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Histology Fall 2019 > Glossary > Flashcards

Flashcards in Glossary Deck (178):
1

absorption

tissue is penetrated by, or absorbs, a dye solution and becomes colored without any other chemical change or chemical reaction occurring. An example is the absorption of oil red O or Sudan black B by fat.

2

achromatic

without color or not easily stained. In microscopy, achromatic lenses are corrected for 2 colors, red and blue. This helps produce images free of chromatic aberrations.

3

acid mucosubstances

a term used to include both the acid mucopolysaccharides (connective tissue mucins) and the acidic glycoproteins (epithelial mucins). Most acid mucopolysaccharides contain sialic acid. Acid mucopolysaccharides and acidic glycoproteins do not stain the same with all mucin techniques.

4

acidophillic

a basic (cationic, positively charged) substance that is easily stainable with acid dyes. An example is cell cytoplasm, which is readily stainable with the acid (anionic, negatively charged) dye eosin.

5

additive

a chemical or substance that adds on to, or combines with, another substance, usually improving, strengthening, or altering it. Many fixative molecules add on to tissue proteins, altering and stabilizing them in the process.

6

adeno-

a prefix denoting a relationship to a gland

7

adenoma

a benign tumor of epithelial tissue with glandular origin or characteristics, or both

8

adenocarcinoma

a cancer of epithelial tissue that has a glandular origin

9

adsorbtion

the accumulation of stain by the surface of a tissue component. this phenomenon is influenced by the affinity of oppositely charged ions for each other (electrostatic attraction or bonding)

10

aldehyde

an organic compound containing carbon, oxygen, and hydrogen arranged C=O and C-H

11

aliphatic hydrocarbon

organic chemical compound composed of carbon and hydrogen, in which the carbon atoms are linked in an open chain rather than a ring arrangement. Aliphatic hydrocarbons can be used as clearing agents

12

amphoteric

describes a substance that is capable of acting as either a base or an acid, depending on the pH of the solution

13

anaplasia

dedifferentiation, loss of cellular differentiation, or reversion to a more primitive form

14

angstrom

a unit of length equal to 100 millionths (10^-8) of a centimeter, or 10^-10 meters. This unit has been replaced by nanometer nm as the official unit of measurement. One nanometer is equal to 10A or 10^-9 meters

15

anion

a negatively charged dye or tissue component. Anionic substances are also referred to as acidic, although it has nothing to do with pH.

16

anisotropism

having unlike properties in different directions, or unequal in refracting power

17

anthracotic pigment

an accumulation of carbon from inhaled industrial pollution, cigarette smoke, or coal dust. The pigment is seen most frequently in the lungs or in lymph nodes from that area

18

antibody

commonly known as immunoglobulins, antibodies are proteins that are produced by B lymphocytes in response to antigenic stimulation

19

antigen

any substance that can induce a detectable immune response

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antigen enhancement

epitopes can be exposed or "unmasked" by either heat or enzymes, thus enhancing the antigen-antibody reactivity

21

antigenic determinant

the area of an antigen that determines the specificity of the antigen-antibody reaction

22

apochromatic

corrected for both spherical and chromatic aberration. Apochromatic microscope objectives have been corrected for 3 colors and other lens aberrations

23

aqueous

a solution prepared in water

24

argentaffin

a reaction in which certain tissue components have the ability to bind or be impregnated with silver ions and then reduce the silver to its visible metallic form

25

argyrophilic

the ability to bind or be impregnated with silver ions: however, a reducing agent is required to reduce the silver to its visible metallic form

26

aromatic hydrocarbon

organic chemical compound composed of carbon and hydrogen, in which the carbons are linked in a ring arrangement. Aromatic hydrocarbons are used as clearing agents.

