Histotechniques Flashcards
Predominant cell type of the epidermis
Keratinocytes
“-itis” means
Inflammation
Vascular and EXUDATIVE; infiltration by the PMNs/neutrophils; INCREASED VASCULAR PERMEABILITY
Acute inflammation
Vascular and FIBROBLASTIC; infiltration by the MONONUCLEAR CELLS; granuloma formation
Chronic inflammation
These are measurable indications of PHYSICAL OBSERVATION (e.g. fever, rashes, swelling)
Signs
These are indicators as DESCRIBED BY THE PATIENT (e.g. headache, aches, fatigues, nausea)
Symptoms
_____ wounds include lacerations, abrasions, punctures, incisions, and avulsions
Open
_____ wounds include contusions, blisters, seroma, HEMATOMA, and crush injuries
Closed
BENIGN tumor of epithelial origin
Papilloma
MALIGNANT tumor of epithelial origin
Carcinoma
Form of necrosis seen in TUBERCULOSIS and is characterized by a CHEESY APPEARANCE
Caseous
Liquefaction (colliquative) necrosis is associated with what organ
Brain and spinal cord
Mortality refers to
Death
Purpose of autopsy
To know the cause of death
of physicians involved to declare that a person is already dead
2
1st and most critical step in histotechnology
Fixation
Ideal pH of fixative
Neutral (6.0 - 8.0)
Ideal osmolality of fixative
Slightly hypertonic (400 - 450 mOsm)
Ratio of FIXATIVE to TISSUE volume
20:1
Fixation is _____ by INCREASED size and thickness of tissues, presence of mucus, fat or blood, and cold temperature
Retarded
Fixation is _____ by DECREASED size and thickness of tissues, and agitation
Enhanced
__________ ACCELERATES fixation but hastens autolysis
Moderate heat (37-56C)
It works as a physical agent to increase the movement of molecules and ACCELERATE fixation
Microwave
Also used to ACCELERATE staining, decalcification, immunohistochemistry and electron microspcopy
Microwave
Chief advantage of microwave fixation
Tissue is heated right through the block in a very short period of time
900 mL water; 100 mL 37% formaldehyde, 3.5g monobasic sodium phosphate, 6.5g sodium phosphate dibasic
10% NBF formula
Commercial formalin is buffered with phosphate at a pH of
7.0
What is done to prevent formation of hematin when using formalin as a fixative
Add buffer
Both microanatomical and cytoplasmic fixative
Helly’s fluid
Placing a fixed tissue in another fixative is called
Post-mordanting
Grossly NORMAL lungs when placed in a solution will
Float
Step done before decalcification
Fixation
When should decalcification be perfomed
After fixation and before impregnation
Ratio of DECALCIFYING AGENT to TISSUE volume
20:1
Decalcifying agent that contains hydrochloric acid
Von Ebner’s
The most common and fastest decalcifying agent used
Nitric acid
Best way to detect the extent of decalcification
X-ray method
Ratio of DEHYDRATING AGENT to TISSUE volume
10:1
What is the grading of alcohol during tissue dehydration
Increasing
Dehydration starts by placing the fixed specimen in what % alcohol
70%
Last concentration of alcohol used in tissue dehydration
100%
Clearing is also known as
Dealcoholization
Property of a clearing agent in order to combine with dehydrating agent and paraffin wax
Miscibility
Cheap, most rapid, simplest, and most commonly used CLEARING AGENT
Xylene
Substitute for xylene and benzene
Toluene
Clearing agent recommended for CNS, smooth muscles and skin
Cedarwood oil
Xylene turns milky, what is the cause
Incomplete dehydration
Picric acid, sodium azide, silver salts and DIOXANE are _____ materials
Explosive