Exercises 29 and 30

Blood

Portland Community CollegeBI 232

Blood

• Highly specialized connective tissue that consists of formed elements (blood cells) suspended in a fluid matrix (plasma)

• Formed elements comprise about 45% of total volume

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Plasma• Fluid portion of blood

• About 90% water

• Proteins

• Albumins transport solutes and buffer the plasma

• Globulins function in immunity

• Fibrinogen is a clotting protein

• Electrolytes (Na⁺, K⁺, Cl⁻)• Nutrients

• Hormones

• Wastes

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Erythrocyte

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Erythrocyte (RBC)

• Flattened biconcave discs that lack nuclei and most organelles.

• Most of the cytoplasm is filled

with the protein hemoglobin

• Function: Transport of O2

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Iron Deficient RBC

• More pale and smaller

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Sickle Cell

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Reticulocyte

• Count: 1-2% of RBC

• RBC precursor

• Increased when RBC turnover is high

• Still contains nuclear fragments

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Platelets

• Also called thrombocytes

• Fragments of a bone marrow cell called a megakaryocyte

• Count: 150-500,000 per mm3

• Function: mediates blood clotting chemically and mechanically

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Platelets

Megakaryocytes Platelet

White Blood Cells

• Also called Leukocytes

• Defend the body from pathogens and foreign proteins.

• Capable of migrating from blood vessels to surrounding tissues by diapedesis.

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Response types

• Innate immunity: a person having a reaction to microorganisms and foreign substances without prior exposure

• Adaptive immunity in which exposure initiates immune response

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Leukocyte Groups

• Granular leukocytes are named because they have granules in the cytoplasm

• Agranular leukocytes lack granules

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Neutrophil (Granulocyte)

• Nuclei: 2 to 5 lobes connected by thin strands

• Fine, pale lilac practically invisible granules

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Neutrophil

• Count: 60- 70% • Fastest response of

all WBC to bacteria

• Functions:• Phagocytic: engulf pathogens or debris in tissues

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Eosinophil (Granulocyte)

• Nucleus with 2 or 3 lobes connected by a thin strand

• Large, uniform-sized orange-red granules

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Eosinophil

• Count: 2-4%

• Functions: • Attack parasitic worms; mitigate the effects of

allergy and inflammation

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Basophil (Granulocyte)

• Large, dark purple, variable-sized granules

• Obscure the nucleus

• Irregular, s-shaped, bi-lobed nuclei

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Basophil

• Count: <1%

• Functions: • Enter damaged tissues and release histamine

and other chemicals that promote inflammation

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Lymphocyte (Agranulocyte)

• Dark, oval to round nucleus

• Cytoplasm sky blue in color

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Lymphocyte

• Count: 25-33%

• Functions:• Mount immune response by direct attack or via

antibodies, mediates other cellular immune response,

• Includes B and T cells

B cells and T cells

• Won’t be able to distinguish between these with Wright's stain

• B cells become plasma cells which make antibodies

• T cells mature in thymus and provide cell-mediated immunity

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Monocyte (Agranulocyte)

• Nucleus is kidney or horse-shoe shaped

• Pale cytoplasm

• Largest blood cells

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Monocyte

• Count: 3-8%

• Functions:• Enter tissues to become macrophages• Engulf pathogens or debris

Differential WBC count

• Differential white blood cell count is performed to determine the percentages of each white blood cell type

• Any deviation in the normal percentage ranges could indicate an abnormal condition such as bacterial, viral or parasitic infection

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Leukopenia and Leukemia

• Leukopenia is a decrease in the number of circulating leukocytes.

• Can be caused by radiation therapy, chemotherapy and some drugs.

• Leukemia is an increase in the number of WBCs

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ABO Blood Types

• RBC surfaces are marked by genetically determined glycoproteins (surface antigens or agglutinogens) • The glycoprotein determines the

blood type

• Plasma contains antibodies or agglutinins to the A or B antigens not found on your blood cells

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Type A

• Type A: Display only antigen A

• The plasma contains antibodies against Type B

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Type B

• Type B: Display only antigen B

• The plasma contains antibodies against Type A

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Type AB

• Type AB: Display both antigens A & B

• The plasma contains no antibodies

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Type O

• Type O: Display neither antigen

• The plasma contains antibodies against A and B

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Blood Transfusions

• Only RBC are donated.• Transfusion Reactions: The recipients plasma interacts with

the donors RBC• Causes clumping then hemolysis

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RH blood groups

• 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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Hemoglobin Concentrations

• Normal hemoglobin concentration in females is 12-16 g/deciliter.

• Normal hemoglobin concentration in males is 13-18 g/deciliter.

• Hematocrit can be estimated from the hemoglobin concentration:

3x hemoglobin=hematocrit.• Normal hematocrit in females is 37-48%. • Normal hematocrit in men is 42-52%.

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Gender Differences in Hb

• Testosterone stimulates synthesis of erythropoietin which in turn stimulates erythropoiesis (red cell formation) in the red marrow.

• Lower values in women of reproductive age may also reflect their red cell losses due to menstruation.

Lab activities

• ID blood cells on slides can use prepared class slides or make your own.

• Do differential white blood cell count

• Determine your blood type

• Determine hemoglobin levels

• Calculate hemotocrit from your hemoglobin levels

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The End