Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Intro Classes > Histology > Flashcards

Histology Flashcards

1
Q

epithelia

A

singular: epithelium; a diverse group of tissues that include both surface epithelia and solid organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

surface epithelia

A

cover or line all body surfaces, cavities and tubes and form the interface between different biological compartments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

keratin intermediate filaments

A

characteristic of epithelial cells, and can be used to recognise epithelial cells using immunohistochemistry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

polarized (cells)

A

one side faces the basement membrane and underlying supporting tissues (the basal surface) and the other faces outwards (the apical surface).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

three morphological classifications of surface epithelia

A

number of cell layers

type of cell (profile perpendicular to basement membrane)

special features (e.g. cilia, goblet cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

glands

A

invaginations of epithelial surfaces which are formed during embryonic development by the proliferation of epithelium into the underlying tissues

often found in epithelia involved in secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

exocrine glands

A

solid organs (epithelia) that are connected to the surface epithelium of by a branching system of ducts

e.g. major salivary glands, liver, pancreas (acinar tissue)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

endocrine glands

A

solid organs (epithelia) that have lost their connection to the epithelial surface from which they developed and release their secretions directly into the blood

E.g. thyroid, anterior pituitary, adrenal, pancreas (islets of Langerhans)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

simple epithelia definition and locations

A

surface epithelia consisting of a single layer of cells

almost always found at interfaces involved in selective diffusion, absorption, and/or secretion

provide little protection against mechanical abrasion and thus are not found on surfaces subject to such stresses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

examples of flattened simple epithelia locations

A

ideally suited to diffusion and are therefore found in:

the air sacs of the lung (alveoli)
the lining of blood vessels (endothelium)
the lining body cavities (mesothelium)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

metric resolution limit for the unaided human eye

A

0.2 mm (200 µm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

metric resolution limit for the light microscope

A

200 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

metric resolution limit for the electron microscope

A

0.2 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

RBC size

A

7-8 µm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Escherichia coli size

A

~2.5 µm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Powers of 10

A 
mm = visible with eye (macro -> collections of cells)
µm = visible with light microscope (cells -> organelles)
nm = visible with electron microscope (proteins -> molecules)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

structural hierarchy btw molecules and human organ systems

A

chemical -> cellular -> tissue -> organ -> system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

fixation (light microscopy)

A

the first step of tissue sample preparation for examination under a light microscope

small pieces of fresh tissue are placed in fixative solutions which generally cross-link proteins, inactivate degradative enzymes, and preserve cell structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

dehydration (light microscopy)

A

the second step of tissue sample preparation for examination under a light microscope

the fixed pieces undergo “dehydration” by being transferred through a series of increasingly more concentrated alcohol solutions, ending in 100% which effectively removes all water from the tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

clearing (light microscopy)

A

the third step of tissue sample preparation for examination under a light microscope

removes the alcohol from the dehydration stem within a clearing solution that is miscible in both alcohol and melted paraffin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

infiltration (light microscopy)

A

the fourth step of tissue sample preparation for examination under a light microscope

after clearing, the tissue is then placed in melted paraffin at 58°C, becoming completely infiltrated with this substance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

embedding (light microscopy)

A

the fifth step of tissue sample preparation for examination under a light microscope

after infiltration, the tissue is placed in a small mold containing melted paraffin, which is then allowed to harden. The resulting paraffin block is trimmed to expose the tissue for sectioning (slicing)

(electron microscopy uses epoxy resins, which become much harder than paraffin to allow very thin sectioning)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

microtome

A

used for sectioning paraffin-embedded tissues for light microscopy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

sectioning (light microscopy

A

the sixth step of tissue sample preparation for examination under a light microscope

the embedded tissue specimen is mounted on a trimmed block with a rotating drive wheel that moves the tissue-block holder up and down

the specimen holder is advanced at a controlled distance, generally between 1 and
10 μm

after each forward move, the tissue block passes over the steel knife edge, which cuts the sections at a thickness equal to the distance the block advanced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

staining step (light microscopy)

