Quiz: Physiology of Body Fluid Compartments — 23 questions

1. Regarding physiology, which of the following statements are correct?

A. Physiology studies physiological variables that remain constant over time.

B. Physiology studies organs, tissues, cells, and cellular organelles.

C. Physiology includes relationships between organisms and their environment.

D. Physiology excludes interactions among structures within the same organism.

E. Physiology examines functions and interactions within living organisms.

Answer: (B), (C), (E)

Explanation

Physiology examines biological functions and interactions among organisms, their structures, and their environments. It includes organs, tissues, cells, and organelles, as well as physiological variables that can change over time. It does not focus exclusively on disease or exclude interactions among structures within an organism.

2. The levels of organization in the human body include:

A. Chemical organization provides the foundation for higher biological levels.

B. Whole-organism organization represents the highest listed level.

C. Organizational levels are formed from unrelated units at lower levels.

D. Cellular organization is followed by tissue organization.

E. Systemic organization precedes chemical organization in the hierarchy.

Answer: (A), (B), (D)

Explanation

The sequence includes chemical, cellular, tissue, organ, systemic, and whole-organism levels, with each level built from lower-level units. Thus cellular organization follows chemical organization, and whole-organism organization is highest; unrelated construction and reversed ordering are incorrect.

3. Concerning tissues, organs, and systems, which statements are accurate?

A. A system may consist of organs or tissues forming a functional unit.

B. A tissue combines several organs into one specialized functional unit.

C. A tissue contains similar cells performing a specialized function.

D. A system consists exclusively of individual cells performing one task.

E. An organ is a coordinated group of tissues with a defined function.

Answer: (A), (C), (E)

Explanation

A tissue is made of similar specialized cells, an organ coordinates tissues, and a system may combine organs or tissues. An organ does not combine organs, and a system is not defined as a collection of individual cells.

4. Regarding body water in adults, tick the correct statements:

A. Adult body fluid content is commonly estimated at about 30% of body mass.

B. A value of 60% body fluid is assumed for adults in the course.

C. Adult body fluid generally represents about 80% of total body mass.

D. Body fluid accounts for approximately 50% to 70% of adult body mass.

E. The assumed adult body-fluid proportion is expressed as a percentage.

Answer: (B), (D), (E)

Explanation

Adult body fluid comprises approximately 50% to 70% of body mass, with 60% used as the assumed value. The estimates of 80% and 30% are inconsistent with the stated adult range.

5. A plasma sodium concentration below 120 mmol/L is associated with which findings?

A. It indicates a plasma sodium concentration above 150 mmol/L.

B. It represents hyperkalemia caused by excessive potassium.

C. It commonly prevents cerebral cells from accumulating water.

D. It defines hyponatremia in the stated clinical threshold.

E. It makes plasma hypertonic and promotes cellular shrinkage.

Answer: (D)

Explanation

A plasma sodium concentration below 120 mmol/L defines hyponatremia and makes plasma hypotonic, which can cause dangerous cerebral cellular swelling. Hypertonicity, hyperkalemia, prevention of swelling, and a sodium value above 150 mmol/L do not describe this condition.

6. Concerning plasma potassium above 5 mmol/L, which statements are correct?

A. Hyperkalemia causes cerebral swelling through plasma hypotonicity.

B. A plasma potassium concentration above 5 mmol/L defines hyperkalemia.

C. Severe hyperkalemia can produce fatal cardiac arrhythmias.

D. Hyperkalemia can depolarize excitable cells.

E. Hyperkalemia is defined by plasma sodium below 120 mmol/L.

Answer: (B), (C), (D)

Explanation

Potassium above 5 mmol/L defines hyperkalemia, which depolarizes cells and may cause fatal arrhythmias. Sodium below 120 mmol/L defines hyponatremia, while hypotonic cerebral swelling is associated with hyponatremia rather than hyperkalemia.

7. How are body fluid volumes measured indirectly?

A. The marker measurement requires removal of the entire compartment.

B. The method depends on tracking marker distribution in body fluid.

C. The resulting dilution provides an indirect basis for estimating volume.

D. A marker is allowed to dilute within the compartment being studied.

E. Body fluid volume is determined by directly weighing every compartment.

Answer: (B), (C), (D)

Explanation

Body fluid volumes are measured indirectly by allowing a marker to dilute within the compartment of interest and assessing its distribution. The method does not require weighing or removing the entire compartment.

8. A suitable marker for measuring a body-fluid compartment should have which properties?

A. It remains chemically unchanged rather than being metabolized or synthesized.

B. It distributes homogeneously throughout the studied compartment.

C. It readily enters several unrelated compartments during measurement.

D. It requires a slow and poorly reproducible measurement procedure.

E. It produces toxic effects that improve compartment detection.

Answer: (A), (B)

Explanation

A suitable marker distributes homogeneously within the studied compartment and is not metabolized or synthesized. It should not enter other compartments, be toxic, or require slow and poorly reproducible measurement.

