5.13: 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

Urinalysis and UTI Inference

1. A 26‑year‑old presents with fever, dysuria, and increased urinary frequency. Urinalysis shows cloudy urine, positive leukocyte esterase, many white blood cells, and only a trace of protein.
   1. What process is most likely occurring in the urinary tract?
   2. What does the presence of white blood cells in the urine indicate about the underlying condition?
   3. Which regions of the urinary tract are most likely involved?

Diabetes Mellitus vs. Diabetes Insipidus: Comparing Urine

1. Two patients report excessive thirst and very high urine output. One is diagnosed with diabetes mellitus, the other with diabetes insipidus.
   1. Compare the expected characteristics of their urine (glucose content, specific gravity, osmolarity, volume, color).
   2. Explain how these differences reflect the underlying pathophysiology in each disorder.

Anatomical Risk Factors for UTIs

1. A clinician counsels two patients about urinary tract infection prevention: one has a female reproductive system and recurrent bladder infections; the other has a male reproductive system and has never had a UTI. Explain why people with female anatomy generally have a higher risk of bladder infections than those with male anatomy. Include urethral length, proximity to the anus, and any protective factors.

Normal Micturition vs. Neurogenic Bladder

1. In a healthy person, describe how forceful urination is normally accomplished. Include the roles of the detrusor muscle, internal and external urethral sphincters, abdominal pressure, and the autonomic vs. somatic nervous systems.

Protection of the Kidneys from Trauma

1. A car‑crash victim sustains a forceful blow to the lower back, raising concern for kidney injury.
   1. Identify the anatomical structures that normally protect the kidneys (e.g., ribs, fascia, fat, surrounding muscles).
   2. Explain how damage to these protective layers could increase the risk or severity of renal injury.

Structures at the Renal Hilum

1. A radiology report describes a mass at the renal hilum of the right kidney that may be compressing nearby structures.
   1. List the normal structures that pass through the renal hilum.
   2. For each (renal artery, renal vein, ureter, lymphatics, nerves), briefly describe how compression could affect kidney function or produce symptoms.

The Renal Corpuscle and Filtration

1. A biopsy report shows damage localized to the renal corpuscles of several nephrons.
   1. Identify the main structures that make up a renal corpuscle.
   2. Explain how injury to each component (glomerular capillaries, Bowman’s capsule, filtration membrane layers) could alter glomerular filtration.

Glomerular Net Filtration Pressure and Edema

1. A patient presents with peripheral edema and rising serum creatinine, and the nephrologist suspects reduced glomerular filtration pressure.
   1. State the formula for net filtration pressure (NFP) at the glomerulus.
   2. Explain how changes in each component (glomerular blood hydrostatic pressure, capsular hydrostatic pressure, blood colloid osmotic pressure) could decrease filtration and contribute to fluid retention.

Clinical Signs of Kidney Failure

1. A middle‑aged patient with long‑standing high blood pressure and diabetes now reports fatigue, nausea, and swelling of the ankles and around the eyes.For each sign or symptom, briefly explain how reduced kidney function could cause it. In your explanations, refer to at least one of the following:
   1. problems with fluid balance
   2. problems with electrolyte (ion) balance
   3. buildup of wastes in the blood
   4. loss of normal kidney hormone functions (for example, making erythropoietin or activating vitamin D).

Countercurrent Multiplication and the Medullary Gradient

1. Identify which nephron segment and which blood vessels are responsible for countercurrent multiplication and exchange.
2. Explain how this system creates and maintains the corticomedullary osmotic gradient required for urine concentration.

Osmolarity Changes Along the Nephron

1. Describe how the osmolarity (solute concentration) of the tubular fluid changes as it moves through the nephron in a healthy, normally hydrated person. In your answer, briefly compare the tubular fluid in:
   1. the proximal convoluted tubule
   2. the descending limb of the loop of Henle
   3. the ascending limb of the loop of Henle
   4. the distal convoluted tubule
   5. the collecting duct (when ADH is present)

For each region, state whether the fluid is about the same as blood, more concentrated, or more dilute, and explain in one sentence why

Increasing Renal Sodium Excretion

1. Without naming specific drugs, describe at least two physiological strategies/mechanisms by which the kidneys can excrete more Na⁺. Include the roles of aldosterone, atrial natriuretic peptide (ANP), changes in glomerular filtration rate, and/or tubular transporters.

Renin–Angiotensin–Aldosterone System (RAAS)

1. Identify the organs and specific cell types that produce renin, angiotensinogen, and angiotensin‑converting enzyme (ACE). Explain how their coordinated actions in the RAAS help restore blood pressure and maintain glomerular filtration.

PTH, Calcium, and Phosphate Handling

1. Explain how PTH affects calcium and phosphate:
   1. absorption in the intestines,
   2. reabsorption (or excretion) in the kidney.
2. Describe how these actions help correct low blood calcium levels.

ADH as Vasopressin in Shock

1. An ICU patient with severe hemorrhage develops very low blood pressure and is given vasopressin (ADH). Explain why ADH is also called vasopressin by describing its dual effects on:
   1. the kidneys,
   2. the blood vessels.

Clarify how each effect is beneficial in this clinical scenario.

Low Plasma Proteins, Starling Forces, and Edema

1. A severely malnourished patient with low plasma protein levels presents with generalized edema.
   1. Using Starling forces, explain how reduced plasma proteins lead to fluid accumulation in the interstitial spaces.
   2. Briefly relate how the kidneys may respond in terms of fluid and sodium handling, and why this can worsen edema.

Key Electrolytes in Kidney Regulation and Their Clinical Impact

1. A patient with advanced kidney disease develops dangerous cardiac arrhythmias and muscle weakness. Lab work shows multiple electrolyte abnormalities.
   1. Identify three electrolytes most tightly regulated by the kidneys (e.g., Na⁺, K⁺, Ca²⁺, H⁺/HCO₃⁻).
   2. For each, explain why disturbances are particularly significant for neuromuscular and/or cardiovascular function.

Estimating GFR in Clinical Practice

1. Explain what glomerular filtration rate (GFR) represents and why it is clinically important.
2. Describe how GFR can be estimated using creatinine and outline at least one limitation of this approach.

Acid–Base Balance and the Kidney

1. Describe two major ways the kidneys help maintain acid–base balance.