2.4 and 2.5 Platelets

Question 1

Platelets adhere to _______________, which is mediated by ____________

Answer 1

subendothelial collagen; vWF

Question 2

Platelet dense granules contain

Answer 2

ADP

Question 3

Platelet alpha granules contain (5)

Answer 3

β-thromboglobulin; platelet factor 4; PDGF; fibrinogen; factor V

Question 4

Platelet lysozymes contain

Answer 4

hydrolase

Question 5

To quantify platelets, you should collect blood into what type of tube

Answer 5

purple top (EDTA)

Question 6

When it comes to MPV, there is an inverse relationship between ______ and _______

Answer 6

size and number (more platelets but smaller size vs less platelets but larger size)

Question 7

what can artifacturally lower platelet counts in an analyzer

Answer 7

platelet clumping

Question 8

shift platelets indicate

Answer 8

increased thrombopoiesis

Question 9

small platelets can be a sign of

Answer 9

iron deficiency; ITP

Question 10

platelet concentration changes due to (3)

Answer 10

decreased thrombopoiesis; increased destruction of platelets; increased consumption of platelets

Question 11

what can be used to assess platelet function/number

Answer 11

BMBT

Question 12

when would you NOT do a BMBT test

Answer 12

if the patient has thrombocytopenia

Question 13

BMBT is _____________ with coagulation factor deficiencies

Answer 13

unaltered

Question 14

if you wanted to assess the entire clotting mechanism, what test would you use

Answer 14

thromboelastography

Question 15

T/F petechial hemorrhages are characteristic of Von Willebrands Disease

Answer 15

F

Question 16

what are the clinical signs of von willebrands disease

Answer 16

1) bleeding from mucous membranes
2) prolonged bleeding after trauma, surgery, venipuncture

Question 17

vWF allows platelet adhesion to_____________, _________________ and stabilizes

Answer 17

subendothelium, platelet-platelet adhesion, FVIII

Question 18

_______ is an example of thrombocytopenia due to destruction and causes (marked/moderate) thrombocytopenia

Answer 18

ITP; marked

Question 19

______ is an example of thrombocytopenia due to consumption and causes (marked/moderate) thrombocytopenia

Answer 19

DIC; moderate

Question 20

most of the pro-coagulation factors are made in the _________ and are ________

Answer 20

liver; enzymes

Question 21

what are the vitamin K dependent factors

Answer 21

2, 7, 9, 10

Question 22

what are the contact factors

Answer 22

11, 12, 13, prekallikrein

Question 23

what are the non-enzymatic factors

Answer 23

5, 8, fibrinogen

Question 24

what are the three anti-coagulant factors

Answer 24

antithrombin III; protein C; tissue factor pathway inhibitor

Question 25

the main protein responsible for degrading fibrin is

Answer 25

plasmin

Question 26

the intrinsic pathway is also called the

Answer 26

contact pathway

Question 27

the extrinsic pathway is also called the

Answer 27

tissue factor pathway

Question 28

in vivo, which pathway is activated first

Answer 28

extrinsic

Question 29

activation of coagulation occurs on the surface of _________, which have a ________ charge

Answer 29

platelets; negative

Question 30

what is the role of calcium in the coagulation cascade

Answer 30

provides the positive charge between the negatively charged platelet membrane and negatively charged coagulation factors

Question 31

which tests require citrated tubes

Answer 31

APTT, OSPT, fibrinogen

Question 32

ACT tests which pathways

Answer 32

intrinsic and common

Question 33

what is an important consideration before running ACT

Answer 33

need to do a CBC first to make sure patient does not have thrombocytopenia, because the test relies on the patients own platelets

Question 34

what is an advantage of ACT

Answer 34

inexpensive and easy to do in practice

Question 35

APTT (PTT) tests which pathways

Answer 35

common and intrinsic

Question 36

what is an advantage of APTT

Answer 36

is not affected by thrombocytopenia

Question 37

with clotting factor disorders, we tend to see ________, whereas with platelet disorders, we tend to see __________

Answer 37

hematomas; petechiae

Question 38

hemophilia A is a deficiency of

Answer 38

Factor VIII

Question 39

OSPT tests which pathways

Answer 39

extrinsic and common

Question 40

APTT tests which 5 diseases

Answer 40

hemophilias; DIC; hereditary factor XII or XI deficiency; vitamin K deficiency; therapeautic anticoagulation

Question 41

OSPT tests which 3 diseases

Answer 41

factor VII deficiency; DIC; vitamin K deficiency

Question 42

what is an advantage of OSPT

Answer 42

not affected by thrombocytopenia

Question 43

which test is inversely proportional to TCT

Answer 43

fibrinogen

Question 44

fibrinogen tests for what 3 disorders

Answer 44

hereditary hypo or dysfibrinogenemia; DIC; therapeutic anticoagulation

Question 45

elevated FDPs can indicate which diseases (3)

Answer 45

DIC; renal disease; internal hemorrhage

Question 46

DIC is diagnosed by _____ OSPT and APTT; _____ FDPs; ____ fibrinogen; _______ platelets and ____________________

Answer 46

increased; increased; decreased; decreased; RBC fragmentation

Question 47

what is an RBC abnormality seen in DIC

Answer 47

shistocytes

Question 48

what are some causes of hypercoagulability

Answer 48

DIC hypoalbuminemia loss of antithrombin III polycythemia hyperviscosity, proteins/cells shock drugs, platelet agonists snake bites, other toxins

Question 49

what can cause thrombocytosis

Answer 49

1) splenic contraction 2) iron deficiency 3) hemorrhage 4) paraneoplasia 5) myeloproliferative disease 6) FelV associated disease (non-neoplasia) 7) inflammatory disease