Hematology

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• Lecture 9
• Hematology
• Bio-5
• JPHubbard

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• Cells of the body are serviced by 2 fluids
• blood
• composed of plasma and a variety of cells
• transports nutrients, wastes, hormones
• interstitial fluid
• bathes the cells of the body
• Hematology- the study of blood, blood forming
  tissues, and the disorders associated with them.

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• 1 Drop of blood contains 250 million blood cells.
• Blood is denser than water.
• Blood temperature is about 100.4 F.
• pH 7.35-7.45.
• Blood is about 8 of total body weight.
• Blood volume in
• Men is 5-6 liters (1.5 gallons).
• Women is 4-5 liters (1.2 gallons).
• Hypervolemic, normovolemic, hypervolemic

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Techniques of Blood Sampling

• Venipuncture
• sample taken from vein with hypodermic needle
  syringe
• median cubital vein
• why not stick an artery?
• less pressure
• closer to the surface
• Finger or heel stick
• common technique for diabetics to monitor daily
  blood sugar
• method used for infants

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Components of Blood

• By volume
• 55 plasma
• 45 cells
• 99 RBCs
• lt 1 WBCs and platelets

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Blood Plasma

• 0ver 90 water
• 7 plasma proteins (see table 20.2)
• 3 other substances
• Similar to Interstitial Fluid
• Differing
• dissolved gas concentration
• Dissolved proteins

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Plasma Proteins

• Three Categories
• Albumins 60 important in maintenance of
  water balance between blood and tissues
• Globulins 35 involved in transport of such
  things as cholesterol and fighting disease
  (antibodies)
• Attach to lipids (as do albumins) as lipoproteins
• Fibrinogen 4 proteins involved in formation of
  clots when a blood vessel is broken

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• 3 other substances
• Electrolytes
• Nutrients
• Hormones
• Gases
• waste products
• Regulated/important in various physiological
  mechanisms

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• Formed Elements (45) cells
• Red Blood Cells Erythrocytes
• White blood cells Leukocytes
• Several classes, based on staining
  characteristics
• Immune response
• Platelets cell fragments from megakaryocytes
• Clotting process

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Hematocrit (Hct, Crit, Packed Cell Volume)

• Percentage of blood occupied by cells 45
• Depends on altitude
• female normal range
• 38 - 46 (average of 42)
• male normal range
• 40 - 54 (average of 46)
• How is one prepared?
• Monitor/test for conditions
• Anemia
• not enough RBCs or not enough hemoglobin
• Polycythemia
• too many RBCs (over 65)
• dehydration, tissue hypoxia, blood doping in
  athletes

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• Red Blood Cells Erythrocytes
• Highly specialized cell for transport of oxygen
  and to a lesser extent CO2
• Contain hemoglobin a protein involved in binding
  Oxygen
• 1/3 of cells weight is hemoglobin
• Do not respire
• Very flexible
• Lack a nucleus and most other organelles
• Biconcave disk high surface area to volume ratio
• Produced in bone marrow, life of 120 days
• new RBCs enter circulation at 2 million/second

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Anemia

• Reduces ability of blood to carry oxygen two
  reasons of a combination thereof
• Too little hemoglobin
• Too few functional RBC
• Failure of RBC to mature ( pernicious anemia)
  vitamin B12, iron and folic acid required for
  maturation
• Hemolytic disease red blood cells lyse
• Genetic conditions resulting in altered
  hemoglobin forms
• Sickle cell anemia defective hemoglobin
• Thalassemias deficiency of either alpha or beta
  hemoglobin

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• Polycythemia
• Abnormally high hematocrit
• Polycythemia vera primary polycythemia
• Cause unk
• Usually over 40 years
• Secondary
• Usually related to increased erythropoietin
  levels natural or not

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• Hematopoiesis or (hemopoiesis) Formation of
  Blood Cells
• Most blood cells types need to be continually
  replaced
• die within hours, days or weeks
• process of blood cells formation is hematopoiesis
  or
• In the embryo
• occurs in yolk sac, liver, spleen, thymus, lymph
  nodes red bone marrow
• In adult
• occurs only in red marrow of flat bones like
  sternum, ribs, skull pelvis and ends of long
  bones

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Hematopoiesis
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Hemopoietic Growth Factors

