ANAPHY 4th Quarter

• Blood


  Transports everything that must be carried from one place to another such as: Nutrients, Wastes, Hormones, Body Heat
• Blood


  The only fluid tissue, a type of connective tissue
• Components of Blood


  • Formed Elements (Living Cells)
  • Plasma (Nonliving Fluid Matrix)

  
• Physical Characteristics of Blood


  • Sticky, opaque fluid
  • Heavier and thicker than water
  • Oxygen-rich blood is scarlet red
  • Oxygen-poor blood is dull red or purple
  • Metallic, salty taste
  • Blood pH is slightly alkaline, between 7.35 and 7.45
• Plasma


  • Straw-colored fluid
  • 90% water
  • Includes many dissolved substances: Nutrients, Salts (electrolytes), Respiratory gasses (Carbon dioxide and oxygen), Hormones, Plasma protein, Waste products
• Plasma Proteins


  • Most abundant solutes in plasma
  • Most are made by the liver
  • Include: Albumin, Clotting proteins, Antibodies
• Hematopoiesis


  1. Process of Blood Cell Formation

  2. Occurs in the red bone marrow (myeloid tissue)

  3. All blood cells are derived from a common stem cell (hemocytoblast)

  4. Hemocytoblasts form two types of descendants: Lymphoid stem cells - produce lymphocytes, Myeloid stem cell - produce all other formed elements

  
• Erythrocytes


  • Red blood cells
  • Does not have nucleus
  • Main function is to carry oxygen
  • RBC's differ from other blood cells: Anucleate (No nucleus), Contain few organelles; lack mitochondria, Shaped like biconcave discs, Carries hemoglobin
  • Normal count is 5 million RBCs per cubic millimeter (mm3) of blood

  
• Hemoglobin


  • Iron-bearing protein
  • The reason why oxygen is attracted to red blood cells
  • Binds oxygen
  • Each hemoglobin molecule can bind 4 oxygen molecules
  • Each erythrocyte has 250 million hemoglobin molecules
  • Normal blood contains 12–18 g of hemoglobin per 100 milliliters (ml) of blood

  
• Disorders of Erythrocytes


  • Anemia - Decrease in the oxygen-carrying ability of the blood due to lower than normal number of RBC or abnormal/deficient hemoglobin content
  • Hemorrhagic Anemia - Results from sudden hemorrhage
  • Hemolytic Anemia - Lysis of RBCs as a result of bacterial infections
  • Pernicious Anemia - Due to lack of vitamin B12
  • Aplastic Anemia - Depression/destruction of bone marrow
  • Iron-Deficiency Anemia - Lack of iron in diet or slow/prolonged bleeding
  • Polycythemia - Excessive or abnormal increase of RBCs
• Formation of Red Blood Cells

  1. RBCs are anucleate, unable to divide, grow, or synthesize

  2. Wear out in 100 to 120 days

  3. Eliminated by phagocytes in the spleen or liver

  4. Lost cells are replaced by division of hemocytoblasts in the red bone marrow

  5. Reticulocytes are young RBCs which enter the blood to become oxygen transporting erythrocytes

  
• Erythropoietin


  • Hormone that controls the rate of RBC production
  • Kidneys produce most erythropoietin as a response to reduced oxygen levels
  • Homeostasis is maintained by negative feedback from blood oxygen levels

  
• Homeostasis: Normal Blood Oxygen Levels


  1. Stimulus: Low Blood of Oxygen levels

  2. Kidneys (and liver, to a smaller extent) release erythropoietin

  3. Erythropoietin will then stimulate red bone marrow

  4. Enhanced erythropoietin increases RBC count

  5. Oxygen carrying ability of blood increases

  
• Leukocytes


  • White blood cells
  • Crucial in the body's defense against disease
  • Complete cells, with nucleus and organelles
  • Able to move into and out of blood vessels or walls (diapedesis)
  • Respond to chemicals released by damaged tissues (known as positive chemotaxis)
  • Moved by amoeboid motion
  • 4,800 to 10,800 WBCs per mm3 of blood

  
• Disorders of Leukocytes


  • Leukocytosis - Normal response to an infection but excessive production of abnormal WBCs during infectious mononucleosis or leukemia is pathological
  • Leukopenia - Abnormally low WBC count, commonly caused by certain drugs
  • Leukemia - Bone marrow becomes cancerous, numerous immature WBC are produced
• Types of Leukocytes


  • Granulocytes - Granules in their cytoplasm can be stained, possess lobed nuclei (Neutrophils, Eosinophils, Basophils)
  • Agranulocytes - Lack visible cytoplasmic granules, nuclei are spherical, oval, or kidney-shaped (Lymphocytes, Monocytes)

