2S [LEC]: Platelets Flashcards
(129 cards)
1
Q
Normal size of platelets
A
2-4 um in diameter
2
Q
T/F: Platelets are nucleated cells that are fragments of megakaryocytes
A
False (platelets are anuclear)
3
Q
Largest cells found in the bone marrow
A
Megakaryocytes
4
Q
Maturation sequence of megakaryoblast to platelets takes how many days?
A
5 days
5
Q
The life span of platelets
A
8-11 days (ave. 9 days)
6
Q
How long is a platelet concentrate viable?
A
5 days at room temp with constant agitation
7
Q
What cell characteristic mostly differentiates the maturation of the megakaryocytic cell series?
A
Cytoplasmic appearance
8
Q
Hormone that gives rise to megakaryocytes
A
Thrombopoietin
9
Q
Where is the thrombopoietin primarily produced?
A
Liver
10
Q
What maturation stage of the megakaryocytic cell has 2-6 nucleoli with homogenous chromatin?
A
Megakaryoblast (MK-I)
11
Q
What maturation stage of the megakaryocytic cell has an N:C ratio of 3:1?
A
Megakaryoblast (MK-I)
12
Q
What maturation stage of the megakaryocytic cell has basophilic cytoplasm with no granules?
A
Megakaryoblast (MK-I)
13
Q
What maturation stage of the megakaryocytic cell is irregularly shaped with cytoplasmic tags?
A
Megakaryoblast (MK-I)
14
Q
Earliest thrombocyte stage where endomitosis occurs
A
Megakaryoblast (MK-I)
15
Q
Process known as the division of nucleus without cytoplasmic division
A
Endomitosis
16
Q
Invagination of the plasma membrane that becomes the future site of platelet fragmentation
A
Demarcation Membrane System (DMS)
17
Q
The presence of DMS is seen at what megakaryocytic stage?
i. Megakaryoblast (MK-I)
ii. Promegakaryocyte (MK-II)
iii. Megakaryocyte (MK-III)
A
i, ii, iii
18
Q
What maturation stage of the megakaryocytic cell has an N:C ratio of 1:2?
A
Promegakaryocyte (MK-II)
19
Q
What maturation stage of the megakaryocytic cell has an indented or lobulated nucleus, containing variable number of nucleoli with moderately condensed chromatin?
A
Promegakaryocyte (MK-II)
20
Q
What maturation stage of the megakaryocytic cell has a basophilic cytoplasm with granules beginning to appear?
A
Promegakaryocyte (MK-II)
21
Q
What maturation stage of the megakaryocytic cell does endomitosis ends?
A
Promegakaryocyte (MK-II)
22
Q
What maturation stage of the megakaryocytic cell has an N:C ratio of 1:4?
A
Megakaryocyte (MK-III)
23
Q
What maturation stage of the megakaryocytic cell is the largest cell in the bone marrow?
A
Megakaryocyte (MK-III)
24
Q
What maturation stage of the megakaryocytic cell contains a multilobed nucleus with deeply and variably condensed chromatin with no nucleoli visible
A
Megakaryocyte (MK-III)
25
What maturation stage of the megakaryocytic cell has an azurophilic cytoplasm that has many granules that stain purple with Wright's stain?
Megakaryocyte (MK-III)
26
What maturation stage of the megakaryocytic cell is capable of shedding?
Megakaryocyte
27
How many platelets are formed per megakaryocyte?
2 000 to 4 000
28
Mitosis is seen at what megakaryocytic stage?
i. Megakaryoblast (MK-I)
ii. Promegakaryocyte (MK-II)
iii. Megakaryocyte (MK-III)
none
29
The presence of a-granules is seen at what megakaryocytic stage?
i. Megakaryoblast (MK-I)
ii. Promegakaryocyte (MK-II)
iii. Megakaryocyte (MK-III)
i, ii, iii
30
The presence of dense granules is seen at what megakaryocytic stage?
i. Megakaryoblast (MK-I)
ii. Promegakaryocyte (MK-II)
iii. Megakaryocyte (MK-III)
i, ii, iii
31
Endomitosis occurs at what megakaryocytic stage?
i. Megakaryoblast (MK-I)
ii. Promegakaryocyte (MK-II)
iii. Megakaryocyte (MK-III)
i, ii
32
Which of the following is not a normal maturation stage for platelets?
i. Megakaryoblast
ii. Promegakaryocyte
iii. Micromegakaryocyte
iv. Megakaryocyte
v. Metamegakaryocyte
iii
33
How much platelet is sequestered in the spleen?