27

artifact

a structure or substance not normally present but produced by some external force or action. examples are mercury pigment, tissue floaters, knife lines, and air bubbles

28

autolysis

destruction or digestion of tissues and cells by the enzymes normally present in the cells

29

auxochrome

the chemical group present in a dye that causes it to bind to certain tissue elements. This group can develop a charge (+ or -) and thus bind to oppositely charged groups present in the tissue. The amino (NH2) and carboxyl (-COOH) groups are frequently occurring auxochromes

30

axon

the nerve process that conducts impulses away from the cell body of the neuron. Neurons have a single axon. Axons are included along with dendrites in the term "nerve fibers"; axons have also been referred to as the axis cylinder

31

bacilli (singular bacillus)

rod shaped bacteria

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bacteria (singular bacterium)

single cell microorganisms

33

barcode

an optical machine representation of data related to the object to which it is attached. Linear, or one dimensional, barcodes represent data by a series of parallel lines of varying width and spaces. 2-dimensional (2D) barcodes use dots, hexagons, and other geometric patterns to represent data

34

basophilic

an acidic (anionic, negatively charged) substance that is easily stainable with basic (cationic, positively charged) dyes

35

bevel angle

the angle made when the 2 cutting facets of a microtome knife intersect. On most American-made knives, the bevel angel is 28 to 32 degrees

36

binocular

having 2 oculars. a binocular microscope has two eyepieces or oculars

37

birefringence

splitting of a light wave into 2 waves that are refracted in different directions. this phenomenon is also referred to as anisotropsism or double refraction

38

buffer

a solution containing acid and alkaline components in the desired concentration so that the pH will be maintained when small amounts of acids or bases are added

39

carbohydrate

compounds containing, carbon, hydrogen, and oxygen only. Included are sugars, starches, and cellulose.

40

carcinoma

a malignant new growth arising from epithelial tissue

41

catalyze

to modify, speed up, or slow down a reaction without being consumed in the process. Enzymes catalyze biological reactions

42

cation

a positively charged dye or tissue component. Cationic substances are also referred to as basic

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chelation

forming a ring compound by joining a chelating agent to a metal ion. Chelating agents are organic compounds. An example is ethylenediaminetetraacetic acid EDTA, which decalcifies by binding calcium ions

44

chromatic aberrations

the distortion of color in an image produced by a microscopic lens

45

chromatin

the stainable material (a complex of nucleic acids and protein) in the nucleus.

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dispersed chromatin (euchromatin)

DNA that is active in RNA synthesis

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condensed chromatin (heterochromatin)

DNA that is not active in RNA synthesis. Hematoxylin stains only heterochromatin

48

chromagen

a benzene derivative containing a color-bearing group, or chromophore

49

chromophore

the chemical grouping that bestows the property of color on a compound

50

cirrhosis

diffuse fibrosis or sclerosis of any organ, especially the liver

51

clearance angle

the angle formed by the intersection of the block face and the adjacent cutting facet of the knife. This angle should be ~3-8 degrees

52

clearing

process of replacing the alcohol (dehydrating agent) with a reagent that is miscible with paraffin. Most clearing agents leave the tissue transparent, hence the name clearing agent

53

clone

a group of cells that are all derived from a single progenitor cell, all having the same characteristics as one another

54

coagulation

cloudiness, flocculation, and clot formation are stages of grades in the process of coagulation Several reagents coagulate protein sols during the process of fixation

55

flocculation

In colloid chemistry, flocculation refers to the process by which fine particulates are caused to clump together into a floc. The floc may then float to the top of the liquid (creaming), settle to the bottom of the liquid (sedimentation), or be readily filtered from the liquid.

