4. Cell injury. Definition. Categories of cellular injury. Causal factors. Pathogenetic anti Morphogenetic mechanisms.

Question 1

What is the 19th Century Dominant Humoral Theory?

Answer 1

Diseases occurred DUE to IMBALANCE between 4 Fluids:

• Blood
• Black Bile
• Yellow Bile
• Phlegm

Question 2

Who was Considered the ‘Father of Modern Pathology’?

Answer 2

RUDOLPH VIRCHOW

Confirmed BASE of All Diseases is DUE to Cellular Damage (Small Unit of Life)

Question 3

What is a Cell?

Answer 3

Smallest Unit of Life aka Building Block

Containing Fundamental Molecules of Life + All Living Things are Composed

Dependent on Homeostasis = Stability of Internal Environment

Question 4

What is the Role of a Cell?

Answer 4

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

Question 5

What is Cellular Damage?

Answer 5

When Adaptive Response of Cell has EXCEEDED / LIMITED / NO LONGER Possible

REVERSIBLE to an extent

IRREVERSIBLE = STRONG Damaging Agent / PROLONGED Action

Question 6

What does the Reaction of Cells to Damage, Depend on?

Answer 6

Type

Duration

Severity of Injurious Stimuli

Question 7

What are the Main Functions of a Cell?

Answer 7

• Metabolism Regulation
• Cellular Differentiation + Specialisation
• Relations with Other Cells

Question 8

What is Cellular Degeneration / Injury?

Answer 8

Complex Pathological Process

DUE to Tissue Damage

Where Cellular Metabolism LEADS to Structural Changes

Question 9

What is Cellular Degeneration Classified into?

Answer 9

1. According to Area Infected
2. According to Accumulating Substance
3. According to Influence of Genetic Factors
4. According to Dissemination of Process
5. According to Reversibility of Process

Question 10

1| How is Cellular Degeneration Classified, According to Area Infected?

Answer 10

a. Parenchymatous Degeneration
b. Stromal Degeneration (Extracellular; Interstitial + Mesenchymal)
c. Mixed

Question 11

2| How is Cellular Degeneration Classified, According to Accumulating Substance?

Answer 11

a. Protein Degeneration
b. Fatty Degeneration
c. Carbs Degeneration
d. Degeneration in Salt + Fluids

Question 12

3| How is Cellular Degeneration Classified, According to Influence of Genetic Factors?

Answer 12

a. Acquired Degeneration

b. Hereditary Degeneration

Question 13

4| How is Cellular Degeneration Classified, According to Dissemination of Process?

Answer 13

a. Local Degeneration

b. General Degeneration

Question 14

5| How is Cellular Degeneration Classified, According to Reversibility of Process?

Answer 14

a. Reversible Cell Injury

b. Irreversible Cell Injury

Question 15

5a| What is Acute / Reversible Cell Injury?

Answer 15

Cell RETURNS to Normal State

AFTER WITHDRAWAL of Acute Stress

Question 16

5a| What are the Characteristics of Reversible Cell Injury?

Answer 16

• 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

Question 17

5b| What is Irreversible Cellular Injury?

Answer 17

Presented VIA Necrosis + Apoptosis

Question 18

5b| What are the Characteristics of Irreversible Cell Injury?

Answer 18

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

Question 19

What are the Causes for Cellular Damage?

Answer 19

1. Genetic Causes

2. Acquired Causes

Question 20

2| What are the Acquired Causes of Cell Damage, Classified into?

Answer 20

a. Hypoxia
b. Physical Agents
c. Chemical Agents
d. Environmental Agents
e. Nutritional Derangement
f. Infectious Agents
g. Immunological Responses
h. Iatrogenic Factors

Question 21

2a| How does Ischaemia & Hypoxia Lead to Cell Damage?

Answer 21

INSUFFICIENT Blood Supply LEADS to Anaemia

Hypoxia Occurs in People WITH Anaemia

LEAD to CO Poisoning / HF + RF

Question 22

2b| What Physical Agents can Lead to Cell Damage?

Answer 22

Mechanical Trauma

Extremely High / Low Temp

Sudden Change in Atm Conditions

IR / UV

Electrical Trauma

Question 23

2c| What Chemical Agents can Lead to Cell Damage?

Answer 23

Strong Acids + Bases

Salts of Heavy Metals

Extremely HIGH Levels of OXYGEN

Question 24

2e| How does Nutritional Derangement Lead to Cell Damage?

Answer 24

Malnutrition

• Undernutrition
• Overnutrition

Question 25

2f| What Infectious Agents Lead to Cell Damage?

Answer 25

Parasites Viruses Bacteria Fungal Infections

Question 26

2g| What Immunological Responses Leads to Cell Damage?

Answer 26

Allergic Reaction Autoimmune Reactions = Immune System loses ability to differentiate BTW Foreign + Own bodies; Attacking itself

Question 27

2h| How do Iatrogenic Factors Lead to Cell Damage?

Answer 27

DUE to Treatment

Question 28

What are the 4 Pathogenetic Causes of Cellular Damage?

Answer 28

1. Disrupted Auto-Regulation of Cell 2. Disruption of Functions of Transport Systems 3. Damages to Endocrine + Neurological Systems 4. "Intrauterine Degenerations" = where Damaging Factor is transferred to Foetus VIA Placenta

Question 29

What are the 5 Mechanisms of Cellular Damage?

Answer 29

1. Lack of Oxygen / HIGH Free O2 Radicals = Free OR are Unstable w/ Odd e- N.O LEADING to Lipid Peroxidation 2. Disruption of Calcium Homeostasis = LOW Conc of Ca2+ in Cytoplasm; Hypoxia Causes INCREASED Ca2+ Influx, ACTIVATING Powerful Enzymes LEADING to Self-Destruction (3) 3. Enzymatic Self-Destruction = Phospholipases DESTROY CM; Proteases DESTROY CM + Cytoskeletal Protein; ATP accelerates REMOVAL of ATP; Endonucleases DESTROY Nucleic Acids 4. Removal of ATP DUE to Ischaemic Changes 5. DEFECT in Membrane Permeability DUE to Bacterial Toxins (C.Perfringens produce PHOSPHOLIPASE attacking Ph-Cell Membrane)

Question 30

What are the 4 Mechanisms of Abnormal Accumulation of Substances in cells? {Morphogenesis of Intracellular & Stromal Degeneration)

Answer 30

1. Infiltration = Pathologically INCREASED Reabsorption of Cells / Abnormal Factors in ECM 2. Decomposition = Disintegration of Membranous Structures of Cells 3. Pathological Synthesis = Synthesis of Amyloid / Alcoholic Hyaline / Glycogen in Henle's Loop (DM) 4. Transformation INTO other Structures