1/3
34
Effect of splenomegaly in platelet count
Decrease
35
Effect of splenectomy in platelet count
Increase
36
Indicate premature release of platelet from the bone marrow and result from increased demand
Giant platelets
37
Which of the following would not exhibit giant platelets?
i. Bernard Soulier Syndrome
ii. Gray Platelet Syndrome
iii. May-Hegglin Anomaly
iv. All will exhibit giant platelet
iv
38
Common CD markers for megakaryocytes
CD41, CD61
39
Size of the cell recognized by automation to be platelets
2-20 fL
40
Normal MPV range
6.8-10.2 fL
41
Microscope that is most optimal in platelet counting
Phase-contrast microscope
42
Reference value of platelet
150 000 - 400 000/uL (cumm)
150 - 400 x 10^9 / L
43
Normal platelet estimate per oil immersion field is ___
8-20
44
Factor for platelet estimate is ___
20 000
45
The use of Rees-Ecker diluting fluid in platelet count must be completed within how many minutes?
30 mins
46
A platelet diluting fluid that remains stable for 8 hours
1% ammonium oxalate
47
Excess of this anticoagulant often leads to platelet fragmentation and satellitosis
EDTA
48
Uncontrolled malignant proliferation of platelets
Primary Thrombocytosis
49
What is the approximate platelet count in patients with primary thrombocytosis?
> 1000 x 10^9/ L
50
T/F: Thrombocytosis is associated with either hemorrhagic or thrombotic complications
True
51
T/F: In essential thrombocytopenia, there is an excess of functional platelets
False (non-functioning PLT)
52
Increased platelet production in response to thrombopoietin
Secondary thrombocytosis
53
What is the approximate platelet count in patients with secondary thrombocytosis?
< 1000 x 10^9 / L
54
Thrombocytosis is a characteristic of:
i. DIC
ii. Splenomegaly
iii. Polycythemia vera
iv. Idiopathic thrombocytopenia purpura
iii
55
Identify whether the condition would cause thrombocytopenia or thrombocytosis:
Inflammatory disease
Thrombocytosis
56
Identify whether the condition would cause thrombocytopenia or thrombocytosis:
Blood regeneration, especially in hemolytic anemia and acute blood loss
Thrombocytosis
57
Identify whether the condition would cause thrombocytopenia or thrombocytosis:
Post-operative state from tissue damage
Thrombocytosis
58
Identify whether the condition would cause thrombocytopenia or thrombocytosis:
Splenectomy
Thrombocytosis
59
Identify whether the condition would cause thrombocytopenia or thrombocytosis:
Chemotherapy
Thrombocytopenia
60
Identify whether the condition would cause thrombocytopenia or thrombocytosis:
Marrow replacement by malignant cells
Thrombocytopenia
61
Identify whether the condition would cause thrombocytopenia or thrombocytosis:
Aplastic anemia
Thrombocytopenia
62
Identify whether the condition would cause thrombocytopenia or thrombocytosis:
Megaloblastic anemia
Thrombocytopenia
63
Identify whether the condition would cause thrombocytopenia or thrombocytosis:
Severe hemorrhage and massive transfusion
Thrombocytopenia
64
A condition characterized by microthrombi formation due to fragmentation of RBC, causing thrombocytopenia
Microangiopathic Hemolytic Anemia (MAHA)
65
A condition characterized by fibrin degradation product causing systemic clotting followed by fibrinolysis, causing thrombocytopenia
Disseminated Intravascular Coagulation (DIC)
66
A condition characterized as an accumulation of large vWF, causing hemolytic anemia with schistocytes and thrombocytopenia
TTP (Thrombotic thrombocytopenia purpura)
67
In splenomegaly/ hypersplenism, the result of platelet sequestration can be as high as ___
90%
68
When platelet adheres to neutrophils due to EDTA exposure, this is called ___
Platelet satellitosis
69
Effect of platelet satellitosis on platelet count
Falsely decreased
70
To correct platelet satellitosis, which anticoagulant and factor for dilution is used?