56

cocci (singular coccus)

spherical or spheroid bacteria

57

decalcification

the process of removing calcium from bone or tissue, thus allowing routine microtomy on paraffin embedded material

58

decolorization

the removal of color, or excess color, from tissue. Only some tissue components are decolorized in a process known as regressive staining. Common decolorization methods involve the use of acidic or basic solutions, excess mordant (typically an inorganic oxide, that combines with a dye or stain and thereby fixes it), or oxidizers

59

dehydration

the removal of water from tissue. This is usually accomplished using alcohols

60

denaturation

to change the nature of. fixatives denature proteins by changing the soluble (liquid) contents of the cell into insoluble substances so that those substances are not lost during the subsequent processing steps. This change can be caused by either chemical (fixative solutions) or physical (heat, desiccation) means. Denaturation causes the protein molecule to unfold and the internal bonds to become disrupted

61

denatured alcohol

ethyl alcohol containing another reagent that has been added to make the alcohol undrinkable. Frequently methyl or isopropyl alcohol are used to denature ethyl alcohol

62

differentiation

excess stain is removed from a tissue section, so that only the desired element is left stained and may be visualized easily against the colorless or counterstained background

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endogenous

pigments or minerals that arise or are produced from within the body

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enzyme digestion

the use of enzymes to digest certain tissue components. examples are the use of diastase to remove glycogen, or hyaluronidase to remove some types of connective tissue mucin

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enzymes

proteins that catalyze chemical reactions in biological systems

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epithelium

a layer of cells that covers or lines all the free, open surfaces of the body including the skin and mucus membranes that communicate with the outside

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epitope

the simplest form of antigenic determinant present on a complete antigenic molecule

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esterases

hydrolytic enzymes that act on carboxylic acid esters of alcohols, phenols, and naphthols

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exogenous

pigments or minerals that originate from outside the body

70

Fire triangle

fuel, oxygen, and an ignition source form what is known as the fire triangle. all 3 of these elements are necessary for a fire

71

fixation

the stabilization of protein

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fixative

a chemical that alters tissue by stabilizing protein in such a way that the tissue is resistant to further changes

73

flash point

the lowest temperature at which a liquid produces enough vapors near the surface of the liquid or within the container used to form an ignitable mixture with air

74

fungi (singular fungus)

primitive plants that possess no roots, stems, leaves, or chlorophyll

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glia (neuroglia)

cells that provide the supporting network for the central nervous system. There are 4 types of glial cells: oligodendroglia, astroglia, microglia, and ependymal cells

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gliosis

a condition marked by excessive proliferation of glial cells and or processes

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glycogen

the chief storage polysaccharide in animals. It is especially abundant in muscle and liver tissue. Glycogen is readily hydrolyzed by a- and B-amylase to form glucose and maltose

78

Health information system

an electric system that captures a patients health information and documents their visits or encounters throughout a health system

79

hematein

the oxidation product of hematoxylin and the active staining ingredient in hematoxylin solutions. Hematein is the active dye formed by the action of either light and air or a chemical oxidizing agent on hematoxylin

80

hematin

granular, brownish black crystalline deposit occurring in tissue. Hematin typically denotes formalin pigment, formed by the action of acidic formaldehyde on blood rich tissue, but malarial pigment and acid hematin are also hematins

81

hematogenous

pigments derived from blood

82

hematoidin

a yellow-brown, crystalline, bile related pigment, probably a heme breakdown product. It is found primarily within old hemorrhagic foci and frequently within old splenic infarcts. It is demonstrated by the techniques for bile.

83

hemochromatosis

disease characterized by excessive deposition of hemosiderin in tissues, often interfering with the function of the organs of deposition

84

hemofuscin

a brown pigment derived from hemoglobin

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hemosiderin

a loose complex of ferric iron Fe3+ and protein; hemosiderin is the storage form of iron. It is a yellowish brown pigment and is stored primarily in the bone marrow

86

histology

the study of the microscopic anatomy of cells and tissue

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hydrolases

enzymes that act on various substrates by either adding or removing water

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hydroxyapatite

a major and essential ingredient of normal bones and teeth. hydroxyapatite makes up bone mineral and the matrix of teeth, and gives bone and teeth their rigidity

