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Histology Exam 1 > Lec2&3 > Flashcards

Lec2&3 Flashcards

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
Q

Basic dyes

A

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

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26
Q

Acid Dyes

A
  • 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
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27
Q

Ex. of acidic dyes

A

acid fuchsin, aniline blue, eosin, orange g

28
Q

Metachromasia

A

pehnomonen whereby dye changes color after reacting w tissue comp..
EX: toluidine blue used to stain cartilage ground substance or mast cell granules

29
Q

TEM tissue staining

A

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
Q

Histochemical techniques

A

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
Q

Schiff reagnet rxns

A

histochemical rxn that depends on the formation of aldehyde groups following exposure to HCL or periodic acid

32
Q

Fielgen rxn

A

Histochemical rxn uses mild hydrolosis w HCL exposes aldehyde groups on deoxyribose

33
Q

PAS rxn

A

a schiff ragent rxn uses periodic acid to cleave bonds between adjacent carbons of carbohydrates and form aldehyde groups, forms deep-pinkish color

34
Q

PAZ rxn positive substances

A

plusacharides, GAGs, proteoglycans, glycoproteins, glycolipids

35
Q

Best Carmine

A

Histochemical staining technique dye that ay also be used to demonstate glycogen deposits

36
Q

RNA stains

A

a type of ‘special’ staining technique where RNA rich organelles may be stained w basic dye
EX: toluidine blue, methylene blue, methyl green

37
Q

Immunochemical staining techniques

A

uses monoclonal antibodies to study presecence of specific tissue constituents

38
Q

Epithelial tissue characteristics

A

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
Q

Function of basement membrane

A

selective filtration barrier

  • scaffold for embryogenesis and regeneration
  • stabilization of tissue shapes
40
Q

Psuedostartified epi

A

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
Q

Transitional Epi

A

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
Q

Simple Column. Epi details/locations

A
  • 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
Q

Stratified squamos details/locations

A

heavily kertanized:epidermis w CT papillae, cornea wo CT papillae
-lightly/non kert. esophagus, vagina, lining of mouth, tongue, part of epiglottis

44
Q

Stratified cubodial details/locations

A

seldom found, small areas of anal mucosa, large excretory ducts of some glands, part of male urethra

45
Q

Simple squamos details/locations

A

lines lumina of ducts, vessels, other tubular structures

-forms walls of alveoli, bowmans capsule and inner surface of membranous labyrinth and tympanic membrane

46
Q

Simple cubodial details/locations

A

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
Q

stratified columnar epi details/locations

A

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
Q

Pseudostratified details/locations

A

ciliated in trachea

w sterocilia in epididymis

49
Q

transitional details/locations

A

urinary system, often called urothelium

50
Q

2 kinds of epithelium

A
  1. Covering and lining

2. glandular

51
Q

Epithelial tissue function

A
  • protection: esp. sratified sq.

- conc differnces w tight or leaky barriers (ie leaky lining gall bladder y proximal conv renal tubule

52
Q

Secretion or absorption in epi tissue

A
  • 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
Q

Microvilli

A

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
Q

microvilli structure

A

actin filament core, look at slide at end of lec 3

55
Q

Structure of cilium

A

9 peripheral doublets + central pair of microtubules (ref to fig 1-29)

56
Q

Phospholiid bilayer

A

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
Q

contents of outer leaflet

A

cholesterol (2nd most common membrane lipid, hphobic), phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, glycolipids, glycosylphosphatidyllinositol (imp for cell siganling)

58
Q

inner leaflet

A

chosletorol, phosphatidylethanolamine, phosphatidyllinositol (- charged) and phosphatidylserine )- charged)

59
Q

transmemebrane proteins

A

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
Q

Glycolipids

A

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
Q

Lipid rafts

A

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
Q

Glycocalyx

A

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
Q

Cholesterol (membrane)

A

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
Q

Membrane proteins

A

associated thru protein-protein interactions typically involving ionic bonds that can easily dissacoiate
-found on both inner and outer leaf

65
Q

integral proteins

A

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
Q

lipid to protein ration on cell membrane

A

50/50 by weight but since proteins are larger usually 1 protein per 50-100 lipid molecules

67
Q

Transmembrane proteins

A

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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