AIM STEP 10
Student Memory Support
Acute Inflammation: Recognition, Vascular and Cellular Responses
3rd Year MBBS • Infection and Inflammation • High-yield revision and memory reinforcement
1. High-Yield Flashcards
Tap each question to reveal the answer.
What is acute inflammation?
A rapid protective response of vascularized tissue to infection, tissue injury or other harmful stimuli.
Which leukocyte predominates early in many acute bacterial inflammatory reactions?
Neutrophils.
What happens to circulating monocytes after they enter tissues?
They differentiate into macrophages that phagocytose debris, produce mediators and support repair.
Which leukocyte pattern is classically associated with allergy and parasitic infection?
Eosinophilia.
What are PAMPs?
Conserved microbial structures recognized by innate immune pattern-recognition receptors.
What are DAMPs?
Host-derived molecules released or exposed by damaged or necrotic cells that activate inflammation.
Which receptors recognize PAMPs and DAMPs?
Pattern-recognition receptors, including Toll-like receptors.
Which vascular event produces redness and warmth during acute inflammation?
Arteriolar vasodilation causing increased local blood flow and hyperemia.
Why does inflammatory edema develop?
Increased vascular permeability allows protein-rich fluid to escape into tissues.
What is an inflammatory exudate?
Protein-rich extravascular fluid formed because vascular permeability increases.
What causes vascular stasis during acute inflammation?
Loss of plasma fluid causes hemoconcentration, increased viscosity and slowing of blood flow.
What is the correct sequence of leukocyte recruitment after stasis?
Margination → rolling → firm adhesion → transmigration → chemotaxis.
Which adhesion molecules mainly mediate leukocyte rolling?
Selectins.
Which leukocyte molecules mainly mediate firm endothelial adhesion?
Integrins.
What is chemotaxis?
Directed leukocyte movement along a chemical concentration gradient toward the inflammatory focus.
What are the major stages of phagocytosis?
Recognition and attachment → engulfment → intracellular killing and degradation.
2. Mnemonics
Mnemonic Title: Major Causes of Acute Inflammation
I-FIN
Meaning: Infection • Foreign bodies • Immune reactions • Necrosis
Mnemonic Title: Leukocyte Recruitment Sequence
MRAT-C
Meaning: Margination → Rolling → Adhesion → Transmigration → Chemotaxis
Mnemonic Title: Phagocytosis Sequence
REK
Meaning: Recognition/attachment → Engulfment → Killing and degradation
3. Memory Tables
Exudate vs Transudate
| Feature | Exudate | Transudate |
|---|---|---|
| Mechanism | Increased vascular permeability | Altered hydrostatic or osmotic forces |
| Protein | Relatively protein-rich | Relatively protein-poor |
| Inflammation | Typical inflammatory fluid | Usually non-inflammatory |
Inflammatory Cells — Rapid Comparison
| Cell | Main Role | High-Yield Association |
|---|---|---|
| Neutrophil | Rapid phagocytosis | Acute bacterial inflammation |
| Monocyte/macrophage | Phagocytosis and repair | Later/prolonged inflammation |
| Lymphocyte | Adaptive immunity | Immune responses |
| Eosinophil | Granule-mediated response | Allergy and parasites |
| Basophil/mast cell | Mediator release | Hypersensitivity |
4. Rapid Revision Points — Last-Minute Revision
Must Remember:
- Acute inflammation is a rapid response of vascularized tissue to harmful stimuli.
- Vasodilation produces hyperemia, causing redness and warmth.
- Increased permeability produces protein-rich exudate and edema.
- Plasma loss causes hemoconcentration and vascular stasis.
- Stasis promotes leukocyte margination toward the endothelial surface.
- Selectins mediate rolling; integrins mediate firm adhesion.
- Transmigration occurs after firm adhesion and is followed by chemotaxis.
- PAMPs come from microbes; DAMPs come from injured host cells.
- Opsonization improves microbial recognition and phagocytosis.
- Neutrophilia favors acute bacterial inflammation; eosinophilia favors allergy or parasites.
KMU Exam Trap: Rolling and firm adhesion are different steps: rolling is selectin-mediated, whereas firm adhesion is integrin-mediated.
5. Clinical Memory Hooks
Acute bacterial wound → neutrophil-rich early response → rapid phagocytosis and microbial killing
Red, warm inflamed skin → arteriolar vasodilation → increased local blood flow
Swollen inflamed tissue → increased vascular permeability → protein-rich exudate
Sterile tissue necrosis → DAMP release → pattern-recognition receptor activation → inflammation
Allergic or parasitic inflammation → eosinophil increase → eosinophilia
6. Starred High-Yield Exam Points
- ⭐ PAMPs are microbial signals, whereas DAMPs arise from damaged host cells.
- ⭐ Pattern-recognition receptors link recognition of injury or microbes to initiation of inflammation.
- ⭐ Increased vascular permeability produces protein-rich exudate and inflammatory edema.
- ⭐ Selectins mediate leukocyte rolling; integrins mediate firm adhesion.
- ⭐ Recruitment sequence: margination → rolling → adhesion → transmigration → chemotaxis.
- ⭐ Phagocytosis proceeds through recognition/attachment → engulfment → intracellular killing and degradation.