Lecture 1 & 2: Cellular Injury and Acute Inflammation Flashcards
STEATOSIS
Hepatocytes with white globs
- intracelullar accumulation of fat and triglyceride
What are the following:
- Hypoxia (Anoxia)
- Chemical
- Physical
- Biological
- Immunologic
- Genetic
- Nutritional
- Aging (Degenerative)
8 general categories of injury
State the following:
- Cells maintain a steady state in which the intracellular milieu is kept within fairly narrow range of physiologic parameter
- process by which cells change in size, number and appearance in response to changes in cell environment
- _____: Increase in the number of cells
- _____; Increase in the size of a cell because of increased cellular substance
- ______: Decrease in the size of a cell because of loss of cellular substance
- ___: Substitution of one type of an adult cell for another type of adult cell (due to continuous stress)
- Homeostasis
- Adaptation
- Changes may be physiologic or pathologic - Hyperplasia
- Hypertrophy
- Atrophy
- Metaplasia
H&E stain
What is a basic dye that stains an acidic nucleus?
What is an acidic dye that stains cyoplasm?
- hemotoxylin
2. Eosin
What are some morphologic changes reflective of loss of brain substance?
- Widening of sulk
2. Narrowing of gyri
What is metaplasia?
Substitution of one type of an adult cell for another type of adult cell (due to continuous stress)
Clinical Example: Normal endocervix and endocervical glands are lined by simple columnar epithelium.
Chronic irritation and inflammation of the cervix uteri may cause replacement of columnar cells by stratified SQUAMOUS cells.
What is the key hallmark of REVERSIBLE cellular injury?
irreversible?
- Cellular swelling
- Membrane damage
- necrosis
- apoptosis
What happens in reversible cell injury to cell function?
What are the 4 occurrences of IRREVERSIBLE cellular injury (graph)
- Cell function declines
- Cell death
- Ultrastructural changes
- Light microscopic changes
- Gross morphologic changes
the principle mechanisms of cellular injury affect what four vulnerable biochemical systems? (4)
- Mitochondria (ATP)
- Cellular calcium
- Integrity of membranes (internal & external)
- Integrity of genetic material
ULTIMATE BIOCHEMICAL CHANGES WHICH DETERMINE DEGREE OF CELL INJURY OR INDUCTION OF CELL DEATH are what? (4):
- Depletion of adenosine triphosphate.
- Oxygen deprivation or generation of oxygen-derived free radicals.
- Concentration of intracellular calcium and loss of calcium homeostasis. (due to increase membrane permeability)
- Defective cell membrane permeability
The following describes what injury model?
- Ischemia due to cutoff of blood supply
- Mitochondria injured
- Decreased ATP produced
- Decreased Na/K pump
- Increased Na in cell, followed passively by water
End result is _____
- Hypoxic Injury Model
2. CELLULAR SWELLING
Loss of energy leads to increase in cellular _____ which leads to altered membrane permeability and activation of intracellular enzymes
What increases?
Calcium
- Phospholipase
(decrease phospholipids) - Protease - membrane & cytoskeleton is disrupted
= NUCLEAR DAMAGE - Increase endonucleases = NUCLEAR DAMAGE (DNA)
- ATPases increase which decrease ATP
What are the clinical correlations to measure diagnosis of disease due to altered membrane permeability of the cell (allowing intracellular enzymes to leak out)
What enzymes leak out?
creatine phosphokinase and lactic dehydrogenase, to leak from the cell into the vascular
compartment.
Example: Elevated level of troponin in acute myocardial infarction.
Elevated CK or troponin = acute MI (acute thrombis acute hypoxia/ischemia)
Elevated AST/ALT = hepatitis (viral hepatitis, or steatosis of liver)
Decrease intracellular oxygen (decreased ATP) causes the cell to switch from ____ to ____ respiration.
The ultimate buildup?
Clinical example?
_____ Clearance is an emerging way of confirming adequate resuscitation in shock
- aerobic to anaerobic
- lactic acid levels increase as a by-product of anaerobic glycolysis, leading to a state of metabolic acidosis in the body
- Example: Cardiac arrest (anoxia) may lead to metabolic acidosis, which may be addressed during CPR.
- Lactate
What is the free radical injury model?
A free radical is an atom or group of atoms which have a single unpaired electron in the outer orbit.
Free radicals are chemically unstable and very reactive with components of the cell, ie membrane, intracytoplasmic organelles.
What are the steps of generating a free radical?
What are 3 methods of free radical injury?
- O2 superoxide
(converted to H2O2 by SOD) - H2O2 decomposed to H20 by glutathione peroxidase
- OH radical
a) - membrane damage
b) breakdown/misfolding of proteins
c) mutations
What 3 species that are intermediate between O2 and H2O.
O2 ̅ superoxide;
H2O2, hydrogen peroxide
OH, hydroxyl radical.
Key free radical scavengers: 3
- catalase
- superoxide dismutases
- glutathione peroxidase
What is converted in hepatocytes that can cause to lipid preoccupation & damage to cell structures?
CCL4 (dry cleaning solvent) to CCL3 in hepatocytes
The following are examples of what type of injury:
1. CCL4 (carbon tetrachloride)
2. Reperfusion injury
(explain)
Free radical
- Reperfusion injury:
a) Return of blood/oxygen to ischemic tissue
b) Oxygen derived free radicals produced
c) (Paradoxical) Further injury to cells
What are 5 examples of REVERSIBLE cell injury?
- Cellular swelling
- influx of Na pulling H20 in - Steatosis (fatty change)
- Myelin figures
- ER swelling
- Membrane blebs
_____ ischemic injury
showing surface BLEBS,
increased EOSINOPHILIA of cytoplasm,
and SWELLING of occasional cells
______ injury of
epithelial cells, with pyknosis, loss of nuclei* , fragmentation of cells, leakage of contents
- Early (reversible)
- Necrotic (irreversible)
** fragmentation of CELLS**
What are the two subtypes of irreversible injury?
- Necrosis
2. Apoptosis
What is necrosis?
Necrosis: The sum total of morphologic changes, which occur in living tissue following cell death.
Necrosis includes structural changes in the nucleus and cytoplasm of dead cells.
It also is characterized by the presence of LEUKOCYTES (esp. neutrophils) infiltrating dead tissue from adjacent living tissue.
The morphologic changes occur as a result of enzymatic breakdown of the cell and denaturation of proteins.
Define the following:
- Karyolysis
- Pyknosis
- Karyorrhexis
- Karyolysis - basophilia of the chromatin may fade, a change that reflects loss of DNA because of enzymatic degradation by endonucleases.
- Pyknosis - Characterized by nuclear shrinkage and increased basophilia. The chromatin condenses into a solid, shrunken basophilic mass (also seen in apoptosis) –> DARK BLACK
- Karyorrhexis - the pyknotic nucleus undergoes FRAGMENTATION.
In a day or two, the nucleus in the necrotic cell totally disappears.
Breakdown of plasma membrane, organelles, and leakage of contents = ______
Fragmentation, chromatin condensation = ____
- Necrosis
2. Apoptosis