Summary of Urinorganen del 1 (5)

Scientific Concepts and Discoveries Presented

• Anatomy of the Urinary Organs:
  • The urinary organs include a pair of Kidneys, ureters, bladder, and urethra.
  • Kidneys are located retroperitoneally (behind the peritoneum) near the lower costal arch and medial towards the spine.
  • Urine is continuously produced by the Kidneys, collected in the renal pelvis, transported via ureters to the bladder, and expelled through the urethra.
  • Kidneys are divided into renal cortex (outer layer) and renal medulla (inner layer).
• Kidney Blood Supply:
  • Kidneys receive a large blood supply via the Renal arteries (arteria renalis).
  • Blood is filtered in the Kidneys and leaves via the renal veins (vena renalis) to the inferior vena cava.
  • Kidneys receive more blood than needed for nutrition, highlighting their role in filtration and urine production.
• Urine Formation and Blood Filtration:
  • Urine is formed by filtering blood plasma; the composition of urine differs from blood plasma.
  • Kidneys remove various substances from the blood, including metabolic waste and foreign substances.
  • If Kidneys fail, Dialysis is used to artificially filter blood.
• Functions of the Kidneys:
  • Regulation of Extracellular Fluid:
    • Control volume of extracellular fluid (fluid outside cells), adjusting urine output to maintain fluid balance.
    • Regulate osmolarity (concentration of dissolved particles, e.g., salt) to prevent cell swelling or shrinking.
  • Removal of Waste Products:
    • Major metabolic wastes removed include:
      • Carbon dioxide (exhaled via lungs)
      • Nitrogenous wastes such as urea (from protein breakdown)
      • Uric acid (from DNA breakdown)
      • Creatinine (from muscle metabolism, used clinically to assess kidney function)
      • Bilirubin (from red blood cell breakdown, gives urine yellow color)
  • Removal of Foreign Substances:
    • Kidneys help eliminate foreign molecules like medications, food additives, and plant-derived compounds.
  • Regulation of Electrolytes:
    • Control concentrations of key ions (electrolytes) in extracellular fluid: sodium, potassium, calcium, phosphate, chloride.
  • Acid-Base Balance:
    • Adjust urine pH by excreting hydrogen ions or bicarbonate to maintain body’s acid-base homeostasis.
    • Urine pH can be influenced by diet (acid-forming vs. base-forming foods).
• Other Kidney Functions Beyond Urine Production:
  • Hormone Production:
    • Erythropoietin (EPO): Stimulates red blood cell production in bone marrow; important for oxygen transport. EPO doping is common in endurance sports.
    • Calcitriol: Active form of vitamin D produced by Kidneys; important for calcium absorption.
  • Blood Pressure Regulation:
    • Kidneys produce renin, an enzyme initiating the Renin-angiotensin-aldosterone system (RAAS) which regulates blood pressure and fluid balance.
    • Diuretics (medications that increase urine production) are used to lower blood pressure by reducing blood volume.

Methodology/Processes Outlined

• Locating Kidneys in the body relative to anatomical landmarks (lower costal arch, spine).
• Blood flow into Kidneys via Renal arteries, filtration, and outflow via renal veins.
• Urine formation process involves filtering blood plasma, removing wastes, and adjusting fluid and electrolyte balance.
• Dialysis as an artificial method for blood filtration when Kidneys fail.
• Using urine pH measurement to assess acid-base balance influenced by diet.
• Hormonal regulation of erythropoiesis and blood pressure via kidney-secreted substances.

Researchers or Sources Featured

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