Unit 2 Lecture 10

Question 1

What are platelets called?

Answer 1

Thrombocytes

Question 2

What are platelets?

Answer 2

fragments of megakaryocytes

Question 3

How long can thrombocyte cell fragments circulate for before death?

Answer 3

5-9 days

Question 4

What percent of platelets circulate in the body?

Answer 4

66%

Question 5

Where does the remaining 33% of platelets reside in the body?

Answer 5

In the spleen

Question 6

Define thrombosis

Answer 6

the formation of a clot

Question 7

Define thrombus

Answer 7

A clot

Question 8

Define embolus

Answer 8

A circulating clot

Question 9

Define hemmorage

Answer 9

a severe uncontrolled bleeding

Question 10

What term describes how thrombocytes are made?

Answer 10

Thrombocytopoiesis

Question 11

What type of stem cell produces megakaryocytes?

Answer 11

Myeloid stem cells

Question 12

How are thrombocytes made from megakaryocytes?

Answer 12

Thrombopoietin (TPO) lets thrombocyte fragments to fall off the megakaryocyte

Question 13

What internal process is responsible for bleeding to stop?

Answer 13

Hemostasis

Question 14

What 3 phases make up hemostasis?

Answer 14

1. Vascular spasm
2. Platelet plug formation
3. Coagulation (blood clotting)

Question 15

What does a vascular spasm do?

Answer 15

Immediately vasoconstricts (makes diameter smaller) in response to injury -> stops blood flow

Question 16

Where do vascular spasms occur?

Answer 16

In vessels with smooth muscle walls

Question 17

What is angiotensin II?

Answer 17

a vasoconstricting hormone that effects the renal sympathetic nerves

Question 18

During plug formation, what do platelets normally NOT do?

Answer 18

do not stick to each other or the endothelial lining of blood vessels

Question 19

What do platelets stick to in a damaged blood vessel?

Answer 19

Collagen fibers

Question 20

What do platelets do when they are activated by collagen fibers in damaged blood vessels?

Answer 20

• liberate thromboxane A2, serotonin, and ADP

- release ADP

Question 21

How does the damaged vessel make a “plug”

Answer 21

ADP makes platelets sticky and thromboxane A2 and serotonin causes cell contraction -> plug

Question 22

What word means blood clotting

Answer 22

coagulation

Question 23

Where do most of the clotting factors come from in the body?

Answer 23

Liver

Question 24

During coagulation, what type of stimulations are present?

Answer 24

intrinstic and extrinsic stimulations

Question 25

Which type of stimulation is slower during coagulation?

Answer 25

intrinsic

Question 26

What must be completed in order for effective clotting to occur?

Answer 26

the common pathway

Question 27

What happens during the common pathway?

Answer 27

Prothrombinase is activated and it converts prothrombin into thrombin

Question 28

What are the 2 main functions of thrombin?

Answer 28

1. converts fibrinogen to fibrin

2. Activates factor XIII, which stabilizes the fibrin network

Question 29

What are some of the different clotting factors found in the liver?

Answer 29

Prothrombin, fibrinogen, factors V, VII, IX, and X

Question 30

What is needed for the synthesis of clotting factors?

Answer 30

Vitamin K

Question 31

What is the importance of vitamin K during coagulation?

Answer 31

W/out vitamin K leads to failure of blood clotting = wont stop bleeding

Question 32

What are people called who lack factor VIII?

Answer 32

Hemophilacs

Question 33

What can’t form without factor VIII?

Answer 33

prothrombinase

Question 34

What is prothrombinase?

Answer 34

A clotting factor that turns prothrombin into thrombin with Ca2+

Question 35

What must happen to an embolus before entering the blood stream?

Answer 35

it must dissolve

Question 36

What word means the dissolution of a clot?

Answer 36

fibrinolysis

Question 37

What digests the fibrin strands and breaks the clot?

Answer 37

plasmin

Question 38

What makes plasmin?

Answer 38

tissue plasminogen activator, thrombin, and plasminogen