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Histology (ek)
Cells & Organelles
130
Histology
Graduate
08/04/2011

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Term
what's the most common way to prep histo slides?
Definition
1. fix tissue in formalin
2. embed in paraffin wax
3. section tissue and place on glass slides
4. stain
Term
whats the most common stain for light microscopy?
Definition
hematoxylin and eosin
Term
what are the properties of a basic dye? and how do they work?
Definition
dye+Cl-. they react with anionic groups in tissues/cells
Term
what does hematoxylin stain, why?
Definition
heterochromatin and nucleoli of the nucleus b/c they have nucleic acids that are anionic
Term
What other cell parts does hematoxylin stain and why?
Definition
glycosaminoglycans b/c of sulfate grps
rough ER b/c of nucleic acids in mRNA
Term
what do we call things that stain with hematoxylin?
Definition
basophilic
Term
what does eosin react with? give examples
Definition
cationic grps. cytoplasmic filaments (muscles cells), cytoplasm, mitochondria, collagen type I fibers/
Term
what color does eosin and hematoxylin stain things?
Definition
eosin=pink, hema=purp
Term
what are substances that stain with eosin called?
Definition
eosinophilic or acidophilic
Term
what is TEM? what is it used for?
Definition
transmission electom micro. used for sub-cellular analysis like inside cells to see organelles
Term
how are tem slides prepped?
Definition
fixed, embed in plastic, sectioned, stained with heavy metals.
Term
what are the two main types of stained structures we see in TEM?
Definition
electron dense=black
white/pale gray=electron lucent
Term
inclusions
Definition
cell-type specific membrane or non-mem bound materials in cytoplasm
Term
organelle vs inclusion
Definition
organelles are also mem and nonmem bound structures in cytoplasm but are common to ALL cells
Term
what else do we call cell membrane? (2)
Definition
plasma mem (pm) and plasmalemma
Term
what things are in cell mems?
Definition
prot, cholesterol, lipids, carbs
Term
what microscopy lets us look at mems?
Definition
transmission electron microscopy (TEM) or freeze gracture technique use with TEM
Term
what are phospholipids
Definition
polar head with 2 fatty a chains
Term
what are phospholipids
Definition
polar head with 2 fatty a chains
Term
what are glycolipids?
Definition
lipids with 1+ carb attached to it
Term
what side of a cell are glycolipids found?
Definition
outside (extracellular) side
Term
what do plasma membranes (pms) look like in TEM? what's the seen structure called?
Definition
two electron dense dark likes with and electron lucent stip in between. called unit membrane or trilaminar mem.
Term
describe structure of cholesterol (chol) in a pm
Definition
hydroxyl (OH) grp that aligns with phosphate heads of bilayer
Term
what does cholesterol do for pms?
Definition
helps prevent to stiff or too rigid pms
Term
how do we classify prots in pms
Definition
based on how they interact with phosopholipids.
Term
what are the types and definitions of pm prots?
Definition
1. integral mem prots: partially or fully embedding in bilayer, cant be removed without busting up the pm. two types(transmembrane prots and glycoprots where transmem prots are exposed on both mem sides and glycoprots have carbs attached)
2. peripheral mem prots: prots indirectly linked to pm by prot-prot interactions. often associated with cytoskeleton/cytoplasmic side, but can do both sides.
Term
what are the 6 specific types of mem prots ?
Definition
1. pumps: tport ions, aas, sugars using E
2. channels: make pores
3. receptors: bind to extracellular prot ligands and initiate something inside cell
4. linkers: transmem prots that link cytoskeleton to extracellular matrix
5. enzymes: anything from ion tport to digestion
6. structural prots: from cell2cell anchoring or adhesion junctions, or cell2extracellmatrix adhesion junctions
Term
glycocalyx
Definition
carbohydrate coat on xtracell surface or cells that have glycoprots and glycolipids.
Term
two examples where glycocalyx is
Definition
1. small intestine absorptive cells(enterocytes)
2. cells lining proximal convoluted tubule in kidney
Term
two examples where glycocalyx is
Definition
1. small intestine absorptive cells(enterocytes)
2. cells lining proximal convoluted tubule in kidney
Term
function of glycocalyx
Definition
protect cell surgace, cell cell interactions, holds fluids to cell surface, receptor sites, enzyme reactions
Term
ex of glycocalyx holding liquid
Definition
tears to corneal surface
Term
ex of when glycocalyx participates in enzyme rxns
Definition
small intestine
Term
describe the freeze fracture technique and the resulting image
Definition
freeze specimen, fracture with knife blade, and the cell splits along phospholipid bilayer. you get two faces, E face (extracellular) and P face (protoplasmic/cytoplasmic face). then a metal replica is prepared of the two faces. integral prots look like lil bumps on image but mostly integral prots stay on the P face side. the E side has pits on it where the transmem proteins once were.
