Blood Composition and Functions
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Blood Composition and Functions

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Questions and Answers

What is the primary function of hemoglobin in erythrocytes?

  • To regulate body temperature
  • To transport glucose to cells
  • To carry oxygen in the bloodstream (correct)
  • To assist in blood clot formation

    • What percentage of whole blood is composed of plasma?

  • 45%
  • 55% (correct)
  • 65%
  • 75%

    • Which component serves a critical role in coagulation and blood clot formation?

  • Fibrinogen (correct)
  • Water
  • Globulin
  • Albumin

    • What is the normal range for hematocrit in men?

    <p>47% ±5%</p> Signup and view all the answers

    What is the primary role of albumin in blood plasma?

    <p>Maintain osmotic pressure</p> Signup and view all the answers

    Which type of blood cell is primarily responsible for the immune response?

    <p>Leukocyte</p> Signup and view all the answers

    How is carbon dioxide primarily transported in the blood?

    <p>As bicarbonate (HCO3–) or dissolved in solution</p> Signup and view all the answers

    What is the average volume of blood in a healthy adult human?

    <p>5 liters</p> Signup and view all the answers

    What is the primary function of platelets in the blood?

    <p>Controlling hemorrhage and promoting blood clotting.</p> Signup and view all the answers

    Which component of platelets is responsible for the storage of calcium ions?

    <p>Dense tubular system.</p> Signup and view all the answers

    During the clot removal process, which enzymes are involved?

    <p>Plasmin and lysosomal enzymes.</p> Signup and view all the answers

    In hemophilia, what is the primary underlying issue?

    <p>Deficiency of clotting factors.</p> Signup and view all the answers

    What initiates primary platelet aggregation?

    <p>Platelets adhering together to form a plug.</p> Signup and view all the answers

    What is the average lifespan of red blood cells?

    <p>120 days</p> Signup and view all the answers

    What is the typical diameter of a red blood cell?

    <p>7.5 µm</p> Signup and view all the answers

    Which condition is characterized by abnormally shaped red blood cells?

    <p>Sickle cell anemia</p> Signup and view all the answers

    What component is NOT part of the red blood cell structure?

    <p>Mitochondria</p> Signup and view all the answers

    What happens to red blood cells in a hypertonic solution?

    <p>They shrink and undergo crenation</p> Signup and view all the answers

    Which of the following correctly describes anisocytosis?

    <p>High percentage of erythrocytes with great size variations</p> Signup and view all the answers

    What percentage of a red blood cell's membrane consists of protein?

    <p>50%</p> Signup and view all the answers

    Which of the following blood groups can be determined by the antigens on the surface of red blood cells?

    <p>Type A, B, O and Rh</p> Signup and view all the answers

    What percentage of hemoglobin composition is globin?

    <p>96%</p> Signup and view all the answers

    Which of the following characterizes hypochromic hemoglobin?

    <p>Less than normal levels of hemoglobin</p> Signup and view all the answers

    Which type of anemia is characterized by a bone marrow defect in infants?

    <p>Aplastic anemia</p> Signup and view all the answers

    What is the primary role of hemoglobin in the blood?

    <p>To facilitate gas exchange</p> Signup and view all the answers

    Which type of leukocyte is classified as agranulocytes?

    <p>Monocytes</p> Signup and view all the answers

    What type of granules do neutrophils contain?

    <p>Specific and non-specific granules</p> Signup and view all the answers

    Which type of white blood cell is motile after leaving blood vessels?

    <p>Leukocytes</p> Signup and view all the answers

    What is the function of specific granules in eosinophils?

    <p>To bind acidic stains</p> Signup and view all the answers

    What is a characteristic of leukaemia?

    <p>It is a type of cancer that begins in the white blood cells.</p> Signup and view all the answers

    Which type of white blood cell has the longest life span?

    <p>Lymphocyte</p> Signup and view all the answers

    What is the normal range for platelet counts in blood?

    <p>200,000 to 400,000/mm3</p> Signup and view all the answers

    Which type of granulocyte is primarily involved in allergic reactions?

    <p>Basophil</p> Signup and view all the answers

    What is the primary function of neutrophils?

    <p>They are involved in phagocytosis.</p> Signup and view all the answers

    What is the diameter of a typical platelet?

    <p>2–4 um</p> Signup and view all the answers

    Which component of platelets is involved in adhesion?

    <p>Hyalomere</p> Signup and view all the answers

    Which of the following white blood cells is the largest?

