90 likes | 261 Views
Anatomy and Physiology I (BIO130) Spring 2010. Prof. AnnMarie Armenti, MS. Exercise 3: The Microscope. Care of the Compound Microscope Hold in an upright position with one hand on the arm and the other supporting the base
E N D
Anatomy and Physiology I (BIO130)Spring 2010 Prof. AnnMarie Armenti, MS
Exercise 3: The Microscope • Care of the Compound Microscope • Hold in an upright position with one hand on the arm and the other supporting the base • Use grit-free lens paper to clean the lenses. Clean all lenses before and after use • Begin focusing on the lowest power objective • Use the coarse adjustment knob only with the lowest power lens • Always use a coverslip with wet mount preparation • Before returning the microscope: • Remove the slide from the stage • Rotate the lowest-power objective lens into position • Replace the dust cover or return it to the storage area
Exercise 3: The Microscope Activity 1: Identifying the Parts of the Microscope Activity 2: Viewing Objects through the Microscope Activity 3: Estimating the Diameter of the Microscope Field Activity 4: Perceiving Depth Activity 5: Preparing and Observing a Wet Mount
(10x) Head (support) Rotating Nosepiece Iris Diaphragm Lever (specimen) (regulates the light passing through the condenser – contrast) (precise focusing) (support) Condenser (Small lens that concentrates The light on the specimen)
Exercise 3: The Microscope • Magnification • Interplay of 2 lenses • Ocular Lens (10x) – Virtual image that we see • Objective Lens (4x, 10x, and 40x) – Real image • Total Magnification: • Power of Ocular Lens x the power of Objective Lens • 10 x 4 = 40x • Field: the area seen through the microscope
Exercise 3: The Microscope • Microscope Field • Size of the microscope field decreases with increasing magnification • Determining the diameter of the field • Field diameter = 4mm • Object extends across half the field 4 ÷ ½ = 2 mm • Remember: Start lowest-power objective to bring the grid lines into focus
Exercise 3: The Microscope • Perceiving Depth • Depth of the Field (depth of the specimen clearly in focus) • is greater at lower magnification 1. Use Iris diaphragm lever to reduce the light • Increase contrast 2. Focus with the coarse adjustment until threads are out of focus 3. Slowly focus them again, note which thread comes first
Exercise 3: The Microscope • Preparing a Wet Mount 1. Place a drop of saline in the center of slide 2. Rub the inside lining of your cheek 3. Transfer cheek scrapings into saline on slide 4. Add a tiny drop of iodine or methylene blue 5. Stir 6. Coverslip: prevents soiling of the lens if you misfocus • Bottom edge should touch one side of the fluid drop • Then carefully lower the coverslip. *** Probably want to dim the light with the iris diaphragm • Increase Contrast
How do you Prepare for Next Week? • Lecture: • Read Chapter 1 and 2 in the Text • Read over handouts • Laboratory: • Finish Lab. Exercise 1 and 3 • Read Lab. Exercises 4 and 5A