Intracellular Accumulation And Cellular Aging Flashcards
(23 cards)
Intracellular accumulation in
Cytoplasm (lysosomes)
Nucleus
INTRACELLULAR ACCUMULATION
MECHANISMS
1 abnormal metabolism
2 Defect in protein folding receptor
3 Lack of enzyme
4 Ingestion of indigestible materials
Alpha 1 antitrypsin
Defect in protein folding transport
Ingestion of indigestible materials
Carbon or silica particles
Fatty change (steatosis) is mostly seen in
Liver
Cholesterol and Cholesteryl Esters diseases
• Atherosclerosis
• Xsantomas
• Cholesterolosis
• Niemann-Pick diesase
Hyaline change in
• Plasma cells
• eosinophilic Russell bodies
• Liver
Hyaline change• alcoholic hyaline
• Neurons
• neurofibrillary tangles
reabsorpted proteins accumulate in the cell as
Hyaline
Accumulation of cytoskeletal proteins, keratin intermediate filaments
Mallory bodies
Hyaline change
Intracellular
Extracellular
Russell bodies, reabsorption droplets, alcoholic
hyaline
collagenous fibers in old scars
Glycogen accumulates in the
renal tubular epithelium, cardiac myocytes, and β
cells of the islets of Langerhans
Lipofuscin “wear-and-tear pigment”
• insoluble brownish-yellow granular intracellular
material
• accumulates in heart, liver and brain
• age or atrophy.
• complexes of lipid and protein, free radical–catalyzed
peroxidation of polyunsaturated lipids of subcellular
membranes
• when present in large amounts an appearance to the
tissue that is called brown atrophy
• insoluble brownish-yellow granular intracellular
material
• accumulates in heart, liver and brain
• age or atrophy.
• complexes of lipid and protein, free radical–catalyzed
peroxidation of polyunsaturated lipids of subcellular
membranes
• when present in large amounts an appearance to the
tissue that is called brown atrophy
Melanin
• an endogenous, brown-black pigment
• synthesized by melanocytes located in the epidermis
• screen against harmful ultraviolet radiation
• adjacent basal keratinocytes in the skin accumulate the pigment
• dermal macrophages • an endogenous, brown-black pigment
• synthesized by melanocytes located in the epidermis
• screen against harmful ultraviolet radiation
• adjacent basal keratinocytes in the skin accumulate the pigment
• dermal macrophages
Hemosiderin
• hemoglobin-derived granular pigment
• accumulates in tissues when there is a local or systemic excess of iron
• Iron is stored within cells with apoferritin, forming ferritin micelles.
• Hemosiderin pigment represents large aggregates of ferritin micelles
• Excessive deposition of hemosiderin
• hemosiderosis
• hereditary hemochromatosis
Pathological calcification
• Dystrophic calcification
• deposition occurs in dead or dying tissues
• no defect in calcium metabolism
• serum levels of calcium is normal
• Metastatic calcification
• deposition of calcium salts in normal tissues
• is almost always secondary to hypercalcemia
After a fixed number of divisions, cells become arrested in a
terminally nondividing state
senescence
Two mechanisms are believed to underlie cellular
senescence:
*Telomere attrition
*Activation of tumor suppressor genes
Telomere length is maintained by
nucleotide addition by an enzyme
Telomerase
Telomerase activity
Present in germ cells
Not present in somatic cells
Reactivated in cancer cells
It is thought that caloric restriction increases longevity
both by :
• reducing the signaling intensity of the IGF-1 pathway and
• increasing sirtuins.
↑growth hormone secretion
IGF-1 secretion
Sirtuins
• Sirtuins are a family of NAD-dependent protein deacetylases.
• There are at least seven types of sirtuins
• Sirtuins are thought to promote the expression of several genes
whose products increase longevity.
• These include proteins that
• inhibit metabolic activity,
• reduce apoptosis,
• stimulate protein folding, and
• inhibit the harmful effects of oxygen free radicals.
