HUMAN ANATOMY AND PHYSIOLOGY

  • Blood and Lymphatic System
    • Ex. 20 and Ex. 24
    • Bio 204-A&P II Lab

Exercise 20: Blood

Learning Outcomes

Upon completing Exercise 20, students should be able to:

  • Identify the following components in a human blood smear:
    • Red blood cells (RBCs)
    • White blood cells (WBCs)
    • Platelets
  • Describe the functions of each blood component.
  • Identify the five types of WBCs in a human blood smear.
  • Perform a differential white blood cell count.
  • Determine ABO and Rh blood types using synthetic blood samples and synthetic antiserum (Carolina blood kit).

Functions of Blood

  • Transportation:
    • Carries oxygen, nutrients, wastes, carbon dioxide, and hormones.
  • Defense:
    • Protects against invasion by pathogens.
  • Regulatory Functions:
    • Maintains body temperature, water-salt balance, and body pH.

Composition of Blood

Blood is analyzed as follows:

  • Formed Elements (Blood Cells):
    • Produced in red bone marrow.
    • Red Blood Cells (RBCs):
    • Make up 99.9% of formed elements.
    • White Blood Cells (WBCs):
    • Platelets (thrombocytes)
  • Plasma:
    • Consists of 91% water and 9% salts (ions) and organic molecules.
    • Plasma proteins are the most abundant organic molecules, including:
    • Albumins
    • Globulins (Immunoglobulins)
    • Fibrinogen

Activity 20.1: Identifying Blood Cells

  • Procedure:
    • View a slide of a normal blood smear under low power with a compound light microscope.
    • The majority of cells in focus will be red blood cells, which appear as relatively small, pink-staining discs.
  • Comparison Questions:
    • How do the size and shape of white blood cells compare to red blood cells?
    • Identify characteristics and types of cells.

The Hematocrit

  • Definition:
    • The hematocrit is the percentage of whole blood composed of cells (the formed elements).
  • Significance:
    • Since RBCs constitute 99.9% of formed elements, hematocrit levels indicate RBC levels and assess oxygen-carrying capacity.
  • Normal Range:
    • Men: 42% to 52%
    • Women: 37% to 47%

Characteristics of Red Blood Cells

  • Structure:
    • Flattened biconcave discs, lack nuclei and most organelles.
    • Cytoplasm primarily consists of Hemoglobin (Hb), which is the oxygen-carrying protein.

White Blood Cell (WBC) Types

Granulocytes

  1. Neutrophils:
    • Most abundant WBC, comprising 50 to 70% of all WBCs (1800–7300 cells/μL).
    • Size: 10–14 μm in diameter.
    • Function:
      • Act as phagocytes, engulfing and destroying pathogens while releasing cytotoxic enzymes.
  2. Eosinophils:
    • Comprise 2 to 4% of all WBCs (0–700 cells/μL).
    • Size: 10–14 μm in diameter, bilobed or multilobed nuclei with red or orange granules.
    • Function:
      • Attack parasitic organisms and alleviate allergic reactions by releasing antihistamines.
  3. Basophils:
    • Less than 1% of all WBCs (0–150 cells/μL).
    • Size: 10–14 μm in diameter, bilobed nuclei masked by dark blue or purple granules.
    • Function:
      • Involve in inflammation and tissue repair by releasing histamine and heparin.

Agranulocytes

  1. Monocytes:
    • Largest WBCs, 14 to 24 μm in diameter, make up 2 to 8% of all WBCs (200–950 cells/μL).
    • Have kidney-shaped nuclei.
    • Function:
      • Differentiate into macrophages for attacking and destroying bacteria and viruses via phagocytosis.
  2. Lymphocytes:
    • Comprise 20 to 30% of all WBCs (1500–4000 cells/μL).
    • Size: 5 to 17 μm in diameter, round nuclei that dominate cell volume.
    • Function:
      • Regulate immune response through direct cellular attack or antibody production.

Activity 20.2: Identifying White Blood Cell Types

Check-up Questions

  • Name the laboratory test for determining white blood cell type percentages in peripheral blood.
  • List the two major groups of leukocytes.
  • Identify two types of WBCs that are not granulocytes.
  • Specify the most abundant type of leukocyte in normal human blood.
  • Identify which type of leukocyte is found in the lowest concentration.

Activity 20.3: Performing a Differential White Blood Cell Count

  • Definition:
    • A differential WBC count identifies the percentage of each WBC type in a blood sample.
  • Procedure:
    • Identify and count 100 WBCs on a stained slide.
    • Categorize counts into Neutrophils, Lymphocytes, Monocytes, Basophils, and Eosinophils.
  • Table 20.1:
    • Contains specific data regarding differential WBC count proportions in diverse samples.

