the study of cell formation, structure, and function
To understand histology you need to understand __________.
To understand anatomy and physiology you need to understand __________.
What is the purpose of prepping a sample?
To keep the sample as close to it's natural state as possible; life-like
What is artifact in sample prep?
human made mistakes
What type of solution is used in fixation of a sample?
An aldehyde based solution; for example, paraformaldehyde
How does fixation work?
The aldehyde solution cross-links the proteins which fixes the sample in place
What does dehydration of the sample refer to?
The removal of water
What is the name of the process that dehydrates the sample? How does it work?
A graded alcohol series; it works by exposing the the sample to increasing amounts of ETOH (50%,70%, 90%,95%, 100%x3)
What does the process of clearing the sample refer to? How does it work?
replacing the ETOH from the dehydration step with xylene as a solvent. The sample is exposed to increasing amounts of xylene (90%,95%,100%x3)
How does embedding the sample work?
for light microscopy the sample is penetrated with liquid parafin that eventually hardens and preserves the sample while electron microscopy uses plastic in the same manner
How big should the samples for light microscope (paraffin) be?
How big should the samples for the electron microscope (plastic) be?
What does sectioning refer to?
the cutting of the sample into thin slices
How thick should the samples for the light microscope be?
How thick should the samples for the electron microscope be?
< 100 nanometers thick
What is the purpose of staining a sample?
to produce a contrast so that the sample and it's structures are visible
What is the most common stain used?
hematoxylin and eosin (H&E)
What property does hemtoxylin have? What does it stain?
it is acidophilic; stains DNA, RNA, some proteins a dark blue or purple color
What property does eosin have? What does it stain?
it is basophilic; stains cytoplasm a pink color
What is toluidine blue?
A general stain that stains most things blue, but will stain some things pink (ie:cartilage)
Describe the direct method of using antibodies to stain samples.
The marked or tagged antibody will recognize a specific protein in or on the cell and binds to this protein only. It is a much cleaner way of staining.
Decribe the indirect method of using antibodies to stain samples.
the unmarked/untagged primary antibody binds to the specific protein. Marked or tagged secondary antibodies bind to the primary antibody (up to 6 secondary antibodies). This intensifies the sample, but may give you non-specific staining.
What are the 2 types of stains used in antibody staining?
Fluorescence and Enzyme staining
How does fluorescence staining work?
the marker is activated by a certain wave length of light causing the stain to fluoresce, this is done using a phase microscope
How does enzyme staining work?
the enzyme (ie: horse radish peroxidase) is introduced to the sample and a substrate is added, this reaction causes a colored product which stains the sample. Typically a counter stain is needed.
What does intercellular refer to?
material outside of the cell or between cells
What are the three components of the intercellular material?