Blood Cells Overview
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Questions and Answers

What is the main structural component of large elastic arteries, such as the aorta?

  • Circular smooth muscle only
  • Basal lamina
  • Concentric layers of elastic laminae (correct)
  • Collagen fibers
  • Which type of artery is defined as having a relatively thin tunica adventitia and mainly consists of elastic fibers?

  • Medium-sized arteries
  • Large (elastic) arteries (correct)
  • Metarterioles
  • Arterioles
  • What type of capillary is characterized by endothelial cells that have no fenestrae?

  • Fenestrated capillary
  • Sinusoidal capillary
  • Discontinuous capillary
  • Continuous capillary (correct)
  • Which functional role do pericytes in capillaries potentially serve?

    <p>Assist in angiogenesis</p> Signup and view all the answers

    Where can sinusoidal capillaries primarily be found?

    <p>In the liver, bone marrow, and spleen</p> Signup and view all the answers

    What is the typical diameter range of normal red blood cells (erythrocytes)?

    <p>6 - 9 microns</p> Signup and view all the answers

    Which type of white blood cell constitutes 50-70% of the total leukocyte count?

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

    What is the primary function of eosinophils in the vascular system?

    <p>Antiallergic and antiparasitic response</p> Signup and view all the answers

    What is the structure of neutrophils characterized by?

    <p>Segmented nucleus formed of 2-5 lobes and specific/non-specific granules</p> Signup and view all the answers

    What distinguishes reticulocytes from mature erythrocytes?

    <p>Larger diameter and presence of ribosomes</p> Signup and view all the answers

    How many millions of red blood cells (RBCs) are typically found in one mm³ of blood?

    <p>4.5 - 5.5 million</p> Signup and view all the answers

    What type of leukocyte has a nucleus that often appears S-shaped?

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

    What characterizes the cytoplasm of eosinophils?

    <p>Central crystalline dense core in specific granules</p> Signup and view all the answers

    What is the function of heparin secreted by specific granules?

    <p>Acts as an anticoagulant</p> Signup and view all the answers

    Which type of lymphocyte is primarily responsible for humoral immunity?

    <p>B-lymphocytes</p> Signup and view all the answers

    What characteristic is used to differentiate large lymphocytes from small lymphocytes?

    <p>Amount of cytoplasm</p> Signup and view all the answers

    Which layer of blood vessels contains circular smooth muscle cells?

    <p>Tunica media</p> Signup and view all the answers

    What is a primary function of monocytes?

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

    What components are found in the granulomere of blood platelets?

    <p>Alpha, delta, and lambda granules</p> Signup and view all the answers

    Which structure is considered the innermost layer of blood vessels?

    <p>Tunica intima</p> Signup and view all the answers

    What type of granules do mast cells contain that is similar to specific granules?

    <p>Heparin and histamine</p> Signup and view all the answers

    Study Notes

    Blood Cells

    • Red Blood Cells (RBCs or Erythrocytes)
      • Shape: Biconcave discs
      • Size: 6-9 microns in diameter (average 7.5 µm)
        • Normocytes: Normal size RBCs
        • Macrocytes: RBCs larger than 9 µm (e.g., macrocytic anemia)
        • Microcytes: RBCs smaller than 6 µm (e.g., microcytic anemia)
      • Number: 4.5-5.5 million/mm3 of blood
      • Structure:
        • Lack nuclei and organelles
        • Contain hemoglobin (Hb) enclosed by cell membrane
      • Reticulocytes: Immature RBCs (1% of circulating RBCs)
        • Slightly larger than mature RBCs
        • Contain free ribosomes and a few mitochondria

    White Blood Cells (WBCs or Leukocytes)

    • Total Leukocytic Count: 4,000 – 11,000/mm3 of blood
    • Differential Leukocytic Count: Percentage of each type of WBC in total WBC count

    Granular Leukocytes

    • Neutrophils (Polymorphs or Polymorphonuclear Leukocytes): 50-70% of WBCs

      • Nucleus: Segmented (lobulated) with 2-5 lobes (usually 3)
      • Cytoplasm: Contains specific granules (small, numerous) and non-specific (azurophilic) granules (large, less numerous, lysosomes)
      • Function: Antibacterial, crucial for acute inflammation
    • Eosinophils: 1-4% of WBCs

      • Nucleus: Bilobed, horse-shoe shaped
      • Cytoplasm:
        • Specific eosinophilic granules: Contain antiparasitic and histaminase
        • Non-specific granules: Lysosomes containing hydrolytic enzymes
      • Functions: Antiallergic, antiparasitic
    • Basophils: 0-0.5% of WBCs

