组织学实验学指导英文课件

1、A laboratory guide for histologyIntroduction As other medical courses, the study of histology consists of two parts: lectures and laboratory work. The purpose of laboratory work is mainly to integrate theoretical knowledge with practical work and to train the ability of observing the structures of c

2、ells, tissues and organs with microscope. Preparation and rules of laboratory workPreview the relevant text well before the laboratory work and know the contents and objects of each laboratory work.Have the tools ready. These include microscope, slides, paper, pencils, rubber, ruler and so on;Keep t

3、he laboratory clean and quiet. Raise your hand before asking the teacher. No spiting, no smoking and no eating in laboratory.Take good care of specimens and instruments.At the end of each laboratory work return the slides in order. Put the slide box and microscope back where they belong. Clean the r

4、oom and turn off the light. Be sure that the windows are closed before you leave the laboratory.The structure of the microscope1234567Mechanical part:1. Base 2. Stand 3. specimen holder4. Observation tube5. Nosepiece6. Coarse adjustment ring7. Fine adjustment ring2341Opticalcomponents: 1. The source

5、s of light 2. Condenser lens3. Objective lenses4. EyepieceA. low power objective1. Turn the power switch on, open the iris diaphragm and center the low power objective by turning the nosepiece;2. place a slide on the stage then center the object by adjusting the mechanical stage；3.Turn the coarse ad

6、justment to raise the stage until the objective is about 0.5cm form the specimen, look through eyepieces and turn the coarse adjustment slowly to lower the stage until the specimen is seen；The use of microscopeThe use of microscope4. Adjust the interpupillary distance. Hold the 2 eyepiece tubes with

7、 your both hands to push the tubes together or pull them apart, until you can see the same image with both eyes；5. Look at the image through the right eyepiece with your right eye and make the specimen in sharp focus by turning the fine adjustment. Look at the image through the left eyepiece with yo

8、ur left eye and rotate the tube length adjustment ring to focus on the specimen. High power objectiveAfter observing with low power objective enter the high power one. A slight turn of the fine adjustment will bring the image into sharp focus. Dont turn the coarse adjustment to avoid damaging the sp

9、ecimen or the objective.Oil immersion objectiveIt requires more careful use than the others.First place a small drop of cedar oil on the slide, then center the lens slowly. Turn the coarse adjustment until the lens touches the oil and then turn the fine adjustment upward or downward to focus.Note th

10、at the cedar oil must be wiped off with lens paper after using the oil immerse lens.The care of microscopeCheck the microscope assigned to you. If you find anything wrong, inform the teacher immediately.Don not take apart of the microscope.Keep the microscope clean. Clean lens with lens paper only.

11、Avoid blowing or wiping it with finger, rough paper or cloth.Before replacing your microscope, be sure that lenses or stage and condenser are at the lowest position. Then cover the microscope with soft silk. Procedure of observationFirst observe the shape, color and the features of the specimen with

12、 naked eyes.Observe the general structure and its components with low power objective. Then select a representative area and observe it in detail with high power objective then with the oil immersion lens when necessary.Make a drawing of the representative area and label it clearly.A drawing of the

13、representative areaInterpret your sampleMust think in 3 dimensionsFor best interpretation, must have serial sectioning and reconstruction.Preparing a Biological Specimen for Light Microscopy1. Obtain sample and cut into workable pieces (1cm cube)Biopsy, surgical excision, postmortem examinationFrom

14、animalsTaken quickly, use sharp instruments2. Fixation generally in reactive aldehydes like formaldehyde. This cross links macromolecules, particularly proteinsHas hardening effect on soft tissuesDone rapidly to prevent enzymes from live cells degrading the tissue3.Dehydrate the sample by running th

15、rough a series of increasing concentrations of ethanol.Paraffin (embedding material) is not water soluble, so water is removed4. Clear the sample of ethanol and pass through several changes of xyleneParaffin is also insoluble in ethanol5. Embed the sample in a supporting medium like wax (paraffin) o

16、r resin Tissues are soft and fragilePass through several changes of warm paraffin waxMelted wax occupies space formerly filled with waterCooled wax hardens, easier to cut6. Section on a microtome, which slices like a mini meat slicer, into sections 1-10mm thick.7. Mount the sections on microscope slides.Unstained section8. Stain the tissue sections with stain of your choice.stains are aqueous so need to reverse x