structure of kidneys

• Kidneys


  Remove waste products like urea from the blood, regulate the levels of ions in the blood, and regulate the amount of water in the blood
• Blood flow through the kidneys

  1. Enters through renal arteries

  2. Passes through the kidneys

  3. Exits through renal veins
• Urine


  Produced by the kidneys, passes down the ureters, stored in the bladder, and released through the urethra
• Nephron


  • The basic functional unit of the kidney
  • Contains a tubule (yellow part) that carries the filtered fluid that will become urine
  • Contains blood vessels (red parts)
• Filtration in the nephron

  1. Liquid part of the blood is forced from the glomerulus into the Bowman's capsule

  2. Only small substances like water, amino acids, urea, glucose, and ions are filtered through

  3. Around 20% of the plasma in the blood is filtered through to the Bowman's capsule
• Selective reabsorption in the nephron

  1. Kidneys reabsorb useful substances like glucose and amino acids back into the blood vessels

  2. Kidneys reabsorb some water and ions but not urea
• Parts of the nephron

  • Glomerulus
  • Bowman's capsule
  • Proximal convoluted tubule
  • Loop of Henle
  • Distal convoluted tubule
  • Collecting duct
• Fluid that passes out of the collecting duct is classed as urine
• Urine passes down the ureter to the bladder and can then be released as waste