• Regulate differentiation proliferation
• Erythropoietin (EPO)
• produced by the kidneys increase RBC precursors
• Thrombopoietin (TPO)
• hormone from liver stimulates platelet formation
• Cytokines are local hormones of bone marrow
• produced by some marrow cells to stimulate
  proliferation in other marrow cells
• colony-stimulating factor (CSF) interleukin
  stimulate WBC production

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• How Red Blood Cell Production is Regulated
• Response to hypoxia
• Hypoxia low oxygen tension in blood, ie.
  tissues not getting enough oxygen
• Kidney response to hypoxia
• release erythropoietin
• speeds up development of proerythroblasts into
  reticulocytes
• Tissue hypoxia
• high altitude since air has less O2
• anemia
• RBC production falls below RBC destruction
• circulatory problems

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Hemoglobin

• Globin protein consisting of 4 polypeptide chains
• One heme pigment attached to each polypeptide
  chain
• each heme contains an iron ion (Fe2) that can
  combine reversibly with one oxygen molecule

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RBC Life Cycle

• RBCs live only 120 days
• wear out from bending to fit through capillaries
• no repair possible due to lack of organelles
• Worn out cells removed by fixed macrophages in
  spleen liver
• Breakdown products are recycled

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White Blood Cells
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White blood cells function in defense and various
immune responses
NEUTROPHILS
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• WBC Anatomy and Types
• All WBCs (leukocytes) have a nucleus and no
  hemoglobin
• Granular and agranular
• presence/absence of cytoplasmic granules made
  visible by staining
• Granulocytes
• neutrophils, eosinophils and basophils
• Agranulocytes
• lymphocytes and monocyes

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WBC Physiology

• Less numerous than RBCs
• 5000 to 10,000 cells per drop of blood
• 1 WBC for every 700 RBC
• Leukocytosis is a high white blood cell count
• microbes, strenuous exercise, anesthesia or
  surgery
• Leukopenia is low white blood cell count
• radiation, shock or chemotherapy
• Only 2 of total WBC population is in circulating
  blood at any given time
• rest is in lymphatic fluid, skin, lungs, lymph
  nodes spleen

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• Differential WBC Count
• Detection of changes in numbers of circulating
  WBCs (percentages of each type)
• indicates infection, poisoning, leukemia,
  chemotherapy, parasites or allergy reaction
• Normal WBC counts
• neutrophils 60-70 (up if bacterial infection)
• lymphocyte 20-25 (up if viral infection)
• monocytes 3 -- 8 (up if fungal/viral
  infection)
• eosinophil 2 -- 4 (up if parasite or allergy
  reaction)
• basophil lt1 (up if allergy reaction or
  hypothyroid)

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• RBC surfaces are marked by genetically determined
  glycoproteins glycolipids
• agglutinogens or isoantigens
• distinguishes at least 24 different blood groups
• ABO, Rh, Lewis, Kell, Kidd and Duffy systems

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ABO Blood Groups

• Based on 2 glycolipid isoantigens called A and B
  found on the surface of RBCs
• display only antigen A -- blood type A
• display only antigen B -- blood type B
• display both antigens A B -- blood type AB
• display neither antigen -- blood type O
• Plasma contains isoantibodies or agglutinins to
  the A or B antigens not found in your blood
• anti-A antibody reacts with antigen A
• anti-B antibody reacts with antigen B

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RH blood groups

• Antigen was discovered in blood of Rhesus monkey
• People with Rh agglutinogens on RBC surface are
  Rh. Normal plasma contains no anti-Rh
  antibodies
• Antibodies develop only in Rh- blood type only
  with exposure to the antigen
• transfusion of positive blood
• during a pregnancy with a positive blood type
  fetus
• Transfusion reaction upon 2nd exposure to the
  antigen results in hemolysis of the RBCs in the
  donated blood

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Hemolytic Disease of Newborn

• Rh negative mom and Rh fetus will have mixing of
  blood at birth
• Mom's body creates Rh antibodies unless she
  receives a RhoGam shot soon after first delivery,
  miscarriage or abortion
• RhoGam binds to loose fetal blood and removes it
  from body before she reacts
• In 2nd child, hemolytic disease of the newborn
  may develop causing hemolysis of the fetal RBCs

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• Blood Types summary
• Protein flag on cell surface
• Different types of markers
• Important in transfusions, certain other
  situations

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