Subcellular Responses To Injury Flashcards
Subcellular responses to injury
Lysosomal Catabolism Induction (Hypertrophy) of Smooth Endoplasmic Reticulum Mitochondrial Alterations Cytoskeletal Abnormalities Heat Shock Proteins
membrane bound intracellular organelles containing a variety of hydrolytic enzymes
Primary lysosomes
when the primary lysosomes fuse with vacuoles containing material for digestion.
Secondary lysosomes, “phagolysosome”
Type of phagocytosis seen especially with atrophy and aging.
Autophagy
engulfment of soluble small material
Pinocytosis
Lysosomes with undigested debris may persist within cells as residual bodies or may be extruded
Examples:
Lipofuscin pigment granules represent indigestible material resulting from intracellular lipid peroxidation, and certain indigestible pigments, such as carbon particles inhaled from the atmosphere or inoculated pigment in tattoos, can persist in phagolysosomes of macrophages for decades
large and abnormal shapes (megamitochondria)
alcoholic liver disease
Kartagener
Immotile cilia syndrome
immobilizing cilia of the respiratory epithelium, resulting in chronic infections due to defective clearance of inhaled bacteria
Drugs that prevent microtubule polymerization (colchicine)
are therefore useful in
treating gout
, in which symptoms are due
to movement of macrophages toward urate crystals with
subsequent frustrated attempts at phagocytosis.
Cytoplasmic proteins that are involved in protein kinesis and repair, like protein folding, transport and disaggregation
Important adaptive response found in all species
Heat shock proteins; HSP
Synonymous: stress proteins, molecular
chaperones
HSP induced after injurious stimuli leads to…
Refolding denatured proteins before causing
death.
If not responding, the protein is directed to bind with ubiquitin-proteasome pathway, leading to degradation.
Families of HSP(Heat Shock proteins)
Two families:
Produced always at low levels; HSP 60, 90
Produce under stress; HSP 70
