Mod 1 histo lab

• Histological diagnosis is still the "gold standard" of clinical practice
• A histological diagnosis is valuable when tissue sections are evaluated by a competent pathologist or laboratorian aided by microscopes
• Diagnosis of a disease depends 80% on laboratory data, including histologic/histopathologic examination
• Proper use of a microscope is necessary for histological examination
• In microscopy, light microscopes are used to examine wax-embedded sections with a resolution of 0.2 um - 0.6 um
• Resolution of structure in microscopy is limited by the wavelength of light
• Electron microscopy in research laboratories allows for much greater magnification and resolution, permitting the study of subcellular morphology
• There are two main types of electron microscopes: transmission electron microscope (TEM) and scanning electron microscope (SEM)
• Samples of human biological materials can be obtained from different parts of the body
• Instruments like scalpels are used for directly accessible tissues such as the skin, mouth, and nose
• Needles are utilized for samples from solid organs
• Endoscopic tubes are used for samples from the alimentary tract or body cavities
• Special flexible cannulae are used for samples from blood vessels
• Histological sections are thin, transparent shavings cut from body tissue, stained, and mounted on glass slides
• Histological sections are two-dimensional slices of a three-dimensional object
• Structural characteristics of tissue or organs may undergo normal cyclic, intermittent, progressive, or regressive changes with time
• A histological section may not look the same under the microscope as described in a textbook due to the preservation and preparation process
• Students should visualize how a histological slice has been cut to better interpret the variations in pictures encountered
• Two major considerations in the study of organ/tissue methodology are the type of microscope used and the preparation of the tissue/organ for viewing
• Chromatin - DNA + proteins, condensed into chromosomes during mitosis/meiosis
• Nucleolus - site of ribosome synthesis
• The nucleus is the control center of the cell.