SECTION 2 CELL INJURY

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SECTION 2 CELL INJURY
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Cellular Swelling Fatty Change Hyaline
Change Amyloid Change Mucoid Change Pathologic
Pigmentation Pathologic Calcification

• Reversible

Degeneration

• Irreversible

Cell Death
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Reversible Cell Injury
Degeneration

• Intracellular /or extracellular abnormal
  accumulation
• Excess amounts of various normal substances
  (water,lipids,proteins,pigments)
• Abnormal substances (exogenous, endogenous)

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Cellular Swelling
(1)
(hydropic degeneration)

• Intracellular accumulation
• Sodium
• Water

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Cellular Swelling
(2)
Morphology
the organs
NE

• Cloudy swelling
• Increase in the weight

the cells
LM

• Large
• Small fine granules in the cytoplasm

Ballooning change

• Swelling
• Endoplasmic reticulum
• Mitochondria

EM
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Injurious agents
Mechanism
Mitochondria damage
Cellular swelling
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Fatty Change
(1)
Steatosis

• Intracellular abnormal accumulation
• Triglycerides

Often occurred in the liver and the heart
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Fatty Change
(2)
Morphology

• Large
• Yellow
• Soft
• Greasy

NE
Fat vacuoles
LM

• Round, clear vacuoles
• Orange-red color by staining with Sudan ? or Oil
  Red O (Frozen tissue sections!)

Liposomes
EM

• Membrane-bound inclusions

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Fatty Change of the Liver
(1)
NE

• Mild fatty change
• Not affect the gross appearance
• With progressive accumulation

• Large
• Yellow
• Soft
• Greasy

Fatty Liver Severe diffuse fatty change
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Fatty Change of the Liver
(2)
LM
Fat vacuoles
Small , in the cytoplasm around the
nucleus
Displacing the nucleus to the cell periphery
Fatty cysts
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Fatty Change of the Liver
(3)
Mechanism
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Fatty Change of the Myocardium
NE

• Mild fatty change
• Not affect the gross appearance
• With progressive accumulation

Tigered effect
Apparent bands of yellowed myocardium alternating
with bands of dark,red-brown,uninvolved
myocardium
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Hyaline Change
(1)
A descriptive morphologic term

• Intracellular or extracellular abnormal
  accumulation
• Proteins

• A homogeneous, translucent, pink appearance in
  HE staining

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Hyaline Change
(2)

• Hyaline change in arteriolosclerosis
• e.g. Hypertension, Diabetes
• Hyaline change in connective tissues
• e.g. Old scars
• Hyaline change within the cytoplasm
• e.g. Nephrotic syndrome, Russell bodies,
  Mallory body

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Amyloidosis

• Extracellular abnormal accumulation
• Amyloid

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Physicochemical characteristics of amyloid

• Iodine--- a brown color--- H2SO4 --- blue
• Staining Congo red--- red,
• HE--- homogeneous pink
• EM nonbranching fibrils 7.5-10 nm wide
• X-ray a pleated ?sheet structure
• (rendering protein very resistant to
• enzymatic degradation, contributing
• to its accumulation in tissues)

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Mucoid Change

• Extracellular abnormal accumulation
• Mucopolysaccharide
• (Glycosaminoglycans, Hyaluronic Acid)

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Pathologic Pigmentation
Intracellular extracellular abnormal
accumulation
Colored substances

• Exogenous
• Endogenous

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Pathologic Pigmentation

• Exogenous
• Endogenous

• Carbon

• Hemosiderin
• Lipofuscin
• Melanin

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Pathologic Calcification
(1)

1. Except for the bones and teeth
2. Pathologic conditions

• Intracellular extracellular abnormal
  accumulation
• Calcium salts

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Pathologic Calcification
(2)

• Dystrophic Calcification
• In areas of necrosis
• No calcium metabolic derangements
• Metastatic calcification
• In normal tissues
• Some calcium metabolic derangements

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Irreversible Cell Injury
Cell Death
1. Necrosis

A sequence of morphologic changes that follow
cell death in living tissue
2. Apoptosis
A distinctive and important mode of cell death
regulated by genes
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Necrosis
(1)

• Two essentially concurrent processes to produce
  the morphologic changes
• 1. Enzymatic digestion of the cell
• 2. Denaturation of proteins

Autolysis Heterolysis
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Necrosis
(2)

• Basic pathologic changes
• Types of necrosis
• Sequences of necrosis

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Necrosis
(3)

• Basic Pathologic Changes

Pyknosis

• Nuclear changes

Karyorrhexis
Karyolysis

• Cytoplasm

Increased eosinophilia
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Necrosis
(4)

• Types of Necrosis

• Coagulative necrosis

• Liquefactive necrosis

• Caseous necrosis

• Fat necrosis

• Gangrene

• Fibrinoid necrosis

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Coagulative Necrosis

• A mass of coagulated, pink-staining, homogeneous
  cytoplasm
• Preservation of the basic structure outline of
  the coagulated cell or tissue for several days
• In solid organs (kidney, heart, spleen )

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Liquefactive Necrosis

• Liquefaction of necrotic cells
• Condition Presence of more abundant proteolytic
  enzymes
• Most often in suppurative inflammation in the
  brain

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Caseous Necrosis

• A distinctive form of coagulative necrosis
• Cheese-like
• An amorphous coarsely granular eosinophilic
  debris
• Most often in foci of TB

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Fat Necrosis

• A special type of liquefactive necrosis
• Focal areas of fat destruction
• Calcium soaps
• Enzymatic fat necrosis(acute pancreatitis)
• Nonenzymatic fat necrosis (following direct
  trauma to adipose tissue extracellular
  liberation of fat)

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Gangrene

• Extensive tissue necrosis
• Secondary bacterial infection

• Dry gangrene
• Wet gangrene
• Gas gangrene

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Fibrinoid Necrosis

• A type of connective tissue necrosis
• Loss of normal structure
• A homogeneous,bright pink-staining necrotic
  material that resembles fibrin microscopically

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Necrosis
(5)

• Consequences of Necrosis

• Autolysis inflammation

• Dissolution absorption

• Sloughing

Ulcer, Cavity, Sinus, Fistula

• Organization encapsulation

• Calcification