Number the steps of hemostasis in order, putting 1 by the first event, 2 by the second, and so on.
____The intrinsic/contact activation and extrinsic/tissue factor pathways produce factor Xa.
____The clot retracts.
____Thrombin converts fibrinogen to fibrin, and fibrin glues the plug together.
____Platelets are activated, and the platelet plug forms.
____Vasoconstriction and increased tissue pressure decrease blood flow through the vessel.
____Tissue plasminogen activator activates plasmin, which degrades fibrin.
____The common pathway produces thrombin.

Question

Number the steps of hemostasis in order, putting 1 by the first event, 2 by the second, and so on.

____The intrinsic/contact activation and extrinsic/tissue factor pathways produce factor Xa.

____The clot retracts.

____Thrombin converts fibrinogen to fibrin, and fibrin glues the plug together.

____Platelets are activated, and the platelet plug forms.

____Vasoconstriction and increased tissue pressure decrease blood flow through the vessel.

____Tissue plasminogen activator activates plasmin, which degrades fibrin.

____The common pathway produces thrombin.

Accepted Answer

Hey, everyone. Let's take a look at this question together when a blood vessel wall is damaged, which of the following is the first step in hemostasis. Is it answer choice. A degradation of fibrin. Answer choice B activation of thrombocytes. Answer choice C activation of the common pathway or answer choice D vasoconstriction in the affected vessel wall. Let's work this problem out together to try to figure out which of the following answer choices is the first step in hemostasis. So in order to solve this question, we have to recall what we have learned about the process of hemostasis. And what the first step is, which we note that hemostasis is the mechanism to stop the blood vessel from bleeding. And hemostasis can be divided into four steps. The first step involves constriction of the blood vessel. The next step in hemostasis is the formation of a temporary platelet plug. And the third step is the activation of the coagulation cascade with the final step of hemostasis as being the formation of the fibrin plug or the final clot. And since we are focusing on only the first step, which is constriction of the blood vessel, looking at our answer choices, we can identify answer choice D as the correct answer. Since the first step in hemostasis, which is that mechanism to stop the blood vessel from bleeding is vasoconstriction in the affected vessel wall. So answer choice D is the only correct answer choice. I hope you found this video to be helpful. Thank you and goodbye.

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Key Concepts

Hemostasis

Coagulation Pathways

Clot Retraction and Fibrinolysis