89

hyphae (singular hypha)

vegetative, tubular fungal structures that may or may not possess cross walls (septa). Many hyphae together compose a matlike fungal colony known as the mycelium

90

hypo

a term used to refer to sodium thiosulfate

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hypotonic

a solution that will cause cells to swell. sodium chloride solutions of less than 0.9% concentration are hypotonic to animal tissue cells

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immunogen

an antigen or a substance that can induce an immune response

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impregnation

the deposition of silver or gold on or around, but not in, the tissue component to be demonstrated

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incubation

to maintain sections at optimal environmental conditions for the desired reaction to occur

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infiltration

permeation, as in paraffin permeating tissue. Infiltration is also known as impregnation

96

informatics

the practice of information processing

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ion exchange resin

a substance that exchanges one ion for another. ion exchange resins are used in decalcification and exchange ammonium ions for the calcium ions removed from the tissue. The formic acid used for decalcification is rapidly cleared of calcium ions, and thus daily solution changes are avoided

98

isotonic

fluids that will cause animal cells to neither swell nor shrink. a 0.9% solution of sodium chloride (saline) or a 5% glucose solution is approximately isotonic

99

laboratory information system

database used by the laboratory that securely maintains patient information and documents clinician and healthcare provider activities, orders, and results

100

lake

the combination of a mordant (eg, aluminum) with a dye (eg, hematein). The dye-lake can bind to tissue components and form an insoluble colored deposit

101

lipid

any of the numerous fats and fatlike materials that are generally insoluble in water but soluble in common organic solvents

102

lipofuscin

commonly referred to as "wear and tear" pigments, these yellow-brown pigments are probably breakdown products resulting from the oxidation of lipids and lipoproteins

103

lymphoma

a malignant tumor that arises in lymph nodes, spleen, bone marrow, blood, or other organs when B or T lymphocytes divide faster and live longer than normal

104

magnification

the enlargement of an optical image. the magnification of a microscopic image is calculated by multiplying the magnification of the ocular and the objective used

105

empty magnification

an enlargement or magnification of a microscopic image without any further useful information being obtained

106

medical record number

unique patient identifier used in association with encounter numbers. This number identifies the patient at each step o their care and associates all record keeping activities; that is, diagnostic reporting, healthcare records, and billing that is maintained in a health system permanent repository for each patient

107

meniscus

the curved upper surface of a non turbulent liquid in a container. The surface is typically concave as the surface of the container is wet by the liquid

108

mesothelioma

a form of cancer arising from the cells of the mesothelium, a protective layer of cells covering or lining many internal organs. Mesotheliomas most often are caused by exposure to asbestos

109

metachromasia

a change of color. certain tissue elements stain metachromatically with certain dyes in that they give a color that differs from that of the stain used. Mast cell granules stain metachromatically toluidine blue in that they give a rose to violet color against the normal blue (orthochromatic) staining of the background

110

metallic impregnation

the deposit of silver or gold on or around, but not in, the tissue component to be demonstrated. The metal is then reduced to its visible metallic form either by the tissue or by a reducing agent

111

microincineration

heating microscope sections at a very high temperature (~650C). All organic material is burned off and the inorganic residue can be studied

112

micrometer (uM, formerly micron)

1 millionth 10^-6 of a meter

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micrometry

the measurement of minute distances with the microscope

114

microtomy

the cutting of thin sections of tissue for microscopic examination

115

middleware

data processing software from a vendor or third party that's function is to connect a laboratory instrument with a laboratory information system. The software links or "sits between" the operating systems of teh instruments and the LIS

116

milliliter (mL)

a unit of volume measurement. 1 milliliter is equal to 10^-3 liters. milliliter is used interchangeably with cubic centimeter (cc).

