THE BLOOD

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THE BLOOD

• CHAPTER 11

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3 FUNCTIONS OF BLOOD

• TRANSPORTATION- gases such as 02 co2, waste
  products, nutrients, hormones
• REGULATION- keeps fluid electrolyte balance,
  acid-base balance body temperature
• PROTECTION- defense against pathogens blood
  loss

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BLOOD

• The average person has 4-6 liters of blood
• 38-48 of the blood is the formed elements
• Remaining portion, 52-62 is plasma
• Arterial blood is bright red
• Venous blood is a darker, dull red color
• pH of the blood is 7.35 to 7.45
• Viscosity or thickness of the blood is about 3-5
  x that of water

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BLOOD PLASMA

• Plasma is made up of about 91 water
• 7 of the plasma is plasma proteins such as
• albumin-the most abundant plasma protein
• clotting factors
• globulins such as gamma globulins that are
  antibodies

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PLASMA

• Nutrients such as glucose
• Hormones such as insulin
• Nitrogenous wastes
• Respiratory gases
• Electrolytes- chloride, carbonate, phosphate,
  potassium
• Also carries body heat as it circulates through
  the internal organs

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FORMED ELEMENTS-fig 11-2

• All formed elements start out as stem cells
• Red blood cells or erythrocytes, RBCs
• White blood cells or leukocytes, WBCs
• Platelets, also known as thromboctyes
• Table 11-2

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RED BLOOD CELLS

• SHAPE biconcave disks
• NORMAL RBC COUNT 4.5-6.0 million cells per mm3
• HEMOGLOBIN, the oxygen carrying component of RBCs
  should be 12-18 grams per 100ml blood

• PRODUCTION- red bone marrow of flat irregular
  bones
• ERYTHROPOIETIN is a hormone that stimulates
  increased production of RBCs
• MATURATION- originate as stem cells
• Lifespan is 120 days

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BLOOD TYPES

• ABO GROUP
• A, B, AB, O
• Letters AB represent antigens present on the RBC
  membrane
• O means that neither A nor B antigens are present
• AB means that both A B antigens present

• Rh FACTOR
• Another type of antigen that may be present on
  the RBCs
• If it is present blood type will be Rh positive,
  if it is not blood type will be Rh negative

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WHITE BLOOD CELLS OR LEUKOCYTES

• Larger than RBCs
• Nucleus may be in one piece or in several lobes
• Special staining of the nucleus for microscopic
  examination allows for differentiation of WBCs
  called a differential count in the CBC
• Normal range is 5,000 to 10,000 per mm3

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TYPES SITES OF PRODUCTION

• GRANULAR- have distinctly colored granules when
  stained see fig 11-3
• Produced in the red bone marrow
• Neutrophils
• Eosinophils
• Basophils

• AGRANULAR no granules present when stained
• Produced in the lymphatic tissue of the spleen,
  lymph nodes, thymus, red bone marrow
• Lymphocytes
• Monocytes

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Functions of the WBCsImmunity

• Neutrophils perform phagocytosis
• Monocytes which differentiate into macrophages
  perform phagocytosis
• Eosinophils detoxify foreign proteins-work in
  allergic reactions

• Basophils work in coagulation allergic
  reactions
• Lymphocytes
• T cells which recognize foreign antigens,
  directly destroy some antigens stop the immune
  response once the antigen has been destroyed
• B cells produce antibodies to foreign antigens

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WBCS

• Leukocytosis or high WBC count is often an
  indication of infection
• Leukopenia or a low WBC count such as occurs with
  some radiation chemotherapy treatments early
  stages of TB would leave a person susceptible to
  infection
• WBC types are called human leukocyte antigens or
  HLAs

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PLATELETS

• Also called thrombocytes-are pieces or fragments
  of cells
• Normal is 150,000-300,000 /mm3
• Essential to coagulation or clotting
• Formed when large cells called megakaryocytes
  break into small pieces
• Thrombocytopenia is a low platelet count

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BLOOD CLOTTINGfig 11-6

• Platelets function in homeostasis or prevention
  of blood loss by
• VASCULAR SPASM-when a large blood vessel is
  injured the smooth muscle in the vessel wall
  contracts to make the opening smaller, easier to
  plug with the clot
• PLATELET PLUGS works in the small capillaries
  when they are damaged
• CHEMICAL CLOTTING started by the rough surface
  within a vessel such as plaque buildup or injury
  to a vessel begins within 15-120 secs table
  11-3, fig 11-7

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Prevention of Abnormal Clotting

• Clots do not form in intact vessels due to the
  smooth texture of the lining of the vessel
• Heparin, produced by basophils is a natural
  anticoagulant
• Liver produces antithrombin which combines with
  and inactivates excess thrombin
• Thrombus a clot
• Embolism a clot or other tissue that has lodged
  in a vessel and obstructs it, box 11-7