17. The Blood

Platelets are similar to erythrocytes in that both structures do not contain a _________________. Platelets are similar to leukocytes in that both their primary functions involve ________________ the body.

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

Which of the following statements about vascular spasms is false?

Prostacyclin is a hormone that is normally active in the blood but becomes inactive when a blood vessel ruptures and hemostasis begins. Considering this, which of the following is the most likely function of prostacyclin?

The following is a list of the phases involved in the process of hemostasis:

1. Coagulation
2. Fibrinolysis
3. Vascular spasm
4. Retraction
5. Platelet phase

The correct sequence of these phases is:

(a) 5, 1, 4, 2, 3

(b) 3, 5, 1, 4, 2

(c) 2, 3, 5, 1, 4

(d) 3, 5, 4, 1, 2

(e) 4, 3, 5, 2, 1

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

a. Platelet phospholipids

b. Factor XI

c. Thrombin

d. Ca²⁺

More than one choice may apply.

A condition resulting from thrombocytopenia is

a. Thrombus formation

b. Embolus formation

c. Petechiae

d. Hemophilia

___ 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