Lab 4: Introduction to Histology: Epithelial Tissue

Compound light microscope: a series of lenses and a light source

view specimens in 3 dimensions, but at a LOWER magnification.

• thin specimen sections.
• (THIN)... THINNNNNN! there's like no other way I can remember this other than yelling it out loud.

• because the lab told me to. and i want an A. and I know you want it too.
• Real answer: ideal for observing cells and cell structure.

• magnifying glass that is about 10times (10X) magnification.
• (For some reason, this didn't make sense to me, is it because they want me to know how to get the cheapest microscope?)

• 1) ocular/eyepiece lens (one would look into this lens)
• 2) objective lens - lens CLOSEST to the OBJECT

acts as a magnifier and produces an enlarged image of the image produced by the objective lens.

• SIMPLY multiply the eyepiece magnification, usually 10X, by the magnification of the objective lens, usually 4X,10X,40X,100X
• (10X times 4X = 40X, 10X times 10X = 100X, 10X times 40X = 400X, 10X times 100X = 1000X)

• Oil immersion lenses.
• (labeled "oil" or "ol")
• USE: drop of oil is applied to slide before putting objective into place! don't forget or she'll charge you for damaging the microscope.

• oil does not mean petroleum oil for my car that I am currently needing of. but glad gas prices are cheap here. for now.
• 1) Lubrication - for protection
• 2) improves the resolution at high magnification

• we will use the lesser version of microscopes = 1000X max magnification.
• With a limit of 2000X magnification you can view bacteria, algae, protozoa, and a variety of human/animal cells
• (soo that's ok though, cause I would freak out a bit if I have the power to look at the bacteria on my lab benchtop).

eyepiece

seen through the the ocular lens; allows viewer to point to specific structures on microscope slide (not on all models of our scopes ....OMG I call the scope that has it cause I'm cooler ... jk :D ... we're all cool people).

supports lenses and provides carrying handle

holds and moves (resolves) the objective lenses

series of 3 or 4 lenses (4X,10X,40X,100X), ALWAYS start on the lowest power objective

flat surface that supports the slide

secures the slide on the stage

two black knobs under the stage used to move slide on the stage

lever or dial under the stage that regulates the amount of light going through the specimen

a series of lenses that you move up or down to clarify and condense the light shining through the specimen, found under the stage

lamp that shines a beam of light up through object

supports microscope

large knob found on BOTH sides of scope that moves the stage, first initial focusing knob ( you use this first not the fine adjustment knob)

small knob found within coarse adjustment knob used to bring specimen into FINAL focus

one ocular lens

two ocular lenses

the circle that you see when you look through the ocular lens

the space between the slide and the objective

the ability to distinguish between 2 adjacent points

• the 3rd to the last alphabet letter.
• real answer: the times or power of lens.

• 1. working distance = decrease
• 2. diameter of field = decrease
• 3. light intensity = decrease

cross section

longitudinal section

whole mount

section

• Lens tissue paper: not scratch but not very absorbent
• Kimwipes: relatively absorbent but can scratch

the microscopic study of tissues and cells.

made in either cross (sometimes called transverse) sections, or in longitudinal sections.

• 1. fixation
• 2. sectioning
• 3. visualization or staining

• processing the tissue to stop cell metabolism, thereby preventing its decomposition.
• use: FORMALIN, 37% aqueous solution of formaldehyde
• FORMALDEHYDE: reacts with the amino groups of proteins, and thus preserves the general structure of the cell and extracellular components

• refers to slicing (Sectioning Slicing ... SS) the tissue in very thin layers, on the level of micrometers (1/1000th of a millimeter).
• thinness varies with the tissue type.
• Very LITTLE contrast is observed between adjacent regions of tissue

• solution to bad contrasting.
• Preferential visualization.
• 2 of the most common stains:
• Hematoxylin and Eosin

stains nuclear substances, chromosomes, mitochondria and muscle striations blue and to black

stains the cytoplasm and other structures various shades of red

a combination of an array of cell types that are especially suited to perform certain limited functions.

• 1) epithelial (covered into this lab): cover "exposed (either internally or externally) areas, as well as form glands.
• 2) connective
• 3) muscle
• 4) neural