117

mineral

any naturally occurring, homogeneous inorganic substance having a definite chemical composition and characteristic crystalline structure. minerals can be studied by microincineration in addition to the frequent demonstration by chemical stains

118

miscible

capable of mixing or being mixed

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monoclonal

derived from a single clone of cells, such as an antibody

120

mordant

a reagent used to link the stain, or dye molecules, to the tissue. Many mordants in histology are metals, especially those linking hematein to tissue (ie aluminum, tungsten, iron, and chromium)

121

mycelium

a fungal colony composed of a mat of intertwined hyphae

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myo-

a prefix denoting muscle

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myobacteria (singular mycobacterium)

a genus of slender, rod shaped bacteria. included are the causative organisms of tuberculosis and leprosy

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myelin

a white fatty material encasing and providing a protective sheath for some nerve fibers

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nanometer (nM)

1 billionth 10^-9 of a meter

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neoplasm

an abnormal new growth of tissue

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neuron

a nerve cell

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neuroma

a benign tumor or swelling of the nervous tissue, including nerve fibers and their myelin sheath

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nissl substance

clumps of rough, or granular, endoplasmic reticulum. Because of the RNA content, Nissl substance stains sharply with basic aniline dyes such as thionin and cresyl echt violet

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noncoagulation

absence of clot formation

131

objective

the lens at the lower end of the barrel, or body tube, of the microscope. several objectives, yielding different magnifications, are found on most microscopes

132

ocular

the eyepiece of the microscope, or the lens found at the upper end of the barrel or body tube

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-ology

a suffix denoting an area of knowledge or a branch of science

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-oma

a suffix denoting a swelling of tumor

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orthochromatic

dyes that stain tissue components as expected or the same color as the dye solution

136

osmolality

the concentration of osmotic solutions expressed in terms of particles in solution. 1 osmol is the number of particles in a gram molecular weight of undissociated solute. If the solute dissociates into 2 ions, 1 g molecular weight of the solute equals 2 osmols

137

oxidation

occurs by combining with oxygen, by the loss of hydrogen, or by the loss of electrons. Hematoxylin is oxidized to hematein by the loss of hydrogen

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oxidizing agent

a substance that causes oxidation. hematoxylin is oxidized to hematein by either chemical means or by light and air. for some staining techniques, certain tissue components are oxidized to a more reactive state , such as the oxidation of some carbohydrates to aldehydes by either periodic acid or chromic acid prior to the schiff reaction

139

parfocal

in the same plane of focus. microscope objectives are said to be parfocal when they can be changed without the need to refocus

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pathology

a medical specialty concerned with the diagnosis of disease

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permissible exposure limit PEL

the maximum allowable 8 hour time weithed average of exposure to a substance as defined by OSHA. the PEL is expressed in parts per million ppm

142

phosphatase

a hydrolytic enzyme that breaks the bond between an alcohol and a phosphate group. Phosphatases are present in a wide variety of plant and animal tissue. some phosphatases such as adenosine triphosphatase (ATPase) act specifically on a single substrate; others act with less substrate specificity and are divided into 2 groups: alkaline phosphatases (optimal in alkaline pH) and acid phosphatases (optimal at low pH)

143

phosphorylase

a transferase that transfers phosphate groups. Phosphorylases are widely distributed in animal and plant tissues, and they catalyze a number of reversible reactions, leading to the synthesis and decomposition of saccharides. Glycogen phosphorylase is the best known phosphorylase.

144

pigments

a heterogeneous group of substances that contain enough natural color to be visible without any further staining. examples are melanin, a brownish black pigment normally found in skin, hair, and eyes; and hematin (formalin pigment), a brownish black pigment found in blood rich tissues fixed in acidic formalin solution

145

polarization

the examination of slides by using a polarizer and an analyzer to obtain light vibrating only in one plane. Anisotropic or birefringent material will be bright against a dark background if the optical paths of the polarizer and analyzer are crossed

146

polychromatic

describes a single dye solution that stains tissue components different colors by a phenomenon other than metachromasia. One example is a solution prepared from a dye that is not pure but contains several dyes. The variety of color in the tissue is due to the selective adsorption of the different dye components by various tissue elements