9. Regarding hematocrit, which statement is correct?

A. Hematocrit directly measures the total volume of circulating plasma.

B. Hematocrit is the liquid plasma fraction of total blood volume.

C. Hematocrit is the percentage of blood volume occupied by red blood cells.

D. Hematocrit represents the percentage of blood occupied by white cells.

E. Hematocrit is calculated from the concentration of plasma sodium.

Answer: (C)

Explanation

Hematocrit measures the percentage of total blood volume occupied by red blood cells. Plasma volume measures the liquid fraction, while white-cell percentage and plasma sodium concentration do not define hematocrit.

10. The relationship between plasma volume, blood-cell volume, and total blood volume includes:

A. Average plasma volume is approximately 3 L.

B. Total blood volume equals plasma volume plus blood-cell volume.

C. Plasma volume is approximately 5 L in the stated average values.

D. Average total blood volume is approximately 8 L in the stated values.

E. Typical hematocrit values range from 40% to 45%.

Answer: (A), (B), (E)

Explanation

Total blood volume is the sum of plasma and blood-cell volumes; average plasma volume is about 3 L, and typical hematocrit is 40% to 45%. The stated average total blood volume is about 5 L, not 8 L, and plasma volume is not 5 L.

11. Which statements correctly distinguish the principal concentration measures?

A. Molar concentration expresses amount of substance per solution volume.

B. Equivalent concentration accounts for electrical charge per unit volume.

C. Equivalent concentration expresses solvent mass per amount of substance.

D. Molal concentration expresses amount of substance per solution mass.

E. Mass concentration expresses mass per unit volume.

Answer: (A), (B), (E)

Explanation

Mass concentration expresses mass per volume, and molar concentration expresses amount of substance per solution volume. Molal concentration expresses amount of substance per solvent mass, whereas equivalent concentration accounts for electrical charge per unit volume. Solution mass is not the denominator used for molal concentration.

12. A comparison of plasma and interstitial fluid supports which statements?

A. Plasma contains about 72 g/L protein, compared with 2 g/L in interstitial fluid.

B. Plasma and interstitial fluid have similar osmolarity.

C. Interstitial fluid contains 72 g/L protein compared with 2 g/L in plasma.

D. Plasma contains substantially more protein than interstitial fluid.

E. Plasma and interstitial fluid have similar electrolyte composition.

Answer: (A), (B), (D), (E)

Explanation

The two fluids have similar electrolyte composition and osmolarity, but plasma contains much more protein. The concentrations are approximately 72 g/L in plasma and 2 g/L in interstitial fluid, not the reverse.

13. Water crosses a semipermeable membrane that excludes solutes. Which statements are correct?

A. Water movement is directed toward the more concentrated osmole solution.

B. Solutes cross freely through the stated semipermeable membrane.

C. The membrane permits water passage but excludes solute passage.

D. Water moves passively toward the medium containing more osmoles.

E. Water originates from the medium containing fewer osmoles.

Answer: (A), (C), (D), (E)

Explanation

With water able to cross but solutes excluded, water moves passively from fewer osmoles toward more osmoles. The stated membrane does not permit free solute passage.

14. Which statements accurately describe osmosis?

A. Osmosis is the passive movement of water.

B. Water moves toward the compartment with higher osmole concentration.

C. Osmosis contributes to equalizing osmole concentrations.

D. Water movement during osmosis tends to dilute the concentrated compartment.

E. Osmosis requires solute movement across the membrane.

Answer: (A), (B), (C), (D)

Explanation

Osmosis is passive water movement toward the compartment with higher osmole concentration. This movement dilutes that compartment and promotes concentration equalization; solute movement describes diffusion rather than osmosis.

15. Regarding routes of water movement across biological barriers, which statements are correct?

A. Water crosses these barriers mainly through solute-specific transporters.

B. Water can cross cell membranes through the lipid bilayer.

C. Aquaporins provide a major pathway for water crossing membranes.

D. Aquaporins are specific membrane channels for water movement.

E. Water can cross capillary walls through the lipid bilayer.

Answer: (B), (C), (D), (E)

Explanation

Water crosses cell membranes and capillary walls through the lipid bilayer and mainly through aquaporins. Aquaporins are water channels, not general solute-specific transporters.

