NURS 1114 Blood Pt 2

Overview of the Cardiovascular System

  • Instructor: Pamela Paynter-Armour

Blood

  • Component of the cardiovascular system

Learning Objectives

  • Understand the production and maturation of white blood cells.
  • Describe the structure, function, and production of platelets.
  • Explain reaction sequences for blood clotting.
  • Recognize blood typing importance and the basis of ABO and Rh incompatibilities.

White Blood Cells (Leukocytes)

  • Function: Fight infections
  • Characteristics:
    • Larger than red blood cells (RBCs)
    • Contains a nucleus

Leukocyte Characteristics

  • Only complete blood cells in circulation
  • Normal range: 4,000 - 11,000 cells/mm³
  • Less numerous than RBCs (1% of total blood volume)
  • Ability to leave capillaries through diapedesis
  • Movement through tissues in ameboid motion
  • Leukocytosis: >11,000 WBCs/mm³ indicates infections

Types of Leukocytes

  • Granulocytes:

    • Neutrophils (40-70%)
    • Eosinophils (1-4%)
    • Basophils (<1%)

  • Agranulocytes:

    • Lymphocytes (20-45%)
    • Monocytes (4-8%)

Granulocyte Characteristics

  • Contain specific cytoplasmic granules with staining capabilities
  • Lobed nuclei
  • All are phagocytic
  • Neutrophils: Most abundant, two types of granules, aids in bacterial defense
  • Eosinophils: Attack parasitic worms and modulate allergic reactions
  • Basophils: Secretes histamine and heparin, involved in inflammation responses

Agranulocyte Characteristics

  • Lymphocytes:

    • Large nucleus, plays critical role in adaptive immune response
    • T-cells: immune response management
    • B-cells: produce antibodies, mature into plasma cells

  • Monocytes:

    • Largest WBC, kidney-shaped nucleus
    • Differentiate into macrophages for phagocytosis

Formation of Leukocytes

  • Originates from hemocytoblasts
  • Detailed pathway: myeloid stem cells -> myeloblasts (eosinophils, neutrophils, basophils) and monoblasts (monocytes)

Platelets (Thrombocytes)

  • Smallest blood component, no nucleus
  • Lifespan: 2-4 days
  • Function: Clotting of blood

Platelet Formation

  • Derived from megakaryocytes
  • Involved in the hemostatic mechanism through temporary plug formation

Hemostasis

  • Series of processes to prevent blood loss:
    1. Vascular spasms: Immediate vasoconstriction
    2. Platelet plug formation: Activated platelets adhere and aggregate
    3. Coagulation: Transformation of liquid blood to gel form

Coagulation Process

  • Follows intrinsic and extrinsic pathways.
    • Intricate series of reactions:
    • Prothrombin activator forms
    • Prothrombin converts to thrombin
    • Thrombin converts fibrinogen to fibrin strands

Clot Retraction and Repair

  • Stabilization of the clot and tissue regeneration via PDGF and VEGF.

Blood Types

  • RBC membranes possess antigens (agglutinogens); classified into different blood groups.
  • ABO Blood Groups: A, B, AB, and O with respective antibodies in plasma.

Rh Factor

  • Rh+ indicates antigens present; Rh- indicates absence.
  • Key in transfusion compatibility and pregnancy complications.

Hemostasis Disorders

  • Thromboembolic Conditions: Blood clot (thrombus) formation leading to conditions like coronary thrombosis.
  • Bleeding Disorders: Lack of platelets or clotting factors leading to conditions like thrombocytopenia or hemophilia.

Platelet and Plasma Volume Expanders

  • Administered when blood volume loss occurs; options include purified plasma products.

Diagnostic Blood Tests

  • Microscopic and chemical analysis of blood used to assess health status, revealing conditions like anemia and infections.

References

  • Austin Community College (2004). Blood topics discussed in detail.
  • Additional resources from Windward Community College and Iteachbio.