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Introduction,Review of Cell morphology,
and Cytoskeleton,
Compiled by:
Dr Muhammad Ashraf
06.07.20102
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General Pathology:Pathologic conditions that are commonly
seen in most diseases and organs. 3
Pathology: Study of disease, especially structuraland functionalchanges caused by human disease.
Four aspects of disease process studied in pathology are:
Etiology: The cause of disease (Gr. aitia, cause)
(intrinsic (genetic) or external (environmental))
Pathogenesis: The mechanism &stages of disease
developm
ent.Morphology: Gross and microscopic study of structural
alterations produced by disease in the tissues andcells of the body. (Footprints of disease in tissues)
Clinical features: Corelation between structural changes
with alteration in functions of body.
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Small
molecule
Relativesizesofcellsandtheircomponents
Virus BacteriumSmall
molecule
Animal
cellPlant
cell
1 mm = 1000 m
1 m = 1000 nm
1 nm = 10 A
1 m = 100 cm (102 )
1 m = 1000 mm (103 )
1 m = 1000,000 m (106 )
1 m = 1000,000,000 nm (109 )
1 m = 1000,000,000,0 A (1010) 5
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Animal Cellwith
organelles
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ADP combine with PitoformATP inacontinuouscycle
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Mitochondrionis a cell organelle of ovoid shape
that is the majorsourceforintracellularenergy.
Mitochondria can migrate
through the cytoplasm and
change their shape. These
organelles have an outerunit
membrane and an innermembrane. The latter has
cristae, crest-like protrusions,
into the matrix
(mitochondrial plasma).
Mitochondrial half-life is thought
to be about 5-12 days.
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Plasma Membrane
Lipid-GlobularproteinmosaicModel
Plasma membrane is a structure enveloping a cell,
enclosing the cytoplasm and forming a selective
permeability barrier. It consists of lipids, proteins and
some carbohydrates, the lipids thought to form a
bilayer in which integral proteins are embedded to a
varying degrees,
Lipidbilayer
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GranularEndoplasmicReticulumRibonucleoprotein
particles (Ribosomes)
Flattened Cisterna of E.R.
TubularE.R.
Vesicles of E.R.
Rough endoplasmic reticulum, Golgi complex
andlysosomes are functionally and
structurally related to one another and the
plasma membrane. Membranbound transport vesicles shuttle back and
forth with materials. Proteins are synthesized
in ribosomes and reach the Golgi complex.
Finally the proteins reach the trans Golgi
network (TGN) at the end of stack and sorted
out to their final destination.11
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The endoplasmic reticulum is a series
of interconnected, intracytoplasmic,
membrane bounded sacs.
The "rough" appearance of the rough
endoplasmic reticulum (RER
) resultsfrom the presence of ribosomes that
are bound to the cytosolic side of the
endoplasmic reticulum membrane.
The presence of ribosomes on the
RER indicates that it is involved in
Protein synthesis.
The smooth endoplasmic reticulum (SER)
has no such bound ribosomes and is notinvolved in protein synthesis.
However, the SER is involved in cholesterol
metabolism, membrane synthesis,
detoxification, Ca++ storage along with other
cellular processes.
EndoplasmicReticulum
Ribosomes Membrane
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Golgi Complex
Transport vesicles
Secretory
granules
Golgi
cisternae
Camillo Golgi, 1843-1926. Italianneurologist and histologist; won
Nobel prize for physiology in 1906 forstructure of the nervous system.
The Golgi Complexfunctions as
a processing plant,modifying the
membranecomponents and cargo
synthesized in theendoplasmic reticulumbefore it moves on tothe target destination.
The materials enterthe stack at the cis
face and move byvesicle transport
towards the oppositeor trans face
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Proteins and lipids built in the smooth and roughendoplasmic reticulum bud off in tiny bubble-like vesicles
that move through the cytoplasm until they reach the Golgicomplex.
