The Blood

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The Blood
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Functions of Blood

• Transportation
• O2, nutrients, waste, hormones, heat
• Regulationmaintain homeostasis of body fluids
• Regulate pH, body temperature, maintain fluid
  volume
• Protection
• Clotting prevents loss of fluids
• White blood cells protect against disease
• Blood proteins protect against disease

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Physical characteristics and volume

• Salty and metallic tasting
• More dense than water
• Slightly alkaline, pH between 7.35 and 7.45
• Temperature 38o C or 100.4o F
• Makes up 8 of body weight
• Volume in adult males is 5-6 L and in females 4-5
  L
• Only fluid tissue in the body

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Blood components

• Blood plasma 55
• Formed elements 45
• RBCsmeasurement is hematocrit 14 5
• Leukocytes and platelets

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Blood plasma

• Includes over 100 different dissolved solutes

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Formed Elements
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Hematopoiesis

• Occurs in the red bone marrow from hemocytoblast/
  hematopoietic stem cell
• Specialization based on receptors that respond to
  hormones

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Erythrocyte structure

• Flexible structure, large surface area
• Lack a nucleus and other organelles.
• 33 of weight is hemoglobin molecules.
• Other proteins include antioxidants and those to
  maintain RBC shape (spectrin)

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Erythrocyte function

• Dedicated to carry respiratory gas

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Regulation of RBCs
Erythropoietin (EOP)? glycoprotein hormone
produced by kidneys to liver
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Dietary needs to produce RBCs

• Iron, AAs, lipids, and carbohydrates.
• Iron is absorbed from the diet
• 65 found in hemoglobin
• The rest stored in liver, spleen and bone marrow
• Iron is toxic and requires transferrin as a
  transporter
• Some iron is lost in feces and menstrual blood
• Vitamin B12 and folic acid are necessary for DNA
  synthesis

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Fate and death of RBCs

• RBCs have a lifespan of 100 to 120 days
• Age makes them less flexible and the hemoglobin
  begins to degenerate.
• Old RBCs get trapped in the small capillaries of
  the spleen
• Macrophages destroy and digest RBCs
• Heme and globin are separated
• Globin broken down into a.a.s
• Heme? bilirubin?urobilinogen?stercobilin
• Blood?liver?intestine?anus

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Erythrocyte Imbalances

• Anemia ? reduced O2 carrying capacity of the
  blood
• Insufficient number of RBCs
• Hemorrhagic - due to blood loss associated with
  an injury, undiagnosed bleeding ulcer, etc.
• Hemolytic - due to blood loss due to transfusion
  reactions certain bacterial and parasite
  infections
• Aplastic - due to destruction or inhibition of
  red marrow by drugs, ionizing radiation or
  certain bacterial toxins.

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Erythrocyte Imbalances

• Anemia ? reduced O2 carrying capacity of the
  blood
• Low hemoglobin content
• Iron Deficiency - inadequate intake or absorption
  of iron, forms microcytes.
• Pernicious - dietary deficiency of Vitamin B12 or
  inadequate production of intrinsic factor for
  absorption of Vitamin B12 , forms macrocytes

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Erythrocyte Imbalances

• Anemia ? reduced O2 carrying capacity of the
  blood
• Abnormal Hemoglobin in RBCs
• Thalassemias- one globin chain is absent/faulty
• Polycythemia-excess of erythrocytes increasing
  blood viscosity

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Erythrocyte Imbalances

• Polycythemia - abnormally high number of RBCs (8
  - 11 million/mm3). Increases blood viscosity
  blood pressure.
• most often the result of bone marrow cancer.

• Lecuopenia - abnormally low number of WBCs
  (less than 5,000/mm3).
• drugs, steroids anti-cancer agents.

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Leukocytes Structure

• WBCs have a nucleus and other organelles.
• WBCs can undergo diapedesis using amoeboid motion
  when in the tissues
• Use chemical chemotaxis to follow trail to
  infection or damaged tissue.

