Necrosis Flashcards
What is Necrosis?
termed used to describe the range of morphological changes that occur following cell death in the living animal.
the morphological appearance of necrosis is due to what?
Denaturation of proteins
Enzyme digestion of the cell
end result is inflammation
What does Karolysis mean?
nuclear fading, chromatin dissolution due to action of DNAases and RNAases
What is pyknosis?
Nuclear Shrinking
DNA condenses into shrunken basophilic (purple) mass
What is Karyorrhexis?
Nuclear fragmentation
Pyknotic nuclei membrane ruptures and nucleus undergoes fragmentation
Karyolysis, Pynosis, and karyorrhexis all lead to what?
Nuclear dissolution then to Anuclear necrotic cell
What is coagulative necrosis?
form in which the dead tissue is perserved for days, affected tissue is firm.
what is coagulative necrosis caused by?
caused commonly by ischemia in all solid organs except the brain.
what is an infarct?
a localized area of coagulative necrosis- ischemia necrosis infarcts can appear white.
what is liquefactive necrosis?
dead cells are digested- resulting in transformation of the tissue into a liquid mass.
what happens in liquefactive necrosis?
microbes stimulate the accumulation of WBCs and liberation of enzymes from these cells
what does malacia mean
softening of the tissue
what does polio mean?
grey matter
what is myliomalacia?
softening of the spinal cord
liquidofactive necrosis is always in the?
CNS
in a histology off liquidofactive necrosis there is ?
loss of cellular detail, cannot tell the tissue type
difference between liquiofactive necrosis and an abscess
Abscess is surrounded by a fibrous capsule layer chronic
result of bodies defensive rxn to foreign material
what is the most common cause of pyogenic (pus) abscess?
staph and strep
What is caseous necrosis?
chronic necrosis, Cheeselike, crumble, necrotic due to dead WBC
myco, and coryne and fuso bact along with fungal
What is Dry Gangrenous Necrosis?
no bacterial superinfection
How does gangrenous necrosis begin
begins mostly as coagulative necrosis, likely due to ischemia
What is Wet Gangrenous necrosis?
bacterial superinfection, tissue looks wet and liquiofactive
what does the dark color come from in wet gang green?
bursting RBC and release of hemoglobin
what is the color from in dry gang green?
black, post mortem change although attached to a live animal
What is enzymatic necrosis of fat?
Pancreatic necrosis, looks white like soap
What is tramatic necrosis of fat?
tend to mineralize and get really hard, dystosia, subQ sternum in recumbent cattle
Necrosis of abdominal fat in cattle
idopathic (dont know cause)
Jersey and Guernesy most common (channel island breeds)
What is Fibroid necrosis?
special form of necrosis typically seen in immune reactions involving blood vessels.
Ag-Ab complexes are deposition in the walls of arteries
what is a cause of fibroid necrosis?
Viral, bacT Dz infection inducing inflammation for too long - forming immune complexes
Cell size in necrosis
enlarged
nucleus in necrosis
Pykinosis > Karyorrhexis > karyolysis
Plasma membrane in necrosis
Disrupted
Cellular contents in necrosis
enzymatic digestion, may leak out of cell
adjacent inflammation of necrosis
frequent
physiological or pathologic role of necrosis
invariably pathological (culmination of irreversible cell injury)
