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Histology Exam 1 > Lec2&3 > Flashcards

Lec2&3 Flashcards

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1
Q

Compound Microscope comp.

A 
light source
condensor
state
objective lens
occular lense
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2
Q

Comp. Microscope pros/cns

A

ability to magnify
ability to resolve structural detail
specimen must be thin
relatively little contrast in the unstained specimen

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3
Q

Phase contrast microscope

A

converts phase shiftsIinvisible to eye) in light passing through a transparent specimen to brightness changes(visible to eye) in the image
-useful to examine living cells

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4
Q

Fluorescence Microscope

A

detects molecules that emit light of wavelengths when exposed to UV light source

  • detection of antigens or Ab in immunochemical staining
  • detection of fluorescent tracers inj into animals
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5
Q

Confocal scanning microscope

A

eables reconstruction of 3D imagess
inc optical resolution and contrast by means of adding pinhole at confocal plane of the lens to eliminate out of focus light
-employs a laser beam
-mirror system moves laser beam across specimen and data from each spot of specimen is recorded and stored in comp

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6
Q

confocal advantages

A
  • very thin optical images of the specimen are created
  • out of focus images are subtracted from the image by the compter program
  • comp can make 3D reconstructions of the specimen by stacking individual images
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7
Q

TEM

A

utilizes beam of e- rather than light

  • comp: cathode, tungsten filament (e source), anode, series of electro magnents, specimen holder, viewing screen and photographic film
  • potential diff btwn cathode y anode impart an accelerating voltage of btwn 20k and 200k volts
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8
Q

4 steps of tissue F & E

A

Fixing, dehydration, removal of Alcohol, Embedding

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9
Q

Fixing

A

-prevents further deterioration, helps harden tissue prior to embedding y sectioning
any fiaxative will distort specimen but ideal fixative give greater optical contrast w least amnt of distorting

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10
Q

Formalin

A

One of the most widely used fixing agents

  • can be used alone or in combo w others such as alcohol
  • not good if fine cytological detail reqd
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11
Q

Acid Fixatives good for:

A

chromatin, nucleoli, and spindle fibers

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12
Q

Basic Fixatives good for:

A

mitochondrial staining, in this fixing chromtin is dissolved

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13
Q

Fixatives for TEM

A

Glutaraldehyde- preserves proteins by cross linking them

-Osmium tetroxide- rxcts w lipids and imparts e- density to cell and tissue structures

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14
Q

Dehydration in tissue fixing

A

Bc tissue sample will eventually be embedded and infiltrated w hydrophobic material (usually paraffin) all h2o must be removed

  • place tissue in succesively inc. strenghts of ethanol
  • ethonol dissolves neural fats and cannot be used for those
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15
Q

Clearing tissue fixing steps

A

clearing is replacing alcohol (used in dehydr step) with an agent such as xylene or cedar oil

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16
Q

Embedding fixing step

A

Tissue spec. is moved sequentially through several (usually 3) melted paraffin baths

  • after finals bath specimen placed in a mold that is then filled with melted paraffin
  • paraffin mold is rapidly hardened by placing in cold water bath
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17
Q

Embedding for TEM

A

tissue infiltrated w a monomeric resin (epoxy resin)

-resin is then polymerized, tissue smaples typically less than 1mm^3

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18
Q

Tissue sectioning fro TEM

A
  • diamond knives used to cut at 50 to 150nm
  • section fragile, must be floated onto a plastic-coated copper mesh grid
  • plastic left in place for viewing
  • holes in copper grid allow e- beam to pass through sample
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19
Q

Tissue sectioning

A

typically done on a rotary microtome which utlizes a sharp blade over which th paraffin block is raised and lowered after being advanced a fixed distance per cycle

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20
Q

Tissue staining

A

-animal tissue usually colorless so req staining
-use xylene to remove parffin (now mounted on micrscope slide)
-xylene then removed using graded series of alcohol down to h20
-stains then applied and section dehhyrated with graded series of alcohol, alcohol then removed w xylene, drop of cement followed by a cover slip is applied
-

