A.pathology Exam-unit 1+2+3 Flashcards
What is disease?
Not just illness or sickness, but alterations of normal form and function.
Clinically apparent or not
What is pathogenesis?
The development of a disease from initiation to cellular and molecular manifestations
When does cell injury occur?
When a cell no longer can maintain a steady state
When does cell death occur?
If cellinjury is excessive, beyond the point of no return
What is autolysis?
- post mortem
- self-digestion/degradation of cells and tissues by hydrolytic enzymes
- autolysis combined with putrefaction (bacterial breakdown of tissues)
What is the histomorphology of acute cell swelling?
Tremendous swelling of all mitochondria+ER
- clumped chromatin
- folded nuclear membrane
- pale+structureless cytoplasm
- poorly visualized organelles
What is pyknosis?
Shrunken, dark, homogenous and round nucleus
What is karyorrhexis?
Nucleus ruptures and dark nuclear fragments released into cytoplasm
What is karyolysis?
Extremely pale nucleus due to dissolution of chromatin, mainly by RNAase and DNAase action
What does absence of nucleus mean?
A later stage of karyolysis where nucleus has been completely dissolved or lysed
What is coagulation necrosis?
-preservation of outline of necrotic cells
- homogenous and eosinophilia cytoplasm due to protein coagulation
- pyknotic, karryohectic, karyolytic or absent nucleus
After lysis necrotic tissue will be phagocytosed
What is coagulation necrosis?
Mainly seen in kidney, liver, muscles but never in brain parenchyma
-due to hypoxia or ischemia, can be caused by toxins
What is caseation/caseous necrosis?
Conversion of dead cells into granular friable mass (cottage cheese appearance)
-coagulase of nuclear, cytoplasmic debris, mainly leukocytes
-older/chronic lesions
-all types of tissues
-surrounded by granulomatous inflammatory cells and fibrous CT capsule
Disrupted cell walls and tissue architecture is lost, mineralization is common
Classic cause is tuberculosis/paratuberculosis
What is liquefactive necrosis?
Mainly in the CNS
- due to hypoxic death of cells resulting in rapid enzymatic dissolution
What is gangrenous necrosis?
The continuation of coagulation necrosis
Three types
What is moist gangrene?
Area of necrotic tissue further degraded by liquefactive action of saphrophytic bacteria from local environment that usually cause putrefaction
Causes:
-infarction of an extremity or intestine
-aspirated irritant agent in lungs
Grossly:
-soft, moist reddish to black tissues
- If bacteria produce gas, gas bubbles and putrid odor from hydrogen sulfide and marcaptans May occur
May eventually be separated from the normal tissue and slough
What is dry gangrene?
-coagulation necrosis following infarction, results in mummification
- in lower part of extremity, tail, ears, udder
-could be due to ingested toxins or frostbite
-no proliferation of bacteria
-Grossly:
Shriveled, dry and brown to black tissue
What is gas gangrene?
-anaerobic bacteria proliferating and producing toxins (c.perfringens, C.septicum)
- in penetrating wounds, which is anaerobic (clostridium)
Grossly:
-dark red to black with gas bubbles and fluid exudate (May contain blood)
Microscopically:
-coagulation necrosis of muscle, serohemorrhagic exudate, gas bubbles
What is fat necrosis?
Three types -enzymatic/pancreatic fat necrosis - traumatic fat necrosis -fat necrosis of abdominal fat in cattle Microscopically: Necrotic fat remains after solvents used in histologic preparations, when sapofication of fat necrotic adipocytes become basophilic
What is enzymatic/pancreatic fat necrosis?
Destruction of fat in abdominal cavity, adjacent to pancreas
- due to activated pancreatic lipases in pancreatic fluid escaped from duct system
What is traumatic fat necrosis?
When adipose tissue is crushed.
-in fat adjacent to pelvic canal, subcutaneous tissue or in fat over sternumof recumbent cattle
What is fat necrosis of abdominal fat in cattle?
Large masses of necrotic fat in mesentery, omentum, retroperitoneally
