Exam 1 Flashcards
Characteristics of reversible cell injury
i. Light Microscopic Changes: Cell swelling, Chromatin clumping, Lipidosis
ii. Dilation of endoplasmic reticulum
iii. Ribosomal detachment from RER
iv. Loss of microvilli and cilia
v. Mitochondral swelling
vi. Chromatin clumping
vii. Membrane blebs
viii. Lipid accumulation
ix. Organ will be discolored, enlarged, or discolored
Characteristics of irreversible cell swelling
Nuclear changes!
a. Pyknosis
c. Chromatolysis
2. Increased eosinophilia of cytoplasm (can have vacuolization and/or calcification)
ii. High amplitude mitochondrial swelling
iii. Membrane defects of ER
iv. Lysomal membrane rupture
Occurs due to general mechanisms of cell injury. Dead cells have active proteases, phospholipidases, and endonucleases that will break down cell components
coagulation necrosis
Occurs in tissue with high neutrophil recruitment and enzymatic release with digestion of tissue. Also, occurs in tissues with high lipid content such as the brain.Loss of cell borders occurs.
Liquefactive necrosis
Occurs commonly with mycobacterial infections. Macrophages are recruited and cells become necrotic as the organism persists
caseous necrosis
ischemic necrosis of distal extremeties
gangrenous necrosis
Necrosis of adipocytes and white lesions in fat due to cleavage of neutral fat by lipase to triglycerides and FAs with precipitation of FA by calcium to form FA soaps
Fat necrosis
Triggered by specific cell-mediated stimulus or loss of signals
Can be pathogenic
Will see chromatin condensation and fragmentation, formation of membrane blebs and cell fragments being phagocytize
apoptosis
Commonly induced by ATP depletion (ischemia), free radicals, membrane damgae, or CA influx. Will see large amplitude of mitochondrial swelling, membrane defects, lysosomal membrane rupture, nuclear condensation, fragmentation, and dissolution
Necrosis (irreversible cell injury)
What are the 2 primary mechanisms in the induction of apoptosis
Extrinsic (death receptor initiated pathway)
Intrinsic (mitochondrial pathway)
TNF receptor or Fas receptors binding to ligands to activate initiator caspases or injury
extrinsic pathway of apoptosis
Increase in mitochondrial permeability releases pro-apoptotic molecules, like cytochrome c
intrinsic pathway of apoptosis
What role does Bcl-2 play in the development of apoptosis?
inhibitor at the intrinsic level
What factor released from mitochondria in response to injury induces capase cascade activation
cytochrome C
What cell components and/or cell functions are most susceptible to injury that induce necrosis?
cell membranes
aerobic respiration
synthetic apparatus (proteins, enzymes)
genetic apparatus
What terminal biochemical and structural processes are nduced by influx of large concentrations of calcium (from ER and cell exterior) into cytosole that occur in necrosis
phospholipase- leads to membrane phospholipis and membrane lysis
ATPase- leading to decreased ATP
Protease- leading to disruption of membrane and cytoskeletal proteins
Endonuclease- leading to damage in the nucleus
What are the main sources of free radicals in tissue that contribute to tissue injury?
absorption of radiation energy (UV light)
Redox reactions (e.g. FENTON REACITON)
Exposure to toxins such as oxygen, CCl4, drugs
How do free radicals contribute to cell injury and cell death?
Lipid peroxidation of membranes (loss of membrane function, increased permeability) DNA damage (leads to mutations and death) Cross linking of proteins
Name 2 important free radical scavengers
Vitamin E and Glutathione
Terminates lipid peroxidation and membrane damage
Vitamin E
Decrease in cell size due to decrease in demand or lack of nutrients, oxygen, endocrine, or nerve stimulation
atrophy
Increase in cell size (substance)
hypertrophy
Increase in cell number
hyperplasia
Replacement of one adult cell type with another
metaplasia
Abnormal calcium deposit in normal tissue secondary to hypercalcemia
metastatic calcification
Elevated serum Ca and abnormal Ca metabolism that leads to calcification
Metastatic calcification
Hypervitaminosis D and Primary (or secondary) hyperparathyroidism
Metastatic calcificaiton
Abnormal calcium deposition in dead or degenerating tissue
Dystrophic calcification
Normal serum Ca levels and Ca metabolism that leads to calcification
Dystrophic calcification
Vitamin E or selenium deficiency (ex: white muscle disease) and renal infarction calcification
Dystrophic calcification
Accumulation of abnormal proteinaceous substances from several protein sources, eosinophilic, and accumulates between cells and has beta pleated sheet conformation
amyloidosis
Amyloid composed of immunoglobulin light chains- AL associated with beta cell proliferative diseases
Primary amyloidosis
amyloid composed of unique, non-immunogenic protein- SAA (serum amyloid A)
Secondary amyloidosis (most common in animals)
Islet amyloid in cats- islet amyloid polypeptide (IAPP)
Endocrine amyloidosis
Formation of senile plaques-APP (amyloid precursor protein)
Beta-amyloid amyloidosis
Brief mechanism that is responsible for chronic inflammatory reactions leading to the deposition of amyloid in tissues
chronic inflammation–>macrophage activation, interleukins 1 and 6 and TNF–>liver cells produce SAA–>SAA undergoes limited proteolysis–>AA protein
How does amyloid contribute to tissue dysfunction in renal amyloidosis
results in protein-losing nephropathy
marked increase in permeability of serum protein
How could you distinguish necrosis of skeletal muscle from autolysis in a cow during the gross examination of a necropsy
Both would cause tissue to be bale and diffuse changes..