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21
Q

H&E stain

A

good for structural features but dont say much about chemical characteristics of the tissue

  • H isnt a basic dye but behaves like one-drk blue to lght blue/purple
  • E is an acid dye - yellowish to pinkish color
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22
Q

Orcein and resourcin statins used for:

A

reveal elastic material

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23
Q

silver impregnation stain used for;

A

to show reticular fibers and basement membranes

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24
Q

Sudan stains used for:

A

Lipids, but remember preservation of lipids requires techniques that do not utilize alcohol for dehydration etc

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25
Basic dyes
react w anionic groups of tissue comp. such as phosphate groups, sulfate and carboxyl groups. -exact nature of binding depends on ph, high ph all 3 groups available for binding with dye -any tissue comp. that reacts w basic dye is basophillic EX: methyl green, mehtylene blue, pyronine G, toluidine blue
26
Acid Dyes
- bind to tissue compnents by forming electrostatic linkages with cationic groups such as the maino groups of proteins - diff acid dyes have diff properties and can be used in seq. to give diff results - any tissie that reacts with an acid dye is said to be acidophilic
27
Ex. of acidic dyes
acid fuchsin, aniline blue, eosin, orange g
28
Metachromasia
pehnomonen whereby dye changes color after reacting w tissue comp.. EX: toluidine blue used to stain cartilage ground substance or mast cell granules
29
TEM tissue staining
utilizes ions of heavy metals tht are very E- dense -heavy metals can be added during fixation, dehydration or by soaking in ionic solutions after scetioning EX: osmium tetroxie, uranyl nitrate, uranyl acetate y lead citrate
30
Histochemical techniques
can be used to study the chemistry of cells and tissues ex: perls rxn-used to demonstarte precense of iron in tissues, incubate tissues in mixture of potasium ferrocyanide and HCL
31
Schiff reagnet rxns
histochemical rxn that depends on the formation of aldehyde groups following exposure to HCL or periodic acid
32
Fielgen rxn
Histochemical rxn uses mild hydrolosis w HCL exposes aldehyde groups on deoxyribose
33
PAS rxn
a schiff ragent rxn uses periodic acid to cleave bonds between adjacent carbons of carbohydrates and form aldehyde groups, forms deep-pinkish color
34
PAZ rxn positive substances
plusacharides, GAGs, proteoglycans, glycoproteins, glycolipids
35
Best Carmine
Histochemical staining technique dye that ay also be used to demonstate glycogen deposits
36
RNA stains
a type of 'special' staining technique where RNA rich organelles may be stained w basic dye EX: toluidine blue, methylene blue, methyl green
37
Immunochemical staining techniques
uses monoclonal antibodies to study presecence of specific tissue constituents
38
Epithelial tissue characteristics
it does not contain blood vessels -may be derived from ectoderm (skin epidermis and glands), Endoderm (lining of GI tract) or Mesoderm (lining of bv, mesothelium bowmans capusle etc
39
Function of basement membrane
selective filtration barrier - scaffold for embryogenesis and regeneration - stabilization of tissue shapes
40
Psuedostartified epi
type of simple - all cells in contact with basal lamina, appearance of stratified bc of nuclei - arrangement of some epithelia may reflect role of stem cells tht are necessary to balance cell turnover by replacing more mature cells when they become damaged
41
Transitional Epi
thought to be a type of simple epi but w appearance of having more than one layer bc of nuceli position, all cells in contact w basal lamina - dome shaped surface cells - associated w urinary tract may be referred to as urothelium
42
Simple Column. Epi details/locations
- may have striated border on apical of micro villi (intestinal) - ciliated upper respiratory, uterine tubes, uterus, paranasal sinuses, central canal spinal cord - non ciliated digestive tract starting at stomach, gall bladder, parts of exretory ducts of glands
43
Stratified squamos details/locations
heavily kertanized:epidermis w CT papillae, cornea wo CT papillae -lightly/non kert. esophagus, vagina, lining of mouth, tongue, part of epiglottis
44
Stratified cubodial details/locations