Term
what type of mem does the nucleus have?
Definition
double membrane
Term
what BIG processes does the nucleus split up?
Definition
transcribing DNA to mRNA from translation of mRNA into prots
Term
chromatin
Definition
complex of DNA histones and other nuclear proteins
Term
nucleosome
many nucleosomes put together
Definition
DNA wrapped around histones into "beads on a string". then several nucleosomes put together are called chromatin fibers or fibrils.
Term
what level of dna organization is transcriptionally active?
Definition
nucleosomes
Term
organizational levels of genetic info
Definition
dna--(+histones)--> beads on a string/nucleosomes--(more histones)--> nucleosome--(+chromosome scaffold)-->extended scaffold associated form---(+folding)-->condensed scaffold associated form--(+more folding)-->chromosome
Term
what are the two forms of chromatin? how can we see them?
Definition
euchromatin: stretched out chromatin thats transcribing.
heterochromatin: condensed that is not transcribing. can see with light and electron microscopy.
Term
what do euchromatin and heterochromatin look like with TEM and light micro?
Definition
euchromatin: under light micro it is less basophilic or less blue b/c of less hematoxylin. in TEM i is pale (electron lucent). heterochromatin is basophilic in light micro and electron dark in TEM
Term
what are the three locations and names of heterochromatin in a cell
Definition
1. marginal heterochrom around the perimeter of nuc
2. karyosomes:clumps around the nuc
3. heterochromatin of the nucleolus
Term
what happens at nucleolus?
Definition
rRNA transcription and processing and and the site of initial ribosome assembly
Term
what's an "initial ribosome"
Definition
rRNA and protein
Term
nucleolus
Definition
discrete aggregate of rRNA, genes that code for rRNA and protein in nucleus. no mem. originates from specific chrom sites called nucleolar organizing regions.
Term
describe the process of genes that code for rRNA making ribosomes
Definition
genes that code for rRNA are in nucleolus. they are transcribed into rRNA there. Then rRNA make small and large subunits of ribosomes. they leave nucleus thru nuc pores. then more stuff is added/adjusted and they are put together to make ribosomes in the cytoplasm.
Term
structure of nuc envelope. what each part does or touches, kind of.
Definition
inner and outer mem with middle perinuclear space. inner mem is attached to nuclear lamina (made of intermediate filaments) that organizes nuc materials, direct cell ccle reg and differentiation. the perinuc space is continuous with ER. outer nuc mem is continuous with ER mem and may have ribos in it.
Term
describe stucture of nuclear pores
Definition
the inner and outer nuc mem are continuous with eachother
Term
avg amount of nuc pores?
Definition
2000
Term
how are nuc pores identified
Definition
using TEM and look fro breaks in marginal heterochromatin
Term
what diffuses freely thru nuc pores?
Definition
ions and small molecules
Term
what diffuses freely thru nuc pores?
Definition
ions and small molecules
Term
draw nuclear pore with lumenal subunit, column subunit, nuclear fibril, nuclear basket, cytosolic fibrin, annular subunit, ring tunit, nuclear lamina
Definition
[image]
Term
what are the two types of fibrils seen in nuclear pore?
Definition
nuclear fibril (which is the stringy things attaching the nuclear basket) and cytostolic fibril which is the ones sticking out of the ring subunit
Term
how do proteins get in and out of nuc?
Definition
for import they need a nuclear localization signal, for export they need a nuclear export sequence
Term
how do types of RNA get out of nuc
Definition
they also need a nuclear export sequence which is unique to the type of RNA it is (rRNA, mRNA and tRNA)
Term
what is the function of the sER?
Definition
depends on cell
Term
where do we see a lot of developed sER? ex? what does it look like?
Definition
steroid secreting cells like Leydig teste cells, ovary cells and adrenal gland cells. looks like cytoplasm has a bunch of oval, circular and irreular slices of sER tubules
Term
what does sER in liver do?
Definition
convert water insoluble things into hydrophilic things that can leave body via urine. they can deal with lipophilic drugs to excrete them.
Term
what ares sER in skeletal and cardiac muscles called, what do they do?
Definition
sarcoplasmic reticulum. functions as resovoir for calcium.
Term
what does rER look like in TEM
Definition
parallel mem-limited flat sacs called cisternae with lil dots attached
Term
what does rER do?
Definition
prot translation
Term
what does rER do to cell slides using light micro?
