blood

• plasma:

  • liquid that carries the components in the blood
  • rbc, wbc, platelets, glucose, amino acids, urea, hormones, etc
• red blood cells:

  • carry oxygen molecules from the lungs to all the cells in the body
  • biconcave disc shape provides a large surface area
  • no nucleus - more room to carry oxygen
  • contain hemoglobin, binds to oxygen and forms oxyhemoglobin
• white blood cells:

  • part of immune system
  • have nucleus
  • phagocytes - engulf and digest pathogens
  • lymphocytes - produce antitoxins and antibodies
• platelets:

  • help blood clot
  • clot dries and hardens to form a scab - allows new skin to grow
  • small fragments of cells
  • no nucleus
  • without them, cuts would result in excessive bleeding and bruising