Intercellular Accumulations Flashcards
4 main types of accumulation pathways
1 ingestion of exogenous subs - with not way of dealing with them
2 accumulation of endogenous substrates - which can’t be degraded ( pigments )
3 abnormal metabolism ( glucose, lipids proteins )
4 defect in protein folding - accumulation of defected proteins
List the type of pigment accumulation ( both Endo and exogenous)
1 melanin 2 lipofuschin 3 hemosiderin 4 coal dust 5 tatoo deposits
How is melanin made
Is melanin the only endogenous black brown pigment
What does melanin do
- tyrosinase enzyme catalyzes oxidation of precursor tyrosine to dihydroxyphenylalanine in melanocytes
- yes
- gives color to skin , hair , brain ( substatia nigra)
What is the special stain for melanin and the color for positivity
-massona fonta. ( black )
How is Fe transferred and stored in body
Outcome of excess stored Fe
-transferretin proteins transfer Fe
/stored with apoferritin to form ferritin miecelles
-Excess Fe causes excess ferritin miecelles which aggregate to form hemosiderin
Where are hemosiderins mainly seen inside the body and why
- liver, bone marrow , spleen
- sites of RBC breakdown
How do bruises acquire hemosiderins and the other changes that occur
- at site of Bruise injured RBC r phagocytized to recover Fe. Which is incorporated in apoferritin-ferritin miecelles - hemosiderin
- heme group is converted to biliverdin ( green bile ) and then bilirubin ( red bile ). Causes color change of a bruise
How does local overload of Fe occur and systematic
What is hemosiderosis
-during hemorrhaging
- increases Fe absorption due to metabolism error ( hemochromatosis )
- hemolytic anemia’s : premature lysis of RBC
- repeated blood transfusions
-accumulation of Fe in numerous organs due to overload systematic overload of Fe
Colour and characteristic description of Fe under microscope
Special stain for Fe and colour for positivity
- golden yellow
- refractive
-Perls stain , Prussian blue stain ( hemosiderin will be blue )
How is lipofuschin formed and its components
Why does lipofuschin form !?
- perioxidation of cellular lipids by lysosomes
- complex of lipids and proteins
- as people age cell damage occurs more frequently and lipids peroxidized
What does accumulation of lipofuschin show
Colour in light M/S
Characteristic location of lipofuschin
Special stains for lipofuschin
- tell tale sign of free radical damage
- yellow brown in light M/S
- peri nuclear
- osmium tetraoxide , oil red o , Sudan black b
Causes of lipofuschin and where seen
- prominent in heart and liver of aging patient
- cancer cachexia
- severe malnutrition
Describe how coal dust accumulates and why
Where seen
What is anthracosis
- when carbon is inhaled macrophages in lungs engulf but have no mechanism to deal with the coal dust
- so keep the dust
- in lungs and at lymph nodes
- blackening of tissue due to aggregates of macrophages with coal dust trapped
How is coal workers pneumoconiosis formed
-coal miners inhale coal dust which induces emphysema and causes the disease at hand
How do tattoos cause pigment accumulation and effects
- the ink is engulfed by macrophages at all dermis levels and they have no way of dealing with it so kept
- tattoos permanent for the remainder of the embellished life
What is the most common accumulated lipid , where mostly seen and why
Effect of lipid trapped in heart
- TRIG. Seen mostly in liver as it is sight of major lipid metabolism
- Tigered effect , tabby coat appearance ( alternating red / brown color of heart and yellow deposits of lipids )
Special stains of lipids and brown colors for positivity
What is frozen section
We used and which stain is used on it
1 oil red o - red
2 Sudan black - black
3 osmium tetroxide
- fresh untreated tissue
- treating sample might degrade some components
- oil red o
What is steatosis
List the major causes of fatty exchange and describe them
- abnormal accumulation of lipid in cells ( TRIG )
- protein malnutrition : reduces apoprotein levels and TRIG not converted into lipoprotein
- anoxia : reduced O2 and TRIG can’t be oxidized causing steatosis
- alcohol : inhibits sER and mito functioning and TRIG not converted into phospholipids or oxidized
Briefly describe lipid metabolism
- lipids catabolized in GIT to form free fatty acids wc r introduced into liver
- FA anabolized into TRIG which is then converted into lipoproteins, cholesterol, phospholipids and oxidized into acetone , acetonic acid
Describe how foamy cells are formed
-excess cholesterol is phagocytized by macrophages and the chol accumulates as vacuoles in cell which look foamy
Describe atherosclerosis formation and appearance
Describe xanthoma formation
- smooth muscle Cells in arterial initima are filled with lipid vacuoles with chol and chol esters
- cells have a foamy appearance
/intercellular accumulation of lipids in macrophages and the clusters form tumor masses called xanthoma
What is cholesterolosis
-accumulation of cholesterol laden macrophages in Lamina propia of gallbladder
What is Niemann-Pick disease how it occurs
-lysosomal storage disease where there is an error in cholesterol metabolism and cholesterol is stored in multiple organs
Structure and appearance of protein accumulations
- rounded eosinophilic vacuoles in cyto
- can be crystalline or amorphous