  
• Neutrophils


  • Most numerous WBC
  • Multilobed nucleus
  • Cytoplasm stains pink and fine granules
  • Acts as phagocytes at active sites of infection
  • Numbers increases during infection
  • First to respond to bacteria of a virus

  
• Eosinophils


  • Nucleus stains blue-red
  • Brick-red cytoplasmic granules
  • Function is to kill parasitic worms and play a role in allergy attacks
• Basophils


  • The rarest of WBC
  • Large histamine-containing granules that stain dark blue
• Lymphocytes


  • Large, dark purple nucleus
  • Slightly larger than RBCs
  • Reside in lymphatic tissues
  • Play a role in immune response
  • 1,500–3,000 lymphocytes per mm3 of blood (20–45 percent of WBCs)

  
• Monocytes


  • Largest of the white blood cells
  • Distinctive U- or kidney-shaped nucleus
  • Function as macrophages when they migrate into tissues
  • Important in fighting chronic infection
  • 100–700 monocytes per mm3 of blood (4–8 percent of WBCs)

  
• Thrombocytes (Platelets)


  • Fragments of megakaryocytes (multinucleate cells)
  • Needed for the clotting process
  • Normal platelet count is 300,000 platelets per mm3 of blood

  
• Hemostasis


  1. Process of stopping the bleeding that results from a break in a blood vessel

  2. Involves three phases: Vascular spasms, Platelet plug formation, Coagulation (blood clotting)

  
• Disorders of Hemostasis


  • Undesirable Clotting - Thrombus (a clot in an unbroken blood vessel), Embolus (a thrombus that breaks away and floats freely in the bloodstream)
  • Hemophilia - Hereditary bleeding disorder, normal clotting factors are missing

  
• Vascular Spasms


  • Immediate response to blood vessel injury
  • Vasoconstriction causes blood vessel to spasm
  • Spasms narrow the blood vessel decreasing blood loss

  
• Platelet Plug Formation


  1. Collagen fibers are exposed by a break in a blood vessel

  2. Platelets become "sticky" and cling to fibers

  3. Anchored platelets release chemicals to attract more platelets

  4. Platelets pile up to form a platelet plug (white thrombus)

  
• Coagulation


  1. Injured tissues release tissue factor (TF)

  2. PF3 (a phospholipid) interacts with TF, blood protein clotting factors, and calcium ions to trigger a clotting cascade

  3. Prothrombin activator converts prothrombin to thrombin (an enzyme)

  4. Thrombin joins fibrinogens proteins into hairlike molecules of insoluble fibrin

  5. Fibrin forms a meshwork (the basis for a clot)

  6. Within the hour, serum is squeezed from the clot as it retracts
• Blood Groups


  • Blood contains genetically determined proteins known as antigens
  • Antigens are substances that the body recognizes as foreign and that the immune system may attack
  • Antibodies are the "recognizers" that bind foreign antigens
  • Blood is "typed" by using antibodies that will cause blood with certain proteins to clump (agglutination) and lyse

  
• ABO Blood Groups


  • Type A
  • Type B
• Rh Blood Groups


  • An inherited protein found on the surface of red blood cells
  • If your blood has the protein, you're Rh positive
  • If your blood lacks the protein, you're Rh negative
  • Rh positive is the most common blood type
  • If an Rh–(Rh-negative) person receives Rh+ blood, the immune system becomes sensitized and begins producing antibodies; hemolysis does not occur, because as it takes time to produce antibodies
  • Second, and subsequent, transfusions involve antibodies attacking donor's Rh+ RBCs, and hemolysis occurs (rupture of RBCs)
  • Danger occurs only when the mother is Rh–, the father is Rh+, and the child inherits the Rh+ factor
  • RhoGAM shot can prevent buildup of anti-Rh+ antibodies in mother's blood
  • The first pregnancy usually proceeds without problems; the immune system is sensitized after the first pregnancy
  • In a second pregnancy, the mother's immune system produces antibodies to attack the Rh+ blood (hemolytic disease of the newborn)
• Albumn

  A plasma protein that is an important blood buffer that contributes to osmotic pressure
• Clotting proteins


  A plasma protein that helps to stem blood loss when a blood vessel is injured
• Antibodies


  A plasma protein that helps protect the body from pathogens
• Blood vessels


  Form a closed vascular system that transports blood to the tissues and back to the heart
• Arteries and aterioles


  Vessels that carry blood away from the heart
• Capillary beds


  Vessels that play a role in exchanges between tissues and blood vessels
• Venues and veins


  Vessels that return blood toward the heart
• Tunica intima, tunica media, tunica externa


  What are the three layers of blood vessels (except capillaries)?
• Tunica intima


  - Forms a friction-reducing lining

  - Endothelium
• Tunica media


  - Smooth muscle and elastic tissue

  - Controlled by sympathetic nervous system