The vesicles fuse with the Golgi membranes and releasetheir internally stored molecules into the organelle.
Once inside, the compounds are further processed by the
Golgi apparatus, which adds molecules or chops tiny piecesoff the ends.
When completed, the product is extruded fromthe GA ina vesicle and directed to its final destination inside or
outside the cell.
The exported products are secretions of proteins orglycoproteins that are part of the cell's function in the
organism.
Other products are returned to the endoplasmic reticulum ormay undergo maturation to become lysosomes
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The Rough ER manufactures
membranes and secretoryproteins. In leukocytes the
rough ER produces antibodies.
In pancreatic cells the rough
ER produces insulin.
The rough and smooth ER are
usually interconnected and the
proteins and membranes made
by the rough ER move into the
smooth ER to be transferred toother locations.
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1. Nuclear membrane2. Nuclear pore
3. Rough endoplasmic
reticulum (REM)
4. Smooth endoplasmic
reticulum
5. Ribosome attached to REM
6. Macromolecules7. Transport vesicles
8. Golgi apparatus
9. Cis face of Golgi apparatus
10. Trans face of Golgi
apparatus
11. Cisternae of Golgi apparatus
12. Secretory vesicle13. Cell membrane
14. Fused secretory vesicle
releasing contents
15. Cell cytoplasm
16. Extracellular environment
Secretorypathwaydiagram,includingnucleus,endoplasmicreticulumandGolgiapparatus.
10. Trans
face
9.
Cis
face
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All animals have skeletons tokeep up their shape and
forms and get help for
locomotion.
What about the animal cells?How they keep up their shape
and form and how they move
about?
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The cytoskeleton (also CSK) is a cellular
scaffolding" or skeleton" contained within
the cytoplasm.
The cytoskeleton is present in all cells; It is a dynamic
structure that maintains cellshape, often protects the cell,
enables cellular motion (using structures such as
flagella and cilia), and
plays important roles in both intracellulartransport(the movementofvesicles and
organelles),
and cellulardivision.(W)19
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Microfilaments
8 nm diameter: Double helical polymers
of the protein Actin.
Microtubules
Intermediate Filaments
24 nm diameter. Wall is a polymer of
globular protein subunit - tubulin
Mitotic spindle, core of cilia and flagella
10 nm diameter, intermediate between
microtubules & microfilaments
Help in cell motility
Solid, smooth surfaced, unbranched
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RoleofCytoskeleton
inPhagocytosis
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RoleofCytoskeletonin Phagocytosis
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Endothelialcellsunderthemicroscope.Nuclei are stained blue
with DAPI, microtubules
are marked green by anantibody bound to FITC
and actin filaments are
labeled red with phalloidin
bound to TRITC.DAPI or 4',6-diamidino-2-phenylindole isa fluorescent stain that binds strongly to DNA.It is used extensively in Fluorescencemicroscopy. Since DAPI will pass through anintact cell membrane, it may be used to stainboth live and fixed cellsFITC Fluorescein isothiocyanate; used as afluorescent label for proteins, especially antibodies.
TRITC Tetramethyl Rhodamine Iso-Thiocyanate
Phalloidin is one of a group of toxinsfrom the death cap (Amanita phalloides)
known as phallotoxins. It binds actin,
preventing its depolymerization and
poisoning the cell.
Bovinepulmonaryarteryendothelialcells
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Cytoskeleton:anetworkofproteinfibersinthecytoplasmthatgivesshapetoacell,holdsand
movesorganelles,andistypicallyinvolvedincell
movement.
Cytoskeleton of
a cultured
epithelialcell.
Microtubules
are shown in
green, actin isshown in red
and DNA in the
nucleus is in
blue.
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Crosssectionthrough Spermaxoneme
Electronmicrograph
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StructureofSpermaxoneme,Diagramatic
Nexin
bridge
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Asimplifieddepictionofanaxonemalcross-section.
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3D StructureofAxoneme
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