Persistent prelethal stress leads to cellular adaptation.
1-Adaptation of growth.
a) Increased growth and cellular activity e. g.Hypertrophy & Hyperplasia
b) Decreased growth and cellular activity e.g. Atrophy.
c-Disturbances of cellular differentiation and morphology e.g.
2-Intra and Extra cellular accumulations e. g.
a) Lipids as in fatty change & Cholesterol deposits.
b) Proteins as in Hyaline change& Amyloidosis.
c) Calcium as in Pathologic Calcification
d) Pigments as in Pathologic pigmentation.
normal substance produced at normal or increased rate/rate of
metabolism inadequate for removal (fatty liver)
cell cannot degrade substance (carbon)
Fatty Change (Steatosis)
the liver is one of the main organs of the body involved in pathways involving
metabolism of fats or lipids.
Accumulation of lipids in hepatocytes is termed fatty change (also known
as, hepatic steatosis, fatty liver,.
Another example of accumulation of lipids in cells is atherosclerosis
characterized by the accumulation of lipid-laden foam cells in the walls
of arteries. The significance of atherosclerosis in
humans is obviously reflected in the high incidence of myocardial and cerebral
infarction (heart attack and stroke).
Fatty Change (Steatosis)
increased weight, yellow color
fat vacuoles within
cytoplasm of hepatocytes
Another example of accumulation of an endogenous
substance, is the accumulation
of protein in tubular epithelial cells of the kidney known
Abnormal accumulation occurs in liver, muscles and
kidney in case of:Diabetes mellitus ( hyperglycemia)
defect in metabolism of glucose or glycogen
Pigments are colored substances, synthesized within
the body (endogenous) or coming from outside
Endogenous pigments: include melanin, lipofuscin and
Lipofuscin (“wear and tear pigment)
..) It contains complexes of lipid and protein derived from
peroxidation of lipids by free radicals. insoluble brownish-yellow
granular intracellular material that accumulates in a variety of
tissues (particularly the heart, liver, and brain) as a function of age
or atrophy( ageing pigment)
when appear in tissue grossly
it is called brown atrophy
brown-black pigment produced in melanocytes
It is synthesized exclusively by melanocytes located in the
epidermis and acts as a screen against harmful ultraviolet
Albinism: absence of melanin. Such individuals
have melanocytes but are unable to synthesize
melanin. These patients are vulnerable to cancer.
golden-yellow pigmen accumulate in tissues when there is local
or systemic excess of iron
Local excesses of iron and hemosiderin result from
hemorrhages or vascular congestion,. With lysis of the
erythrocytes, the hemoglobin eventually undergoes
transformation to hemosiderin.
hemosiderin is systemic deposited in many organs and tissues [ liver, bone marrow,
spleen, and lymph nodes
increased absorption of dietary iron,
hereditary more extensive accumulations of iron with tissue injury including liver
fibrosis, heart failure, and diabetes mellitus.
When inhaled, it is phagocytosed by alveolar macrophages and
transported by lymphatics to lymph nodes
mild accumulations usually are of no consequence--heavy
accumulations may induce a fibroblastic response
Most of these are dust particles in the inhaled air,
deposited in the lungs and associated lymph nodes.
The dust particles act as mild irritants and induce
proliferation of fibrous connective tissue( FCT)(fibrosis) and collection of macrophages.