Human Histology (Laboratory) Exercises 1-4 PDF

Prayer before study Lord, true source of light and wisdom, give me a keen sense of understanding, a retentive memory and the capacity to grasp things correctly. Grant me the grace to be accurate in my expositions and the skill to express myself with thoroughness and clarity. Be with me at the start...

Prayer before study Lord, true source of light and wisdom, give me a keen sense of understanding, a retentive memory and the capacity to grasp things correctly. Grant me the grace to be accurate in my expositions and the skill to express myself with thoroughness and clarity. Be with me at the start of my work, guide its progress and bring it to completion. Grant this through Christ our Lord. Amen.  Human Histology (Laboratory) MT120225 EXERCISES 1-4 POST-LABORATORY DISCUSSION UST General Santos - School of Health Sciences Department of Medical Technology Second Semester A.Y. 2024-2025 Topic Outline I. Microscopy II. Epithelial Tissue Learning Outcome At the end of the exercise, the student must be able to Apply the principles of microscopy in the identification of images formed using the different types of microscope Describe different types of epithelial tissues based on their structural characteristics 01 | Microscopy Light Microscopy: Range of wavelength for visible light: 0.4 - 07 um Light source: tungsten Can be modified by using different light sources, by modifying its condenser or adding special types of prism or filter Light Microscopy: Components 1. Light source 2. Condenser 3. Stage 4. Objective lens 5. Ocular lens Light Microscopy: Brightfield Microscopy - Image appears dark against a bright background USES: stained tissue is examined with ordinary light passing through the preparation MAGNIFICATION: total magnification is obtained by multiplying the magnifying power of the objective and ocular lenses (40x - 1000x) RESOLUTION: 0.2 um Light Microscopy: Brightfield Microscopy ADVANTAGE: easy to use, widely available DISADVANTAGE: limited resolution, requires thin sections, can be difficult to see unstained structures Light Microscopy: Dark Field Microscopy - Image appears bright against a dark background USES: examining urine for crystals (uric acid and oxalate), demonstrating specific bacteria (spirochetes) MAGNIFICATION: total magnification is obtained by multiplying the magnifying power of the objective and ocular lenses (40x - 1000x) RESOLUTION: 0.2 um Light Microscopy: Dark Field Microscopy MODIFICATION: utilizes opaque disc which is located under the condenser Light Microscopy: Fluorescence Microscopy - Fluorescent substances appear bright on a dark background - Utilizes fluorophore to generate fluorescence in a biological sample USES: studying intercellular junctions, tracing pathway of of nerve fibers, detecting growth markers of mineralized tissues MAGNIFICATION: total magnification is obtained by multiplying the magnifying power of the objective and ocular lenses (40x - 1000x) Light Microscopy: Fluorescence Microscopy RESOLUTION: 0.2 um MODIFICATION: composed of xenon arc or mercury vapor lamps, excitation filter, dichroic mirror and emission filter ADVANTAGE: highly specific for targeted molecules, can visualize multiple targets simultaneously. DISADVANTAGE: requires fluorescent label Light Microscopy: Phase-Contrast Microscopy - Image formed presents a combination of areas exhibiting varying degrees of light intensity (from dark to light) surrounded by a halo USES: to study unstained cells and tissues, especially living cells (tissue culture) MAGNIFICATION: total magnification is obtained by multiplying the magnifying power of the objective and ocular lenses (40x - 1000x) RESOLUTION: 0.2 um Light Microscopy: Phase-Contrast Microscopy MODIFICATION: presence of annular ring positioned in the substage condenser front focal plane ADVANTAGE: can visualize intracellular parts of unstained living cell and tissues DISADVANTAGE: halo effect around structures, can be difficult to interpret for complex samples. Light Microscopy: Differential Interference Contrast Microscopy - Image formed is 3D shadowed under very oblique illumination USES: provide contrast in unstained and transparent samples MAGNIFICATION: total magnification is obtained by multiplying the magnifying power of the objective and ocular lenses (40x - 1000x) Light Microscopy: Differential Interference Contrast Microscopy MODIFICATION: uses two coherent beams of light coming from the same light source and prism Light Microscopy: Confocal Microscopy - Combines components of a light optical microscope with a scanning system - Biologic specimen appears in three dimension USES: utilizes fluorophore to visualize sample, view stained structures with high resolution and sharp focus MAGNIFICATION: total magnification is obtained by multiplying the magnifying power of the objective and ocular lenses (40x - 1000x) RESOLUTION: 0.2 um - 0.5 um Light Microscopy: Confocal Microscopy MODIFICATION: detector aperture (pinhole) ADVANTAGE: avoids stray light that reduces contrast of the image, greatly improves resolution of the object in focus, allows localization of specimen components with greater precision than with bright-field microscope DISADVANTAGE: Expensive, slower image acquisition Light Microscopy: Polarizing Microscopy USES: allows recognition of stained or unstained structures made of highly organized subunits (striated muscle, crystalloid inclusions in the testicular interstitial cells) MAGNIFICATION: total magnification is obtained by multiplying the magnifying power of the objective and ocular lenses (40x - 1000x) RESOLUTION: 0.2 um Light Microscopy: Polarizing Microscopy MODIFICATION: addition of polarizer and analyzer ADVANTAGE: reveals information about the orientation of macromolecules DISADVANTAGE: requires specialized filters, only produces image of material having repetitive, periodic macromolecular structure Electron Microscopy: More defined ultrastructural intracellular details of individual cells Utilizes electron beams and electromagnetic fields Electron Microscopy: Transmission EM - Produces black and white two dimensional image USES: visualizing internal structures of cells and viruses. MAGNIFICATION: 400,000 times RESOLUTION: 3 nm Electron Microscopy: Transmission EM Essential Systems: 1. Electron gun and condenser 2. Image-producing system - objective lens, movable specimen stage, intermediate and projector lenses 3. Image-recording system Electron Microscopy: Transmission EM ADVANTAGE: can achieve atomic-level resolution, provides detailed internal structures DISADVANTAGE: expensive, tissue preparation is challenging, addition of materials with high density to the specimen Electron Microscopy: Scanning EM - Produces three dimensional image of the surface of the specimen USES: designed for directly studying surfaces of solid objects MAGNIFICATION: