58 terms

Histology Chapter One

Histology definition
the study of the microscopic structure of tissue
Cytology definition
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?
5-10 microns
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?
1) fiber components 2) ground substance 3) interstitial fluid/tissue fluids
What are 2 examples of fiber components?
extracellular matrix and collagen
What are 2 examples of ground substance?
bony material and cartilage
What are 3 examples of tissue fluids?
plasma, serum, lymph
What are the major components of the cell?
the nucleus and the cytoplasm
What are the 8 components of the general functions of cells?
1) ingestion & egestion 2) communication &excitation 3) energy production 4) movement 5) digestion & detoxification 6) synthesis 7) storage 8) reproduction
What are the components of the interphase nucleus?
1) nuclear membrane (envelope) 2) nuclear chromatin 3) the nucleolus 4) nuclear matrix
Describe the nuclear membrane/envelope.
A double membrane; demonstrates the fluid mosaic model for each membrane; outside membrane is attached to ER and has ribosomes attached to it; has pores; not visible with light microscope
What is the perinuclear space or cistern?
the space between the inner and outter layers of the nuclear membrane; 10-30 nm apart
Describe the nuclear pore complexes.
a central plug with about 8 spokes going out from it
What does nuclear chromatin consist of?
DNA, proteins, and RNA
How did chromatin get its name?
It was named for its ability to take up stain "chroma" = color
What are the 2 regions of chromatin?
heterochromatin and euchromatin
What is heterochromatin?
the stainable portion, it is condensed and is regions of the DNA that are not in use
What is euchromatin?
the invisible, dispersed chromatin regions of DNA that are being used
What are two things to notice about the distribution or heterochromatin and euchromatin?
some cells patterns are unique and the ratio of heterochromatin to euchromatin
What is the most conspicuous organelle of the nucleus?
the nucleolus
The nucleolus is _______ in cells with active protein synthesis.
What are three examples of cells with active protein synthesis?
liver, pancreas, and embryonic cells
The nucleolus is _______ in cells with limited protein production.
small or absent
What are two examples of cells with limited protein production?
muscle cells and sex cells
What is the shape of the nucleolus?
it is a rounded body
How does the nucleolus stain?
intensely with basic dyes
What are the two functions of the nucleolus?
ribosome assemby and gene packaging
What are the two components of the nuclear matrix?
the nucleoplasm/nuclear sap and intermediate filaments
What is the nucleoplasm/nuclear sap consistency?
it is a semi gel solution
What does the intermediate filament consist of and what is its function?
it consists of the nuclear laminin which gives the nucleus its shape and structure
What are some of the other nuclear features to take notice of?
the shape and size of the nucleus (polymorphic), the position of the nucleus in the cell (centrally or basally located), the nuclear cytoplasmic ratio, and the number of nuclei in the cell
Give and example of a cell the does not have a nucleus.
A mature red blood cell
Give examples of some of the cells that may have more than one nucleus.
skeletal muscle, osteoclasts, and placental cells