Measuring Area

Content

Microbiology
  Introduction
  The Microscopy
  The Bright Field Microscope
  Introduction to the Microscope and Comparison of Sizes and Shapes of Microorganisms
  Cell Size Measurements: Ocular and Stage Micrometers
  Measuring Depth
  Measuring Area
  Cell Count by Hemocytometer or Measuring Volume
  Measurement of Cell Organelles
  Use of Darkfield Illumination
  The Phase Contrast Microscope
  The Inverted Phase Microscope
  Aseptic Technique and Transfer of Microorganisms
  Control of Microorganisms by using Physical Agents
  Control of Microorganisms by using Disinfectants and Antiseptics
  Control of Microorganisms by using Antimicrobial Chemotherapy
  Isolation of Pure Cultures from a Mixed Population
  Bacterial Staining
  Direct Stain and Indirect Stain
  Gram Stain and Capsule Stain
  Endospore Staining and Bacterial Motility
  Enumeration of Microorganisms
  Biochemical Test for Identification of Bacteria
  Triple Sugar Iron Test
  Starch Hydrolysis Test (II Method)
  Gelatin Hydrolysis Test
  Catalase Test
  Oxidase Test
  IMVIC Test
  Extraction of Bacterial DNA
  Medically Significant Gram–Positive Cocci (GPC)
  Protozoans, Fungi, and Animal Parasites
  The Fungi, Part 1–The Yeasts
  Performance Objectives
  The Fungi, Part 2—The Molds
  Viruses: The Bacteriophages
  Serology, Part 1–Direct Serologic Testing
  Serology, Part 2–Indirect Serologic Testing
Materials
  • Microscope
  • Square ocular grid
  • Prepared slide of a blood smear
Procedure
  1. Obtain an ocular grid etched with a square, and insert it into an ocular of the microscope (or use a microscope previously set up by the instructor).
  2. Calibrate the ocular grid in a manner similar to that outlined in Exercise 3, and determine the area of each marked grid section. Draw the grid in the space below and add all pertinent dimensions.
  3. Place a prepared slide of a blood smear on the microscope and focus on the slide using the 40X objective. Count the number of cells within the 4 margins of the grid area. Count only cells that touch the top and left margins of the grid. Do not count any cell that touches the right or bottom margin of the grid. Record
    the number in the following box.
  4. Select 4 additional random fields of view with approximately the same density of cells and count the number of cells per grid. Record the numbers in the space provided.
  5. Average the results and, based on the known dimensions of your grid, calculate the number of cells per mm2 for the blood smear.
    Area of the grid (40X) ____________________