Preparing for the CNN (Certified Nephrology Nurse) exam? Physiology is one of the areas our deck drills hardest: 60 of its 1020 flashcards focus on physiology, covering topics like GFB, Glomerular Filtration Barrier, JGA, TGF. Try the sample questions below — every card is a real question-and-answer pair from the full deck.
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A patient presents with nephrotic-range proteinuria. Which layer of the Glomerular Filtration Barrier (GFB) provides the final size-selective barrier, and what specific cell type is involved?
Show answer →The podocyte (visceral epithelial cell) and its slit diaphragm. The GFB consists of: 1. Fenestrated endothelium (prevents blood cell passage), 2. Glomerular Basement Membrane (GBM) (prevents large protein passage via negative charge), and 3. Podocyte slit diaphragms (final size-selective barrier). Exam Tip: NNCC focuses on the charge-size selectivity; albumin (negatively charged) is repelled by the GBM's heparan sulfate.
Genetic testing in a pediatric patient with steroid-resistant nephrotic syndrome identifies a mutation in the NPHS1 gene. Which structural protein is defective?
Show answer →Nephrin. The NPHS1 gene encodes nephrin, a structural protein essential for the integrity of the podocyte slit diaphragm. Other key proteins include podocin (NPHS2). Dysfunction leads to massive proteinuria due to the loss of the final filtration barrier. Clinical Pearl: Podocytes are post-mitotic cells; their loss or effacement often leads to irreversible glomerulosclerosis (FSGS).
Describe the components of the Juxtaglomerular Apparatus (JGA) and the mechanism of Tubuloglomerular Feedback (TGF) when sodium delivery to the distal tubule is high.
Show answer →The JGA consists of the Macula Densa (distal tubule), Juxtaglomerular cells (afferent arteriole), and Extraglomerular Mesangial cells. Mechanism: High NaCl at the macula densa (indicating high GFR) triggers adenosine release, causing afferent arteriole vasoconstriction. This lowers glomerular hydrostatic pressure and GFR. Exam Strategy: Distinguish TGF from the systemic RAAS trigger.
Why is the Proximal Convoluted Tubule (PCT) the most common site of injury in ischemic Acute Tubular Necrosis (ATN)?
Show answer →The PCT is the most metabolically active segment, reabsorbing ~65% of filtered solutes (Na+, water, glucose, amino acids). It relies heavily on aerobic metabolism and ATP-driven pumps (like Na+/K+-ATPase). High oxygen demand paired with the relatively low oxygen tension in the renal medulla makes it highly susceptible to ischemia and nephrotoxins. Key Exam Point: SGLT2 inhibitors act here.
Which specific segment of the nephron is known as the diluting segment, and what is its unique permeability characteristic?
Show answer →The Thick Ascending Limb (TAL) of the Loop of Henle. It is impermeable to water but actively reabsorbs solutes (Na+, K+, Cl-) via the NKCC2 transporter. This makes the tubular fluid dilute (hypotonic) while contributing to the hypertonic medullary interstitium. Exam Tip: Loop diuretics (furosemide) inhibit the NKCC2 transporter in this specific segment.
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Try 30 free CNN cards firstThe full CNN deck contains 1020 flashcards, and 60 of them focus on physiology. This page shows 5 free samples.
Our CNN deck dedicates 60 of 1020 cards (6%) to physiology — always cross-check the official NNCC exam outline for the current blueprint weighting.
Yes — the samples on this page are free, and the CNN preview page has 30 more free cards. Full access to all 1020 cards is a one-time $7.
Assessment
20 cards
Basics
110 cards
Diagnostics
70 cards
Management
200 cards
Pathology
280 cards
Pharmacology
160 cards
Procedures
120 cards
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