147

polymer

a covalently bonded chain of individual building blocks called monomers

148

polymer detection system

a polymer with an enzyme label chemically attached in the place of biotin, typically used in 2 step detection system

149

polymerization

a chemical reaction in which 2 or more small molecules join together to form a larger molecule containing repeating structural units of the original molecules. Formaldehyde tends to polymerize into paraformaldehyde; methanol is added to stock formaldehyde solutions to retard polymerization

150

polysaccharide

a group of 9 or more monosaccharides joined by glycosidic bonds. Starch and cellulose are examples.

151

precipitate

to separate from solution, usually caused by chemical action. in the Prussian blue reaction, iron is dissolved by hydrochloric acid and then immediately precipitated by potassium ferrocyanide. The ferric ferrocyanide precipitate is known as Prussian blue

152

preservative

a fluid that will neither shrink nor swell tissue, will neither dissolve not distort its constituent parts , will kill bacteria and molds, and will render enzymes inactive. Unlike a fixative, a preservative will not alter or modify tissue constituents in such a way that they retain their form during the subsequent processing steps

153

progressive staining

staining to the desired intensity and stopping the stain. No differentiation step is used

154

protozoans (singular protozoan)

single celled animals that are simple structurally but complex functionally

155

pseudo-

a prefix denoting something false or pretending to be something it is not

156

pseudomelanin

a brownish yellow pigment sometimes seen in the lamina propria of the colon, appendix, and rarely the small intestine. The pigment gives positive Fontana-Masson and Schmorl reactions

157

reduction

accomplished through the loss of oxygen, or by the gain of hydrogen or electrons

158

refractive index

the ratio of the speed of light in a vacuum to the speed of light in the medium under consideration

159

regressive staining

the tissue is over stained and then decolorized, or differentiated, until the desired component contrasts sharply with the background. The Verhoeff elastic stain is an example of regressive staining

160

resolution

the optical ability to distinguish two objects a minimal distance apart as two objects. The light microscope has a resolving power of 0.2um. Two objects closer together than 0.2um will be seen as one object

161

rhabdo-

a prefix meaning rod shaped or pertaining to a rod

162

ripening

oxidation, as in the ripening of hematoxylin to hematein

163

sarcoma

a malignant growth arising from transformed cells of mesochymal origin (eg, bone, cartilage, connective tissue proper)

164

short term exposure limit STEL

the maximum allowable time weighted exposure for any 15 minute period during an 8 hour work period

165

solute

the substance or chemical being dissolved

166

solvent

the liquid in which a substance is being dissolved

167

spirochetes

spiral or corkscrew shaped argyrophilic bacteria

168

substrate

the substance on which an enzyme acts

169

supernatant

the liquid or fluid on top

170

time weighted average

the amount of substance a worker is exposed to averaged over an 8 hour period

171

tophus

a deposit of urate crystals in tissue

172

universal precautions

safeguards or barriers used to minimize or prevent contact with blood or other potentially infectious material

173

universal solvent

chemical reagent that can be used for both the dehydrating and clearing steps in tissue processing. Dioxane, tertiary butanol, and tetrahydrofuran are universal solvents

174

urothelium

transitional epithelium lining much of the urinary tract (renal pelvis, bladder, ureter

175

validation

confirmation through a defined process that a test performs as intended or claimed. New procedures for tissue processing or staining must be validated; this involves procedures on new instrumentation, relocated instruments, or changes in methodology

176

verification

ensuring that a new product (eg, instrument or reagent) is capable of achieving the performance required and that it performs in agreement with the manufacturer's claims. Instruments must be reverified if relocated

177

yeasts

true fungi, usually single celled, oval shaped fungi that reproduce by budding at the smaller end of the cell

178

validation.

establishing documented evidence that a process or system, when operated within established parameters, can perform effectively and reproducibly to meet the expected outcome