1: Celluar Changes - Damage Flashcards
Apoptosis
programmed cell death
Ischemia
deficit of oxygen supply to cells
- due to reduced blood flow
- dec O2 levels
What can ischemia lead to?
Hypoxia
Hypoxia
reduced oxygen in tissues
- reduced O2 available
Physical damage in result from?
Excessive heat or cold
- frost bite, burn
Radical exposure
- free radicals: damages DNA
Mechanical damage can result from?
Excess pressure and tearing
ie: injuries/cuts
Chemical toxins can be?
Exogenous
Endogenous
Exogenous
from environment (external)
Endogenous
from inside of body (internal)
- ie: unwannted by products -> free radicals (cause chain rxn of cell damage)
Other causes of damage
- microorganisms: bacteria + viruses + protozoa+ fungi
- abnormal metabolites: altered metabolism, genetic disorders, inborn errors of metabolism
- nutritional deficits: vitamin deficiencies
- imbalances of fluid or electrolytes
Describe the process of cellular damage
- cells wells with waters/lipids
- lose control of storage and transport capability
- store increased amts of lipids/water - altered metabolic reactions -> loss of function
* if injury/cause removed quickly -> cell recover/repair - irreversibly changes -> apoptosis or necrosis
- morphological changes in nucleus + w/i cell
- cell swelling -> rupture
- nucleus disintegration -> cell death - lysis
Lysis
dissolution of cell by lysosomal enzymes into tisse
- cell bursting
- causes inflammation and damage to nearby cells (necrosis)
Necrosis
when group of cells dies
- disintegration of cell nucleus
What are the 5 types of necrosis
- Liquefaction
- Coagulative: infarction
- Fat
- Caseous
- Gangrene
What are the the 5 types of necrosis based on?
based on outcome of cell death
Liquefaction Necrosis
dead cells LIQUIFY due to released cell enzymes
- creamy yellow fluid
Coagulative Necrosis
cell proteins are altered or denatures
- cells cannot function -> lose distinct shape/design
- maintain organization of tissue BUT are not receiving blood supply
maintain cell architecture post death
- ischemia or infarction may be cause of death
Infarction
area of dead cells as a result of O2 deprivation
tissue death from failure of blood supply
Fat Necrosis
fatty tissue (adipocytes) is broken down into fatty acids
- may cause inflammation
ie: trauma to surrounding area -> releases lipases (fat splitting enzymes) - only relevant to fat tissue
Caseous (Caseation) Necrosis
Form of coagulative & liquefactive necrosis
- thick, yellowish “cheesy” substance forms
- unique to TB
Gangrene Necrosis
area of necrotic tissue invaded by bacteria (infection)
- infection common after infarction in intestines or limb (due to interfered blood supply)
- must be removed surgically to prevent spread of infection
What are the 3 types of gangrene necrosis
- Dry
- Wet
- Gaseous
Dry gangrene (mummification)
arterial (to tissue) blood supply involved
- coagulative necrosis: due to anoxic injury then infected
Wet gangrene
fluid/pus producing
due to impaired venous supply return (venus drainage)
- from tissue back to heart, blood pools in limited space -> compression on surrounding nerves
- excess blood pooled = feeding ground for infec
- solution usually amputation as in extremities/organs
- usually seen with diabetics and develops rapidly
Gas gangrene
due to gas producing bacteria (clostridia)
- enters dead tissue -> prod. toxin & gas bubbles inside affect area
tx: antimicrobial & antitoxin