A

the final step of ttissue sample preparation for examination under a light microscope

after sectioning, paraffin sections are then adhered to glass slides, deparaffinized, and stained

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

most common staining methods used for

light microscopy in histology and pathology

A

Hematoxylin & Eosin (H&E) and Periodic acid-Schiff (PAS) staining

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Hematoxylin & Eosin (H&E)

A

commonly used staining method for medical diagnosis (pathology)

basophilic cell nuclei are stained purple while cytoplasm stains pink

cell regions with abundant oligosaccharides on glycoproteins, such as the apical ends of the cells (glycocalyx) or the scattered mucus-secreting goblet cells, are poorly stained

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Eosin

A

acidic

stains cytoplasm pink/orange (eosinophilic)

stains basic structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Hematoxylin

A

basic

stains acid nucleic acids (DNA, RNA) purple

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Periodic acid-Schiff (PAS)

A

commonly used staining method

most intense at the cell surface, where projecting microvilli have a prominent layer of glycoproteins and in the mucin-rich secretory granules of goblet cells

cell surface glycoproteins and mucin are PAS-positive due to their high content of oligosaccharides and polysaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

fixation (TEM)

A

the first step of tissue preparation for TEM

the tissue must be hardened and crosslinked, and osmium tetroxide (OsO4) is useful for crosslinking membranes and glutaraldehyde crosslinks proteins into a resistant 3D matrix

(needs careful pH buffering, because it generates acid as it works. Sodium cacodylate is the most widely used buffer).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

osmium tetroxide (OsO4)

A

useful for crosslinking membranes and glutaraldehyde crosslinks proteins into a resistant 3D matrix for TEM fixation

requires careful pH buffering bc it generates acid as it works

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

sodium cacodylate

A

most commonly used buffer for TEM fixation if OsO4 is being used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

dehydration (TEM)

A

the third step of tissue preparation for TEM

since the specimen will be viewed in a vacuum, all water must be removed (water scatters electrons)

usually accomplished with a dehydrating ethanol series from 70% to 100%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

embedding (TEM)

A

the fourth step of tissue preparation for TEM (skips clearing and infiltration steps of light microscopy tissue preparation)

soaks the dehydrated specimen in propylene oxide-containing epoxy or acrylic resin monomers

the resin is crosslinked (cured) using heat, UV light, or chemical hardeners, depending on specific chemistry, and the specimen is now embedded in a solid block of plastic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

sectioning (TEM)

A

the fifth step of tissue preparation for TEM

the embedded specimen is sectioned using a microtome, which is a glass or diamond knife that can cut extremely thin sections (100
nm)

such thin sections allow electrons to pass easily with moderate scattering, allowing image formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

staining (TEM)

A

the second step of tissue preparation for TEM

organelles of interest must be electron dense to contrast with the background, and since electron density increases with atomic number, non-biological heavy atoms work best

Sections are therefore often stained with osmium tetroxide, uranyl acetate, and/or lead citrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

osmium tetroxide

A

common staining solution for TEM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

uranyl acetate

A

common staining solution for TEM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

lead citrate

A

common staining solution for TEM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

four types of tissues in the human body

A

connective (blood, bone)

epithelium (lining all body cavities, glands)

nerve (CNS, PNS)

muscle (skeletal, cardiac, smooth)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

basal lamina

A

lies at the interface of epithelial cells and connective tissue

the basal laminae to two neighboring epithelia can fuse or appear to fuse in places where there is no intervening connective tissue

nutrients for epithelial cells must diffuse across the basal lamina as small blood capillaries (being epithelial themselves) never enter an epithelium across a basal lamina, but nerve fibers normally penetrate this structure,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

simple epithelium

A

a classification based on the number of layers from the basement membrane to the surface (all cells are in contact with the basement membrane)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

stratified epithelium

A

a classification based on the number of layers from the basement membrane to the surface (two or more layers of cells)

45
Q

columnar epithelium

A

a classification based on the shape of the individual cell (tall like a column) or, if stratified, the shape of the uppermost cell

46
Q

cuboidal epithelium

A

a classification based on the shape of the individual cell (square like a cube) or, if stratified, the shape of the uppermost cell

47
Q

squamous epithelium

A

a classification based on the shape of the individual cell (flat; Lat: squama = scales) or, if stratified, the shape of the uppermost cell

48
Q

five main locations of simple squamous epithelium

A

the lining of heart, blood, and lymphatic vessel walls (endothelium)

blood-tissue and lymph-tissue barriers

serous membranes of plural and abdominal cavities (mesothelium)

parietal layer of Bowman’s capsule in kidneys plus thin loops of Henle

pulmonary alveoli

49
Q

basement membrane

A

the structure seen when components of a basal lamina are resolved with the light
microscope

50
Q

skeletal muscle

A

composed of large, elongated, multinucleated fibers that show strong, quick, voluntary contractions

51
Q

cardiac muscle

A

composed of irregular branched cells bound together longitudinally by
intercalated disks and shows strong, involuntary contractions

52
Q

smooth muscle

A

composed of grouped, fusiform cells with weak, involuntary contractions. The density of intercellular packing seen reflects the small amount of extracellular connective tissue present

53
Q

rouleaux

A

aggregates of RBC stacks which occur in small vessels

54
Q

what germ embryonic layers form epithelial cells

A

all three germ embryonic layers form epithelial cells (endoderm, mesoderm, and ectoderm)

55
Q

three main functions of epithelial cells

A

forming membranes (sheets of epithelial cells) covering body surfaces (e.g. skin)

lining internal cavities (e.g. digestive, respiratory, cardiovascular, genitourinary)

invaginates from surfaces to form secretory glands

56
Q

epithelial cell structure

A

epithelial cells are separated from underlying tissue by a basement membrane, and epithelial cells in basement membranes are firmly attached to underlying connective tissue

epithelial cells are avascular as nutrients and oxygen come from the underlying connective tissue (except for digestive tract epithelia, which can receive nutrients by apical absorption)

57
Q

mesothelium

A

epithelial membranes lining serous body cavities

58
Q

endothelium

A

epithelial membranes lining blood and lymph vessels and heart chambers

59
Q

the three main epithelial membrane specializations

A

cell-cell junctions: form both mechanical and barrier (diffusive) functions

projections: motile = cilia
projections: non-motile = microvilli, stereocilla

60
Q

what helps epithelial cells cope with stress and trauma of their cells

A

a high mitotic index, which means they are regenerative and proliferative

61
Q

where are epithelia’s stem cell population or “compartment” located

A

at the basal layer, next to the basement membrane

62
Q

what two factors make epithelial cells susceptible to transformation (cancer)

A

1) high division rate

2) relatively high exposure to carcinogens and pathogens, particularly viruses

63
Q

papillomas

A

slow-growing tumors (benign) that arise from surface epithelia

64
Q

adenomas

A

slow-growing tumors (benign) that arise from glandular epithelia

65
Q

carcinomas

A

malignant neoplasms arising from surface epithelia

66
Q

adenocarcinomas

A

malignant neoplasms arising from glandular epithelia

67
Q

apical domain

A

the surface of the epithelium that faces the lumen or external environment

68
Q

lateral domain

A

the geographic domain of epithelial cells which face neighboring epithelial cells linked to each other by cell adhesion molecules and junctional complexes

69
Q

basolateral domain

A

the plasma membrane of an epithelial cell which is connected by sealing tight junctions and is distinct from the apical domain

70
Q

stratified squamous endothelia - keratinized function

A

strong, sheer-resistant layer, which protects against abrasion and dehydration and prevents invasion by bacteria and viruses (this is b/c the apical keratinized cells are dead, ergo stronger but without organelles or nuclei)

found on surfaces open to air (e.g. skin, hard palate)

71
Q

stratified squamous endothelia - non-keratinized

A

a strong, sheer-resistant layer, which protects against abrasion and dehydration and prevents invasion by bacteria and viruses

found on moist surfaces (e.g. esophagus, vagina, male and female urethra, cornea)

72
Q

simple cuboidal epithelia structure and function

A

comprised of a spherical, centrally placed nucleus and has a protective function

important in the formation of gland ducts (e.g., kidney collecting ducts) or as exocrine glands as an acinus (cluster) (e.g. salivary glands, pancreas)

73
Q

acinus

A

a cluster of simple cuboidal epithelia that can function as exocrine glands

E.g., salivary gland, pancreas

74
Q

simple non-ciliated columnar epithelia structure

A

basal surface contacts the basement membrane, the apical surface contacts a lumen (and often contain microvilli), lateral surfaces contain anarray of junctional complexes

has an ovoid nucleus that is centrally or basally positioned

75
Q

simple non-ciliated columnar epithelia function

A

protection of wet surfaces

nutrient absorption

secretion (e.g., convoluted tubules of kidney, intestines, gallbladder, oviducts, uterus)

76
Q

simple pesudo-stratified columnar epithelia structure and function

A

all cells attach to the basement membrane (thus ‘pseudo’, should be called simple epithelium), but only a subset of cells reach the lumenal surface

lines the upper respiratory tract (respiratory epithelium) (e.g., nasopharynx, larynx, trachea, bronchi); a mucociliary escalator, if you will

77
Q

simple ciliated columnar epithelia structure and function

A

some simple columnar have cilia on most cells (scattered among non-ciliated cells in the same sheet) and can have several hundred cilia

cilia function to propel fluids & particles along surface, so mainly located in the female reproductive tract (oviduct)

78
Q

stratified cuboidal epithelia structure and function

A

mainly protective, as it is more robust than single layer

usually has two layers (e.g. sweat gland ducts, exocrine gland ducts)

can contain goblet cells for mucus secretion and lubrication

79
Q

stratified transitional epithelia function

A

restricted to lower parts of the urinary tract; thus often referred to as a urothelium

adapts to lateral stretching forces, and impermeable – protects underlying tissues from urine

80
Q

simple glandular epithelia locations

A

colon

stomach

eccrine sweat glands

81
Q

compound glandular epithelia locations

A

sebaceous glands

Brunner’s glands of duodenum

small salivary glands

breast

prostate

82
Q

tight junctions

A

membrane specialization of epithelia, which seals neighboring cells together in an epithelial sheet to prevent leakage of molecules between them

83
Q

adherens junctions

A

membrane specialization of epithelia, which joins an actin bundle in one cell to a similar bundle in a neighboring cell

84
Q

desmosomes

A

membrane specialization of epithelia, which joins the intermediate filaments in one cell to those in a neighboring cell

85
Q

gap junctions structure and function

A

membrane specialization of epithelia, which forms channels that allow small water-soluble molecules, including ions, to pass from cell to cell

made up of clusters of closely packed connexons, as the connexon hemichannel in one cell membrane docks with a connexon hemichannel in an adjacent cell to form the channel

86
Q

hemidesmosomes structure and function

A

membrane specialization of epithelia, which anchors the basal domain of a cell to the underlying basal lamina using intermediate filaments

cytoplasmic plate associates with keratin (tonofilaments)

outer membrane plaque contains integrins that bind tightly to laminin filaments in
basement membrane

87
Q

zonula adherens structure and function

A

AKA adherens junctions/belt desmosomes

lies just deep to tight junctions (relative to the apical surface), and forms a continuous “belt” of cadherin around cells; cadherin binds to β-catenins in the cytoplasm

joins actin filaments (microfilaments) rather than intermediate filaments from one cell to another

88
Q

gap junction structure

A

made up of clusters of closely packed connexons and the connexon hemichannel in one cell membrane docks with a connexon hemichannel in an adjacent cell

