1.2 Cellular Changes Flashcards
- What is (cellular) STRESS?
- What does it lead to?
- Stress is a physical, emotional, or chemical factor
- Leads to changes/injuries that are initially reversible
- Leads to increased functional demand
When do cellular changes become irreversible?
After prolonged stress
What is NECROSIS?
- Death of cells in tissues or organs
- Result of severe/prolonged stress
What are all the reversible CELL GROWTH CHANGES?
- ATROPHY - cell size decrease
- HYPERTROPHY - cell size increase
- HYPERPLASIA - cell number increase
- METAPLASIA - cell type change
- DYSPLASIA - cell structure change/mismatch
Define ATROPHY
- DECREASE in cell SIZE
- caused by DISUSE of cell
Define HYPERTROPHY
- INCREASE in cell SIZE
- may/not be beneficial
- Enlarged tissue mass
Define HYPERPLASIA
- INCREASE in cell NUMBER
- Enlarged tissue mass
Define METAPLASIA
- CHANGE in cell TYPE
Define DYSPLASIA
- CHANGE in cell STRUCTURE
- cells become IMMATURE
- all cells NON UNIFORM
What are the irreversible CELL GROWTH CHANGES
- NEOPLASIA - cancer
- ANAPLASIA - undifferentiated cells
Define NEOPLASIA
- new growth/tumor
Define ANAPLASIA
- extremely undifferentiated cells
- implies advanced cancer
What are other REVERSIBLE cell injuries?
- Cellular swelling
- Intracellular Accumulations
What are the Etiologies (causes) of CELL INJURY?
- Hypoxia
- Ischemia
- Free radical
- Nutritional
- Infectious
- Chemical
- Physical
- Mechanical
Define HYPOXIA
Injury due to Lack of oxygen
Define ISCHEMIA
Lack of blood flow
- leads to buildup of metabolic waste
- & lack of nutrition
Define FREE RADICAL INJUY
Injury due to Poor/lack of metabolism of certain substances
or, due to large amount of energy exposure
Define INFECTIOUS INJURY
An additional injury due to the triggering of an immune response & the attacking of bacteria
Define CHEMICAL INJURY
- Can be directly from chemicals
- Or indirectly from substances that metabolize into chemicals that react negatively with the body
Give examples of situations that give rise to PHYSICAL INJURIES
- changes in altitude
- changes in atmospheric pressure
- extreme temperature changes
Define MECHANICAL INJURY
Injury resulting from trauma
- can be ELECTRIC - which disrupts neural & cardiac impulses & leads to thermal burns
What is HYDROPIC SWELLING
- CELLULAR SWELLING
- usually the FIRST manifestation of REVERSIBLE cell injury
- due to WATER accumulation from malfunction of SODIUM POTASSIUM PUMP
- –megaly
What are INTRACELLULAR ACCUMULATIONS
- when normal body substances (protein, melanin) build up in body
- or, build up due to faulty metabolism
- or, exogenous (foreign) product that is unable to be processed/metabolized
What is one type of reversible intracellular accumulation?
- LIPID DEPOSITION
- or Lipid accumulation
Define FREE RADICAL FORMATION
- FREE RADICAL = uncharged atom/atoms that contain unpaired electron = negative charge
- Unstable, damaging to cell
- Occurs due to exposure to large amounts of energy
- Cause damage via lipid peroxidation
Define LIPID PEROXIDATION
- when free radicals steal electrons from lipid membranes & damage the cell
- the lipid then degrades
Define NECROSIS
- Cell death in organ/tissue
- Can result in addtl. damage (starts locally, spreads)
- Usually results from ischemia/injury
- Cell ruptures (membrane damage) & contents spill out
- Triggers inflammatory process
What are the 4 types of NECROSIS
- coagulative
- liquefactive
- fat
- caseous
Define COAGULATIVE NECROSIS
- Cell death due to ISCHEMIA/lack of blood flow
then
- energy is lost
- sodium-potassium pump stops working
- sodium → water builds up in cell
- cell swells
- attempts to produce ATP (b/c energy lost) results in acid build up
- acid + water ruptures membrane
Define LIQUEFACTIVE NECROSIS
- Dead cell/tissue becomes liquid
- Dead cells are dissolved by lysosomal enzymes
- surrounding healthy tissue is damaged
- abscess/cyst forms = with liquid inside
Define CASEOUS NECROSIS
- Death to lung cells
- Result of TUBERCULOSIS
Define FAT NECROSIS
- Adipose/fat tissue death due to TRAUMA
What are some consequences of NECROSIS
- loss of function
- localized inflammatory response
- or, systemic response e.g. fever
- bacterial invasion site → infection
Define GANGRENE
- cell death of LARGE area of tissue
- due to lack of blood supply to body part
What are the types of GANGRENE?
- dry
- wet
- gas
Define DRY GANGRENE
- form of COAGULATIVE necrosis (cell death-lack of blood from poor circulation)
- slow spreading
- black, dry, wrinkled tissue
- strict line of demarcation
- tissue must be removed
Define WET GANGRENE
- form of LIQUEFACTIVE necrosis
- fast spreading
- found more often in internal organs
- no strict line of demarcation
Define GAS GANGRENE
- comes after dry/wet gangrene
- from infection of dead/necrotic tissue by Clostridium (anaerobic bacteria)
- forms gas bubbles (as bacteria is metabolized)
Define Necrotic Tissue
DEAD TISSUE
Define APOPTOSIS
- triggering of cascade that activates cell suicide
- no inflammation, no further damage
- “clean, neat, cell suicide”
- allows new healthy cell formation
