Tissue fluid & lymph

• What is blood primarily responsible for in the human body?

  Transporting substances around the circulatory system
• What are the main components of blood?

  • Plasma
  • Red blood cells
  • White blood cells
  • Platelets
• What is the primary function of plasma in blood?

  Transports substances in solution
• What do red blood cells carry?

  Oxygen
• What is the role of white blood cells?

  Immune cells
• What are platelets involved in?

  Clotting
• What are the functions of blood?

  • Transports oxygen and carbon dioxide
  • Transports nutrients from digestion
  • Transports waste for excretion
  • Transports hormones
  • Transports food from storage
  • Transports clotting factors
• What is tissue fluid also known as?

  Interstitial fluid
• What is the primary role of tissue fluid?

  Site of diffusion between blood and body cells
• What does tissue fluid provide to cells?

  Nutrients and oxygen
• How does tissue fluid help in fighting infection?

  It forms part of the immune response
• How does tissue fluid differ from plasma?

  • No red blood cells
  • Fewer proteins
  • Fewer white blood cells
• What percentage of blood is plasma?

  About 55%
• What is the primary component of plasma?

  Water (95%)
• Why can many substances dissolve in plasma?

  Because water is a good solvent
• How is tissue fluid formed?

  Plasma leaks out of capillaries
• What prevents proteins from passing through capillary walls?

  Proteins are too large
• What is the role of tissue fluid in substance exchange?

  Facilitates exchange between cells and blood
• What two forces affect the formation of tissue fluid?

  Hydrostatic pressure and oncotic pressure
• What is hydrostatic pressure?

  Pressure exerted by a fluid, like blood
• What generates hydrostatic pressure in blood?

  Contraction of the heart muscle
• What is oncotic pressure?

  Osmotic pressure exerted by plasma proteins
• What happens at the arterial end of a capillary?

  Hydrostatic pressure forces fluid out
• Why do proteins remain in the blood?

  They are too large to pass through pores
• What occurs at the venous end of a capillary?

  Osmotic pressure draws fluid back in
• What percentage of fluid lost at the arterial end is reabsorbed at the venous end?

  About 90%
• What happens to the remaining 10% of fluid?

  It is collected by lymph vessels
• What is oedema?

  Fluid accumulation around tissues
• What happens at the arterial and venous ends of capillaries?

  At the arterial end:

  • Hydrostatic pressure > osmotic pressure
  • Tissue fluid is forced out

  
  

  At the venous end:

  • Hydrostatic pressure < osmotic pressure
  • Fluid is drawn back into capillary
• What is the role of lymph vessels?

  Transport lymph and filter pathogens
• How does lymph enter the lymphatic system?

  Through large pores in lymph vessels
• How is lymph transported through the body?

  By muscle contractions
• What happens to lymph as it passes through lymph nodes?

  It is filtered for pathogens
• Where does lymph eventually return?

  To the bloodstream
• What happens to plasma proteins that escape from blood?

  They are returned via lymph capillaries
• How are lipids transported after digestion?

  By the lymph system to the bloodstream
• What are the differences between lymph and tissue fluid?

  Differences:

  • Lymph has less oxygen and nutrients
  • Lymph has more fatty acids
  • Lymph has more white blood cells (lymphocytes)
• What is the process of lymph formation and transport?

  1. Tissue fluid drains into lymph vessels
  2. Lymph is formed from tissue fluid
  3. Transported by muscle contractions
  4. Passed through lymph nodes for filtering
  5. Returned to the blood