1. Week 2 Microscopic Anatomy

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

3. Parts of the Microscope
Revolving
Substage light

5. Expect to see this on the Practical
Can you name the following parts and their function?
Expect to see this on the Practical

6. 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”

7. “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

8. 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

9. 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

10. 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

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

12. 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?

13. NOTE: Total Magnification included in score
Don’t forget the “X” symbol
TM = 400 X

14. Objective 2: Specimen Preparation

15. 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

16. 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

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

18. Cross Section
Lumen
Lumen

19. Cross Section
Lumen
Lumen

20. Whole Mount
Squash
Smear

21. 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

22. 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

23. 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

24. 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

25. 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

26. Objective 3: Generalized Mammalian Cell

27. Identifying cells and their parts
(Simple columnar)
(Osteocyte)
(Adipocyte)

28. Parts of a cell
Plasma Membrane

29. Parts of a cell as seen under the miscroscope
Nucleus
Cytoplasm
Plasma membrane
Renal Tubule, cs

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

31. The embryonic germ layers are:
Ectoderm
Mesoderm
Endoderm

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

33. 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

34. b/c you will be drawing 19 slides
LAB 3:
HISTOLOGY
Head Start
b/c you will be drawing 19 slides

35. TISSUE =
Two or more cells that share a common: structure, function, & embryological origin
Tissue composed entirely of cells that covers or lines is called EPITHELIAL TISSUE.

36. Objective 1: Epithelial Tissues
Location
Covers body surfaces
Lines internal cavities
Functions
Diffusion, secretion, absorption, filtration, protection
* Look for the edge!
Note: the singular form is epithelium; plural form epithelia

37. Find the epithelia:

38. Classification of epithelium
By cell shape
By number of layers
Flat (Squashed)
One layer =
Simple
Squamous
Cubish
Cuboidal
More then one layer =
Stratified
Column-like
Columnar

39. Putting it all together:
To classify an epithelium state the number of layers then cell shape.

40. Knowing the function and location of each tissue type will help you make sense of them and aid in memorization.

41. Types of Simple Epithelia
Simple squamous
Simple cuboidal
Simple columnar
Look for a flattened nucleus
Look for a rounded nucleus
Look for an oval nucleus

42. Types of Stratified Epithelia Named according to the shape of the apical layer of cells
Stratified cuboidal
Stratified columnar
Stratified squamous

43. Other Epithelia Pseudostratified columnar Transitional
Cells have a tapered appearance
Large cells w/ Large round nuclei
“plumpy” appearance
Apical cells larger than basal cells

44. More than one tissue type can be found in the same image:
Longitudinal Section
Cross Section
lumen
lumen

45. Some specializations:
Cilia
Microvilli

46. Epithelial tissue is connected to the underlying (connective) tissue via an extracellular matrix called basement membrane

47. What to label? Nucleus Cytoplasm Basement Membrane Apical Cells
Basal Cells
Basement Membrane
Basement Membrane

48. What to label?