Definition
if there are large amts of rER in cytoplasm then the cytoplasm will appear basophilic instead of eosinophilic
Term
where do the proteins go that are made in rER?
Definition
some stay in ER, Golgi App (GA), lysosomes, pm and secretion
Term
polysomes
Definition
non ER-bound ribos that make cytosolic prots, peripheral mem prots and other prots for nuc, mito and peroxisomes
Term
what does GA do?
Definition
modifies, packages and sots prots made in rER
Term
what types of prots are modified by GA?
Definition
secretory prots, glycoprots, pm prots, lysosomal prots.
Term
describe pathway of diff prots made by diff ribos
Definition
preprots made by rER go to GA. From there they are modified and go to: excretion, pm, glycoprots, lysosomes.

free ribos make prots that: go to cytosol, nucleus, peroxisome and mito
Term
besides prots what else does GA make?
Definition
mem lipids
Term
what and where are the three faces of the GA
Definition
cis: faces ER and nucleus, medial: mid GA, trans: concave towards cytoplasm
Term
what takes materials from cis to trans golgi
Definition
transport vesicles
Term
how do prots made in rER get to GA?
Definition
COPII coated vesicles
Term
aka for cis face golgi
Definition
cis golgi network (CGN)
Term
how do prots get out of GA?
Definition
clathrin coated vesicles that drop the clathin triskelions. or in non clathrin coated vesicles
Term
which vesicles from GA become endosomes or lysosomes?
Definition
ones with mannose6phosphate residues attached
Term
exocytosis
Definition
when a vesicle fuses with pm and excretes its stuff
Term
exocytosis
Definition
when a vesicle fuses with pm and excretes its stuff
Term
what are the two pathways of exocytosis?
Definition
1. constitutive secretory pathway: prots released right after synthesis
2. regulated secretory path: prots temporarily stored in secretory vesicles and then hormonal or neural stimulation releases them. Ca+ influx stimulates vesicle to fuse with pm.
Term
ex of two exocytosis pathways
Definition
constitutive secretory pathway: immunoglobulin secreted by plasma cells and tropocollagen secreted by fibroblasts.
2. zymogen granules with digestive enzymes released by acinar cells of pancrease
Term
lysosomes
Definition
mem bond organelles that have an acidic pH and have hydrolytic enzymes (NZ)
Term
what is the pH in lysosomes? how can we tell if an NZ is a hydrolase?
Definition
5, any NZ ending in -ase
Term
how do lysosomes maintain pH
Definition
proton pumps
Term
what do lysosomes look like in TEM?
Definition
inactive lysos will be round with a mem that's empty (looks like peroxisome). active lysosomes are heterogenuous looking with more irregular shape and a bunch of stuff inside.
Term
describe lysosome formation
Definition
acid hydrolases are made in rER and go to GA. they are modified and mannose6phosphate is added. the m6p/hydrolase complex moves thru GA. at TGN there are m6p receptors that grap on to m6p/hydrolase complex. this part of TGN is coated in clathrin used for trafficing. coated vesicle buds off. clathrin comes of. meanwhile endosomes coming in from endocytosis are using atp pumps to get real acidic in the inside. these acidic (6-6.8)these "late endososmes" fuse with the vesicles containing the m6p/hydrolase complex and the hydrolase is released and now we have an primary lysosome.
Term
in what ways do lysosomes degrade stuff. name and define
Definition
1. autophagy: eating old cell parts. ER surrounds old cell parts making autophagosomes. these fuse with primary lysosomes making autophagolysosomes (secondary lysosomes). these eat the old cell junk.
2. phagocytosis: pm surrounds larger things like bacteria and make phagosomes. primary lysosomes fuse with pphagosomes to make phagolysosome (secondary lysosome).
3. proteins with lysosome signal go straight to lysosome to get ate
4. some junk brought INTO cell in early endosomes which can be tferred to late endosome which can go to those hydrolase vesicles
Term
fluid phase endocytosis, def and aka
Definition
aka pinocytosis. taking in any fluids, independant of clathrin. constituitive (continuous) process
Term
receptor mediated endocytosis
Definition
uptake of specific molecules that is clathrin dependent
Term
describe process of receptor mediated endocytosis
Definition
specific molecules attach to their receptors on the pm. this part of pm has clathrin coat on inside (called clatherin pit). buds off inside. then one of these things can happen: 1. receptor is kept and ligand degraded 2. receptor and ligand are recycled 3. both are degraded 4. both are tported thru the cell
Term
peroxisomes
Definition
single mem bound organells with tones of diff enzymes but 40% have catalse
Term
where are their most peroxisomes?
Definition
liver and kidney
Term
where are their most peroxisomes?
