ANATOMY 1

• Primary functions of blood


  • Transportation of respiratory gases, nutrients, and wastes
  • Regulation of hormonal and temperature
  • Protection through clotting and immunity
• Cardiovascular system


  Heart: four-chambered pump

  Blood vessels: arteries, arterioles, capillaries, venules, and veins
• Lymphatic system


  Lymphatic vessels, lymphoid tissues, lymphatic organs (spleen, thymus, tonsils, lymph nodes)
• Arterial blood


  Leaving the heart, bright red, oxygenated except for blood going to the lungs
• Venous blood


  Entering the heart, dark red, deoxygenated except for blood coming from the lungs
• Blood composition


  45% formed elements, 55% plasma (by volume)

  
• Plasma constituents


  • Water
  • Dissolved solutes
• Plasma proteins


  • Albumin
  • Alpha and beta globulins
  • Gamma globulins
  • Fibrinogen
• Plasma volume regulation


  Osmoreceptors in the hypothalamus cause the release of ADH from the posterior pituitary gland if fluid is lost
• Erythrocytes (red blood cells - RBCs)

  • Flattened, biconcave discs

  Carry oxygen

  Lack nuclei and mitochondria

  Count - approximately 5 million/mm3 blood

  Have a 120-day life span

  Each contain about 280 million hemoglobin molecules

  Iron heme is recycled from the liver and spleen, carried by transferrin in the blood to the red bone marrow

  
• Anemia


  Abnormally low hemoglobin or RBC count

  
• Leukocytes (white blood cells - WBCs)


  • Have nuclei and mitochondria

  Move in amoeboid fashion

  Diapedesis - movement through the capillary wall into connective tissue

  Count - approximately 5000-9000/mm3 blood

  Types: Granular (neutrophils, eosinophils, basophils) and Agranular (monocytes, lymphocytes)

  
• Platelets (thrombocytes)


  • Smallest formed element, fragments of large cells called megakaryocytic

  Lack nuclei

  Very short-lived (5−9 days)

  Clot blood with several other chemicals and fibrinogen

  Release serotonin that stimulates vasoconstriction

  Count - 130,000 – 400,000/mm3 blood

  
• Hematopoiesis (hemopoiesis)


  Process of blood cell formation

  Hematopoietic stem cells: embryonic cells that give rise to all blood cells

  Process occurs in myeloid tissue (red bone marrow) and lymphoid tissue

  
• Erythropoiesis


  Formation of red blood cells

  Red bone marrow produces about 2.5 million RBCs/sec

  Regulation: Erythropoietin from the kidneys responds to low blood O2 levels, process takes about 3 days

  Most iron is recycled from old RBCs, the rest comes from the diet

  
• Leukopoiesis


  Formation of white blood cells

  Cytokines stimulate the production of the different subtypes: Multipotent growth factor-1, Interleukin-1, Interleukin-3, Granuloctye colony stimulating factor, Granulocyte-monocyte colony-stimulating factor
• ABO system


  Antigens on erythrocyte cell surfaces: Type A has A antigen, Type B has B antigen, Type AB has both A and B, Type O has neither A nor B

  Plasma contains antibodies against the antigens not present on the RBC
• Rh system


  Rh-positive blood has Rh factor antigen present in RBCs, Rh-negative blood has no Rh factor present in RBCs and no anti-Rh antibodies naturally in plasma
• Universal donor and universal recipient blood

  Type O Rh negative: Universal donor blood

  Type AB Rh positive: Universal recipient blood
• Erythroblastosis fetalis


  Hemolytic anemia that may occur when the blood types of a mother and baby are incompatible, more likely during a second or subsequent pregnancy, or following a miscarriage or abortion
• Platelets and blood vessel walls

  Intact endothelium secretes prostacyclin, nitric oxide, and CD39 which vasodilate and inhibit platelet aggregation

  
• Blood clotting


  Clotting factors released at the injury site produce prothrombin activator

  Prothrombin activator and calcium convert prothrombin to thrombin

  Thrombin reacts with fibrinogen and triggers formation of fibrin, which traps RBCs to form a clot

  
• Thrombus


  When a clot stays in the place it has formed, condition is called thrombosis
• Embolus


  When a part of a clot dislodges and circulates through the bloodstream, condition is called embolism
• Dissolution of clots


  Plasmin digests fibrin

  Clotting or coagulation can be prevented with certain drugs: Calcium chelators, Heparin, Coumadin
• components of blood

  label

  A) albumin

  B) Buffy coat

  
• What do erythrocytes do?

  transport oxygen
• Major components of circulatory system

  1. cardiovascular system 


  2. lymphatic system
• Plasma proteins

  1. Make up 7-8% of the plasma
  2. Albumin: creates osmotic pressure to help draw water from tissues into capillaries to maintain blood volume and pressure
  3. Globulins
  4. Alpha and beta globulins – transport lipids and fat-soluble vitamins
  5. Gamma globulins – antibodies that function in immunity
  6. Fibrinogen: helps in clotting after becoming fibrin
  7. serum constitutes the part of blood without fibrinogen.
• Plasma Volume

  1. Regulatory mechanisms - maintain plasma volume to maintain blood pressure


  2. Osmoreceptors - In hypothalamus cause the release of ADH from Posterior Pituitary gland if fluid is lost
• type of Leukocytes

  1. Granular - Neutrophils, Eosinophils and Basophils


  2. Agranular - Monocytes and lymphocytes
• Antigens

  Found on the surface or cells to help immune system recognize self cells
• Basophils contain histamine which causes inflammation during anaphylactic shock
• Eosinophils are involved in allergic reactions and parasite elimination
• antibodies - secreted by lymphocytes in response to foreign cells
• ABO system - antigens on erythrocytes cell surface

  Type A - has A antigen

  Type B - has B antigen

  Type AB - has both A & B antigen

  Type O - has neither A and B antigen