Chapter 2 NECROSIS: Irreversible Injury Flashcards
Refers to the rapid death of a limited portion of an organism and is considered to be the final stage in irreversible degeneration.
Necrosis
Term used for the entire process of degeneration and death of cells.
Necrobiosis
The tissue was dead prior to the time of removal from the live body or prior to the time of the animal’s or human’s death.
Necrosis
Morphological type of necrosis and suggests a semi-solid or fluid mass that has been present for some time undergoing self-digestion.
implies the rapid enzymatic lysis of dead
cells.
Four types of nuclear changes that may occur:
1.Pyknosis – condensed nucleus
2.Karyorrhexis–shattered nucleus
3.Karyolysis – dissolving nucleus
4.Absence of the nucleus - after dissolution
leaving a hollow, ghost appearance.
The gross indications of necrosis are:
- loss of color or paleness of the tissue
- loss of strength of the tissue as it softens
- a definite zone of demarcation between necrotic and viable tissue
- the location or pattern of the lesion.
death of cells following irreversible cell injury. It is the outcome of irreversible cellular degeneration.
Necrosis
Owing to lysosomal
disruption
Lysis of the cytoplasm
refers to severely eosinophilic or reddish cytoplasm
Adicophilia of the cytoplasm
an area of necrosis in which the gross and microscopic architecture of the tissue and some of the cells are recognizable. This condition may result from acute
deprivation of blood supply.
Coagulative or Coagulation Necrosis
Distinctive type of necrosis and occurs in the abdominal cavity or under the skin. On cut surface, there are had white gritty lumps.
Fat Necrosis
Is manifested by loss of recognizable architecture and will contain combinations of much dark nuclear debris and amorphous eosinophilic cytoplasmic debris, perhaps mixed with components of blood clots, hemorrhage, thrombi and calcification.
Caseous or Caseation Necrosis
seen in pancreatitis
Fat necrosis
Implies “curdle or cheesy” as in tuberculous lesions.
Caseous or Caseation Necrosis
characterized by the presence of friable, cheesy, amorphous material in necrotic area. This term is usually reserved for tuberculous lesions.
Caseous or Caseation Necrosis
and in adult cow, can cause death due to necrosis and hardening of intestines (lipomatosis).
Fat necrosis
The requirement for GANGRENE is?
necrosis plus putrefaction
Occurs when saprophytic
bacteria grow in necrotic tissue.
Gangrene or Gangrenous Necrosis
This occurs in necrotized portion of the skin with moisture loss due to evaporation and drainage and presence of saprophytic bacteria. Extremities such as the tail, ears or limbs are the usual location.
Dry gangrene
Two types of gangrene
Dry gangrene and
Wet gangrene
Color is usually black, with gas bubbles and may have much hemorrhage and edema in and around the lesion.
Wet gangrene
A type of coagulative necrosis in striated muscles characterized by loss of striations following necrosis.
Zenker’s Necrosis (Zenker’s degeneration)
A form of coagulative necrosis resulting from a sudden deprivation of blood supply. Commonly occurring in areas or organs with end artery (i.e., kidney) blocked by thromboembolic lesions.
Infarct
a special form of necrosis with fibrinoid accumulating in along walls of blood vessel and connective tissues.
Fibrinoid Necrosis
Is a shallow area of necrosis confined to epidermis that heals without scarring.
Erosion
An excavation of a surface produced by necrosis and sloughing of the necrotic debris and implies involvement of the tissue below the surface layer.
Ulcer
A piece of necrotic tissue in the process of separation from viable tissue and implies a process of shedding when used with reference to a surface.
Slough
A piece of necrotic tissue separating from viable tissue.
Slough
This term is applied to necrosis of surface epithelia.
Slough
An area of liquefactive necrosis of the nervous tissues. Literally means “softening”.
Malacia
An isolated necrotic mass.
Sequestrum
The deposition of calcium salts in soft tissues. Usually occurs following tissue necrosis
Calcification
The process of sequestrum.
Sequestration
When calcium salts are deposited in damaged cells and tissues.
Dystrophic calcification
Deposition of calcium salts in vital tissues and is always associated with hypercalcemia.
Metastatic Calcification
Term sometimes used for extensive metastatic calcification.
Calcinosis
A term that describes widespread of deposition of calcium in tissues of individual treated with a calcium sensitizer.
Calciphylaxis
Considered an experimental condition.
Calciphylaxis
Sensitizers include vitamin D, parathyroid hormone or calcium ions.
Calciphylaxis
May occur naturally; by overfeeding mineral and vitamins.
Calciphylaxis
Is released from the cytoplasm of injured
liver cells. (in moderate injury)
Alanine transaminase (ALT), also called as serum glutamic pyruvic transaminase (SGPT)
Is located in mitochondria and is released in more extensive injury. This occurs in liver, muscles etc… But take note that it is not tissue specific as in ALT.
Aspartate transaminase (AST), also called serum glutamic-oxaloacetic transaminase (SGOT)
Other enzymes used to evaluate tissue damage
are:
- Lactic dehydrogenase (LHD)
- Creatine phosphokinase (CPK)
- Alkaline phosphatase (AP)
Specific enzymes the heart releases into the blood can be assayed to assess the extent of necrosis.
Troponin, creatine kinase (CK) isoform (cardiac specific)
Specific enzymes the liver releases into the blood can be assayed to assess the extent of necrosis.
Alanine aminotransferase (ALT), Aspartate aminotransferase (AST)
Specific enzymes the Skeletal muscles release into the blood can be assayed to assess the extent of necrosis.
Aspartate aminotransferase (AST), creatine kinase (CK) isoform
Specific enzymes the pancreas releases into the blood can be assayed to assess the extent of necrosis.
pancreatic specific lipase
The rigidity or stiffening of muscles after death. This is due to contraction of
muscle fibers as ATPs are depleted or exhausted.
Rigor mortis
Means self-digestion by the tissues’ enzymes that are present in, or released into, the cytoplasm of the cell after death.
Autolysis
Refers to the gradual cooling of the body after death.
Algor mortis
Term for the gravitational settling of blood to the downside of the animal. In this instance, you will know the position of the individual when it was dead.
Livor mortis
Post-mortem changes
- Imbibition with hemoglobin discoloration results from breakdown of hemoglobin and the action of bacterial hydrogen sulfide on hemoglobin.
- Imbibition with bile
- Post-mortem clots (currant-jelly and chicken fat clots)
Necrosis →
Calcification
Necrosis → Localization →
Sequestration
Necrosis → Localization → Sequestration →
Resorption → Granulation tissue (Scar formation; fibrosis)
Necrosis → Lysis →
→ Cyst
→ Cavity
Necrosis → Secondary infection →
→ Abscess
→Gangrene