    <p>Monocyte</p> Signup and view all the answers

    Study Notes

    Blood

    • Specialized connective tissue, viscous fluid
    • Found in blood vessels and bone marrow
    • Originates from mesenchyme
    • Volume: 5 liters in healthy adult human
    • 1 cubic millimeter of blood is equivalent to a microliter
    • Functions:
      • Transport of gases, nutrients, waste products, hormones
      • Regulation of pH and osmosis
      • Maintenance of body temperature
      • Protection against foreign substances
      • Clot formation

    Blood Composition

    • 55% plasma + 45% blood cells

    Hematocrit

    • Volume percentage of red blood cells in the blood
    • Erythrocytes constitute about 43% of the blood volume after centrifugation
      • 47% ±5% in men
      • 42% ±5% in women
    • Buffy coat: Thin layer of leukocytes and platelets located between the erythrocytes and plasma.

    Blood Film

    • Blood film procedure:
      • Clean slide
      • Prick finger
      • Put a drop of blood on a clean dry slide
      • Put another slide on top at 45° angle
      • Move backward to touch the blood drop
      • Move forward to spread the blood
      • Stain with Leishman stain (mixture of eosin, methylene blue, and azures)

    Plasma

    • Comprises 55% of the blood volume
    • Yellowish fluid
    • Aqueous solution, pH 7.4
    • Composition:
      • Water (92%)
      • Plasma proteins (7%):
        • Albumin (osmotic pressure)
        • Globulin (antibodies)
        • Fibrinogen (coagulation)
      • Organic and inorganic substances (1%)

    Blood Cells (Formed Elements)

    • Red blood cells (RBCs) or Erythrocytes
    • White blood cells (WBCs) or Leukocytes
    • Platelets or Thrombocytes

    Red Blood Cells (RBCs) or Erythrocytes

    • Also known as red blood corpuscles
    • Characteristics:
      • Rounded, biconcave discs
      • 7.5 µm diameter, 2.6 µm thick at the rim, 0.75 µm thick in the center
      • Non-nucleated, no organelles (not a true cell)
      • Non-motile
      • Suspended in an isotonic medium (plasma)
      • Soft and plastic, change shape in capillaries
      • Aggregated in small vessels, called Rouleaux
      • Life span is about 120 days

    Abnormal Red Blood Cell Shapes (Poikilocytosis)

    • Example: Sickle cell anemia, inherited disease where red blood cells are abnormally shaped (sickle shape)

    Red Blood Cell Count

    • Normal:
      • Male: 5-5.5 million/mm3
      • Female: 4.5-5 million/mm3
    • Increase: Polycythemia (erythrocytosis)
      • Physiological: Individuals living at high altitudes (low O2 tension)
      • Pathological: Congenital heart and hypoxic lung
    • Decrease: Anemia

    Red Blood Cell Structure

    • Cell membrane: 40% lipid, 10% carbohydrate, 50% protein
    • Cytoskeletons maintain cell shape
    • Antigens on the surface determine blood group (A, B, O, and Rh)

    Red Blood Cell Size and Osmotic Pressure

    • Isotonic solution (plasma): Osmotic pressure of plasma = in RBCs
    • Hypertonic solution: Water flows from low solute inside the cell to high solute outside the cell, leading to cell shrinking (crenation)
    • Hypotonic solution: Water accumulates inside the cell leading to swelling (hemolysis)

    Red Blood Cell Size Variations

    • Normocyte: 6-9 um (7.5)
    • Macrocyte: Larger than 9 um
    • Microcyte: Smaller than 6 um
    • Anisocytosis: High percentage of erythrocytes with great variations in size

    Hemoglobin (Hb)

    • Protein found in the cytoplasm of red blood cells
    • Haem (4%) + Globin (96%)
    • Normal:
      • Male: 15.5 gm/L
      • Female: 14 gm/L
    • Hb normal: Normochromic
    • Less than normal: Hypochromic
    • Hb more than normal: Hyperchromic
    • Hemoglobin carries O2 from lungs to tissues of the body
    • Heme contains iron, a pigment

    Anemia

    • Causes:
      • Decreased number of RBCs: Aplastic anemia, hemorrhagic anemia
      • Decreased Hb
      • Decreased hemopoietic factors (iron and vitamin B12)
      • Haemolysis (breakdown of RBCs)