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Granular leukocytes

• Neutrophils
• multilobed nucleus, inconspicuous granules
• Phagocytize bacteria some fungi
• Produced in bone marrow by myeloblasts
• Eosinophils
• bilobed nucleus, red granules
• Destroy parasitic worms immune complexes
• Produced in bone marrow by myeloblasts
• Basophils
• lobed nucleus, purple-black granules
• Cause vasodilation by release of histamines
• Produced in bone marrow by myeloblasts

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Agranular leukocytes

• Lymphocyte
• B lymphocytes - Humoral Immunity (antibodies)
• T lymphocytes - Cellular Immunity
• Produced in lymphatic tissues
• Monocytes
• Differentiate into macrophages in tissues.
• Provide defense against viruses intracellular
  bacteria in chronic infections.
• Produced by monoblasts in lymphatic tissues.

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Production of leukocytes

• Leukopoiesis is stimulated by interleukins and
  colony-stimulating factors (CSFs)
• Pluripotent stem cells have the capacity to
  differentiate into several types of cells.
• Myeloid stem cells
• Lymphoid stem cell

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Leukocyte Imbalances

• Leukopenialow WBC count
• Leukemiaunchecked growth of a single
  unspecialized clone. Abnormally high numbers of
  immature WBCs that are mitotic unspecialized
• Acute leukemia occurs if it derives from
  blast-type cells
• Chronic leukemia occurs if it derives from later
  stages
• Bone marrow is compromised and defense system
  becomes nonfunctional
• Infectious mononucleosis derives from excessive
  numbers of agranulocytes (Epstein-Barr virus)

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Platelets

• Under the influence of thrombopoietin, myeloid
  stem cells develop into megakaryocytes (huge
  cells).
• These cells fragment into 2-3K particles.
• They have a very short life of 5- 9 days.

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Hemostasis

• Damaged blood vessels require a rapid, localized
  and controlled hemostatic response to reduce
  blood loss.
• Vascular spasm/constriction
• Platelet plug formation
• Blood clotting/ coagulation

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Platelet plug formation platelet adhesion
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Platelet plug formation platelet release action
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Platelet plug formation platelet aggregation
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Stages of clotting

• Extrinsic (s) and intrinsic (min) pthwys make
  prothrombinase.
• Prothrombinase Ca2 Catalyze prothrombin ?
  thrombin
• Thrombin Ca2 converts soluble fibrinogen
  ?insoluble fibrin (thread of the clot)
• Thrombin activates factor XIII which stabilizes
  strengthens threads

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Hemostasis Animation
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Thromboemolitic Disorders

• Thrombus? clot in an unbroken vessel
• Ebolus? an abnormal object moving through a blood
  vessel, Clot, air bubble, lipid droplet,
  thrombus, etc.
• Disorders
• Embolisms (pulmonary, cerebral, cardiac)
• Artherosclerosis
• Inflammation
• Treatment
• Aspirin
• Heparin
• Warfarin

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Bleeding disorders

• Thrombocytopenialow platelet levels
• Impaired liver function
• Vitamin K
• Hemophilia
• Deficiency of factor VIII (antihemophilic factor)
• Deficiency of factor IX
• Lack of factor XI

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ABO blood typing

• Based on two glycolipid antigens, A and B.
• Blood has agglutinogens (antibodies) that react
  to A or B antigens.

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Blood groups and blood types
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Rh blood groups
Hemolytic disease of newborn (HDN)
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Transfusion reactions

• Agglutination clogs blood capillaries
• Clumped cells will rupture and be phagocytized by
  macrophages
• Hemoglobin is released into the blood
• Oxygen carrying is disrupted
• Blood flow is impaired
• Hemoglobin passing into kidney tubules causes
  cell death and renal shutdown

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Diagnostic blood tests

• Lipidemia is characteristic of those with heart
  disease
• Erythrocyte morphology can detect anemias
• Differential white blood cell count
• High eosinophil indicates allergies or parasitic
  infection
• Platelet count (thrombocytopenia)
• SMAC is blood chemistry profile
• CBC provides information on the formed elements

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Resources

• Heart Anatomy Tutorial
• Hematopoiesis Overview
• BodySmart Blood Bloodcells