A&P: CH. 17 [Blood]

• blood is classifies as a connective tissue because it has cells (rbc, wbc, etc.) suspended in a non-living matrix (plasma)
• composition

  • plasma constitutes 55% of blood
  • buffy coat = <1% (leukocytes & platelets)
  • erythrocytes = 45%
• hematocrit levels

  • male 47% +- 5%
  • females 42% +- 5%
• blood pH is slightly alkaline, 7.35-7.45
• blood account for aprox. 8% body weight
• average blood volume

  • male 5-6L
  • female 4-5L
• Functions

  • delivers oxygen and nutrients
  • transports metabolic waste products
  • transports hormones from endo. organs to target organs
  • maintains body temp
  • maintains normal pH in tissue
  • maintains fluid volume
  • prevents blood loss via clotting factors
  • prevents infection via antibodies, wbc and proteins
• plasma proteins most abundant solute by weight, 8% of plasma weight; produced by liver
• albumin account for 60% of plasma protein. acts as carrier for molecules through circulatory system, important buffer, major contributor to osmotic pressure
• plasma has homeostatic functions
• albumin accounts for 60% of the plasma protein and is a carrier for molecules through circulation, important blood buffer, major protein contributing to osmotic pressure
• clot retraction: platelet contract like smooth muscle to bring ruptured edges closer together
• PDGF: stimulates smooth muscle cells and fibroblasts to divide and rebuild vessel wall
• fibrinolysis: removal of clots when healing has occurred
• thrombus: a blood clot that forms in an unbroken blood vessel
• embolus: a blood clot that breaks off and travels through the bloodstream
• DIC: Disseminated intravascular coagulation which is widespread clotting in intact vessels and residual blood unable to clot