      • Nucleus: S-shaped
      • Cytoplasm:
        • Specific granules: Contain heparin (anticoagulant) and histamine (allergy)
        • Non-specific granules: Lysosomes containing hydrolytic enzymes
      • Functions: Secretion of heparin and histamine

    Non-Granular Leukocytes

    • Lymphocytes: 20-40% of WBCs

      • Small lymphocytes:
        • Nucleus: Large, rounded, condensed chromatin
        • Cytoplasm: Scanty, few organelles
      • Large lymphocytes:
        • Nucleus: Large, rounded with indentation, less condensed chromatin
        • Cytoplasm: Basophilic (due to increased ribosomes)
      • Functions:
        • Humoral immunity (B-lymphocytes)
        • Cellular immunity (T-lymphocytes)
    • Monocytes: 2-8% of WBCs

      • Nucleus: Oval or kidney-shaped, eccentrically placed
      • Cytoplasm: Contains lysosomes
      • Functions: Phagocytosis, production of mononuclear phagocytic system (MPS)

    Blood Platelets (Thrombocytes)

    • Light Microscopy (L/M):
      • Peripheral hyalomere (pale)
      • Central granulomere (granular)
    • Electron Microscopy (EM):
      • Hyalomere: Contains microtubules, actin, and myosin filaments
      • Granulomere: Contains:
        • Dense granules:
          • Alpha granules: Fibrinogen
          • Delta granules: ADP, ATP, epinephrine, and serotonin
          • Lambda granules: Lysosomes

    Blood Vessels

    • Cardiovascular System: Heart + blood vessels
      • Arteries: Carry blood from the heart to tissues
      • Veins: Carry blood from tissues to the heart
      • Capillaries: Arterio-venous connections for exchange

    General Structure of Blood Vessels

    • Tunica Intima (Innermost):

      • Endothelium: Simple squamous cells
      • Subendothelium: Loose connective tissue
    • Tunica Media (Middle):

      • Smooth muscle cells: Circular arrangement
      • Elastic fibers: Variable amounts
    • Tunica Adventitia (Outermost):

      • Loose connective tissue
      • Vasa vasorum: Small blood vessels that supply the outer part of the vessel wall

    Arteries

    • Large (Elastic) Arteries: Aorta and its major branches

      • Specific Features:
        • Tunica media: Concentric layers of elastic laminae with circular smooth muscle between them
        • Tunica adventitia: Relatively thin
    • Medium Sized (Muscular) Arteries:

      • Specific Features:
        • Tunica media: Predominantly smooth muscle
        • Tunica adventitia: Thicker than in large arteries
    • Arterioles: Smallest arteries

      • Specific Features:
        • Tunica media: One or two layers of smooth muscle
        • Tunica adventitia: Thin
    • Metarterioles: Connect arterioles to capillaries

      • Specific Features:
        • Precapillary sphincters: Regulate blood flow into capillaries

    Veins

    • Large veins:

      • Specific Features:
        • Tunica media: Thin with few layers of smooth muscle
        • Tunica adventitia: Thickest layer, contains longitudinal smooth muscle
        • Valves: Prevent backflow of blood
    • Medium sized veins:

      • Specific Features:
        • Tunica media: Thinner than arteries of similar size
    • Venules: Smallest veins

    Capillaries

    • Smallest channels in the circulatory system
    • Arise from metarterioles or directly from arterioles
    • Re-collect to form venules

    Structure of Capillaries

    • Light Microscopy (L/M):
      • Endothelial cells: Single layer (1-3 cells)
      • Basal lamina:
      • Pericytes: Partly surround endothelial cells with long cytoplasmic processes, contain actin and myosin (contractile function), produce new smooth muscle cells after injury

    Types of Blood Capillaries

    • Continuous capillary: No fenestrae (pores)

      • Location: Brain
    • Fenestrated capillary: Large fenestrae in endothelial cells, continuous basal lamina

      • Location: Renal glomeruli, endocrine glands
    • Sinusoidal capillary: Tortuous, wide lumen, multiple fenestrae, discontinuous basal lamina

      • Location: Liver, bone marrow, spleen

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    Description

    This quiz covers the essential characteristics of red and white blood cells, including their structure, types, and functions. Learn about the differences between normocytes, macrocytes, and microcytes, along with the various types of leukocytes and their percentages in blood. Test your understanding of hematology with this informative quiz.

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