Selective reabsorption in the nephron

• What process allows reabsorption in the nephrons?

  Reabsorption occurs in the nephrons
• What should you be able to describe by the end of the video?

  How reabsorption takes place in nephrons
• What is the process called that filters small molecules out of the blood?

  Ultrafiltration
• Where does ultrafiltration take place in the nephron?

  In the glomerulus
• What forces small molecules to pass into the Bowman's capsule?

  High hydrostatic pressure
• Which substances are filtered into the Bowman's capsule?

  Urea, water, glucose, amino acids
• What remains in the blood after ultrafiltration?

  Blood cells and most plasma proteins
• What is the next stage after ultrafiltration?

  Reabsorption or selective reabsorption
• Where does reabsorption take place in the nephron?

  In the proximal convoluted tubule
• What does the lumen of the proximal convoluted tubule contain?

  Filtered small molecules from blood
• What happens to urea during reabsorption?

  It remains in the tubule and is excreted
• What is the role of active transport in reabsorption?

  Transfers sodium ions out of epithelial cells
• What energy source is required for active transport?

  ATP
• How do sodium ions enter the epithelial cells from the fluid?

  Through carrier proteins via facilitated diffusion
• What is co-transport in the context of reabsorption?

  Transport of glucose coupled with sodium ions
• What happens to glucose after it is reabsorbed?

  It diffuses back into the bloodstream
• What is the role of water during reabsorption?

  It is reabsorbed by osmosis
• What adaptations do epithelial cells in the proximal convoluted tubule have for efficient absorption?

  • Microvilli increase surface area
  • Infoldings near blood capillaries enhance transfer
  • Numerous mitochondria provide ATP for active transport
• What is the function of microvilli in epithelial cells?

  Increase surface area for reabsorption
• Why do epithelial cells have infoldings near blood capillaries?

  To provide a large surface area for transfer
• What is the purpose of mitochondria in epithelial cells?

  To provide ATP for active transport
• What will be discussed in the next video?

  The role of the loop of Henle