ramray bhat [email protected] fileganong’sreview of medical physiology , 23rd edition, lange. cell...
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An introduction to cellular anatomy
Ramray Bhat
Molecular Reproduction Development and Genetics
A given prototypical cartoon of a cell
Ganong’s Review of Medical Physiology , 23rd Edition, Lange
Cell size diversity
cytoskeleton
Ganong’s Review of Medical Physiology , 23rd Edition, Lange
Microanatomy: putting cells in their correct context
Nelson and Bissell, Ann Rev Cell Dev Biol, 2006
Cell-cell and Cell matrix interactions structure tissues
Mol Biol Cell, 6th Edition, Garland Science
Tight Junctions
Mol Biol Cell, 6th Edition, Garland Science
Tight Junctions (Zonula Occludens)
Occlude apical and basal side leading to
difference in chemical composition of
fluids.
Also act as “fences” to prevent
extracellular transport molecules from
moving to the wrong side of the cells.
Built around claudins and occludins, TM
proteins mediating homophilic adhesion
and cytoplasmic scaffold proteins such as
ZO proteins that mediate ZO formation.
Complexity of tight junctions and
‘leakiness’
Adherens Junctions
Mol Biol Cell, 6th Edition, Garland Science
Adherens Junctions (Zonula Adherens)
Bind and provide structural integrity to
polarized tissue
Lie below the tight junctions. Mediated by
cadherins on the EC side and catenins
and actin on cytoplasmic side.
Actins form a belt encircling the polarized
tissue.
Desmosomes
Mol Biol Cell, 6th Edition, Garland Science
Hemidesmosomes: Integrins connect to
basal lamina (laminin) and to intermediate
filaments
Gap junctions
Mol Biol Cell, 6th Edition, Garland Science
Present in connective tissues
as well.
Serves to connect cells
chemical electrically and
metabolically.
Made of patches of
connexons which consist of 6
TM connexin proteins.
ECM
Mol Biol Cell, 6th Edition, Garland Science
Extracellular macromolecules
forming scaffolds around cells.
Secreted by fibroblasts but
also by epithelial cells
Composition and physical
properties are specific to
different tissues.
Types of ECM
Mol Biol Cell, 6th Edition, Garland Science
The proteoglycans typically form a
highly hydrated, gel-like ‘ground
substance’ in which collagens and
glycoproteins are embedded. The
polysaccharide gel resists
compressive forces on the matrix
while permitting the rapid diffusion of
nutrients, metabolites, and hormones.
The collagen fibers strengthen and
help organize the matrix, while other
fibrous proteins, such as the rubberlike
elastin, give it resilience.
The matrix glycoproteins help cells
migrate, settle, and differentiate
in the appropriate locations.
Microanatomy: putting cells in their correct context
Nelson and Bissell, Ann Rev Cell Dev Biol, 2006