Tissue fluid

• What is tissue fluid?

  Liquid surrounding the cells in the body
• What does a group of cells performing the same function form?

  A tissue
• What essential molecules does tissue fluid contain?

  Water, glucose, amino acids, fatty acids
• How do cells gain access to essential molecules?

  Through diffusion from tissue fluid
• How is tissue fluid formed?

  From capillaries that are one cell thick
• What causes the formation of tissue fluid?

  High hydrostatic pressure in capillaries
• What is ultra filtration?

  Process where small molecules are forced out
• What molecules are forced out during ultra filtration?

  Water, glucose, and small proteins
• Why is tissue fluid not red in color?

  It lacks red blood cells
• Where does reabsorption of tissue fluid occur?

  At the venule end of capillaries
• What happens to the water potential at the venule end?

  It becomes very negative
• How does water move back into capillaries?

  By osmosis down the water potential gradient
• What waste molecules are reabsorbed with water?

  Carbon dioxide and urea
• Why is not all tissue fluid reabsorbed?

  Equilibrium is eventually reached
• What system absorbs the remaining tissue fluid?

  The lymphatic system
• What is lymph?

  Fluid absorbed by the lymphatic system
• Where does lymph eventually return to the blood?

  Near the heart
• What are the key processes involved in the formation and reabsorption of tissue fluid?

  • Formation:
  • Capillaries are one cell thick
  • High hydrostatic pressure causes ultra filtration
  • Small molecules and water are forced out
  • Reabsorption:
  • Occurs at the venule end of capillaries
  • Water moves back by osmosis
  • Lymphatic system absorbs excess fluid
• What is the significance of tissue fluid in the body?

  • Provides essential molecules to cells
  • Removes waste products from cells
  • Maintains fluid balance in tissues