Autolysis- there would be no tissue response (i.e. inflammation) and in necrosis there would be an inflammatory response
Which of the following changes are seen in reversible cell injury? A. Mitochondrial swelling B. Swelling of ER C. Pyknosis and karyorrhexis D. A and B E. A,B, C
D
Condensation of nucleus
Pyknosis
Nuclear condensation and fragmentation
Karyorrhexis
Chromatin disappearing
chromatolysis
Which are defining characteristics of necrotic cells?
A. Lipid accumulation in cyto B. Swelling of ER
C. Pyknosis and karyorrhexis
D. Nuclear chromatolysis
E. C and D
E
Which of the following mechanisms contributes most to cell death in hypoxic tissue injury?
A. ATP depletion
B. Free radical injury
C. DNA damage
D. Protein misfolding, E. Membrane damage.
A
Ischemia reperfusion injury is characterized by which of the following mechanisms of injury?
A. ATP depletion
B free radical injury
C. protein misfolding and apoptosis
A and B
Causes brown discoloration in tissue and brown, granular pigment in H and E stain
lipofuscin
What causes lipofusin reaction?
Lipid peroxidation reactions (free radical damage), increased with vitamin E deficiency
What stain is ideal for lipofuscin?
acid fast
Pigment that is derived from hemoglobin when RBC’s are phagocytized an degraded intraceullarly
Hemosiderin
Grossly looks reddened, but microscopically is a golden-brown pigment that is intracytoplasmic
hemosiderin
What stain is best for hemosiderin?
Prussian blue
Can form in increased heme breakdown, decreased hepatic uptake, impaired conjugation, impaired intra-hepatic excretion, bile duct obstruction
bilirubin
Seen grossly as very yellow tinged
bilirubin
Calcification in a renal infarct is most likely do for?
a. Dystrophic
b. Metastatic
dystrophic
Which of the following are mechanisms of metatstatic calcification?
a. CCL4 toxicity
b. Primary parathyroid tumor
c. Hypervitaminosis D
d. A, B, and C
e. B and C
E
Vitamin E deficiency and lipid peroxidation contributes to formation of which pigment?
a. Hemosiderin
b. Lipofuscin
c. Bilirubin
d. Melanin
e. Hematoidin
B
Which of the following pigments can result in brown pigmentation of organs and cytoplasm
a. Melanin
b. Hemosiderin
c. Lipofuscin
d. Bilirubin
e. A,B,C
E
The most common form of amyloidosis in animals is derived from?
a) Immunoglobulin- Primary
b) Serum amyloid A protein- secondary
c) Islet amyloid polypeptide
d) Apolipoprotein
e) Amyloid precursor protein
B
The form of amyloid associated with diabetes mellitus in cats:
a) Immunoglobulin- Primary
b) Serum amyloid A protein
c) Endocrine amyloid-islet amyloid polypeptide
d) Apolipoprotein
e) B amyloid
C
Which of the following mechanism most likely explains edema fluid with high protein content
a) increased hydrostatic pressure
b) Increased vascular permeability
c) Decreased oncotic pressure
d) Lymphatic obstruction
e) Sodium retention in renal disease
B
Accumulation of abnormal amounts of fluid in the intercellular and extracellular tissue spaces or body cavities
Edema
What has occurred with tissue that is swollen, and oozes clear or blood-tinged fluid when cut?
Edema
Seen microscopically as interstitial spaces enlarged, often with eosinophilic granular residue of protein in the edema fluid
edema
WHAT ARE THE MAJOR PATHOGENIC MECHANISMS THAT CONTRIBUTE TO EDEMA FORMATION
a. Increased hydrostatic pressure (increased BP in a capillary bed)
b. Increased vascular permeability (e.g. inflammation)
c. Decreased oncotic pressure (hypoalbuminemia)
d. Lymphatic obstruction
e. Sodium retention in renal disease
What are the basic pathogenetic mechanisms responsible for hemorrhage?
