6.8: Applied Thinking Self - Assessment

Writing Guidelines

• Answer each question in your own words.
• Write 4–8 clear, complete sentences per question, organized into short paragraphs (not bullet points).
• Focus on explaining your reasoning, not just stating the answer.
• Use correct scientific vocabulary, and briefly define terms when needed.
• For questions that ask you to compare, contrast, or explain why/how:
  • Clearly state similarities or differences
  • Support your ideas with a brief explanation or example

Basic Fluid & Electrolyte Concepts

1. Movement of Fluid Between Compartments
   1. Explain how fluid moves between the intracellular fluid (ICF) and extracellular fluid (ECF) compartments. In your answer, describe the roles of
      1. Osmosis
      2. Hydrostatic pressure
      3. Oncotic (colloid osmotic) pressure
      4. Include at least one example of a situation that shifts fluid into or out of cells.
2. ADH and the Collecting Ducts
   1. Describe the effect of antidiuretic hormone (ADH) on the renal collecting ducts/tubules. Include:
      1. What happens to the permeability of the tubule
      2. How this changes urine volume and concentration
      3. The main stimulus for ADH release
3. Water Balance: Intake vs. Output
   1. Explain why, over time, water intake must equal water output.
   2. Discuss what happens - if intake is chronically greater or less than output to:
      1. Plasma osmolarity
      2. Blood pressure
      3. Cell volume
4. Imbalance Without Abnormal Total Amount
   1. Explain how a person can have a water or electrolyte imbalance even if the total amount of that substance in the body is not actually increased or decreased.
   2. Use at least one example (e.g., sodium shifting between ECF and ICF, or rapid gain of water without adequate sodium).
5. Compartment‑Specific Changes
   1. Describe how a loss of isotonic fluid (e.g., hemorrhage or isotonic saline loss) affects: ECF volume, ICF volume and Osmolarity in each compartment.
   2. Then describe how a gain of primarily free water (e.g., excessive plain water intake) affects those same variables.

Acid–Base Transport and Regulation

1. CO₂ Transport as Bicarbonate

a. Explain how CO₂ generated by cells is carried to the lungs primarily as bicarbonate (HCO₃⁻) in the blood. Include:

• The role of carbonic anhydrase
• The reaction converting CO₂ and water to carbonic acid and then to bicarbonate and H⁺
• The chloride shift in red blood cells

2. Renal Conservation of Bicarbonate
   1. Describe how the kidneys conserve and regenerate bicarbonate (HCO₃⁻). In your answer, address:
      1. Reabsorption of filtered bicarbonate in the proximal tubule
      2. Secretion of H⁺ and formation of “new” bicarbonate
      3. The roles of phosphate and ammonia buffers in the tubular fluid
3. Respiratory Control of Carbonic Acid
   1. Describe how the respiratory system regulates levels of carbonic acid (H₂CO₃) in the blood. Include:
      1. How changes in ventilation alter CO₂ and thus pH
      2. The role of central and peripheral chemoreceptors
      3. An example of how the body responds to metabolic acidosis via respiration
4. Integrated Acid–Base Response
   1. Compare and contrast respiratory and renal compensation for acid–base disturbances. Address:
      • Speed of onset
      • Mechanisms involved
      • Which system compensates for primarily respiratory vs. primarily metabolic disturbances.

Case Studies – Fluid & Electrolytes

Case Studies – Acid–Base Disorders