Intercellular Accumulations Flashcards
Define it?
Under some circumstances cells may accumulate abnormal amounts of various substances,
Which may be harmless or associated with varying degrees of injury.
The substance may be located in:
In the cytoplasm, within organelles (typically lysosomes) or in the nucleus.
Irreversible fatty liver:
it occurs when some vital intracellular process is irreversibly impaired
e.g ,:CCl4 poisoning
Atherosclerosis:
S.M cells and macrophages are filled with lipid vacuoles composed of cholestrol and cholestryl esters.
These give atherosclerotic plaques
Xanthomas:
In hereditary and acquired hyper lipidemic syndromes, macrophages become filled with cholestrol and cholestryl ester and produce tumorous masses in the subepithelial connective tissue of skin or in tendons.
Accumulation of protein
Morphologically visible protein accumulations are much less common than lipid accumulations
Accumulation of proteins may occur because:
Because excesses are presented to the cells or because the cells synthesize excessive amounts
Protein accumulation in PCT of kidney:
Nephrotic syndrome
Russel bodies occur in:
Multiple myloma
Mallory body occurs in:
Alcoholic liver disease
The neurofibrillary tangle occurs in:
Alzheimer disease
Accumulation of glycogen associated with:
Abnromalities in the metabolism of either glucose or glycogen
In PCDM, glycogen accumulates in:
Renal tubular epithelium, cardiac myocytes and beta cells of the islets of langerhans
Most common exogenous pigment:
Carbon
When carbon is inhaled, it is phagocytosed by alveolar macrophages and transported through lymphatic channels to :
The regional tracheobronchial lymph node
Aggregates of the pigment blacken the draining lymph nodes and pulmonary parenchyma
Anthracosis
E.g of accumulation of carbon pigmenr
Heavy pollution Fibroblastic reaction Emphysema Coal workers Pneumoconiosis
Coal workers pneumoconiosis
Heavy accumulation may induce emphysema or a fibroblastic reaction that result in a serious lung disease.
It is form of localaized exogenous pigment
Tattooing
Explain tattooing?
Pigments like india ink, cinnabar and carbon are introduced into the dermis in the process of tattooing where the pigment is taken up by macrophages and lies permanently in the connective tissue.
Rust discoloration of lungs occurs in:
Siderosis (accumulation of excess of iron)
Type of occupational lung disease (pneumoconiosis) caused by the inhalation of dust or fumes containing iron or iron oxide particles
Siderosis
In silicosis, accumulation of silicon cause:
Fibrosis of lung
An isoluble brownish-yellow granular intracellular material that seen in a variety of tissues as a function of age or atrophy.
Wear and tear pigment ( lipofuscin)
Lipofuscin is seen in :
Heart, liver and brain
Components of lipofuscin:
It consists of complexes of lipid and protein that derive from the free radical-catalyzed peroxidation of polyunsaturated lipid of subcellular membranes.
Lipofuscin is not injurious to the cell but is important as:
As a marker of past free-radical injury
The brown pigment when present in large amounts, imparts an appearance to the tissue that is called:
Brown atrophy
An endogenous brown-black pigment produced in melanocytes
Melanin
Function of melanin pigment:
It acts as a screen against harmful ultraviolet radiation
Endogenous iron containing pigment consists of aggregates of ferritin micelles
Hemosiderin
Hemosiderin color:
It appears in tissues as golden yellow to brown amorphous aggregates
How to identify hemosiderin?
It can be positively identified by its staining reaction(blue color) with prussian blue dye.
Hemosiderin is normally exist in:
IN tissue macrophages of BM, liver and spleen as physiologic iron storing
Define hemosiderosis:
It is accumulation of hemosiderin, primary within tissue macrophages, without associated tissue or organ damage
Hemochromatosis:
More extensive accumulation of hemosiderin, often within parenchymal cells, with accompanying tissue damage, scarring and organ dysfunction.
Causes of systemic hemosiderosis:
Increased absorption of dietary iron.
Impaired utilization of iron
Hemolytic anemia
Transfusions
Hemochromatosis consequences:
Liver cirrhosis
Heart failure
Diabetes mellitus ( Bronze diabetes)
Increased skin pigmentation
Hereditary hemochromatosis caused by :
Mutation in the Hfe gene on chromosome 6.
Pathological cacification:
It refer to abnormal diposition of cacium salts, together with smaller amounts of iron, magnesium and other mineral salts in areas other than bone or teeth.
Gross appearance of calcification:
White granules or grey, chalky masses.
Firm consistency and gritty feelings on cutting like stones.
Microscopic appearance of calcification:
Blue granules or masses with H&E (basophilic deposites)
Special stain Von Kossa gives black color to Ca salts which may be intracellular or extracellular
Types of calcification:
Dystrophic : deposition in dead or dying tissue, with normal serum level of Ca
Metastatic: deposition in normal tissues with hypercalcemia
Common sites of dystrophic calcification:
Area of coagulation. Caseous and liquifactive necrosis. Foci of enzymatic fat necrosis. Damaged heart valves. Atheromas of advanced atherosclerosis. Dead parasitic lesions like trichnosis, onchocercosis. Thrombosis Tumours (Psammoma bodiee in some tumors (meningiomqs papillary carcinoma
Common sites of metastatic calcification:
Interstitial tissues of blood vessels, kidneys, lung and gastric mucosa.(Organs which secrete or excretes acids).
Causes of hypercalcemia:
Hyperparathyroidism Hyperthyrodism Idiopathic hypercalcemia Vid D intoxication Addison's disease (adrenocortical insufficiency,l. \++ bone catabolism -- bone formation: immobilization Systemic sarcoidosis Milk-alkali syndrom
Increased bone catabolism occurs in:
Multiple myeloma, metastatic cancer and leukemia
Calciphylaxis:
A newly described life-threatening type of metastatic calcification in small blood vessels of the skin in patients suffering from chronic renal failure.
Characteristics of calciphylaxis:
Painful multiple skin necrosis with burn like ulcerations, secondary infections and septicemia is common.
Life saving of calciphylaxis
Parathyroidectomy
Hyaline change:
It refers to any homogenous, glassy, pink-appearing substance in routine tissue section.
Hyaline change is widely used:
As descriptive histologic term.
E.g of hyaline change:
Dense collagenous fibrous scar.
Thickening and reduplication of basement membranes, as in arterioles in long standing hypertension.
Hyaline viral inclusion
Alcoholic hyaline( mallory’s hyaline).
Other e.g of hyaline change:
Abnormal extracellular proteinaceous deposite in amyloidosis.
Droplets of reabsorbed protein in renal tubular epithelial cells.