    Red Blood Cell Adaptations for Function

    • Biconcave discs: Increased surface area for gas exchange
    • Plastic: Compress in narrow capillaries
    • No nuclei or organelles: More space for Hb
    • Glucose metabolism enzymes: Energy production

    Leukocytes, WBCs

    • Names: Leukocytes, white blood cells, WBCs
    • Characteristics:
      • True cells (with nucleus and organelles)
      • Originate in bone marrow
      • Spherical when suspended in blood plasma
      • Become amoeboid and motile after leaving blood vessels and invading tissues

    Types of Leukocytes

    • Agranulocytes (Mononuclear): Contains non-specific granules only
      • Lymphocytes
      • Monocytes
    • Granulocytes (Polymorphonuclear): Contains specific and non-specific granules
      • Neutrophils
      • Eosinophils
      • Basophils

    Granular Leukocytes

    • Two types of granules:
      • Non-specific (azurophilic): Lysosomes, stain darkly, present in all leukocytes
      • Specific: Bind neutral, basic, or acidic stains and have specific functions
    • Three types based on specific granule stain:
      • Neutrophils: Neutral
      • Eosinophils: Acidophilic
      • Basophils: Basophilic

    Differential Leukocytic Count

    • Percentage of each type of leukocyte

    Leukemia

    • Cancer that begins in the bone marrow, causing an abnormal increase of immature white blood cells (blasts or leukemia cells)
    • These cells are not fully developed

    Agranulocytes vs Granulocytes

    • Agranulocytes:
      • Monocyte: 2-8% of WBCs, few days lifespan, 20 micrometers diameter, basophilic cytoplasm, kidney-shaped nucleus, phagocytic function
      • Lymphocyte: 20-40% of WBCs, 3 months to years lifespan, 7-8 micrometers diameter, basophilic cytoplasm, large rounded nucleus, immunity function
    • Granulocytes:
      • Basophil: 0-0.5% of WBCs, few days (life span), 10-12 micrometers diameter, large basophilic specific granules, S-shaped bilobulated nucleus, allergy (Histamine and Heparin) function
      • Eosinophil: 1-4% of WBCs, 8-12 days lifespan, 10-12 micrometers diameter, larger acidophilic specific granules, horse-shoe shaped nucleus, cytotoxic and allergy function
      • Neutrophil: 50-70% of WBCs, 12-15 days lifespan, 10-12 micrometers diameter, small numerous specific granules, multilobulated nucleus, phagocytic function

    Platelets (Thrombocytes)

    • Non-nucleated (not a true cell), oval or disk-like cell
    • 2-4 um in diameter
    • Origin: Megakaryocytes (giant cells) in the bone marrow
    • Normal platelet count: 200,000 to 400,000/mm3 of blood
    • Life span: 5-10 days
    • Structure:
      • Peripheral zone (hyalomere): Rich in GAGs and glycoproteins, involved in platelet adhesion, marginal bundle of microtubules and microfilaments (actin, myosin) for shape maintenance, two membranes:
        • Open canalicular system: Facilitates uptake of factors
        • Dense tubular system: Derived from ER and stores Ca2+ ions
      • Central zone (granulomere): Mitochondria, glycogen, and granules:
        • Alpha: Proteins (clot factors)
        • Delta: Calcium, enzymes (e.g. Serotonin)
        • Lambda: Lysosomes

    Platelet Functions

    • Control of hemorrhage
    • Promote blood clotting
    • Clot factors:
      • Fibrinogen
      • Plasminogen
      • Thromboplastin

    Role of Platelets in Controlling Hemorrhage

    • Primary platelet aggregation: Platelets adhere together forming a platelet plug
    • Secondary platelet aggregation: Release of glycoproteins enhances plug size
    • Blood coagulation: Release of coagulation factors produces fibrin protein, forming a network that traps blood cells, creating a blood clot
    • Clot retraction: Clot contracts due to interaction of platelet actin and myosin
    • Clot removal: Vessel wall is restored with new tissue, and the clot is removed by plasma proteolytic enzymes (plasmin, plasminogen) and lambda granules (lysosomal enzymes)

    Hemophilia

    • Severe hemorrhage after injury
    • Inherited genetic X-chromosome disorder, transmitted by females
    • People with hemophilia have little or no clotting factors

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    Description

    Explore the fascinating world of blood, a specialized connective tissue vital for numerous bodily functions. This quiz covers blood composition, hematocrit, and the essential roles blood plays in transport, regulation, and protection in the human body.

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