Definition
liver and kidney
Term
what do peroxisomes do?
Definition
use catalase and peroxidase to decompose H2O2 making it water or using it to oxidize other organic compds
Term
how are peroxisomes made?
Definition
peroxisomal prots made on free polysomes (ribos) that have a peroxisomal targeting signal and then they are imported into organelles
Term
primary function of mito
Definition
make atp
Term
major processes in mito
Definition
CAC, fatty acid beta oxidation, ETC and oxidative phosphorylation
Term
folds of mito
Definition
crisae
Term
which mito mem has pore?
Definition
outer
Term
which mito mem has pore?
Definition
outer
Term
shelf like crisae are called? where are they found?
Definition
tubulovesicular, steroid secreting cells
Term
shelf like crisae are called? where are they found?
Definition
tubulovesicular, steroid secreting cells
Term
how doe prots made on free ribos know they are going to mito?
Definition
they have a 20-80 aa mito signal pep at amino terminus
Term
3 parts of cytoskeleton and their structure and main function
Definition
1. microfilament: actin prots, work with actin binding prots to organize self
2. intermediate filaments: structure mostly, (types: keratin in epithelial cells, vimentin related prots, neurofilaments, lamins of nuclear lamina)
3. microtubules: dimers of tubulin organized by microtubule organizing centers
2. intermediate filaments
Term
aka for keratins
Definition
cytokeratins, tonofilaments, tonofibrils, soft keratins, hard keratins
Term
aka for keratins
Definition
cytokeratins, tonofilaments, tonofibrils, soft keratins, hard keratins
Term
list of vimentin related prots
Definition
desmin, glial fibrillary acidic prot GFAP
Term
how are lamins built and broken in mitosis?
Definition
phosphorylation disassembles them by making them soluble, dephosphorylation puts em back together after cell division
Term
what major process are microtubules used for? describe their role and components of their organizing center/
Definition
mitosis. during interphase microtubes are organized around microsomal organisin centers called centrosomes. centrosomes have two centrioles with pericentriolar material. each centriole has 9 sets of triplet microtubes. the 2 centrioles are perp to each other.
Term
inclusions and def of each, plus where they are found
Definition
glycogen: storage form of glucosefound in hepatocytes and cardiac muscle cells
lipid droplets: storage forms of triglycerides found in steroid secreting cells
pigments: in long lived cells like nuerons
and crystals: seen in leydig cells
Term
cell proliferation
Definition
increase in cell number
Term
S phase
Definition
DNA duplicated
Term
prophase
Definition
-chromatin condenses into sister chromatids
-nucleolus disassembles
-centrioles duplicate and move to make mitotic spindle
Term
prometaphase
Definition
-nuc envelope broken
-microtubes attach to kinetochores of chromes
-chromes become arranged at right angles to mitotic spindles
Term
metaphase
Definition
chromosomes lined up at metaphase plate and held by kinetochore microtubules
Term
anaphase
Definition
sister chromatids separate and migrate towards opposite poles and cleavage furrow begins to develop
Term
anaphase
Definition
sister chromatids separate and migrate towards opposite poles and cleavage furrow begins to develop
Term
telophase
Definition
kinetochore microtubes dissassemble
nuc mem reforms
chromes begin to decondense
nuclei begin to reform
Term
two methods of cell death
Definition
necrosis and apoptosis
Term
ex of when necrosis may occur
Definition
lack of oxygen
Term
what are the characteristics of necrosis?
Definition
pm damage, cell swelling and lysis
Term
what natural response causes necrosis
Definition
inflammatory response
Term
what are the histo features of necrosis?
Definition
pyknosis: condensation of chromatin and shrinking nuc
karyorrhexis: breaking of nuc
karyolysis: dissolution of nuc
Term
process of apoptosis
Definition
DNA fragments, nuc breaks apart into parts, pm blebs (gets bubbles) then the cell is phagocytosed OR first the cell breaks into several vesicles called apoptotic bodies which get phagocytosed
Term
what does an apoptotic cell look like?
Definition
round with condensed chromatin and pyknotic nucleus (shrunk)
Term
what does hematoxylin have the potential to stain very very dark blue? why?
Definition
cartilage. b/c it has a lot of glycosamino glycans in it.
Term
what heavy metal is used in TEM
Definition
ozmium tetroxide
Term
what makes up glycocalyx?
Definition
glycoproteins and glycolipids
Term
in freeze fracture, what do integral mem prots look like?
Definition
intramembranous particles
Term
what lines the nuc envelope on the inside?
Definition
nuclear lamina
Term
what is the nuclear lamina made of?
Definition
protein
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