A) Nonelectrolytes are the controlling factor in directing fluid shifts.
B) Electrolytes are not as important as proteins in regulating fluid shifts in the body.
C) Electrolytes have greater osmotic power than nonelectrolytes and therefore have the greatest ability to cause fluid shifts.
D) There are always more positive electrolytes than negative in a solution; it is therefore impossible to follow fluid shifts.

C

24) Which of the following hormones is important in stimulating water conservation in the kidneys?
A) aldosterone
B) thymosin
C) antidiuretic hormone
D) atrial natriuretic peptide

C

25) The maintenance of the proper pH of the body fluids may be the result of ________.
A) the control of respiratory ventilation
B) the operation of the various buffer systems in the stomach
C) the active secretion of OH- into the filtrate by the kidney tubule cells
D) control of the acids produced in the stomach

A

26) Which of the following is not a disorder of water balance?
A) excessive hydration due to excess ADH secretion
B) hypotonic hydration, in which sodium content is normal but water content is high
C) edema or tissue swelling, which is usually due to an increased capillary hydrostatic pressure
D) excess water in interstitial spaces due to a low level of plasma proteins

A

27) The regulation of sodium ________.
A) is due to specific sodium receptors in the hypothalamus
B) is linked to blood pressure
C) involves aldosterone, a hormone that increases sodium excretion in the kidneys
D) involves hypothalamic osmoreceptor detection of ion concentration

B

28) Select the correct statement about renal mechanisms of acid-base balance.
A) The kidneys are not able to excrete phosphoric acid.
B) Excreted hydrogen ions are unbound in the filtrate.
C) Kidney tubule cells are able to synthesize bicarbonate ion.
D) The kidneys are the most important mechanism for eliminating all bicarbonate ions.

C

29) 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) metabolic alkalosis
D) respiratory alkalosis

B

30) A patient is breathing slowly and blood pH analysis indicates an abnormally high value. What is the likely diagnosis?
A) respiratory acidosis
B) metabolic acidosis
C) metabolic alkalosis
D) respiratory alkalosis

C

31) One of the major physiological factors that triggers thirst is ________.
A) a dry mouth from high temperatures
B) becoming overly agitated
C) drinking caffeinated beverages
D) a rise in plasma osmolality

D

32) 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) It will increase the osmolality of the blood.
B) There will be a temporary increase in blood volume.
C) She will experience hypotension.
D) There will be a shift in the pH of her body fluids to the higher side of the pH scale.

B

33) The most important force causing net 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

34) Which of the following does not depend on the presence of electrolytes?
A) membrane polarity
B) neuromuscular excitability
C) maintenance of osmotic relations between cells and ECF
D) amount of body fat

D

35) The regulation of potassium balance ________.
A) is not linked to sodium balance
B) includes renal secretion, but never absorption
C) is accomplished mainly by hepatic mechanisms
D) involves aldosterone-induced secretion of potassium

D