1. Week 2 Microscopic Anatomy
Expanded Studies

2. OBJECTIVES Knowing and using the compound light microscope
Slide preparation
Parts of cell
Embryonic germ layers

3. Objective 1: The Compound Light Microscope
Parts of the Microscope
Focusing Procedures
Useful Terms
Microscope Care & Handling

4. Parts of the Microscope
Revolving
Substage light

6. Can you name the following parts and their function?
How about part number: 9 11 3 1
Mechanical stage
Iris diaphragm
Arm
Ocular lens

7. Microscope Care & Handling
Always use both hands when transporting the microscope
Clean lenses before and after use
Never use anything but lens paper to clean lenses
Before plugging in the microscope, check to make sure all components are in proper “starting position”

8. “Starting Position” of Microscope
On/Off switch  OFF
Objective lenses  Rotated such that 4X lens (shortest) is facing down
Stage and Objective lenses as close together as possible (lenses lowered or stage raised)
Substage condenser lens in raised position
Iris diaphragm turned to dimmest setting

9. Focusing Procedures Slide placement Ocular lens adjustment & focusing
Light adjustment
Dimmer
Diaphragm
Substage condenser
Objective lens rules
4X or 10X first
Objective and stage close together
Focusing
Course adjustment - 4X or 10X only
Fine adjustment
Readjusting light with increasing magnification
Oil immersion lens rules

10. Microscope Care & Handling
When finished
Clean lenses before and after use
Never use anything but lens paper to clean lenses
Make sure you have removed the slide
Turn light OFF
Rotate the nosepiece to the lowest power objective
Position the stage & the objective lenses as close together as possible
Raise condenser lens
Switch diaphragm lever to dimmest setting
Return the microscope to it’s proper place

11. Useful Terms
Field of Vision:
40X
100X

12. Use iris diaphragm to adjust the contrast
Increased contrast
Decreased contrast
vs Brightness:
Use dimmer to adjust the brightness
Increased brightness
Decreased brightness

13. Working Distance:
Reminder: Do not use Course Adjustment Knob when either High Power lens or Oil Immersion lens are down

14. Total magnification is calculated by multiplying the magnification of the objective lens by the magnification of the ocular lens
TM = (Objective lens) x (Ocular lens) X
10X 4X
10X
40X
100X

15. TM = (Objective lens) x (Ocular lens)

16. Try these:
The total magnification of this Ə is 40X. The magnification of the ocular lens is 10X.
Which objective lens was used?
The total magnification of this Ə is 400X.
Which objective lens was used?

17. Objectives 2: Specimen Preparation

18. Does this sound familiar?
Always remember:
Structures, organs, and even individual cells can be sectioned in different planes.
Does this sound familiar? LS WM CS

19. There are several ways a specimen can be prepared for light microscopy:
Wholemount - the entire structure is mounted on the slide
Section - a thin slice of a tissue or organ is placed on a glass slide
Smear - most suitable when viewing cell suspensions such as blood, urine, mucus, cyst fluid, etc...
Squash - cells are broken by applying pressure to the slide, intracellular contents are liberated,
e.g., chromosomes

20. Whole Mount Preparation

21. Different planes of section through the seminiferous tubules of the testes

22. Examples of Sections
Nerve Fibers, LS
Nerve Fibers, CS

23. Longitudinal Section
Cross Section
lumen
lumen

24. Cross Section
Lumen
Lumen

25. Cross Section
Lumen
Lumen

26. Examples of a Smear Preparation
Sperm
Blood
High magnification vs Oil immersion

27. Example of a Squash Preparation
Chromosomes

28. Staining
The majority of specimens are stained with a combination of dyes that highlight differences between cellular structure
This is an H&E stained section
of the kidney. The darker blue structures are the nuclei of the cells
See Lab Manual Appendix

29. Some Common Stains Used in Histology or: You can’t judge a slide by it’s color
Liver
Hematoxylin and Eosin
(H & E)
Liver
Iron stain

30. Several steps are used to make a section
Fixation: a specimen is treated with a chemical solution to:
(1) prevent bacterial action and self destruction by cellular enzymes
(2) ensure preservation and hardening

31. Dehydration and Embedding
In order for the tissue to be sectioned, it must be “supported” to ensure accurate cutting. Paraffin wax is often used for this purpose, using the following procedure:
dehydration of the tissue by passing it through a series of alcohol/water mixtures, since wax won’t mix with the water naturally found in the tissue
clearing, which removes the alcohol
transfer into molten wax inside an embedding oven
Dehydration
Embedding

32. Sectioning
a microtome is used to slice the embedded tissue into thin slices ( micrometers thick)
the cut sections are then floated onto a water covered slide to remove any creasing
the slides are then drained and placed over a gentle heat to dry off the water and ensure that the tissue adheres to the slide

33. Objective 3: Generalized Mammalian Cell

34. Some cells of the body
(Simple columnar)
(Osteocyte)
(Adipocyte)
You will be responsible for knowing the various cells of the body by name and their parts

35. The other organelles are not visible under the light microscope
Parts of a generalized cell
Plasma Membrane
The other organelles are not visible under the light microscope

36. Identify these parts of a cell as seen under the microscope:
Nucleus
Cytoplasm
Plasma membrane
Renal Tubule, cs

37. Pluripotent Stem Cells
Objectives 4: Embryonic Germ Layers
Pluripotent Stem Cells

38. Stem Cell Tutorials
Click on the links below to learn more about stem cells & stem cell research:
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- check the links above for more information, or if you do not have Flash Player

39. Totipotent vs. Pluripotent Stem Cells

40. The embryonic germ layers are:
Ectoderm
Mesoderm
Endoderm

41. They will give rise to all the different tissues and organs of the body

42. Section taken from a blastocyst, around the 2nd week of development
Embryonic Germ Layers
Section taken from a blastocyst, around the 2nd week of development

43. For the Practical: Know the microscope parts Be able to calculate TM
Identify the specimen under the microscope
(vessel, tubule, chromosomes, sperm)
Identify the mount preparation
(wm, cs, ls, sq, sm)
Identify the embryonic germ layer &
Name one adult tissue (organ) that is formed from this layer