RN Nursing · Pathophysiology · Practice question
What triggers the intrinsic pathway of coagulation?
-
Tissue factor
-
✓
Anionic surfaces
-
Calcium loss
-
Platelet aggregation
Answer & explanation
Correct: Anionic surfaces
The intrinsic pathway of coagulation is triggered by anionic (negatively charged) surfaces, such as exposed subendothelial collagen following vascular injury, or artificial surfaces like glass. This contact activates Factor XII, initiating a cascade through Factors XI, IX, and VIII before merging with the common pathway at Factor X. This question and question 94734 are effectively asking the same thing from slightly different angles — both confirm that anionic surface contact is the hallmark trigger of the intrinsic pathway. Tissue factor is the trigger for the extrinsic pathway; it is a membrane-bound protein expressed by cells outside the endothelium and released upon tissue damage, binding with Factor VII to activate the extrinsic cascade. Calcium loss (hypocalcemia) would actually impair coagulation overall because calcium ions (Factor IV) are required cofactors in multiple steps of both intrinsic and extrinsic pathways, but calcium loss does not specifically trigger the intrinsic pathway. Platelet aggregation is a component of primary hemostasis (formation of the platelet plug), which precedes the coagulation cascade; it does not serve as the specific trigger for the intrinsic pathway. Recognizing the distinction between anionic surface contact and tissue factor is a foundational concept in coagulation pathophysiology.
Practise Pathophysiology questions
Work through full question sets with instant rationales, timed exams, and progress tracking.
Start practising freeRelated practice questions
- A client who had surgery for colon cancer last year received a report today that cancer has returned and has metastasized. What finding supports this report?
- A client presents to the clinic complaining of flaking dry skin of the elbows. Upon the nurse's assessment she notices red plaques with a scaly silvery appearance. These findings are consistent with which condition?
- Patient's Data. Review the electronic health record. Which 3 factors likely contributed to the client's complication? Select the 3 correct factors.
- A patient comes to the emergency department complaining of swelling in both legs and weight gain. The patient also has ascites (fluid in the abdominal cavity) and jugular vein distention (JVD). The patient's diagnosis is heart failure. The nurse is aware that the clinical manifestations the patient is exhibiting are signs of failure.