Cytology+Lab


 * 25 August 2006**
 * Microanatomy Lab - Cytology**
 * Dr. Robert Crissman, Ph.D.**

toc

=**Mitochondria**=


 * Mitochondria stained using Ragaud’s method
 * Under high power, the nuclei of the cells is clearly visable
 * Mitochondria appear as dark rods arranged radially in bundles
 * They appear to be black splotches
 * Difficult to see because the individual mitochondria are smaller than the resolving power of the light microscope.
 * Resolving power of microscope is 0.5-0.22 μm
 * Mitochondria are on the order of nm and μm
 * Require electron microscope to visualize individual mitrochondria and intra-mitochondrial structures

=**Ribosomes and Rough ER**=


 * Dark blue masses are neurons appearing in the central region of the tissue using low power
 * At 40x, the axons, dendrites and stoma are visible
 * Blue stains the ribosomal RNA, leaving the nucleus mostly unstained because it contains mostly DNA
 * However, nucleolus, the ribosome production factory, is very darkly stained and prominent
 * Ribosomes diffuse from the nucleolus
 * Ribosome staining throughout cytosol
 * Nissal bodies are the Rough ER and associated ribosomes

=**Golgi Apparatus**=


 * Golgi is cresent shaped structure, mostly localized around the nucleus
 * Can be distinguished from nissal bodies because nissal bodies are diffused throughout the cytosol
 * Nucleolus not visible on this stain

=**Skeletal Muscle**=


 * Bands of structure are the filaments
 * Individual filaments are too small for the light microscope to resolve
 * Light bands are actin
 * Dark bands are myosin
 * Filaments are not organelles
 * Not membrane bound, so they are inclusions

=**Liver**=


 * Stained for glycogen – so pink spheres are glycogen
 * Cells are arranged in cords separated by unstained blood vessels
 * Nuclei are unstained circles within a glycogen stained cord
 * Liver cells can be binucleated

=**Interphase Nuclei and Nucleoli**=


 * Smooth muscle cells run circular around a blood vessel
 * Multiple nuclei
 * Tissue layer: Endothelium layer; Tissue type: simple squamous epithelium
 * RBC’s will have no nuclei
 * Chromatin:
 * Heterochromatin – condensed dark nuclei usually found on the nuclear lamin surface
 * Nucleolus is usually found near the center of the nucleus
 * Euchromatin – lightly stained, diffuse
 * Vesicular – mix of heterochromatin and euchromatin

=**Artery, Vein and Nerve**=


 * Artery is surrounded by a thick layer of smooth muscle cells, with simple squamous epithelium lining the center area
 * Simple squamous epithelial layer appears as a dark ring
 * Fat adipose cells are mostly white unstained with a tiny nucleus in the corners of the cell

=** Mitosis**=


 * Interphase
 * Nucleus present with uncondensed chromosomes
 * Prophase
 * Chromatin condenses to discrete chromosomes which appear as squiggly lines
 * Nuclear membrane still partly visible
 * Metaphase
 * Chromosomes lined up in center of spindle at equatorial metaphase plate
 * Big black spots are excess yolk stained black
 * Anaphase
 * Chromosomes migrate to opposite poles
 * **No cleavage furrow**
 * Telophase
 * **Cleavage burrow forms**
 * Midbody is where the microtubules are all condensed
 * Perpendicular to the cleavage furrow
 * Cytokinesis is the division of cytoplasm and occurs in parallel to the division of the chromosomes