Lecture 4 1/29/24 Flashcards
What are the common causes of liquefactive necrosis?
-bacterial infection
-neutrophilic infiltrate
What happens in liquefactive necrosis?
tissue becomes liquified
What are the two main examples of liquefactive necrosis?
-abscess
-center of a tumor (ischemic necrosis)
What is the cause of caseous necrosis?
specific bacterial infection
What are the characteristics of caseous necrosis?
-loss of architecture
-tissue is solid and friable
-present at center of granulomas
What are the characteristics of enzymatic fat necrosis?
-gross appearance is chalky, opaque, white spots in abdominal fat
-leads to pancreatitis
What is the pathogenesis of enzymatic fat necrosis?
-pancreas releases enzymes into tissue
-digestion of abdominal fat
-precipitation of calcium to form soap
What are the characteristics of nutritional/toxic fat necrosis in fish eating carnivores?
-gross appearance is generalized yellow-orange fat
-fat is very firm and necrotic
What is the pathogenesis of nutritional/toxic fat necrosis in fish eating carnivores?
-diet high in (rancid) fish leads to excess oxidized fats
-antioxidant deficiency develops
-free radical injury of the tissue occurs
What are the characteristics of nutritional/toxic fat necrosis in ruminants?
-gross appearance is very firm, opaque abdominal fat
-pathogenesis is unknown
What are the predisposing factors of nutritional/toxic fat necrosis in ruminants?
-grazing fescue
-genetics
-increasing age
What treatment can potentially be used for nutritional/toxic fat necrosis?
vitamin E
What is apoptosis?
programmed cell death/suicide
What is physiologic apoptosis?
cell death required for normal development and homeostasis
What are the examples of physiologic apoptosis?
-embryogenesis
-immune tolerance
-uterine involution
-tissue homeostasis
What is pathologic apoptosis?
excessive or deficient apoptosis that results in disease
What are the examples of pathologic apoptosis?
-virus-induced (increased)
-viral inhibition (decreased)
-autoimmunity (decreased)
-neoplasia (decreased)
What are the general steps of apoptosis?
-signaling
-control
-execution
-removal
What are the potential signals for apoptosis to occur?
-irreparable DNA damage
-death receptor binding
-lack of necessary factors
What is the key takeaway of apoptosis control?
this step determines whether a cell will commit to or abort the apoptotic pathway
What is p53?
-a control molecule that induces apoptosis following irreparable DNA damage
-often mutated in cases of cancer
What are the characteristics of the execution step of apoptosis?
-mediated by caspases
-caspases activate other enzymes that destroy cell
-cell membrane stays intact
What are the steps of the removal stage of apoptosis?
-surface membrane phospholipid is flipped to be exposed on cell surface
-phagocytes recognize this signal and engulf the apoptotic bodies
What is autolysis?
disintegration of cells and tissues after death of the organism
How can autolysis be differentiated from necrosis?
-autolysis lacks a host response/inflammation
-autolysis is diffuse
What are the factors contributing to autolysis?
-tissue type
-temperature
-bacteria
-insulation
-time
What are the characteristics of gas accumulation as a post-mortem lesion?
-gas is produced by bacteria that proliferate post-mortem
-begins in the intestines
-can result in rectal prolapse
-gas bubbles/emphysema seen in many tissues
What is bloat line?
delineation in the tissue in cattle that indicates that bloat occurred prior to death
What is the pathogenesis of bloat line?
-greatly distended stomach compresses thorax
-compression of veins more than arteries at thoracic inlet
-congestion/blood pooling of everything cranial to thoracic inlet
-delineation seen in esophageal mucosa (white tissue)
In which species is post-mortem gastric rupture often seen in?
rabbits and horses
