🧩 Step 5 — Concept Integration
This section integrates development, structure, function, disease mechanisms, and treatment into a single conceptual pathway. Focus on understanding how one event leads to another.
🧭 Whole Topic Core Flow
Cell membrane injury
↓
Activation of phospholipase A₂
↓
Release of arachidonic acid
↓
Two major pathways activated:
COX Pathway
- Produces prostaglandins and thromboxane
- Causes:
- Pain
- Fever
- Inflammation
- Platelet aggregation
LOX Pathway
- Produces leukotrienes
- Causes:
- Bronchoconstriction
- Chemotaxis
- Allergic inflammation
↓
Clinical diseases develop:
- Asthma
- Arthritis
- Fever
- Gastric inflammation
- Thrombosis
↓
Drug actions:
- NSAIDs → inhibit COX
- Aspirin → irreversible COX inhibition
- Steroids → inhibit phospholipase A₂
- Zileuton → inhibits 5-lipoxygenase
- Montelukast → blocks leukotriene receptors
↓
Clinical outcome:
- Reduced pain
- Reduced fever
- Reduced inflammation
- Reduced bronchospasm
- Reduced platelet aggregation
2️⃣ Core Mechanism Integration
Tissue injury or immune activation
↓
Excess arachidonic acid metabolism
↓
Increased prostaglandins and leukotrienes
↓
Effects of Prostaglandins
- Vasodilation
- Increased vascular permeability
- Pain receptor sensitization
- Fever production
Result:
- Redness
- Swelling
- Pain
- Fever
Effects of Leukotrienes
- Bronchial smooth muscle contraction
- Increased mucus secretion
- Recruitment of inflammatory cells
Result:
- Wheezing
- Bronchospasm
- Asthma symptoms
🩺 Clinical Integration Snapshot
A. NSAID-Induced Gastric Ulcer
NSAID use
↓
COX-1 inhibition
↓
Reduced protective gastric prostaglandins
↓
Reduced mucus and bicarbonate secretion
↓
Gastric mucosal injury
↓
Peptic ulcer and GI bleeding
B. Aspirin in Cardiovascular Protection
Aspirin use
↓
Irreversible platelet COX-1 inhibition
↓
Reduced thromboxane A₂ synthesis
↓
Reduced platelet aggregation
↓
Reduced thrombosis
↓
Reduced risk of myocardial infarction
C. Bronchial Asthma Mechanism
Allergic trigger
↓
Increased leukotriene production
↓
Bronchial smooth muscle contraction
↓
Bronchospasm and mucus secretion
↓
Wheezing and dyspnea
↓
Treatment:
- Montelukast
- Zileuton
↓
Reduced airway obstruction
⚡ Ultra-High-Yield Master Summary