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Lab 1 Lab exercise _4

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Lab 1 Lab exercise _4 Powered By Docstoc
					Lab Introduction


Lab safety
Lab #3 - microscopes
Safety info

   Read the pamplet
   Sign the blue sheet
   Under 18? Please see me.
Lab safety

   First aid kit at the front
   Fire extinguisher at the back
   Eye wash at sink
   Showers in the back
Lab Safety

   No eating or drinking in lab
   Clean up rule:
    – It is your responsibility to clean up after
      yourself and put everything back like you
      found it
Lab clean up
   Put models back, like you found them
   Put microscopes back
   Put slides back in the proper box
Lab clean up
   Dispose of other items as follows:
    – Paper towels go in the trash
    – Broken glass and slide cover slips go in
      “broken glass”
    – Biological waste goes in red bucket
    – Empty slides get rinsed, dried, and
      returned to box
    – Dissection tools: put in wash
    – Wipe down your bench area when done
Lab Manual

   Lab assignments will require you to
    turn in the “Review Sheet” at the end
    of each lab exercise
   This must be ripped out of your lab
    manual, not photocopied
   Sometimes you will also be asked to
    turn in separate drawings or data
Lab 3: Intro to microscopes

   Microscopic anatomy:
    – Cells
    – Tissues
Who cares?

   Medically, microscopes are used for
    pathology, the study of disease.
    – If a disease is suspected, a tissue sample
      is taken (biopsy, blood) or a cell sample
      (pap test)
    – Pathologist or technician looks for
      abnormal cells, etc.
Who cares?

   Scientifically, microscopes are used to
    study cells and tissues for all kinds of
    reasons (e.g. brain damage research)
What about us?

   Educationally, microscopes are the
    only way to truly learn about the
    microscopic organizations of cells and
    tissues.
   Knowing how to use a microscope is a
    great skill to have, no matter what
    medical or biology subfield you are
    involved in.
Compound microscope

   Uses multiple lenses to achieve larger
    magnification
Compound microscope
   Key parts:
     – Eyepieces (ocular   – Stage controls
       objectives)         – Coarse and Fine
     – Arm                   focus
     – Base                – Condenser
     – Objectives          – Iris diaphragm
     – Stage (and stage    – Light
       clips)
Microscope Rules

   Carry a microscope with two hands,
    one on arm, one on base
   Put your microscope back in the
    numbered cubby it came from
   Clean lenses only with special lens
    paper
   Start by using low powers, then go up
    to higher powers
Properties

   Compound: occulars = 10x, objectives
    = 4x, 10x, 40x. Multiply to get total
    magnification
   Parafocal
   Inverted optics
   Field of view
How to use a compound
scope
 Start on lowest power (condenser up)
 Load slid into clip

 Look thorough oculars, adjust (one image)

 Focus (coarse)

 Find region of interest, go to higher power

 Focus (fine only because it’s parafocal)

**Adjust light level and iris diaphragm as
  needed (less light at low power)
Careful

   When using higher power objectives, it
    is easy to break slides because the
    working distance is small (lens is close
    to slide)
Activity 1

   ID scope parts
Activity 2

   Get a letter e slide
   Follow instructions and fill in table on
    p.30
   Total mags = ocular x objective
   Measure working distances w/ ruler
   Draw what you see
   Don’t do the 100x (oil) objective
Activity 3

   Get a grid slide and measure the field
    diameter using low power (4x)
    objective by counting the number of
    grid squares that you can see across
    the field of view (1 sq = 1mm)
   Calculate the field diameters for the
    other lenses (not oil)
Field diameter formula
(p.32)
F.D. lens B = F.D. lens A x total magnification lens A
                   total magnification lens B

Example: say you count 10 squares across using the 4x
F.D. (10x obj) = F.D. at low power x total mag @ low power
                        total magnification med power
                = 10mm X 40x
                    100x
                = 4mm
Activity 4 - depth

   Get a thread slide (has three threads that
    cross each other)
   Focus down with the coarse focus until all
    the threads are just out of focus
   Then, slowly focus up, taking note of which
    thread comes into focus first (top), then
    second (middle), and last (bottom)
Activity 5

   Practice making a wet mount slide
    – Put drop on slide
    – Put on over slip at an angle
   Take an epithelial cell slide and
    estimate the diameter of one cell
    based on your field diameter
    measurements. (e.g., if it takes up half
    the field and the filed = 10 mm then
    it’s 5 mm)
Clean up

   Cover slips in lab glass container
   Wash/dry fresh mount slides, put back
   Put prep’d slides back into correct box
   Clean off lens with lens paper and lens
    cleaner ONLY
   Clean off stage and return scope
   Clean up your area
Activities
1.   Get scope and set up, I.D. parts
2.   Letter “e” slides (prepared).
3.   Grid slide: count and calculate –
     measure at lowest power, use this
     figure to calculate answers at higher
     power (table on page 30).
4.   Thread slides (Careful, they’re thick).
     Determine order of threads.
5.   Make pond water wet mount slide
     and observe (practice focusing)
    Clean up
Turn in
   Lab 3 report (review sheet) due next Thurs
    (rip out).
   Turn in page 30 with completed summary
    table (except oil objective)
   Write the correct order of the threads on
    the bottom of page 38 like this:
    Top___________
    Middle____________
    Bottom____________

				
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posted:10/13/2011
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