Cell Injury and Cell Death Flashcards
What forms the basis of most disease states
Loss of homeostasis
How do cells survive short term
Adaptation
Excessive cell swelling and dramatic changes to the cellular organelles
Morphologic characteristics
Hallmark of irreversible cell injury or death
Massive influx of calcium
Cell death due to injury
Necrosis
Cell death due to physiological turn over of cells
Apoptosis
Shrinkage of tissue or organ size due to reduction in cell size
Atrophy
Increase in cell size in response to stress
Hypertrophy
Increase in cell number by mitotic division
Hyperplasia
What cells are capable/ not capable of mitotic division (hyperplasia)
Capable:
Epithelial
Not capable:
Cardiac cells
Reversible process whereby one mature cell type is replaced by another less mature type
Metaplasia
Disordered growth and maturation of the cellular components of a tissue
Dysplasia
Provides useful hallmarks of cell injury. Cells due this under stress in response to metabolic derangements. May lead to cell injury or death.
Cellular accumulations
Where do lipids tend to accumulate in cellular accumulations
Heart and liver
Where does glycogen tend to accumulate in cellular accumulations
Liver and skeletal muscle
Where does melanin tend to accumulate in cellular accumulations
Skin
What cellular accumulations forms hemosiderin
Hemoglobin -Iron
Where does bilirubin tend to accumulate in cellular accumulations
Liver
What are 3 pigments that accumulate in cellular accumulations
Bilirubin
Hemosiderin
Melanin
Fine granular Golden brown pigment formed from phospholipids and proteins derived from degenerating membranes
Lipofuscin
What minerals tend to accumulate in cellular accumulations
Calcium
What determines outcome of pathological stress
Severity and duration of stimuli or pathological stress
What are the 4 cellular adaptations
Hyperplasia Hypertrophic Atrophy Metaplasia Dysplasia
Non dividing cells
Cardiac
Dividing cells
Epithelial cells
These cells can undergo hyperplasia and hypertrophy under stress
Epithelial cells
These cells can not divide so undergo hypertrophy increasing functional muscle mass
Cardiac cells
Pathological stimuli may be intrinsic , meaning
Genetic
Pathological stimuli may be extrinsic meaning
Acquired
Hypoxia cell injury leads to
Impaired energy production
Impaired energy production from hypoxia causes
Free radical injury
Free radical injury forms
Damaging reactive oxygen species ROS
Impaired calcium homeostasis compromises the
Cell membrane
Calcium influx causes cell death
What protects against Reactive oxygen species ROS
Superoxide dismutase SOD
How does SOD protect against ROS
Converts superoxide into hydrogen peroxide then catalase converts hydrogen peroxide into water and oxygen
When do excess ROS (which is damaging to cell proteins and lipids) form
When oxygen is limited
Name the antioxidant system that stops excess ROS/superoxide
Superoxide dismutase
This antioxidant converts hydrogen peroxide to water and oxygen
Catalase
Excess ROS causes
Cell damage
Leaking membranes
Calcium influx
Cell death
Ischemia is caused from
Lack of blood oxygen flow
With Reversible cell injury we will see…
-Reduction in Oxidative phosphorylation
-Reduction in ATP
-Electrolyte imbalance with water reflux
-Cellular swelling
-Blebs
-organelle swelling
Increase in glycolysis
Decrease in PH
ROS
With irreversible cell injury we will see…
Lysosomal enzymes released causing auto digestion of cell
Membrane injury causing calcium influx
This leads to cell death
What type of cell necrosis
Basic cell outline is preserved, Acidosis denatures proteins, protein denaturation causes coagulation
Coagulative necrosis
Type of necrosis
Results from autolysis or heterolysis
Involves digestion of cell remains
Typical abscess puss formation
Liquifactive necrosis
Type of necrosis
Combination of coagulative and liquifactive necrosis
The necrotic debris is not digested completely by hydrolases so tissues appear soft and granular
Cheesy
Caseous necrosis
Types of necrosis
Descriptive term that refers to focal areas of fat destruction, this destruction of lipids is associated abnormal release of pancreatic enzymes lipase
Fat necrosis
Types of cellular necrosis
Result of severe hypoxia . Most commonly caused by loss of blood supply (ischemia )
Gangrene
A coagulative necrosis as a result of ischemia
Dry gangrene
Occurs when tissue is infected with bacteria and phagocytosis cells are recruited , releasing enzymes that lead to liquifactive process
Wet gangrene
Types of cellular necrosis
Occurs when the infection is caused by clostridium , anerobic bacteria that produces toxins that damage the CT and cause gas
Gas gangrene
What are 2 types of cellular death
Necrosis and apoptosis
This type of cell death is initiated by pathologic stimuli from outside the cell and results in the dissolution or removal of that cell
Necrosis
Necrosis involves activation of enzymes that digest cellular components called…
Auto digestion
This type of cell death initiates the inflammatory response
Necrosis
This cell death involves activation of a coordinated internal cellular program(sequence of events) that are mediated by defined cellular proteins
Apoptosis
This cell death has no inflammatory response
Apoptosis