- Trauma and other injury
- Diapedesis (blood passing between endothelial cells at cell junctions)
- Hemorrhagic diathesis (diseases of bleeding)
What factors determine the path. significance of hemorrhage?
location
rate
volume
How does edema contribute to diminished tissue function?
causes fluid compression of adjacent structures
Creates diffusion/transportation barrier
Alters mechanical properties of tissue
Alter cell function in in interstitium
How does hemorrhage contribute to diminished tissue function?
i. Due to hypovolemia and anemia, you can get hypoxemia, can cause poor tissue perfusion locally, can become space occupying and compressive
Formation of fibrin clot
coagulation
process of resulting in the termination of hemorrhage
hemostasis
process of intravascular (or intracardiac) formation of a clot of fibrin and platelets during life
thrombosis
What role doe coagulation play in hemostasis and thrombosis?
helps stop hemorrhage (hemostasis)
Coagulation in non-hemorrhagic vessels will lead to a formation of thrombus
Which of the following mechanism most likely explains edema fluid with high protein content?
a) increased hydrostatic pressure
b) Increased vascular permeability
c) Decreased oncotic pressure
d) Lymphatic obstruction
e) Sodium retention in renal disease
B. Increased vascular permeability
What processes lead to activation of the intrinsic pathway for coagulation?
Activation of Hageman Factor (XII)
What processes lead to activation of the extrinsic pathway for coagulation?
release of thromboplastin (factor III) it is a membrane associated protein of lipoprotein
Are the two pathways (intrinsic and extrinsic) for coagulation ever activated simultaneously?
YES
What is Virchow’s triad?
Alteration in vessel wall
Changes in blood flow
Changes in the blood that promotes thrombosis (HYPERcoagulation)
What is the role of platelets in coagulation and hemostasis?
Forms a platelet plug at the site of vessel injury, enhancing coagulation
What are the three main platelet functions involved in hemostasis?
adhesion
Platelet release action
Platelet aggregation
How do endothelial cells promote coagulation and thrombosis?
release of thromboplastin and expose collagen when injured
How do endothelial cells inhibit coagulation and thrombosis?
Synthesis and release of: Prostacyclin (PGl2), plasminogen activator, and NO
Binds to thrombin and thrombomodulin which activates protein C (has anticoag properties)
Thrombosis centrally involves coagulation, platelet aggregation and….
a) High blood flow
b) Increased vascular permeability
c) Increased hydrostatic pressure
d) Vessel wall
e) Lymphatic obstruction
D. Vessel wall
A thrombus carried from its site of vascular origin to a more distant vessel is a:
a) Thrombus
b) Embolus
c) Blood clot
d) Hematoma
e) Thromboembolus
B and E
Vessel wall damage can initiate coagulation via:
a) Collagen exposure and Hageman factor activation
b) Endothelial cell release of tissue factor (III)
c) Release of plasminogen activator
d) A and B
e) A,B,C
D
SN: plasminogen breaks down fibrin clot
Endothelial cells inhibit thrombosis by:
a) Thromboxane A2 production
b) Prostacyclin production
c) Bind inhibitors of thrombin
d) A, B, C
e) B, C
E
Damaged endothelial cells release the following to promote thrombosis
a) Tissue factor (III)
b) Antithrombin III
c) Von Willebran’s factor
d) A, B, C
e) A, C
E
What types of abnormalities might lead to a hypercoagulable state?
- decrease in anti-coag factors: protein C and S, or antithrombin
- Elevation in clotting factors like fibrogen, prothrombin, factors VII, VIII, and X
- in dieeminated neoplasia, extensive release of factor III
Protein C, S, and antithrombin III are
anti-coag factors
Fibrogen, prothrombin, and factors VII, VIII, and X promote?
clotting
Breaking down of a thrombus
fibrinolysis
What steps are needed for fibrinolysis to initiate?
Factor XII (Hageman) activated plokallikrein-->kallikrein which helps plasminogen form plasmin Also, tissue plasminogen activator activates plasminogen-->plasmin
Plasmin then goes on to form fibrin split products
Which 3 major events are important in the pathogenesis of thrombosis?
Virchow’s triad
i. Alterations in vessel wall
ii. Changes in blood flow (stasis and turbulence)
iii. Changes in blood promoting thrombosis (hypercoagulability)
Firm, friable
Occlude vessel and often red, attached to wall
Often completely occlude vessel
Large thrombi can be laminated (Lines of Zahn)
Venous thrombus