Structure of the Kidneys #28

• What is the focus of today's video?

  The anatomy of the urinary system
• What are the three main roles of the kidneys?

  Remove waste, regulate ions, regulate water
• What waste product do the kidneys remove from the blood?

  Urea
• How does blood flow through the kidneys?

  In through renal arteries, out through renal veins
• What is produced from the filtered blood in the kidneys?

  Urine
• Where is urine stored before being excreted?

  In the bladder
• What is the process of urine formation described as?

  Complicated
• What happens when a kidney is sliced in a cross-section?

  It reveals tiny structures called nephrons
• What is the yellow part of the nephron called?

  The tubule
• What does the tubule carry?

  The filtered fluid that becomes urine
• What is the first step in urine formation?

  Filtration
• What is the glomerulus?

  A tangle of blood vessels
• What is forced into the Bowman's capsule during filtration?

  Liquid part of the blood
• What types of substances can be filtered into the Bowman's capsule?

  Small substances like water and ions
• What percentage of plasma is filtered through to the Bowman's capsule?

  About 20 percent
• What happens to the rest of the blood that is not filtered?

  It continues through the blood vessels
• What is selective reabsorption?

  Reabsorbing only useful substances back into blood
• Which substances are almost completely reabsorbed?

  Glucose and amino acids
• What is absorbed none of during selective reabsorption?

  Urea
• What are the parts of the nephron in order?

  Glomerulus, Bowman's capsule, tubules
• What follows the Bowman's capsule in the nephron?

  The proximal convoluted tubule
• What is the last part of the nephron?

  The collecting duct
• What happens to fluid that passes out of the collecting duct?

  It is classed as urine
• Where does urine pass after the collecting duct?

  Down the ureter to the bladder
• What is the final step in the urinary process?

  Urine is released as waste
• What is the overall process of urine formation in the kidneys?

  1. Filtration: Blood is filtered in the glomerulus.
  2. Selective reabsorption: Useful substances are reabsorbed.
  3. Urine formation: Remaining fluid becomes urine.
  4. Urine transport: Urine passes to the bladder.