seldom found, small areas of anal mucosa, large excretory ducts of some glands, part of male urethra
45
Simple squamos details/locations
lines lumina of ducts, vessels, other tubular structures | -forms walls of alveoli, bowmans capsule and inner surface of membranous labyrinth and tympanic membrane
46
Simple cubodial details/locations
in side view may be low or high (approach squamos or columnar) - mau have brush brder (kidney tubules) on apical of microvilli - surface of ovary, pigmented epi of retina, kidney tubules, glands and ducts, terminal broncholes, choroid plexus, anterior capsule of lens of eye
47
stratified columnar epi details/locations
seldom found, occurs in ducts of adult sweat glands, fornix of the conjuntiva of the eye, parts of male repro/urinary tract, pharynx and the epiglottis
48
Pseudostratified details/locations
ciliated in trachea | w sterocilia in epididymis
49
transitional details/locations
urinary system, often called urothelium
50
2 kinds of epithelium
1. Covering and lining | 2. glandular
51
Epithelial tissue function
- protection: esp. sratified sq. | - conc differnces w tight or leaky barriers (ie leaky lining gall bladder y proximal conv renal tubule
52
Secretion or absorption in epi tissue
- those involved typically simple or pseudo - height of the cell often refelcts level of secretory or absorptive activity - simple columnar functions primarily in secretion of enzymes y mucous and absorption of nutrients and fluids
53
Microvilli
figerlike projections of apical cell membrane supported by cross linked actin bundles - non motile - tend to form uniform brush border - primary func to inc surface area - intestinal epi and parts of renal tubules
54
microvilli structure
actin filament core, look at slide at end of lec 3
55
Structure of cilium
9 peripheral doublets + central pair of microtubules (ref to fig 1-29)
56
Phospholiid bilayer
formed from neural fat in which 1 fatty acid groups on glycerol is replaced by phosphate group -hydriphilic end (phosphate) and hydrophobic( fatty acid moeities) 1 phospholipid has hphillic head and 2 hphobic tails
57
contents of outer leaflet
cholesterol (2nd most common membrane lipid, hphobic), phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, glycolipids, glycosylphosphatidyllinositol (imp for cell siganling)
58
inner leaflet
chosletorol, phosphatidylethanolamine, phosphatidyllinositol (- charged) and phosphatidylserine )- charged)
59
transmemebrane proteins
usually have a helices of 20-25 hphobic AA and are inserted into ER membrane during synthesis EX: band 3 is anion transporter for bicarb and Cl- ions. dimers of band 3 form channels for the ios
60
Glycolipids
found only in outer leaflet w carbohydrate portion facing the EC environemnt - fa tail is couples with sphingosine to a carb head group - create a cell coat involned in c2c interactions and convery antigenicity
61
Lipid rafts
small patches of cholesterol and sphigolipids. compartmentalize cellular processes by serving as organizing centers for: assembly of signaling molecules, influencing membrane fluidity, membrane protein trafficking, regulating neurotransmission and receptor trafficking
62
Glycocalyx
not an integral part of the membrane; is a carb coat on the extracellular surface of cell membrane composed of carb portions of glycolipids and glycoproteins -protects cell from ionic and mechanical stress, barrier against microorganisms, involved in c2c interactions
63
Cholesterol (membrane)
at high temp itefreres with FA chain movement, outer part of mebrane less fluid, reduces permeability to small molecules -low temp: prevents membranes from freeing and maintains fludity
64
Membrane proteins
associated thru protein-protein interactions typically involving ionic bonds that can easily dissacoiate -found on both inner and outer leaf
65
integral proteins
proteins inserted into membrane and that can only be dissociated by reagets that disrupt hydrophobic interactions - EC portion typically glycosolated - can span or anchor to lipid bilayer but dont pass through
66
lipid to protein ration on cell membrane
50/50 by weight but since proteins are larger usually 1 protein per 50-100 lipid molecules
67
Transmembrane proteins
integral proteins that pass completely through membrane, typically serve as channels or transporter, can be single-pass or multi-pass

Histology Exam 1 (3 decks)

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