Cell Injury And Cell Death Flashcards
one of the most crucial events in the
evolution of disease in any tissue or organ.
Cell death
Causes of cell injury
- oxygen deprivation
- chemical/toxicagents
- infectious agents
- immunologic reactions
- genetic defects
- nutritional imbalances
- physical agents
- aging
is the most common cause of
hypoxia, oxygen deficiency can
also result from inadequate
oxygenation of the blood
Ischemia
common cause of cell
injury and death
Hypoxia, or oxygen
deficiency
Øa loss of blood supply in
a tissue due to impeded
arterial flow or reduced
venous drainage.
Hypoxia
Patient with ischemia may also has
Pneumonia
Anemia
Carbon monoxide poisoning
Toxic agents encountered in our environment
- Air pollutants
- Insecticides
- CO
- Asbestos, - Ethanol (social “stimuli“)
- Therapeutic drugs
commonly known as poisons
Agents
Cause severe damage at the cellular level by altering membrane permeability
chemical agents
against one’s own tissues
Autoimmune reaction
against environmental
substances
Allergic reactions
Associated with down syndrome
Congenital malformations
Nutritional deficiencies major cause of cell
injury
- Protein-calorie insufficiency
- Vitamin deficiencies
- Nutrition causes of morbidity and mortality
example of physical agents
- Trauma
- Extremes of temperatures
- Radiation, electric shock
- Sudden changes in atmospheric pressure
Leads to alterations in replicative and repair abilities of individual cells and tissues
aging
Result of failure of energy-
dependent ion pumps in the
plasma membrane
cellular swelling
Diminished ability to respond to damage
Aging
Microscopic examination of cellular swelling
small, clear vacuoles within the
cytoplasm
Inability to maintain ionic and fluid
homeostasis
cellular swelling
Occurs in hypoxic injury and in various
forms of toxic or metabolic injury
Fatty change
manifested by the appearance of
small or large lipid vacuoles in the
cytoplasm
Fatty change
Depletion of ATP
reduced supply of oxygen
reduced supply of nutrients,
mitochondrial damage,
actions of some toxins
mechanism of cell injury
- mitochondrial damage
- entry of calcium
- membrane damage
- protein misfolding, dna damage
type of cell death that is
associated with loss of membrane integrity
and leakage of cellular contents
necrosis
Dead cells may be replaced by
myelin figures
Results from sudden
interruption of blood supply to an
organ, especially to the heart
coagulative necrosis
It characteristically results
from ischemic injury to the
cns
liquefactive necrosis
It also occurs in
suppurative infections
characterized by formation
of pus
liquefactive necrosis
The areas of white chalky deposits represent foci of fat
necrosis with calcium soap formation
fat necrosis
microscopic appearance of caseous necrosis
amorphous eosinophilic
material
Due to vascular occlusion
gangrenous necrosis
complicated by bacterial
infection which leads to
superimposed liquefactive
necrosis
wet gangrene
only coagulative
necrosis without liquefactive
necrosis
dry gangrene
special form of necrosis,
visible by light microscopy
fibrinoid necrosis
pathway of cell death in
which cells activate enzymes that degrade
the cells’ own nuclear DNA and nuclear and cytoplasmic proteins
apoptosis
Apoptosis in Physiologic Situations
eliminate cells that are no longer needed
and to maintain a constant number of cells
of various types in tissues
Responsible for apoptosis in
most physiologic and
pathologic situation
mitocondrial or intrinsic pathway
Responsible for elimination of
self-reactive lymphocytes and
damage by cytotoxic T
lymphocytes.
Death receptor or extrinsic pathway
