Lec 9/8 Flashcards
what is microanatomy?
it is also called histology
histos-tissue
logia-study of
what is cellular level?
smallest unit of life, does all functions of living things
what is tissue level?
group of cells that performs a specific function
what is organ level?
several different types of tissue, function together for a specific purpose
what is organ system level?
several organs working together to perform a function. Different organ systems in a multicellular organism interact to carry out processes of life
what disciplines does microanatomy relate to?
gross anatomy, physiology, biochemistry/cell biology, pathology, dental clinical disciplines(operative, endodontics, periodontics, orthodontics)
what are methods for viewing tissue?
conventional light, confocal light, transmission e, scanning microscopy; x-ray, computer axial tomography, magnetic resonance imaging, position emission tomography
compound microscope
2 lens: 10x and 4,10,40,1000x
what is resolution?
- shortest distance bw 2 points that can still be distinguished by observer as separate entities.
- thinner sections, better resolution
what is resolution dependent on?
- wavelength of electromagnetic radiation
- magnification of objective lens
- thickness of section
how big is cell nucleus?
1-15 microns
how big is red blood cell?
6 microns
what is an artifact?
- sth viewed as a product of human conception or agency rather an inherent element
- a structure or feature not normally present but visible as a result of n external agent or action
what affects the “artifacts”
- preserving/fixation
- embedding
- sectioning
- staining
what are steps to prepare a specimen?
- fixation-formalina(37% buffered formaldehyde)
- embedding-paraffin wax
- cutting
- staining-H&E
what is fixation?
stop tissue deterioration
what are types of fixation?
- freezing
- extreme heat
- acids
- alcohol
- aldehydes-cross-link within and bw amino groups of proteins(lysine)
perfusion
vv
immersion
vv
what are types of aldehyde?
- formaldehyde-little deformation of tissue; may not fully fix tissue
- glutaraldehyde-stronger, can cause deformation of tissue; common in e microscopy
- karnovsky’s-mixture
types of embedding - frozen
\+quick to retrieve, cut, stain \+can preserve antibody-antigencomplexes -can destroy antibody-antigencomplexes -morphologically destructive -poor resolution
types of embedding-paraffin
\+very standardized \+standardized interpretation \+mostly preserve antibody-antigen complexes -long fixation times -resolution can vary w/ technician
types of embedding-plastic
\+very good resolution \+water soluble plastic retains lipids -long fixation times -interpretation can vary depending on procedure -destroy antibody-antigen complexes
what tools for sectioning?
- microtome
- cryomicrotome
what is the ideal thickness?
- frozen sections= 5um-10um
- paraffin sections=2um-50um
- plastic for light microscopy=0.5um -2um
- plastic for e microscopy=40um-100um
there are 3 classes of staining
- differentiate bw acidic and basic components of cell
- differentiate fibrous components of extracellular matrix
- metallic salts that precipitate metal deposits on tissue
Acid Stain-eosin
- net negative charge on colored portion (dye-Na+)
- stain basic structure(cytoplasm+mitochrondria)–>acidophilic
Basic stain-hematoxylin
- net positive charge on colored portions(dye+Cl-)
- stain acidic structure(DNA, RNA)–>basophilic
Hematoxylin and Eosin Staining(H&E)
- most common
- Hematoxylin-blue, basic, stain acidic stuff(DNA,RNA)
- Eosin-pink, acidic, stain basic stuff(basic proteins in cytoplasm; collagen, elastic, reticular fibers but cant distinguish)
H&E doesnt stain certain components
- elastic material, reticular fibers, basement membrane–> all pink, cant distinguish
- lipids–>lost in preparation
Metachromasia
- basic dye reacts w/ tissue, shifts color
- from polyanions in tissue
- red or purple
Weigert’s elastic stain
blue-elastic fibers
silver stain
black-reticular fibers
Periodic aid-Schiff
- Magenta:glycogen and carb rich molecules(mucus, basement membrane of epithelia, reticular fibers)
- Schiff reagent+aldehyde->red
4 primary tissue types
epitheilial, CT,muscle, nervous tissue
common characteristics of 4 tissues
- composed of living matter: cells, intercellular substances, and fluid
- different in types and family of cells, % compositions, arrangement
epithelial tisssue
-protect, absorb, secrete(covers and lines, modified for absorption, modified for secretion
connective tissue
- providing support and holding other tissues together
- additional functions(blood/bone marrow, mineralized tissues, fat storage)
muscle tissue
- contract and conduct
- irritability and conductivity
