Cytology

Light Microscope

uses visible light and lenses to magnify images of samples that produces simple images with the inability to discern veryTra small details in tissue and cell morphology

What kind of electron microscope produces this image?

Transmission Electron Microscope (TEM)

What kind of microscope produces this image?

Scanning Electron Microscope (SEM)

What can cause variations in the results of the staining process? (3)

• user error

• pH differences

• poor fixation

Hematoxylin and Eosin (H&E Stain)

Hematoxylin stains acidic tissue components (RNA/DNA) purple, and eosin stains basic tissue components pink-orange

Basophillic

acidic tissues that are stained purple due to attracting the basic stain

Acidophillic

basic tissues that are stained pink-orange due to attracting the acidic stain

Silver Stain

uses silver salt to make reticular fibers (basement membrane) turn black

Masson’s Trichrome

three color staining protocol in which connective tissue is blue, nulcei and muscle are dark red/purple, and the cytoplasm is stained red/pink

Periodic Acid-Schiff Stain (PAS)

staining protocol that stains the basement membrane, glycogen, and carbohydrates magenta and the nuclei blue

Wright’s Stain

a common stain used for blood samples that is essentially a modified H&E

What is the most common staining technique used in veterinary medicine?

H&E

Phases of Mitosis (5)

1. Interphase

2. Prophase

3. Metaphase

4. Anaphase

5. Telophase

Interphase

genetic material inside the nucleus is dispersed equally to facilitate DNA transciption

Prophase

centrosomes duplicate and begin moving toward opposite ends

• “ball of yarn nucleus”

Metaphase

chromosomes are at the middle of the cell and microtubules pull the centromeres to separate the sister chromatids

Anaphase

Sister chromatids are dragged toward the poles (hand like projections)

Telophase

nuclear envelope starts to reform between the two new cells

Nucleolus

site of RNA transcription that assembles around clusters of rRNA gene repeats

How does the golgi apparatus appear under the microscope?

clear cytoplasm as it has a neutral pH

ONLY visible in cells releasing a lot of material extracellularly

Cillia

coordinate movements to move material along the surface of the cell

Microvilli

NEVER mobile; used to increase surface area of the cell surface for absorption

Cell Inclusions

nonliving components of the cell that do not possess essential metabolic activity

What are the most common inclusions?

Glycogen, lipid droplets, crystals, and pigments

What is the moston biological pigment? comm

Melanin

Hemosiderian

Staining Artifact

staining variations in tissue due to handling; edges may be lighter than the center

Parenchyma

living, functional portion of any tissue or organ

Stroma

non-living, supportive portion of any tissue or organ

Folding Artifact

tissue has folded over onto itself

Tearing Artifact

tissue was torn during process

Lobule

grouping of parenchyma in some organs and tissue

Septa

stroma that separate lobules

When do shrinkage artifacts occur?

when water is removed from the tissue it can cause an artificial space to appear that is NOT present in the living animal

Basal Side

side of a cell that is the closest to the basement membrane (aka Basal Lamina)

Apical Side

side of the cell farthest away from the basement membrane or closest to the lumen or surface

Acini / Acinus

describes a cellular arrangement in a raspberry formation

Closed-Faced Nucleus

little variation between euchromatin (light) and heterochromatin (dark) and means the cell is metabolically inactive

Open-Faced Nucleus

variation between euchromatin (light) and heterochromatin (dark) and means the cell is metabolically active

Zymogen Granules

eosinophilically stained granules considered cell inclusions

True or False: all neuron nuclei are open-faced.

TRUE

What color does the Golgi apparatus stain?

neutral

Cilia

Specializations of the cell surface that can help move material along the surface of the cell

Microvilli

Specialization of the cell surface that increase the surface area of the cell for absorption

Cell Inclusion

Nonliving components of the cell that do not possess essential metabolic activity - OR - anything inside a cell that the cell does not need to live

Glycogen

Cell inclusion that is used as a storage material when glucose supplies are high; common in Liver and Skeletal muscle (PAS stain = magenta)

Lipids

Cell inclusion that is stored as droplets for energy source; appears clear as they are lost during processing

Melanin

Most common biological pigment that protects cells from UV radiation 

Hemosiderin

Cell inclusion in macrophages that is the residue of blood cell destruction

Lipofuscin

Celll inclusion that appears yellow-brown granules that are the sign of incomplete lysosomal digestion; aging cells