chapter 19 part 2 Flashcards Preview

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Flashcards in chapter 19 part 2 Deck (31):
1

platelets
-how many per mm3 of blood
-platelet production
-3 functions

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

2

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

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

3

platelet abnormalities
-2 types

1. thrombocytopenia
2. thrombocytosis

4

thrombocytopenia
-definition
-what does it cause

-abnormally low platelet count
-causes uncontrolled internal bleeding

5

thrombocytosis

abnormally high platelet count

6

hemostasis
-definition
-3 phases

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

7

Vascular phase
-definition
-cutting of vessel wall causes
-component

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

8

vascular spasm
-definition
-minimizes what

-decrease diameter of vessel
-minimizes blood loss

9

Platelet phase
-definition
-2 components

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

10

platelet adhesion

platelets begin to attach to exposed vessel surface

11

platelet plug formation

platelets release various chemicals causing more platelets to adhere

12

coagulation phase
-definition
-what does it involve
-3 steps

-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)

13

fibrinogen

soluable protein in plasma

14

fibrin

insoluable protein in plasma

15

Coagulation: the common pathway
-what does it do
-4 steps

-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

16

Activated factor X is made where

in the liver

17

Is prothrombinase an active or inactive enzyme?

active enzyme

18

prothrombin
-what is it?
-active or inactive enzyme

-protein in plasma
-inactive enzyme

19

thrombin
-active or inactive enzyme

active enzyme

20

2 pathways to activated Factor X

-extrinsic
-intrinsic

21

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

-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

22

intrinsic pathway
-what is it triggered by
-6 steps

-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

23

control of coagulation
-4 requirements

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

24

calcium requirement

any Ca2+ imbalance will have same affect on clotting

25

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

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

26

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

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

27

Fibrinolysis
-definition
-3 steps

-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

28

unwanted blood clots
-2 types

1. embolus
2. thrombus

29

embolus
-type of clot
-definition

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

30

thrombus
-type of clot

stationary blood clot

31

anticoagulants

prevents unwanted blood clots