Sodium citrate
x 1.1
71
Which of the following is not a cause of thrombocytopenia?
i. Splenomegaly
ii. Chemotherapy
iii. Increased thrombopoietin
iv. Aplastic anemia
iii
72
The exterior coat and contain glycoprotein receptor sites
Glycocalyx
73
The receptor for vWF
GPIb
74
The cofactor for VWF
Ristocetin
75
The receptor for fibrinogen
GPIIb/IIIa
76
Identify the anatomic area:
Responsible for platelet adhesion and aggregation
Peripheral zone
77
The submembrane area of the peripheral zone contains the ___, which serves as a surface for interaction of coagulation factors in secondary hemostasis during aggregation
Phospholipid membrane (PF3)
78
Identify the anatomic area:
Contains cytoskeleton microtubules and microfilaments
Sol-gel (structural) zone
79
Contracts the thrombus at the end of the coagulation process
Actomyosin/ thrombosthenin
80
Responsible for clot retration
Thrombosthenin
81
Identify the anatomic area:
Contains the granules, lysosomes, mitochondria, peroxisomes, and glycogen
Organelle zone
82
Part of the membrane system that regulates the intracellular calcium concentration
Dense Tubular System (DTS)
83
Part of the membrane system the releases granular contents through channels leading to the surface of the platelet
Open Canalicular System (OCS)
84
Which of the following promote aggregation:
i. Ca2+
ii. Serotonin
iii. Thromboxane A2
iv. ADP
v. PDGF
vi. Beta-thromboglobulin
i, iv
85
Which of the following promote vasoconstriction:
i. Ca2+
ii. Serotonin
iii. Thromboxane A2
iv. ADP
v. PDGF
vi. Beta-thromboglobulin
ii, iii
86
Which of the following promote vascular repair:
i. Ca2+
ii. Serotonin
iii. Thromboxane A2
iv. ADP
v. PDGF
vi. Beta-thromboglobulin
v, vi
87
Process where platelet adhere to vascular surfaces
Adhesion
88
A plasma protein that binds platelets to exposed subendothelial collagen
von Willebrand factor
89
A qualitative platelet defect where GPIb/IX/V receptor is absent
Bernard Soulier Syndrome
90
Most common hereditary hemorrhagic disorder
von Willebrand disease
91
A qualitative platelet defect where the vWF is missing or defective
Von Willebrand Disease
92
T/F: In von Willebrand disease, both the primary and secondary hemostasis are affected
True
93
vWF is a carrier protein to which coagulation factor?
Coagulation factor VIII
94
Which of the following is not true with von Willebrand disease?
i. Prolonged bleeding time
ii. Decreased aggregation with ADP, Epinephrine/Adrenaline, Collagen
iii. Prolonged clotting time, APTT
iv. Normal PT
v. Normal platelet count
ii
95
Which of the following is not true with Bernard-Soulier Syndrome?
