260 likes | 295 Views
Explore lab safety rules, proper equipment handling, and learn how to use a compound microscope effectively. Activities included for hands-on learning experiences. Turn in a lab report as per instructions.
E N D
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 • Due Wed of the week following the lab
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.
What about us? • Scientifically, microscopes are used to study cells and tissues for all kinds of reasons (e.g. CSI). • 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
Key parts: Eyepieces (ocular objectives) Arm Base Objectives Stage (and stage clips) Stage controls Coarse and Fine focus Condenser Iris diaphragm Light Compound microscope
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 • Get scope and set up, I.D. parts • Letter “e” slides (prepared). • Grid slide: count and calculate – measure at lowest power, use this figure to calculate answers at higher power (table on page 30). • Thread slides (Careful, they’re thick). Determine order of threads. • 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____________