MLT 101: Microscope Lesson

Overview of Microscopy and Hematology

• Recap of previous session regarding microscopy.

  • Engaged in hands-on activities with microscopes (~45 minutes).

  • Developed skills to transition between slides without extensive refocusing.

  • Discussed various blood-related slides observed (e.g., platelet morphology, malaria, sickle cell disease).

Introduction to Hematology

• Transition from microscopy to hematology topic.

• Emphasis on learning from provided material loaded in Blackboard and printed handouts (available Wednesday).

Blood Composition and Formation

• Description of hematology as the study of blood and its forming tissues.

• Primary blood-forming tissue identified as bone marrow.

  • For adults, major locations of active bone marrow include:

  • Axial skeleton (specifically pelvis and sternum).

  • Minimal active marrow is present in the vertebrae and proximal femur.

• Development of blood in infants:

  • Prior to 7 months gestation, blood production occurs in the liver and spleen.

  • Post 7 months, the bone marrow takes over blood production but liver and spleen retain ability for extramedullary hematopoiesis in case of bone marrow failure.

Hematological Values and Measurements

• Importance of memorizing hematological reference values and formulas.

• Brief discussion of an anticipated math component in understanding hematological values.

Blood Components

• Blood composition detailed as approximately 45% plasma and 55% formed elements.

  • Formed elements include three main types of cells:

  • Erythrocytes (RBCs)

    • Most abundant blood cells responsible for oxygen transport.

    • Normal erythrocyte counts:

    • Women: $4.2$ to $5.4 imes 10^6$ cells/microliter.

    • Men: $4.6$ to $6.2 imes 10^6$ cells/microliter.

    • Recent recommendations standardize to $4$ to $6 imes 10^6$ cells/microliter regardless of sex.

    • Hemoglobin content normal range: 12-18 g/dL.

    • Mature erythrocytes lack nuclei, presenting as round, biconcave discs.

    • Life span roughly 120 days; undergo hemolysis upon death, recycling components like iron to liver and marrow.

    • Abnormal shapes (poikilocytes) indicate pathology, including sickle cells.

  • Leukocytes (WBCs)

    • Types include neutrophils, lymphocytes, monocytes, eosinophils, and basophils, with varying functions in immunity and response to infection.

    • Normal leukocyte count $3.6$ to $10.6 imes 10^3$ cells/microliter.

    • Lifespan averages only a couple of days, requiring continuous production, with ratios of production favoring white cells (3-4 WBCs for each RBC).

  • Thrombocytes (Platelets)

    • Normal counts range from $150,000$ to $450,000$ platelets/microliter.

    • Function primarily in hemostasis; lifespan about 9 days.

    • Formed from megakaryocytes, which are noted as the largest cells in the body.

Hematological Indices

• Critical parameters in evaluating red blood cell health and identifying anemias:

  • Mean Corpuscular Volume (MCV): The average volume of a red blood cell, calculated as $rac{HCT}{RBCs} imes 10$, normal range $76$ to $100$ femtoliters.

  • Mean Corpuscular Hemoglobin (MCH): Average hemoglobin content per red blood cell, calculated as $rac{HGB}{RBCs} imes 10$, normal range $26$ to $34$ picograms.

  • Mean Corpuscular Hemoglobin Concentration (MCHC): Ratio of hemoglobin to hematocrit, expressed as a percentage; calculated as $rac{HGB}{HCT} imes 100$; normal range $32$ to $36$%.

• Importance of indices in diagnosing the cause of anemia (e.g., microcytic vs. macrocytic).

CBC and Differential

• Components included in the Complete Blood Count (CBC):

  • Red blood cell count, hemoglobin, hematocrit, indices (MCV, MCH, MCHC), white blood cell count, platelet count.

  • The differential identifies and quantifies each type of white blood cell.

• Significance of smear preparation techniques and appropriate tube usage (EDTA - purple or lavender).

Practical Application and Future Learning

• Students challenged to generate quality blood smears; these slides are essential for differential analysis and must be prepared efficiently.

• Review of parameters affecting slide adequacy, e.g., blood age concerning cell integrity.

• Planned upcoming session to elaborate on coagulation and continue discussions on hematological components with hands-on practice.

Class Performance Recap

• Notable achievements in cell bowl competition; acknowledgment of students performing well in cell identification tasks.

• Recognition of individual student accomplishments and participation evaluated through email feedback.