17. The Blood

Which of the following does not promote multiple steps in the clotting pathway?

a. Platelet phospholipids

b. Factor XI

c. Thrombin

d. Ca²⁺

Which physiological response causes a reduction in blood flow immediately after a blood vessel injury?

More than one choice may apply.

Place the letters of these events in the order they occur during hemostasis.

What are the overall goals of the common pathway of coagulation?

___ and ____ affect almost every aspect of the clotting process.

(a) Calcium, vitamin K

(b) Calcium, vitamin B12

(c) Sodium, vitamin K

(d) Sodium, vitamin B12

A test for prothrombin time is used to identify deficiencies in the extrinsic clotting pathway; prothrombin time is prolonged if any of the factors are deficient. A test for activated partial thromboplastin time is used in a similar fashion to detect deficiencies in the intrinsic clotting pathway. Which factor would be deficient if a person had a prolonged prothrombin time but a normal partial thromboplastin time?

Which of the following is the most likely outcome if platelets could not release aggregating agents?

Which of the following is not an anticlotting agent produced by endothelial cells?

a. Prostacyclin

b. Protein C

c. Antithrombin-III

d. Warfarin

Almost half of our vitamin K is synthesized by bacteria that inhabit the large intestine. Based on this information, how could taking a broad-spectrum antibiotic for a long time cause frequent nosebleeds?