Topics:
Animal Physiology, Animal Refresher
Speed of Blood Clotting Pathways
Which is true about the speed of clotting cascade?
- Intrinsic pathway is faster than extrinsic
- Extrinsic pathway is faster than intrinsic — Correct Answer
- Speed of both pathways is equal
- None of the above
Explanation:
Correct Answer: Extrinsic pathway is faster than intrinsic
The extrinsic pathway is faster than the intrinsic pathway because it has fewer steps and is triggered immediately upon tissue injury by Tissue Factor (Factor III).
Why Extrinsic is Faster
- Extrinsic: Tissue Factor (III) → Factor VII activation → direct activation of Factor X. Fewer steps; rapid response.
- Intrinsic: Collagen → Factor XII → XI → IX → VIII → X. Many sequential steps; slower.
Convergence Point
Both pathways meet at Factor X activation (common pathway):
Factor Xa + Va + Ca²⁺ + Phospholipid → Prothrombinase → Prothrombin → Thrombin → Fibrinogen → Fibrin clot
Anticoagulants Summary
- Heparin: Natural/in-vivo; produced by mast cells and basophils
- Sodium citrate: Used in blood transfusion
- EDTA: Blood morphology and PCV determination
- Sodium fluoride: Glucose estimation
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