16. A red blood cell is placed in a hypotonic medium. Which statements are correct?

A. The cell may burst after excessive water entry.

B. The cell is more concentrated than its surrounding medium.

C. The cell swells in the hypotonic medium.

D. The red blood cell takes up water from its environment.

E. The cell loses water and becomes wrinkled.

Answer: (A), (B), (C), (D)

Explanation

In a hypotonic medium, the red blood cell is more concentrated than its environment, so water enters and the cell swells. Excessive swelling may cause rupture; water loss and wrinkling characterize hypertonic exposure.

17. Concerning red blood cells in an isotonic medium, select the correct statements:

A. The red blood cell does not undergo a net volume change.

B. An isotonic medium preserves the cell's normal appearance.

C. The red blood cell maintains its normal volume.

D. Water movement into the cell balances water movement out.

E. An isotonic medium causes progressive red-cell swelling.

Answer: (A), (B), (C), (D)

Explanation

In an isotonic medium, inward and outward water movements balance, preserving normal red-cell volume and appearance. Progressive swelling is associated with a hypotonic rather than isotonic medium.

18. Which statements describe the response of a red blood cell to a hypertonic medium?

A. Hypertonic exposure produces cellular water loss.

B. The external medium has a higher osmole concentration.

C. The cell becomes wrinkled after losing water.

D. Water leaves the red blood cell toward the external medium.

E. The red blood cell shrinks in a hypertonic environment.

Answer: (A), (B), (C), (D), (E)

Explanation

A hypertonic external medium has a higher osmole concentration, drawing water out of the red blood cell. The cell consequently loses water, shrinks, and becomes wrinkled.

19. After drinking pure water, which changes occur in body-fluid compartments?

A. The final state includes increased body water and body weight.

B. Pure-water intake produces isotonic overhydration without osmolarity change.

C. Water moves from plasma into interstitial fluid and then into cells.

D. Water shifts from cells toward plasma before entering interstitial fluid.

E. Extracellular volume increases while extracellular osmolarity decreases.

Answer: (A), (C), (E)

Explanation

Pure-water intake expands extracellular volume, lowers extracellular osmolarity, and drives water from plasma through interstitial fluid into cells. It produces hypo-osmolar global overhydration with increased body water and weight, not isotonic overhydration or an initial cellular-to-plasma shift.

20. Concerning urinary loss of a hypertonic fluid, which propositions are correct?

A. Water shifts from plasma toward extracellular fluid and then into cells.

B. Extracellular volume decreases after urinary loss of hypertonic fluid.

C. Extracellular osmolarity rises because the lost fluid contains less salt.

D. Total body water and body weight increase following the fluid loss.

E. The resulting condition combines extracellular dehydration with intracellular overhydration.

Answer: (A), (B), (E)

Explanation

Hypertonic-fluid loss reduces extracellular volume and osmolarity, causing water to move from plasma toward extracellular fluid and then into cells. This creates extracellular dehydration with intracellular overhydration; osmolarity rises and body water and weight decrease rather than increase.

21. Regarding the gain of isotonic fluid, tick the correct propositions:

A. Isotonic-fluid gain causes water to enter cells through osmotic movement.

B. The osmolarity of extracellular fluid remains unchanged.

C. Isotonic-fluid gain expands the extracellular fluid volume.

D. The added fluid remains within the plasma compartment.

E. The quantity of body osmoles increases after isotonic-fluid gain.

Answer: (B), (C), (D)

Explanation

Isotonic-fluid gain increases extracellular volume without altering osmolarity or osmole quantity. The fluid remains in plasma, so it does not produce an osmotic water shift into cells or an increase in body osmoles.

22. Which statements accurately compare water removal by the skin and kidneys?

A. Urine is described as hypertonic and richer in salt than water.

B. The kidneys remove water through urinary excretion.

C. The skin removes water through sweating from the body surface.

D. Sweat is hypotonic and contains proportionally more water than salt.

E. Urinary loss of hypertonic fluid can cause hypertension.

Answer: (A), (B), (C), (D)

Explanation

Sweat is hypotonic and relatively richer in water, while the urine described here is hypertonic and relatively richer in salt. Sweating removes water through the skin, whereas urinary excretion removes water through the kidneys. Urinary loss of hypertonic fluid can lower blood pressure rather than cause hypertension.

23. Concerning the relative composition of sweat and urine, which propositions are correct?

A. Sweat is classified as hypertonic in the course description.

B. Sweat contains a higher proportion of water than salt.

C. Urine is characterized as hypotonic compared with body fluids.

D. The kidneys remove water mainly through sweat production.

E. The urine described here contains a higher proportion of salt than water.

Answer: (B), (E)

Explanation

The course describes sweat as hypotonic and richer in water than salt, whereas urine is described as hypertonic and richer in salt than water. Therefore, sweat is not hypertonic, the kidneys remove water through urine rather than sweat, and the described urine is not hypotonic.