MCAT Nephron

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MCAT Nephron
2012-08-02 15:28:14

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  1. Glomerulus
    A tuft of capillaries situated within a Bowman's capsule at the end of the renal tubule in the kidney that filters waste products from the blood and initiates urine formation.
  2. Bowman's Capsule
    The structure surrounding the glomerulus.
  3. Proximal Convoluted Tubule
    • Is responsible for the reabsorption of glucose, amino acids, various ions, and water.
    • Sodium is actively transported, chloride follows passively by electrical attraction, and water follows the salt out of the proximal tubule.
  4. Descending Loop of Henle
    Is permeable to water.
  5. Ascending Loop of Henle
    • Na+ is actively transported out and Cl follows due to electrical attraction.
    • Impermeable to water.
  6. Juxtaglomerular Apparatus
    Located next to each glomerulus, it is involved in the secretion of renin and EPO in response to blood pressure changes.
  7. Distal Convoluted Tubule
    Reabsorbs Na+ through coupled secretion of H+ or K+. Requires the presence of aldosterone. Plays an important role in acid-base balance.
  8. Collecting Duct
    As the collecting ducts pass through the hypertonic renal medulla, water leaves by osmosis and is carried away in surrounding capillaries.

    The permeability of the collecting ducts to water is stimulated by antidiuretic hormone (ADH).

    Urine is collected and moved into the renal pelvis and ureters.
  9. Renal Pelvis
    The funnel-shaped cavity of the kidney into which urine is discharged before passing into the ureter.
  10. Ureter
    The long narrow duct that conveys urine from the kidney to the urinary bladder.
  11. Renal Plasma Clearance
    Inulin is filtered but neither reabsorbed nor secreted. Its clearance is thus equal to the glomerular filtration rate.
  12. Granular (juxtaglomerular cells) secrete _____ when there is a fall in _____ ion concentration.
    Renin / Na+
  13. If you took a drug that inhibited the reabsorbtion of Na+ in the PCT, you would:
    Have an increased urine output
  14. In the nephron glucose is...
    Filtered, and reabsorbed, but not secreted.
  15. Typically, as GFR increases, the [Na+] of the filtrate reaching the DCT will...
  16. What would happen to the GFR if the hydrostatic pressure exerted by the fluid in the capsular space increased?
    GFR would decrease
  17. True or False: Glomerular filtration is an ATP-driven process.
  18. Aldosterone causes...
    Decreased urine output
  19. During reabsorption, Na+ leaves the proximal tubule by means of...
    Active transport
  20. The majority of reabsorption occurs in the...
    Proximal convoluted tubule
  21. Functions of the kidney
    • Release of hormones
    • Maintenance of plasma pH
    • Maintenance of plasma [electrolyte]
    • Gluconeogenesis
  22. In a patient who is dehydrated from vomiting and diarrhea, what is likely to be higher than normal in blood?
    ADH and aldosterone
  23. How do the kidneys respond to drop in blood pressure?
    By activating the renin-angiotensin system. This increases the amount of sodium and water that is reabsorbed by the kidneys, therefore increasing blood volume and pressure.
  24. The effect blood pressure on GFR
    Higher pressure increased GFR or more filtrate.