chapter 19 part 2

Question 1

platelets

• how many per mm3 of blood
• platelet production
• 3 functions

Answer 1

• 350,000
• thrombocytopoieosis
• 1. release chemicals important for clotting process
     
     2. forms temporary patch in wall of damaged blood vessel
• contracts formed clot

Question 2

megakaryocyte

• big or small
• sheds what
• # of platelets produced from 1 megakaryocte
• how many days does it circulate in blood for

Answer 2

• very large
• cytoplasm in small membrane - enclosed packets
• 4000
• 9-12 days

Question 3

platelet abnormalities

-2 types

Answer 3

1. thrombocytopenia

2. thrombocytosis

Question 4

thrombocytopenia

• definition
• what does it cause

Answer 4

• abnormally low platelet count

- causes uncontrolled internal bleeding

Question 5

thrombocytosis

Answer 5

abnormally high platelet count

Question 6

hemostasis

• definition
• 3 phases

Answer 6

• stoppage of bleeding in damaged vessel
• 1. vascular phase
     
     2. platelet phase
     3. the coagulation phase

Question 7

Vascular phase

• definition
• cutting of vessel wall causes
• component

Answer 7

• immediate response that last ~30 min
• contraction of smooth muscle
• vascular spasm

Question 8

vascular spasm

• definition
• minimizes what

Answer 8

• decrease diameter of vessel

- minimizes blood loss

Question 9

Platelet phase

• definition
• 2 components

Answer 9

• begins ~15 sec after injury
• platelet adhesion
• platelet plug

Question 10

platelet adhesion

Answer 10

platelets begin to attach to exposed vessel surface

Question 11

platelet plug formation

Answer 11

platelets release various chemicals causing more platelets to adhere

Question 12

coagulation phase

• definition
• what does it involve
• 3 steps

Answer 12

• begins ~30 sec after injury
• involved Ca++ and 11 different clotting factors
• 1. fibrinogen
     
     2. fibrin
     3. forms threads that seal off damaged vessel (clot)

Question 13

fibrinogen

Answer 13

soluable protein in plasma

Question 14

fibrin

Answer 14

insoluable protein in plasma

Question 15

Coagulation: the common pathway

• what does it do
• 4 steps

Answer 15

• forms a clot
• 1. Activated factor X is converted to prothrombinase
     
     2. Prothrombinase converts prothrombin to thrombin
     3. Thrombin converts fibrinogen into fibrin
     4. fibrin forms the clot

Question 16

Activated factor X is made where

Answer 16

in the liver

Question 17

Is prothrombinase an active or inactive enzyme?

Answer 17

active enzyme

Question 18

prothrombin

• what is it?
• active or inactive enzyme

Answer 18

• protein in plasma

- inactive enzyme

Question 19

thrombin

-active or inactive enzyme

Answer 19

active enzyme

Question 20

2 pathways to activated Factor X

Answer 20

• extrinsic

- intrinsic

Question 21

extrinsic pathway

• what is it triggered by
• 1st or 2nd pathway to initiate clotting
• 7 steps

Answer 21

• factors that lie outside the blood
• 1st pathway
• 1. Tissue damage
     
     2. Tissue Factor III
     3. plasma components (Ca2+ and clotting factor VII)
     4. Factor VII - tissue factor complex
     5. activated factor X
     6. common pathway
     7. clot

Question 22

intrinsic pathway

• what is it triggered by
• 6 steps

Answer 22

• triggered by platelets found in blood
• 1. exposed collagen fibers at injury site
     
     2. activated proenzymes (factor XII)
     3. Plasma components (platelet factor, Ca2+, clotting factors VIII,XI)
     4. activated factor X
     5. common pathway
     6. clot

Question 23

control of coagulation

-4 requirements

Answer 23

1. calcium
2. vitamin K
3. clot retraction (syneresis)
4. fibrinolysis

Question 24

calcium requirement

Answer 24

any Ca2+ imbalance will have same affect on clotting

Question 25

Vitamin K requirement - why is it used - obtained by what - made by what

Answer 25

- to make clotting factors - by diet - bacteria in large intestine

Question 26

clot retraction (syneresis) - definition - occurs over a period of how long

Answer 26

- pulls torn edges of vessel closer together to reduce size of damaged area - over a period of 30 to 60 min

Question 27

Fibrinolysis - definition - 3 steps

Answer 27

- dissolving the clot - 1. plasminogen (plasma protein, inactive enzyme) - tissue plasminogen activator (t-PA) is released from damaged tissue 2. plasmin (active enzyme) 3. digests clot

Question 28

unwanted blood clots | -2 types

Answer 28

1. embolus | 2. thrombus

Question 29

embolus - type of clot - definition

Answer 29

moving clot | -becomes stuck in a blood vessel and blocks circulation in that area

Question 30

thrombus | -type of clot

Answer 30

stationary blood clot

Question 31

anticoagulants

Answer 31

prevents unwanted blood clots