Unit 6.2 PLATELET STUDIES

Question 1

are produced from the cytoplasm of megakaryocytes

Answer 1

Platelets

Question 2

Despite their tiny size, they are complex and metabolically active.

Answer 2

Platelets

Question 3

They function in hemostasis by interacting with their environment to initiate and control hemostasis

Answer 3

Platelets

Question 4

General characteristics of thrombocytes:
• Shape & origin:
• Diameter:
• Reference platelet count:
• Daily turnover:
• Lifespan:
• Function:

Answer 4

Thin disc cytoplasmic fragments

2 - 4 pm; Volume: 5 - 7 fL

150.000 - 450.000/uL

35 X 10%/L (+/- 4.3)

8 - 11 days

(Hemostasis) maintenance of vascular integrity and blood coagulation

Question 5

bears the different glycoproteins

Answer 5

Glycocalyx

Question 6

: Underlies the plasma membrane & receives message from the outside

Answer 6

Submembranous area

Question 7

Peripheral zone:

Answer 7

Glycocalyx

Submembranous area:

Question 8

Consists of a stable gel that regulates arrangement of internal organelles

Answer 8

Sol-Gel zone:

Question 9

• provide the cytoskeleton

Answer 9

Microtubules & microfilaments

Question 10

Where the alpha granules, dense bodies, mitochondria, lysosomes and peroxisomes are located.

Answer 10

Organelle zone:

Question 11

2 membrane systems

Answer 11

Open canalicular system

Dense tubular system

Question 12

• site of arachidonic acid synthesis and functions as a calcium sequestering pump

Answer 12

Dense tubular system

Question 13

delivery routes

Answer 13

Open canalicular system

Question 14

High Molecular Weight Kininogen Fibrinogen;

Answer 14

Promote coagulation

Question 15

Factor V

Answer 15

Promote coagulation

Question 16

von Willebrand Factor

Answer 16

Promote coagulation

Question 17

Alpha granules

Answer 17

Promote coagulation

Question 18

ADP;

Answer 18

Promote aggregation

Question 19

Calcium

Answer 19

Promote aggregation

Question 20

Platelet factor 4

Answer 20

Promote aggregation

Question 21

Thrombospondin

Answer 21

Promote aggregation

Question 22

Dense bodies

Answer 22

Promote aggregation

Question 23

Alpha granules

Answer 23

Promote coagulation
Promote aggregation
Promote vasoconstriction
Promote vascular repair
Other system affected

Question 24

Serotonin

Answer 24

Promote vasoconstriction

Question 25

Thromboxane A2 precursors

Answer 25

Promote vasoconstriction

Question 26

Dense bodies

Answer 26

Promote vasoconstriction

Question 27

Membrane phospholipids

Answer 27

Promote vasoconstriction

Question 28

Platelet derived growth factor

Answer 28

Promote vascular repair

Question 29

Beta thromboglobulin

Answer 29

Promote vascular repair

Question 30

Plasminogen

Answer 30

Other system affected

Question 31

Alpha 2-antiplasmin

Answer 31

Other system affected

Question 32

C1 esterase inhibitor

Answer 32

Other system affected

Question 33

Ability of platelets to attach to non-platelet surface. This allows platelets to adhere to damaged endothelium.

Answer 33

Adhesion

Question 34

Requires plasma von Willebrand Factor and Gp Ib-IX

Answer 34

Adhesion

Question 35

Alpha & dense granules release substances that will contribute to platelet aggregation and activation of the coagulation system

Answer 35

Platelet Release Reaction

Question 36

Platelets stick to one another to form an initial platelet plug.

Answer 36

Platelet aggregation

Question 37

Induced by stimuli such as ADP, thrombin, TxA2, collagen & epinephrine.

Answer 37

Platelet aggregation

Question 38

Requires Gp IIb-IIIa and plasma fibrinogen.

Answer 38

Platelet aggregation

Question 39

Deficiency/Defect in Gp Ib-IX

Answer 39

Bernard-Soulier:

Question 40

Characterized by large platelets, thrombocytopenioa, prolonged and Bleeding Time.

Answer 40

Bernard-Soulier:

Question 41

Platelets show normal aggregation with epinephrine, ADP and collagen but not with ristocetin.

Answer 41

Bernard-Soulier:

Question 42

Aggregation test: same with Bernard-Soulier

Answer 42

von Willebrands disease

Question 43

Deficiency/Defect in Gp IIb-IIIa

Answer 43

Glanzmann’s Thrombasthenia

Question 44

Platelets show normal aggregation with ristocetin but not with epinephrine, ADP nor collagen.

Answer 44

Glanzmann’s Thrombasthenia

Question 45

1. Decreased production

Answer 45

Thrombocytopenia:

Question 46

2. Dilutional (e.g. following blood transfusion)

Answer 46

Thrombocytopenia:

Question 47

3. Increased destruction (immune and non-immune causes)

Answer 47

Thrombocytopenia:

Question 48

4. Splenic sequestration

Answer 48

Thrombocytopenia:

Question 49

1. Myeloproliferative (uncontrolled production by the bone marrow)

Answer 49

Thrombocytosis:

Question 50

2. Reactive thrombocytosis (in response to hemolytic anemias)

Answer 50

Thrombocytosis: