Histology- Assessment 1 Flashcards
1
Q
what do aldehyde fixatives do?
A
cross link- create covalent bonds between proteins
2
Q
what do alcohol fixatives do?
A
precipitate proteins which leads to precipitation and aggregation of proteins
3
Q
what is NBF?
A
neutral buffer formalin
an aldehyde that irreversibly cross links proteins at amino groups
4
Q
what is lost if NBF is used?
A
ions, mRNA, miRNA, and DNA
5
Q
what are mercurials good for and why?
A
immunological specimens because of a slower rate of penetration, get good nuclear preservation in lymphocytes
6
Q
what is an oxidizing agent? what does it bind to?
A
secondary fixative used in EM, binds to phospholipids to preserve the membrane
7
Q
what is an example of an oxidizing agent?
A
osmium
8
Q
what is osmium stain used for?
A
nerves
9
Q
what is picrate fixative?
A
precipitating
10
Q
what affects fixation?
A
pH osmolarity specimen size fixative volume temperature duration time from removal to fixation
11
Q
what are some examples of artifact?
A
specimen shrinkage or swelling
poor penetration
12
Q
what happens to large macromolecules in fixed samples? what are some examples?
A
aggregate
nucleoproteins, intracellular cytoskeletal proteins, extracellular proteins, membrane phopholipid-protein complexes
13
Q
what tissue components are lost during fixation?
A
ions, glycogen, small proteins, nucleic acids
14
Q
how is water removed from a specimen?
A
series of dehydrations
water removed with ethanol
ethanol removed with xylene
then paraffin added
15
Q
what happens after paraffin is put into a specimen?
A
thin sections are cut into a ribbon using a microtome
ribbon floated onto a slide
slide baked
16
Q
after the specimen is on the slide, what next?
A
paraffin removed by reversing the dehydration process
stained with water soluble dye, dehydrated, stain with ethanol soluble dye
17
Q
what do acidic dyes bind to?
A
positive things because they are negative
18
Q
what is eosin?
A
an acidic dye that binds to cytoplasmic filaments, intracellular membrane components, and extracellular fibers (positive things)
pink
19
Q
what do basic dyes bind to?
A
negative things because they are positive
20
Q
what is hematoxylin?
A
a basic dye that binds phosphate groups on nucleic acids, sulfate groups on GAGs, and carboxyl groups of proteins (negative things) *requires an additive pH dependent high pH- binds all groups 5-7- sulfate and phosphate groups <5- sulfate only purple
21
Q
what does hematoxylin stain?
A
heterochromatin, nucleoli, cytoplasm with lots of mRNA, ECM cartilage
22
Q
what is enzyme digestion used for?
A
as a positive control- destroy what you are staining to make sure you are staining the right thing
23
Q
what is enzyme histochemistry?
A
stains the reaction product with a heavy metal
24
Q
what is immunohistochemistry?
A
using fluorescent stains to visualize things
direct and indirect methods exist
25
what is hybridization?
when ssRNA or ssDNA interact with complimentary sequences
| detected with radioactive probes of fluorescent dyes on the sequence that will bind to the target sequence
26
what is FISH?
fluorescent in situ hybridization
| used to screen for trisomy 21
27
what is a benefit of using frozen tissue preparation?
preserves lipid droplets
28
what does a teased preparation look like? what is it used for?
little strings that are pulled apart
| nerves
29
what does a smear look like? what is it used for?
used for blood, smear sample across to get single layer of cells
30
what is a spread?
use the whole sample, spread out on a slide
31
what is a tissue microarray?
up to 1000 samples run at the same time to compare them quickly
32
what is confocal scanning microscopy?
take many image slices through a sample to reassemble to get a 3D image
33
what is 2 photon microscopy? what are benefits of using it?
multiple, low energy photons shot at a sample and a photon is emitted
gives clearer points than fluorescence microscopy
prevents tissue damage
34
what is second harmonic generation microscopy? what is it used for?
photons combine to form higher energy photon when shot at a non linear material
used to determine tumor rigidity
35
what is TEM?
transmission electron microscopy
sample stained with osmium after being sectioned in plastic
electrons shot at sample and deflection is measured
gives 2D image
36
what is SEM?
scanning electron microscopy
stain sample after critically drying it
electron beam rasters over the sample and generates a 3D image of the surface topography
37
what is freeze fracture?
freeze samples and fracture along lipid bilayers to see inside the membrane
38
what is the e face in freeze fracture technique?
ectoplasmic face- inner membrane
39
what is the p face in freeze fracture technique?
protoplasmic face- cytoplasm membrane, very bumpy because you can see all the stuff in the cell
40
what is serial block face SEM?
remove small layers and image each time to reconstruct a 3D image
41
what is atomic force microscopy used for?
stiffness determination
42
what are microfilaments used for?
actin- cell movement
43
what are intermediate filaments used for?
structure maintence
44
what are microtubules used for?
moving organelles
45
which end of actin (microfilaments) grows slowly? fast?
```
pointed end (-) slow growing
barbed end (+)- fast growing
```
46
what does phallodin stain?
actin
47
what is non muscle myosin?
same structure as muscle myosin, but used for cell movement
| appears as a zigzag pattern inside the cell
48
how is non muscle myosin regulated?
phosphorylation of regulatory light chain- induces polymerization
phophorylation of myosin heavy chain- inhibits chain interaction
49
what is the structure of microtubules?
13 alternating chains of alpha and beta subunits in a ring
| gamma subunit is used as regulatory
50
what energy molecule is associated with microtubles?
GTP
51
in what direction do microtubules grow?
positive end
| anchored at negative end
52
in what structure are microtubules found as a ring of pairs?
cilia
53
in what structure are microtubules found as a ring of triplets?
centriole
54
what direction do kinesin proteins move? what do they move on?
retrograde along microtubules
55
what direction do dynesin proteins move? what do they move on?
anterograde along microtubules
56
what is the most stable cytoplasmic filament? most dynamic?
stable- intermediate filaments
| dynamic- microtubules
57
what is the structure of intermediate filaments?
alpha helical monomers form coiled coil dimers which associate to form a tetromer that then packs antiparalelly
58
what is endocytosis?
bringing something into a cell
59
what is pinocytosis
slightt invagination without clatherin involvement
60
what is phagocytosis?
antibody binds and antigen and triggers it be brought in
61
what is receptor mediated endocytosis?
something has to bind a receptor for endocytosis to occur
62
what stains rough ER?
basic dyes- eosin (blue)
63
where are simple squamous cells found?
blood vessel lining
air interface in lung
kidney loop of henley
visceral coverings of organs
64
where are simple cuboidal cells found?
ducts, kidney tubules
65
where are simple columnar cells found?
digestive tract and female reproductive tract
66
where are psudeostratified columnar cells found?
respiratory tract, male reproductive tract
67
where is stratified squamous epithelial tissue found?
keratinized- skin, masticatory areas of oral cavity
| nonkeratinized- esophagus, oral cavity lining, vagina
68
where is stratified cuboidal epithelial tissue found?
ducts
69
where is stratified columnar epithelial tissue found?
ducts
70
where is transitional epithelial tissue found?
bladder, ureters, urethra
71
what are examples of calcium dependent CAMs? what are they for?
cadherins- cell-cell attachment
| selectins- cell-cell attachment but WBC can migrate through them
72
what are examples of calcium independent CAMs? what are they for?
Ig superfamily- WBC migration
| integrin- cell-cell or cell-ECM attachment
73
what is an ADAM protein? what are they for?
a disintegrin and metalloproteinase
prevents integrin attachment to ECM and breaks down connective tissue during embryogenesis, neurogenesis, and angiogenesis?
74
what is the basal lamina made of?
laminin, fibronectin, type 4 collage
75
what makes the basal lamina?
epithelial tissue
76
what is the reticular lamina made of?
type 3 collagen
77
what makes reticular lamina?
connective tissue
78
what are the two components of the basement membrane?
basal lamina and reticular lamina
79
what are microvili?
plasma membrane protection with actin filament core anchored to intracellular actin
80
what are stereo cilia?
long microvili
81
what are cilia?
separate organelles that anchor into the cell surface
82
what is found in basal infoldings?
lots of mitochondria
83
what are occluding junctions?
tight junctions on apical surface to form seal
84
what is unique about zonula adhering?
have terminal bar below in an EM
85
what is the structure of a gap junction?
tubular connexin with 6 subunits, one in each cell
86
what is hyperplasia?
increased cell quantity
87
what is hypoplasia?
absence of normal cells
88
what is hypertrophy?
increase in size
89
what is atrophy?
decrease in size
90
what is metaplasia?
change in morphology that is reversible if a stimulus is removed
91
what is dysplasia?
atypical morphology due to early division of immature cells
92
what is neoplasia?
persistant abnormality
93
how are endocrine glands formed?
break away from epithelium, no ducts-->secrete directly into neighboring vessels
94
how are exocrine glands formed?
stay attached to epithelium, may have ducts, secrete onto surface epithelium
95
what are goblet cells?
unicellular exocrine glands that secrete mucous
96
what are gastric glands?
tubular exocrine glands without ducts
97
what are salivary glands?
acinar exocrine glands with ducts that secrete protein (serous)
98
what is the pancreas?
exocrine gland
99
what do serous glands look like at LM level?
darker, lots of rER (pink)
100
what do mucus glands look like at LM level?
white
101
what do acinar glands look like?
bunch of grapes
102
what is merocrine secretion?
vesicles leave via exocytosis
103
what is apocrine secretion?
some apical cytoplasm is pinched off with secretions
104
what is holocrine secretion?
the cell disintegrates to release its secretion
105
what is a poorly differentiated tumor?
not similar to the source of the tumor- poor prognosis
106
wheat is a well differentiated tumor?
similar to the source of the tumor- good prognosis
107
what is a papilloma?
benign, from surface epithelium
108
what is an adenoma?
benign, from glandular tissue
109
what is an adenocarcinoma?
malignant, from glandular tissue
110
what does the dorsal root carry
sensory
111
ventral root carries
motor
112
sensory ganglia contain
cell bodies of pseudo unipolar neurons
113
sensory ganglia are part of
dorsal root
114
the entrance to the sympathetic chain ganglia is through
white rami communicans
115
the exit from sympathetic chain ganglia is through
gray rami communicans
116
parasympathetic motor ganglia are
outside cranial nerves and lumbosaccral nerves
117
what are the types of neuron endings of pseudo unipolar neurons?
modified neurons-
encapsulated endings
unencapsulated endings
proprioceptors
118
how do modified neurons work?
special cells detect stimulus and gives signal to neuron
119
examples of unencapsulated neuron endings?
free endings, hair follicle
120
examples of encapsulated neuron endings
meissner's corpuscles
pacinian corpusules
ruffini's corpuscles
121
where are purkinje cells?
in cerebellum between molecular and granular layers
122
where are pyramidal cells
cerebrum
123
where are fibrous astrocytes located?
white matter
124
where are protoplasmic astrocytes located?
gray matter
125
where are ependymal cells?
line ventricles of brain and spinal cord
126
what does the choroid plexus do?
make cSF
127
what are microglia derived from?
monocytes
128
what stains myelin well?
osmium- looks like sharpie around the axon
129
what holds the layers of membrane around the axon together to form myelin?
desmosomes, cadherins, and gap junctions
130
what happens with a B12 deficiency?
hypomyelination- myelin doesn't develop in first 2 years so it is missing
131
what happens in heavy metal poisoning?
demyelination
132
what is lyme disease?
demyelination secondary to axon degeneration
133
what is ALD?
adrenoleukodystrophy
| peroxisomal disorder involving defects in lipid synthesis and breakdown leading to defects in myelin synthesis
134
what is MS?
multiple sclerosis
antibodies against myelin formed after some initiating factor
inflammatory response
135
what is PML?
demyelination caused by reactivation of HPV virus in immunocompromised adults
136
what is chromocytolysis?
nerve cell swells in response to injury
137
how is rabies transmitted?
retrograde transport of the virus into the cell body where it proliferates and shed to adjacent neurons
lots of viral particles in cerebellum
138
what is another term for parasympathetic ganglia?
intramural ganglia
139
what triggers glial scar formation?
toxin getting through blood vessel in brain and initiating an as astrocytic reaction
140
what do macrophages look like?
ruffled boarder
| high lysosome activity--junk in cytoplasm
141
what does adipose look like?
light staining
142
what do mast cells look like?
filled with secretory granules, stained with annular blue that only stains the granules and leaves negative impression of nucleus
143
what do plasma cells look like?
oval shaped with clock faced nucleus
144
what is amyloidosis-
intracellular proteins deposited in extracellular area which leads to formation of amyloid plaques in tissues with basement membrane
145
what is Ehler's danlos syndrome?
genetic defect in collagen fibril synthesis characterized by join dislocation and skin hyperlasticity
146
where is type 1 collagen found? what does it look like?
in dense regular CT as large bundles
147
where is type 2 collagen found? what does it look like?
hyaline cartilage as big fibers
148
where is type 3 collagen found? what does it look like?
blood forming tissues as reticular fibers that look like thorny threads
149
what stains reticular fibers?
silver stain
150
where is type 4 collagen found? what does it look like?
basal lamina, no fibers or polymerization
151
what does elastin look like?
wiggly thin fibers in annular blue stained sections
152
what does mesenchyme look like? where is it?
wispy, in immature mesoderm (embryo)
153
what does mucoid look like? where is it?
a few collagen fibers, more eosinophilic than mesenchyme (pinker), in umbilical cord
154
how can you tell if you are looking at a section of umbilical cord?
2 veins and an artery will be present
155
where is loose CT?
under epithelium, more cells present than fibers
156
what does dense irregular CT look like?
collagen fibers in many directions
157
what does dense regular CT look like?
packed collagen fibers in the same direction
| fibroblasts look like they were pushed out of the way
158
what does reticular CT look like?
thorny wire, stained with silver
159
what does reticular CT do?
framework for adipocytes- will look like thorny wire around a bunch of white spaces
160
what does unilocular adipose look like?
chicken wire, few fibers, white
161
what does multilocular adipose look like?
lots of darker droplets
162
what is an abcess?
liquidation of the inside of a fibrotic area
