Presentation on theme: "Persistent prelethal stress leads to cellular adaptation."— Presentation transcript:
1 Persistent prelethal stress leads to cellular adaptation. 1-Adaptation of growth.a) Increased growth and cellular activity e. g.Hypertrophy & Hyperplasiab) Decreased growth and cellular activity e.g. Atrophy.c-Disturbances of cellular differentiation and morphology e.g. Metaplasia2-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 Calcificationd) Pigments as in Pathologic pigmentation.
2 Intracellular Accumulations Endogenousnormal substance produced at normal or increased rate/rate of metabolism inadequate for removal (fatty liver)Exogenouscell cannot degrade substance (carbon)
3 Intracellular Accumulations 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 wallsof arteries. The significance of atherosclerosis inhumans is obviously reflected in the high incidence of myocardial and cerebralinfarction (heart attack and stroke).
4 Intracellular Accumulations Fatty Change (Steatosis)Liverincreased weight, yellow color
6 Another example of accumulation of an endogenous substance, is the accumulation of protein in tubular epithelial cells of the kidney known as,amyloidosisGlycogen:Abnormal accumulation occurs in liver, muscles and kidney in case of:Diabetes mellitus ( hyperglycemia) defect in metabolism of glucose or glycogen
7 Pigment disorders:Pigments are colored substances, synthesized within the body (endogenous) or coming from outside (exogenous).Endogenous pigments: include melanin, lipofuscin and Hemosiderin
8 Intracellular Accumulations Endogenous PigmentsLipofuscin (“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
9 Intracellular Accumulations Endogenous PigmentsMelaninbrown-black pigment produced in melanocytesIt is synthesized exclusively by melanocytes located in the epidermis and acts as a screen against harmful ultraviolet radiation
10 Albinism: absence of melanin Albinism: absence of melanin. Such individuals have melanocytes but are unable to synthesize melanin. These patients are vulnerable to cancer.
11 Intracellular Accumulations Endogenous PigmentsHemosideringolden-yellow pigmen accumulate in tissues when there is local or systemic excess of ironLocal excesses of iron and hemosiderin result from hemorrhages or vascular congestion,. With lysis of the erythrocytes, the hemoglobin eventually undergoes transformation to hemosiderin.
12 hemosiderin hemosiderosis hemosiderin is systemic deposited in many organs and tissues [ liver, bone marrow, spleen, and lymph nodesoccurs inincreased absorption of dietary iron,hemolytic anemias,transfusionshemochromatosishereditary more extensive accumulations of iron with tissue injury including liver fibrosis, heart failure, and diabetes mellitus.
13 Intracellular Accumulations Exogenous PigmentsCarbon (anthracosis)When inhaled, it is phagocytosed by alveolar macrophages and transported by lymphatics to lymph nodesmild accumulations usually are of no consequence--heavy accumulations may induce a fibroblastic response
14 Exogenous pigmentsMost 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.