Introduction Flashcards
(24 cards)
What are the 6 different levels of study?
Chemical Cellular Tissues Organs Organ systems Human
What is cytology?
The study of cells
What is the functional unit of life?
Cells
What is histology?
The study of tissues
What are the four types of tissue?
Epithelium- protection
Muscular- movement
Nervous- control
Connective- support and transport
In tissue preparation what are the 9 steps?
Fixation Dehydration Clearing Infiltration Embedding Sectioning Mounting Removal of Paraffin Staining
The first step in tissue preparation is FIXATION. What is the purpose of fixation?
Preserves the structural organization
Prevents digestion and protects from damage during the tissue preparation process
Ex: formalin
The second step in tissue preparation is dehydration. What is the purpose of dehydration?
Removes the water which eases the penetration of the tissue by clearing agents
Ex: ethanol
The third part of tissue preparation is clearing. What is the purpose for the Clearing process?
Prepares the tissue for infiltration
Ex: Xylene
The fourth part of tissue preparation is Infiltration. What is the purpose of infiltration?
Prepares the cleared tissue for embedding
Ex: paraffin
The fifth part of tissue preparation is embedding.what is the purpose of embedding?
Makes the tissue firm and prevents crushing during sectioning
The sixth part of tisssue preparation is sectioning. What is the purpose of sectioning?
To allow light or electrons to penetrate the specimen and form an image
The seventh part of tissue preparation is mounting. What is the purpose of mounting?
Eases handling and decreases damage to the specimen during examination
Usually uses a glass slide
The 8th part of tissue preparation is the removal of paraffin or plastic. What is the purpose for the removal of paraffin or plastic?
Most stains are water soluble and therefore need to put water back into the tissue using xylene then ethanol then water
The final part of tissue preparation is staining. What is the purpose for staining?
Makes the specimen visible
Ex: H and E are used most commonly and stain the tissue purple or pink
Hematoxylin, Alcian blue and methylene blue stain what parts of the cell?
Stains basophilic parts of the cell: DNA, RNA, ribosomes
Eosin and Orange G are acidic stains that stain what tissue parts?
Stains ACIDOPHILIC tissue parts such as mitochondria, secretory granules, collagen.
Acidic dyes have a high affinity for cytoplasm**
Lipid soluble dyes such as Sudan black and oil red O rain what?
Stains long chain hydrocarbons, fats and oils
Multicomponent histochemical reactions stain such as Periodic Acid Schiff (PAS) stain what?
Stains complex carbohydrates, glycogen
Heavy metals such as lead citrate, Osmium tetroxide, and ruthenium red stains what?
Stains phospholipids, complex sugars
***used in EM work and produces images thata re black and white
________ is the smallest distance that two objects can be seen as two objects
Resolution
If you increase the refractive index what happens to the resolution?
The resolution decreases
Inverse relationship between refractive index (n) and Resolution (d)
If increase the wavelength of light, what will happen to the resolving power?
The resolving power will increase
Direct proportional relationship between wavelength and resolving power
What is magnification and how to you calculate it?
How large the image appears
Mag= objective lens (4X, 10X, 40X and 100X) times ocular lens (10X)
