Week 2 Microscopic Anatomy

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

Ocular lens Arm Stage clips Objective lenses Substage light Revolving nosepiece Mechanical stage Course adjustment knob Fine adjustment knob Parts of the Microscope

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”

When finished: 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

Focusing Procedures 1.Slide placement 2.Ocular lens adjustment & focusing 3.Light adjustment 1.Dimmer 2.Diaphragm 3.Substage condenser 4.Objective lens 1.4X or 10X first 2.Objective and stage close together 5.Focusing 1.Course adjustment - 4X or 10X only 2.Fine adjustment 6.Readjusting light with increasing magnification 7.Oil immersion lens

Total magnification is calculated by multiplying the magnification of the objective lens by the magnification of the ocular lens X TM = (Objective lens) x (Ocular lens)

Objective 2 : Specimen Preparation

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

Different planes of section through the seminiferous tubules of the testes

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

Whole Mount Smear Squash

Cross SectionLongitudinal Section lumen lumen

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

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

The structural, biological, & functional unit of all living organisms CELL= Cell structure

Cells come in many shapes and sizes!

Structure and function are intimately related! Fibroblasts Erythrocytes Epithelial cells Cells that: (a) Connect body parts (b) Form linings (c) Transport gases Cells that move organs and body parts Skeletal muscle cell Smooth muscle cells Nerve cell Cell that gathers information and controls body functions Fat cell Macrophage Sperm Cell that stores nutrients Cell that fights disease Cell of reproduction

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

Simple squamous epithelium: two views Plasma membrane Nucleus Cytoplasm

Objective 4: Embryonic Germ Layers Pluripotent Stem Cells

The embryonic germ layers are: Ectoderm Mesoderm Endoderm

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

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

Histology part 1 The study of the tissues of the body

TISSUE = Two or more cells that share a common: structure, function, & embryological origin

There are four tissue categories: Epithelial Tissue Connective Tissue Muscle Tissue Nerve Tissue Histology is the study of tissues.

Tissues in perspective:

Objective 1: Epithelial Tissues Location –Covers body surfaces –Lines internal cavities Functions –Diffusion, secretion, absorption, filtration, protection Note: the singular form is epithelium; plural form epithelia

Classification of epithelium By cell shapeBy number of layers One layer = Simple More then one layer = Stratified Flat Cubbish Column-like

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

Some specializations: Cilia Function?

Some specializations: Microvilli Function?

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

Stratified Epithelia Named according to the shape of the apical layer of cells Stratified squamousStratified cuboidal Stratified columnar

More Epithelia -Pseudostratified

Transitional

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

Identify the Epithelial Tissue