Cellular Injury and Adaptation (P) Flashcards
*What are the mechanisms of cell injury?
What are the causes of injury?
1) Hypoxia
2) Chemicals and drugs
3) Physical agents
4) Microbiologic agents
5) Immunologic rxns
6) Genetic defects
7) Nutritional imbalances
8) Aging
*What are the targets of injurious stimuli?
(all *)
1) Aerobic respiration
2) Integrity of cell membranes
3) Protein synthesis
4) Cytoskeletal system
5) Integrity of the genetic apparatus of the cell
*Principles and concepts
What are the causes of atrophy?
1) Decreased workload
2) Loss of innervation
3) Diminished blood supply
4) Inadequate nutrition
5) Loss of endocrine stimulation
6) Aging
Atrophy results from what?
It results from decreased protein synthesis and increased protein degradation
What is the function of ubiquitin-proteasome pathway?
It activates ubiquitin ligases
What is the characteristic of ubiquitin-proteasome pathway?
Accelerated proteolysis
What is the characteristic of atrophy?
It is accompanied by increased autophagy
What are the causes of hypertrophy?
1) Physiologic
A. Hormonal
-> estrogen stimulation of uterus in pregnancy
B. Compensatory
2) Pathologic
A. Excessive hormonal stimulation
B. Viral-induced*What is the characteristic of hypertrophy?
*It involves signals
*What are the 2 triggers that involves signals?
(all *)
1) Mechanical triggers
2) Trophic triggers
What are signal transduction pathways and its purpose?
*These are the induction of genes that stimulate protein
*Growth factors
*Growth factors
What are the causes of hyperplasia?
1) Physiologic
A. Hormonal
-> estrogen stimulation of uterus
B. Compensatory
2) Pathologic
A. Excessive hormonal stimulation
B. Viral-inducedWhat are the causes of metaplasia?
1) Persistent irritation
2) Infection
3) Malnutrition
What is deranged development (under dysplasia)?
1) It is the proliferation and atypical cytologic alterations
2) It is the change in size, shape, and organization
What is the characteristic of dysplasia?
It is not an adaptive mechanism but a change for the worse
What are the exs of reversible injury?
1) Cellular swelling
2) Fatty change
*What is the characteristic of necrosis?
It is a form of irreversible injury
What is necrosis?
It is the sum of all the morphologic changes that follow after cell death
What are the types of necrosis?
1) Liquefaction necrosis
2) Coagulative necrosis
3) Enzymatic fat necrosis
4) Caseous necrosis
5) Gangrenous necrosis
Liquefaction necrosis results from what?
It results from the action of powerful hydrolytic enzymes
What are the characteristics of liquefaction necrosis?
1) It is best exemplified by brain infarction
2) It is brought about by ischemic destruction of brain tissue
3) It is a form of common “pus”, abscess
Coagulative necrosis results from what?
It results from the total occlusion of supplying vessels especially in solid organs
*The total occlusion of supplying vessels especially in solid organs (in coagulative necrosis) results to what?
1) Conversion of the cell to acidophilic tombstone
2) Loss of nucleus but cell architecture preserved
3) Protein denaturation (precipitation)
4) Exemplified by myocardial infarction
What is enzymatic fat necrosis?
It is the destruction of fat resulting from abnormal release of enzymes especially lipases
*The principle of action that destruction of fat results from abnormal release of enzymes especially lipases is an ex of what?
*Acute pancreatitis
What is the principle of action of saponification?
The action of lipase on fat results in dissolution together w/ hydroxyl ions (-OH) will produce soap w/ addition of Ca will result in formation of “chalky” mat
What is caseous necrosis?
It is the combination of liquefaction and coagulative necrosis
What are the characteristics of caseous necrosis?
1) It is only seen in tuberculosis process
2) It has a characteristic “cheesy appearance”
What is gangrenous necrosis?
It is the combination of liquefaction and coagulative necrosis
What are the 2 types of gangrenous necrosis?
1) Dry
2) Wet
The classification of gangrenous necrosis regarding on what type is it classified in depends on what?
It depends on the predominance of necrosis
Provide an ex of dry (type of gangrenous necrosis)
Gangrene of the foot due to diabetes
Provide an ex of wet (type of gangrenous necrosis)
Gangrene of loose organs (e.g. appendix)
What is apoptosis?
1) It is a tightly intracellular program whereby cells destined to die activate enzymes that degrade the cell’s own nuclear DNA and nucleo-cytoplasmic protein
2) Programmed cell death
What are the mechanisms of apoptosis in physiologic situations?
1) Programmed destruction of cells during embryogenesis
2) Hormone-dependent involution in aging
3) Cell deletion in proliferating cell populations
4) Death of host cells that have served its purpose
5) Elimination of potentially harmful self-reactive lymphocytes
6) Cell death induced by cytotoxic T cells
*What are the characteristics of intracellular accumulations?
1) Increased production w/ N metabolism
2) Lack of enzymes for endogenous by-products of metabolism
3) Exogenous substance not metabolized because of absence of enzymes