89
Q

zonula occludens functions

A

AKA tight junctions

functions to strongly adhere adjacent cells together in epithelial sheets, and forms a primary barrier to the diffusion of solutes through the intercellular space by creating a boundary between the apical and the basolateral plasma membrane domains

in endothelial cells, tight junctions form the basis for the blood-brain, the blood-ocular, and the blood-testes barriers

90
Q

cadherin

A

associated with zonula adherens/adherens junctions and desmosomes, and it comprises the belt which forms outside the plasma membrane

binds to β-catenins in the cytoplasm

91
Q

macula adherens structure and functions

A

AKA desmosomes

performs cell-cell adhesion via cadherins to join intermediate filaments

connects to cytoskeletal tonofilaments (intermediate filaments - keratin) and to proteins that interact with the cytoplasmic domain of cadherin

also in cardiac muscle (intermediate filament – desmin)

92
Q

intermediate filament joined by desmosomes in cardiac muscle

A

desmin

93
Q

connexons

A

consist of pairs of transmembrane channels that make up GAP JUNCTIONS

hexameric, i.e. they consist of arrays of 6 connexin protein subunits

94
Q

cilia definition and location

A

membrane specialization of epithelia; mobile extensions of the cell surface about 10-12 mm long, which are outgrowths from basal bodies at the apical surface in the cell (similar to centrioles)

found in the respiratory system, and male and female reproductive tracts

95
Q

cilia structure

A

9+2 microtubule core, dynein-driven movement (similar to the structure of flagella)

96
Q

microvilli structure and function

A

membrane specialization of epithelia; projections from the apical surface which function to increase the surface area of a cell for absorption

relatively rigid and ~ 1 μm long

a core of cross-linked actin filaments extends to a supporting ‘terminal web’ located
below the plasma membrane

97
Q

stereocilia structure and function

A

membrane specialization of epithelia; very long specialized microvilli that are not actually cilia

rigid with an actin bundle core

found in the epididymis (involved in spermiogenesis - maturation) and the inner ear (involved in sound transmission)

98
Q

structure subclasses of exocrine gland duct systems

A

simple (single duct)

compound (duct divided)

99
Q

structure subclasses of the secretory units of simple ducts of exocrine gland

A

tubular (straight, coiled, or branched)

alveolar (straight, coiled, or branched)

100
Q

structure subclasses of the secretory units of compound ducts of exocrine gland

A

tubular (straight or branched)

alveolar

tubuloalveolar

101
Q

secretory product subclasses of exocrine glands

A

serous (low viscosity)

mucous (high viscosity) glycoproteins

serous & mucous

102
Q

parotid gland morphology

A

compound tubuloalveolar, serous

103
Q

submandibular gland morphology

A

compound tubuloalveolar, serous & mucous

104
Q

sublingual gland morphology

A

compound tubuloalveolar, serous & mucous

105
Q

functional classifications of exocrine glands

A

merocrine

holocrin

apocrine

106
Q

merocrine glands

A

a functional classification of exocrine glands; secrete products, usually containing proteins, by means of exocytosis at the apical end of the secretory cells

most exocrine glands are merocrine

[μέρος - part, portion; κρῑ́νω - to separate]

107
Q

holocrine gland

A

a functional classification of exocrine glands; secretion is produced by the disintegration of the secretory cells themselves as they complete differentiation which involves becoming filled with product

E.g. sebaceous glands of hair follicles

[ὅλος - whole, entire; κρῑ́νω - to separate]

108
Q

apocrine gland

A

a functional classification of exocrine glands; secretion involves the loss of a large membrane-enclosed portion of the apical cytoplasm, usually containing one or more lipid droplets

this apical portion of the cell may subsequently break down to release its contents during passage into the duct

along with merocrine secretion, it is seen in mammary glands

[ἀπό - away from; κρῑ́νω - to separate]

109
Q

occludin, claudin-1, JAM

A

Intro Classes (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions