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Urinary System key concepts

7 revision pages for Urinary System, each with the key facts, a memory aid where one helps, and the exam traps.

  1. Acetazolamide: carbonic anhydrase inhibition and metabolic acidosis

    Acetazolamide blocks the enzyme carbonic anhydrase in the proximal tubule (first part of the kidney tubule), so lost bicarbonate can cause metabolic acidosis (too much acid in the blood).

  2. Aldosterone antagonists: mechanism and hyperkalaemia

    Aldosterone antagonists such as spironolactone block aldosterone (a salt-retaining hormone), so less potassium is pulled into the urine and hyperkalaemia (a high blood potassium) can follow.

  3. Alport syndrome and its type IV collagen defect

    Alport syndrome is an inherited type IV collagen fault that typically presents with haematuria (blood in the urine) in childhood or adolescence, with hearing loss and sometimes eye changes.

  4. High-pressure versus low-pressure chronic urinary retention

    In chronic urinary retention (a bladder that has long failed to empty), high pressure can damage the kidneys, but with low pressure the kidneys are not usually affected.

  5. Hydrocele: clinical features and mechanism

    A hydrocele is a collection of fluid in the tunica vaginalis, the thin, double-layered sac around the testis, giving a swelling that is typically painless.

  6. Storage, voiding and post-micturition lower urinary tract symptoms

    Lower urinary tract symptoms (LUTS, urinary complaints from the bladder, prostate or urethra) are grouped by when they occur: filling, emptying or just after passing urine.

  7. Vasa recta: counter-current exchange preserves the medullary gradient

    The vasa recta, capillaries where blood flows in opposite directions (counter-current exchange), preserve the medullary gradient: the concentration of dissolved particles rises deeper into the medulla (the inner kidney).

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