i. Prolonged bleeding time
ii. Decreased aggregation with ADP, Epinephrine/Adrenaline, Collagen
iii. Prolonged clotting time, APTT
iv. Normal PT
v. High MPV
ii, iii
96
The reference for mean platelet volume (MPV) is approximately
i. 2-4 fL
ii. 5-7 fL
iii. 8-10 fL
iv. 11-14 fL
iii
97
Which of the following are dense granules:
i. Fibrinogen
ii. vWF
iii. ADP
iv. ATP
v. PDGF
iii, iv
98
Which of the following are alpha granules:
i. Beta-thromboglobulin
ii. vWF
iii. Calcium
iv. Serotonin
v. PDGF
i, ii, v
99
Qualitative defect of the storage pool that is characterized as large platelets and thrombocytopenia due to absence of alpha granules
Gray-platelet syndrome
100
Qualitative defect of the storage pool where patients are prone to lifelong mild bleeding tendencies
Gray-platelet syndrome
101
Qualitative defect of the storage pool where there is a lack of dense body granules
Hermansky-Pudlak Syndrome
102
Qualitative defect of the storage pool where patient exhibit oculocutaneous albinism and are prone to hemorrhage
Hermansky-Pudlak Syndrome
103
Qualitative defect of the storage pool where there is a decreased amount of alpha granules and dense bodies
Wiskott-Aldrich Syndrome
104
Qualitative defect of the storage pool where patients are prone to hemorrhage and recurrent infections
Wiskott-Aldrich Syndrome
105
Triad of Wiskott-Aldrich syndrome includes:
i. Thrombocytosis
ii. Immunodeficiency
iii. Eczema
iv. Thrombocytopenia
ii, iii, iv
106
The process of platelet attaching to each other forming platelet plug
Aggregation
107
Which of the following are platelet release agonist:
i. Thromboxane A2
ii. ADP
iii. PF4
iv. Serotonin
v. Ca2+
vi. PF3
ii, iii, iv, v
108
Which enzyme converts arachidonic acid into thromboxane A2?
Cyclooxygenase enzyme
109
Causes Ca2+ to be released from the dense tubules, promoting platelet aggregation and vasoconstriction
Thromboxane A2
110
Drug commonly used for its antiplatelet effect
Aspirin/ Salicylate/ Acetylsalycilic acid
111
The mechanism of action of aspirin and NSAIDs is that it blocks ___
Cyclooxygenase enzyme
112
T/F: Aspirin affects both primary and secondary hemostasis
False (primary only)
113
Medicine that blocks the IIb/IIIa platelet receptor, preventing platelet aggregation
Plavix/ Clopidogrel bisulfate
114
An aggregation defect caused by lack of GP IIb/IIIa receptor
Glanzmann thrombasthenia
115
An aggregation defect caused by the absence of fibrinogen
Afibrinogenemia
116
An aggregation defect where clot retraction is abnormal due to lack of contractile proteins
Glanzmann thrombasthenia
117
Which of the following are true with Glanzmann thrombasthenia?
i. Prolonged bleeding time
ii. Decreased aggregation with ADP, Epinephrine/Adrenaline, Collagen
iii. Prolonged clotting time
iv. Normal PT and PT
v. Decreased aggregation with ristocetin
i, ii, iv
118
Which of the following are true with Fibrinogen Deficiency?
i. Prolonged bleeding time
ii. Decreased aggregation with ADP, Epinephrine/Adrenaline, Collagen
iii. Prolonged clotting time
iv. Normal PT and PT
v. Decreased aggregation with ristocetin
i, ii, iii
119
In storage pool disease, platelets are primarily deficient in:
i. ADP
ii. PF3
iii. Thrombosthenin
iv. Thromboxane A2
i
120
In vitro test to determine the ability of platelets to aggregate with certain agonist
Platelet aggregation test
121
Anticoagulant of choice in platelet aggregation test
Sodium citrate
122
Platelets interacting with and binding to other platelets is referred to as:
i. Adhesion
ii. Aggregation
iii. Release
iv. Retraction
ii
123
Of the following therapeutic agents, those considered to be antiplatelet medications are:
i. Aspirin and Plavix
ii. Coumadin and heparin
iii. Heparin and protamine sulfate
iv. Tissue plasminogen activator and streptokinase
i
124
A potent inhibitor of platelet aggregation released by endothelial cells is:
i. Epinephrine
ii. Postacyclin
iii. Ristocetin
iv. Thromboxane A2
ii
125
A clot retraction defect is more likely due to:
i. Lack of platelet receptor glycoprotein Ib
ii. Lack of platelet receptor glycoprotein IIb/IIIa
iii. Insufficient ADP in dense bodies
iv. Absence of von Willebrand factor
ii
126
In platelet aggregation studies, certain aggregating agents induce a biphasic aggregation curve. This second phase of aggregation is directly related to:
i. Formation of fibrin
ii. Changes in platelet shape
iii. Release of endogenous ADP
iv. Release of PF3
iii
127
Reference range for bleeding time
2-4 mins
128
Reference range for ivy method
3-6 mins
129
Reference range for template bleeding time
6-10 mins
