PRELIM LEC 1: INTRO TO HISTOLOGY Flashcards
LEVELS OF CELLULAR ORGANISM
CELLS
TISSUE
ORGAN
ORGAN SYSTEM
ORGANISM
is the STUDY OF TISSUES of the body and how these tissues are arranged to constitute organs.
HISTOLOGY
group of cells specialized to carry interrelated functions and their associated extracellular matrix.
TISSUES
MAJOR INTERACTIVE COMPONENTS/ORGANS OF TISSUES
CELLS & EXTRACELLULAR MATRIX (ECM)
Provide support to the cells, transport nutrients and eliminate wastes.
EXTRACELLULAR MATRIX
EXTRACELLULAR MATRIX is composed of many kinds of:
GROUND SUBSTANCE
FIBERS
STEPS IN TISSUE PROCESSING:
Routine (FDCIETS)
FILTRATION
DEHYDRATION
CLEARING
INFILTRATION and EMBEDDING
TRIMMING and SECTIONING
STAINING
For hard/calcified tissue (FDDCITS)
FILTRATION
DECALCIFICATION
DEHYDRATION
CLEARING
INFILTRATION and EMBEDDING
TRIMMING and SECTIONING
STAINING
Since cellular decomposition begins immediately after the death of a human/patient, tissues MUST BE FIXED TO THE CELLS to prevent alterations in their structure through decomposition.
FIXATION
Commonly used fixative in FIXATION process
FORMALIN, preferred 10% NEUTRAL BUFFERED FORMALIN
- Only done in specimens such as bone and calcified tissues.
- Purpose: REMOVAL OF CALCIUM AND LIME SALTS; done after fixation and before dehydration and impregnation, calcium might interfere with accurate evaluation and examination.
- Signification: Facilitate normal cutting of tissue in sectioning.
DECALCIFICATION
HARD/CALCIFIED TISSUES:
BONE
TEETH
TUBERCULOSIS LUNGS
ATHEROSCLEROTIC BLOOD VESSELS
- REMOVAL OF WATER OUT OF TISSUE
- Done by successively bathing the specimen in a mixture of ethanol and water from 70% to 100% (increasing concentration of alcohol)
- Alcohol removes water from the tissue
DEHYDRATION
DEHYDRATION REAGENT?
- best dehydrant because it is fast acting, mixes with water and many organic solvents, and penetrates tissues easily.
- Not poisonous and not very expensive
ETHANOL
- REMOVAL OF DEHYDRATING AGENT by immersing the specimen in the solvent that the alcohol and embedding medium is miscible.
- Makes tissue ‘’translucent’’ or transparent, hence the term clearing.
CLEARING
most commonly used clearing agent.
XYLENE
INFILTRATION AND EMBEDDING
- After the clearing procedure, the tissue is placed in melted paraffin in an oven set at ?
52 - 60 DEGREE CELSIUS
- makes use of a plastic solution which hardens tissue by cross-linking polymers.
- Eliminates the need to use an oven and paraffin; little tissue distortion.
PLASTIC RESINS
CUTTING and SECTIONING
CUTTING is the REMOVAL OF EXCESS
The block is then mounted in a microtome and cut with a ____________
STEEL KNIFE
CUTTING and SECTIONING
Sectioning is done with the aid of a __________ (REAGENT)
MICROTOME
STAINING
- Since paraffin is colorless, staining is a must.
Before staining, the following should be done:
- Removal of paraffin by ________ or ______
- Rehydration of tissue by descending concentration of alcohol.
XYLOL or TUOLOL
Tissue with NEGATIVE charges/acids are readily stained with dyes
BASOPHILIC
Tissues with POSITIVE charges are stained with acidic dyes
ACIDOPHILIC
Most commonly used stain in histology
HEMATOXYLIN and EOSIN
BASIC DYE ; usually stains nucleus and RNA containing portion of cytoplasm
HEMATOXYLIN
ACIDIC DYE;usually stains cytoplasmic components and collagen.
EOSIN
Last procedure in the series that ends with a permanent histological preparation on the table, after the staining.
MOUNTING
MOUNTING
Placing cut sections on a slide with adhesives such as ________ or ________
PINENE or ACRYLIC RESINS
MOUNTING
a solution in which the specimen is embedded, generally under a cover slide.
MOUNTING MEDIUM
for emergency surgery)
- Fixation is done RAPID FREEZING
- Compressed CO2 is emitted.
- Method is rapid.
- Routinely done in the hospital to study specimens during surgery.
- Lipids and enzymes are best preserved in this method.
FROZEN SECTIONS
FROZEN SECTIONS
Sectioning is done through ______, a refrigerated compartment containing a microtome.
CRYOSTAT
