4. Cell injury. Definition. Categories of cellular injury. Causal factors. Pathogenetic anti Morphogenetic mechanisms. Flashcards
What is the 19th Century Dominant Humoral Theory?
Diseases occurred DUE to IMBALANCE between 4 Fluids:
- Blood
- Black Bile
- Yellow Bile
- Phlegm
Who was Considered the ‘Father of Modern Pathology’?
RUDOLPH VIRCHOW
Confirmed BASE of All Diseases is DUE to Cellular Damage (Small Unit of Life)
What is a Cell?
Smallest Unit of Life aka Building Block
Containing Fundamental Molecules of Life + All Living Things are Composed
Dependent on Homeostasis = Stability of Internal Environment
What is the Role of a Cell?
Has a GENETIC Structure
ALLOWING to perform a NARROW RANGE of Functions + Structural Changes
When Pathological Stimuli Occurs = CAUSES Adaptive Response in Cell, providing stability + energy of Cells under new conditions
What is Cellular Damage?
When Adaptive Response of Cell has EXCEEDED / LIMITED / NO LONGER Possible
REVERSIBLE to an extent
IRREVERSIBLE = STRONG Damaging Agent / PROLONGED Action
What does the Reaction of Cells to Damage, Depend on?
Type
Duration
Severity of Injurious Stimuli
What are the Main Functions of a Cell?
- Metabolism Regulation
- Cellular Differentiation + Specialisation
- Relations with Other Cells
What is Cellular Degeneration / Injury?
Complex Pathological Process
DUE to Tissue Damage
Where Cellular Metabolism LEADS to Structural Changes
What is Cellular Degeneration Classified into?
- According to Area Infected
- According to Accumulating Substance
- According to Influence of Genetic Factors
- According to Dissemination of Process
- According to Reversibility of Process
1| How is Cellular Degeneration Classified, According to Area Infected?
a. Parenchymatous Degeneration
b. Stromal Degeneration (Extracellular; Interstitial + Mesenchymal)
c. Mixed
2| How is Cellular Degeneration Classified, According to Accumulating Substance?
a. Protein Degeneration
b. Fatty Degeneration
c. Carbs Degeneration
d. Degeneration in Salt + Fluids
3| How is Cellular Degeneration Classified, According to Influence of Genetic Factors?
a. Acquired Degeneration
b. Hereditary Degeneration
4| How is Cellular Degeneration Classified, According to Dissemination of Process?
a. Local Degeneration
b. General Degeneration
5| How is Cellular Degeneration Classified, According to Reversibility of Process?
a. Reversible Cell Injury
b. Irreversible Cell Injury
5a| What is Acute / Reversible Cell Injury?
Cell RETURNS to Normal State
AFTER WITHDRAWAL of Acute Stress
5a| What are the Characteristics of Reversible Cell Injury?
- Hydropic Changes = Oedema / Swelling
- Dilation of ER
- Detachment of Ribosomes from Granular ER
- Dissociation of Polysomes –> Monosomes
- Mitochondria Swelling + Enlargement
- Blebs of Plasma Membrane
- Nucleolar Alterations w/ Disaggregation of Granular + Fibrillar Elements
5b| What is Irreversible Cellular Injury?
Presented VIA Necrosis + Apoptosis
5b| What are the Characteristics of Irreversible Cell Injury?
Targets 4 Intercellular Systems that are VULNERABLE
(i) Maintenance of Cell Membrane Integrity
(ii) Aerobic Respiration = Oxi.Phospho + ATP Production
(iii) Structural Enzyme + Protein Synthesis
(iv) Maintenance of Cell’s Genetic Apparatus Integrity
What are the Causes for Cellular Damage?
- Genetic Causes
2. Acquired Causes
2| What are the Acquired Causes of Cell Damage, Classified into?
a. Hypoxia
b. Physical Agents
c. Chemical Agents
d. Environmental Agents
e. Nutritional Derangement
f. Infectious Agents
g. Immunological Responses
h. Iatrogenic Factors
2a| How does Ischaemia & Hypoxia Lead to Cell Damage?
INSUFFICIENT Blood Supply LEADS to Anaemia
Hypoxia Occurs in People WITH Anaemia
LEAD to CO Poisoning / HF + RF
2b| What Physical Agents can Lead to Cell Damage?
Mechanical Trauma
Extremely High / Low Temp
Sudden Change in Atm Conditions
IR / UV
Electrical Trauma
2c| What Chemical Agents can Lead to Cell Damage?
Strong Acids + Bases
Salts of Heavy Metals
Extremely HIGH Levels of OXYGEN
2e| How does Nutritional Derangement Lead to Cell Damage?
Malnutrition
- Undernutrition
- Overnutrition
2f| What Infectious Agents Lead to Cell Damage?
Parasites
Viruses
Bacteria
Fungal Infections
2g| What Immunological Responses Leads to Cell Damage?
Allergic Reaction
Autoimmune Reactions = Immune System loses ability to differentiate BTW Foreign + Own bodies; Attacking itself
2h| How do Iatrogenic Factors Lead to Cell Damage?
DUE to Treatment
What are the 4 Pathogenetic Causes of Cellular Damage?
- Disrupted Auto-Regulation of Cell
- Disruption of Functions of Transport Systems
- Damages to Endocrine + Neurological Systems
- “Intrauterine Degenerations” = where Damaging Factor is transferred to Foetus VIA Placenta
What are the 5 Mechanisms of Cellular Damage?
- Lack of Oxygen / HIGH Free O2 Radicals = Free OR are Unstable w/ Odd e- N.O LEADING to Lipid Peroxidation
- Disruption of Calcium Homeostasis = LOW Conc of Ca2+ in Cytoplasm; Hypoxia Causes INCREASED Ca2+ Influx, ACTIVATING Powerful Enzymes LEADING to Self-Destruction (3)
- Enzymatic Self-Destruction = Phospholipases DESTROY CM; Proteases DESTROY CM + Cytoskeletal Protein; ATP accelerates REMOVAL of ATP; Endonucleases DESTROY Nucleic Acids
- Removal of ATP DUE to Ischaemic Changes
- DEFECT in Membrane Permeability DUE to Bacterial Toxins (C.Perfringens produce PHOSPHOLIPASE attacking Ph-Cell Membrane)
What are the 4 Mechanisms of Abnormal Accumulation of Substances in cells?
{Morphogenesis of Intracellular & Stromal Degeneration)
- Infiltration = Pathologically INCREASED Reabsorption of Cells / Abnormal Factors in ECM
- Decomposition = Disintegration of Membranous Structures of Cells
- Pathological Synthesis = Synthesis of Amyloid / Alcoholic Hyaline / Glycogen in Henle’s Loop (DM)
- Transformation INTO other Structures
