Various Mechanisms that Prevent Blood Loss

Question 1

What Term?
(a) A sequence of responses that stops bleeding when blood vessels are injured.
(b) The hemostatic response must be quick, localized to the region of damage, and carefully controlled.

Answer 1

hemostasis
-Be sure not to confuse the two words hemostasis and homeostasis.

Question 2

What are he three mechanisms can reduce loss of blood from blood vessels.

Answer 2

(a) Vascular spasm
(b) Platelet plug formation
(c) Blood clotting (coagulation)

Question 3

_______ can prevent hemorrhage from smaller blood vessels, but extensive hemorrhage from larger vessels usually requires medical intervention.

Answer 3

Hemostatis

Question 4

When a blood vessel is damaged, the smooth muscle in its wall contracts immediately, a response called a _____. This reduces blood loss for several minutes to several hours, during which time the other hemostatic mechanisms begin to operate.

Answer 4

Vascular spasm

Question 5

What is this?
When platelets come into contact with parts of a damaged blood vessel, their characteristics change drastically and they quickly come together to form a plug that helps fill the gap in the injured blood vessel wall.

Answer 5

Platelet Plug

Question 6

True/False
A platelet plug can stop blood loss completely if the hole in a blood vessel is small enough

Answer 6

True

Question 7

The process of clot formation
_______ is a series of chemical reactions that culminates in the formation of fibrin threads.

Answer 7

Coagulation

Question 8

If blood clots too easily, the result can be _______, clotting in an unbroken blood vessel.

Answer 8

thrombosis

Question 9

If Coagulation takes too long, _______ can result

Answer 9

hemorrhage

Question 10

Clotting (coagulation) factors include:

Answer 10

1) Calcium ions (Ca2+)
2) Several enzymes that are made by liver cells and released into the blood.
3) Various molecules associated with platelets or released by damaged tissues.

Question 11

Clotting occurs in three stages What stage is what?
______: Thrombin converts soluble fibrinogen (another plasma protein made by the liver) into insoluble fibrin.
______: Prothrombinase is formed.
______:Prothrombinase converts prothrombin (a plasma protein formed in the liver with the help of vitamin K) into the enzyme thrombin.

Answer 11

3.
1.
2.

Question 12

True/False
Fibrin forms the threads of the clot, cigarette smoke does not contain substances that interfere with this step.

Answer 12

False
Cigarette smoke contains substances that interfere with this step

Question 13

_______ is the consolidation or tightening of the fibrin clot. The fibrin threads attached to the damaged surfaces of the blood vessel gradually
contract as platelets pull on them.

Answer 13

Clot Retraction

Question 14

In time, _______ form connective tissue in the ruptured area, and new endothelial cells repair the vessel lining.

Answer 14

fibroblasts

Question 15

What causes a clot to begin to be digested and dissolve the fibrin threads to remove the clot

Answer 15

Blood and body tissues that activate plasminogen into plasmin.

Question 16

A blood clot, bubble of air, fat from broken bones, or a piece of debris transported by the bloodstream is called an ______

Answer 16

Embolus

Question 17

Clotting in an unbroken blood vessel is called _____

Answer 17

Thrombus