Unit 4 - A & P Module - Platelets and Blood Clotting

Question 1

Put the cells involved in the formation of platelets in the correct order beginning with the events required to produce platelets.
(a) megakaryocyte
(b) myeloid stem cell
(c) hematopoietic stem cell
(d) platelets

Answer 1

c, b, a, d

Question 2

Which of the following events occur during hemostasis?

Platelet adhesion
Vasoconstriction
Platelet aggregation
Thrombus formation

Answer 2

All of these events occur during hemostasis

Question 3

Both the intrinsic and extrinsic pathways of blood clot formation require ________ in order for a thrombus to be produced.

Answer 3

calcium, thrombin, fibrin, factor X

Question 4

Activation of the extrinsic pathway begins with exposure of __________.

Answer 4

tissue factor to plasma and clotting factor VIIa

Question 5

Excessive bleeding can be a symptom of __________.

Answer 5

hemophilia, von Willebrand’s disease, vitamin K deficiency

Question 6

The inactive enzyme, plasminogen, __________.

Answer 6

is trapped within a blood clot as it forms, becomes active in the form of plasmin, and slowly dissolves the clot

Question 7

The process of hemostasis involves __________.

Answer 7

vascular spasm, formation of platelet plug and formation of thrombus

Question 8

The coagulation pathway that is initiated with the appearance of tissue factor is the __________

Answer 8

extrinsic pathway

Question 9

Drugs commonly referred to as “clot-busters” are used to treat strokes and other acute coagulation problems. These drugs are synthetic forms of tissue plasminogen activator (tPA). These drugs act by converting __________.

Answer 9

plasminogen to plasmin

Question 10

The protein responsible for initiating platelet plug formation is __________.

Answer 10

von Willebrand factor

Question 11

What is the stimulus for erythropoietin release?

Answer 11

Low oxygen carrying capacity of the blood

Question 12

What are the substances in the final common pathway activated by both the intrinsic and extrinsic pathways?

Answer 12

Factor Xa, thrombin, factor XIIIa, and fibrin

Question 13

The soft platelet plug is transformed into a firm clot by the action of ________ on ________, which forms a firm meshwork that stabilizes the clot.

Answer 13

thrombin; fibrinogen

Question 14

Calcium is involved in activating several steps of the coagulation pathways. The immediate products of each of these steps are __________.

Answer 14

tissue factor coupled to factor VIIa, factor IXa, factor Xa, and thrombin