Blood Diseases

Chronic Lymphocytic Leukemia

  • Characterized by an abnormal increase in lymphocytes and WBC count.

Eosinophilia

  • Defined by an abnormally high number of eosinophils.

General Leukemia

  • Definition:
    • Blood cancer resulting from uncontrolled proliferation of abnormal WBCs in bone marrow.
  • Classification:
    • Myeloid leukemias involve granulocytes, while lymphoid leukemias involve lymphocytes.
  • Progression:
    • As leukemia advances, abnormal WBCs replace normal cells, leading to significant drops in RBC and normal WBC production, resulting in anemia, heightened infections, and decreased blood clotting.

Iron Deficient Anemia

  • A reduction in the number of red blood cells due to insufficient iron.

Sickle Cell Anemia

  • A genetic disorder affecting the composition and shape of RBCs due to hemoglobin abnormalities.

Terminology to Know

Functions:

  • Formed elements, matrix/plasma, red blood cells, white blood cells, agranulocytes, granulocytes, neutrophils, eosinophils, basophils, monocytes, lymphocytes, chronic lymphocytic anemia, sickle cell anemia, iron deficient anemia.
  • Be prepared to identify these structures under a microscope and describe their relative sizes and percentages in a healthy individual.

Exercise 20.4: Determining Blood Type

ABO Blood System

  • RBC Membrane:
    • Contains specific surface antigens (agglutinogens). An individual's immune system recognizes these antigens as non-foreign.
  • Blood Plasma:
    • Contains antibodies (agglutinins) that can react with specific agglutinogens.
  • Agglutination:
    • Occurs when incompatible blood types are mixed, resulting in clumping.

Blood Type

  • Defined as a genetically-determined trait.
  • Over 50 blood groups exist in humans, with the ABO and Rh groups being clinically significant due to potential agglutination when mismatched.

Rh Blood Groups

  • Rh Antigen (Factor):
    • Present or absent on RBCs.
    • If present, blood type is Rh positive (Rh+); if absent, it is Rh negative (Rh-).
    • Rh antibodies develop only upon exposure to the Rh factor (e.g., during pregnancy).

Clinical Significance of Rh Factor

  • Hemolytic Disease of the Newborn:
    • Occurs when fetal Rh positive RBCs leak into the mother's circulation, prompting the maternal immune system to produce anti-Rh antibodies that can cross the placenta and destroy fetal Rh+ cells.

Check-up Questions

  • Rh Factor Identification:
    • Present in which blood component: A. RBCs B. WBCs C. Plasma?
  • True or False:
    • Rh antibodies develop upon exposure to Rh+ blood from another source.
  • Risk Assessment:
    • In a scenario where the mother is Rh+ and the father is Rh-, is the newborn at risk for developing hemolytic disease?

Blood Typing Procedure

  • Materials Needed:
    • Synthetic anti-D serum (anti Rh), anti-A serum, anti-B serum, blood typing slide, mixing sticks, synthetic samples, paper towels, access to water.
  • Procedure Steps:
    • Conduct steps to mix synthetic blood and respective antisera, analyze for agglutination to determine blood type.

Exercise 24: Lymphatic System

Learning Outcomes

Upon completion, students should:

  • Describe the structure, anatomical relationships, and functions of lymphatic system structures.

Functions of the Lymphatic System

  • Absorbs excess tissue fluid and returns it to the bloodstream.
  • Absorbs fats from the small intestine via lymphatic capillaries (lacteals).
  • Works in the production, maintenance, and distribution of WBCs.
  • Aids in defense against pathogens.

Components of the Lymphatic System

I. Lymphatic Vessels

  • Characteristics:
    • One-way valve system carries fluid called lymph, includes capillaries, vessels, and ducts.

II. Lymphatic Organs

  1. Red Bone Marrow:
    • Site of blood cell production and maturation of some WBCs.
  2. Thymus:
    • Largest in children; shrinks with age, where immature T lymphocytes mature, 95% of which remain.
  3. Lymph Nodes:
    • Small, oval-shaped, found along lymphatic vessels (common in neck, armpit, groin).
    • Cleanses lymph of pathogens and debris.
  4. Spleen:
    • Located in upper left abdominal cavity, filled with white pulp (lymphocytes) and red pulp (filters blood removing worn-out RBCs).

Activity 24.2: Examining Lymphatic Structures

  • Tonsils:
    • Lymphoid tissue regions located in the pharyngeal area.
    • Types to locate:
    1. Pharyngeal tonsil (adenoid)
    2. Palatine tonsils
    3. Lingual tonsils
  • Discussion:
    • Reasoning for high lymphoid tissue volume in the pharyngeal region.

Lymphatic Structures

  • Terminology:
  • Identifiable components in models or images include:
    • Tonsils (pharyngeal, palatine, lingual), thymus, lymph nodes, spleen, lymphatic vessels.