Platelet

Question 1

Aka Thrombocytes

Answer 1

Platelets

Question 2

Arise from bone marrow cell called

Answer 2

Megakaryocytes

Question 3

Important in both primary and secondary hemostasis

Answer 3

Platelets

Question 4

Described as cells with granular cytoplasm but no nuclear material

Answer 4

Platelets

Question 5

Platelet life span

Answer 5

9.0 days + 1 day (8-10 days)

Question 6

Thrombocytes enter the spleen initially, remain for two days, after this period, either ___ or ____ are thrombocytes found

Answer 6

Circulating blood, or active splenic pool

Question 7

Approx. 2/3 of platelets are in

Answer 7

Systemic circulation

Question 8

1/3 of platelets are in

Answer 8

Spleen

Question 9

Platelet diameter in PBS

Answer 9

2.5 µm (2 to 4 µm)

Question 10

Platelet functions

Answer 10

Form plug to stop blood loss, Participate in coagulation, Preserve endothelial lining

Question 11

Platelet on Wright stain, spread on RBC monolayer amount

Answer 11

(7-21 per 100x field)

Question 12

Newly released platelets with RNA, larger than usual

Answer 12

Reticulated platelets aka stress platelets

Question 13

Diameter of reticulated platelets

Answer 13

Exceeds 6 µm (MPV 12-14 fL)

Question 14

Clinical use of reticulated platelets

Answer 14

Differentiate bone marrow failure from peripheral destruction, early predictor of recovery after chemotherapy

Question 15

Potentially prothrombotic, may increase cardiovascular disease risk

Answer 15

Reticulated platelets

Question 16

Size of normal platelets

Answer 16

2.5 µm (average)

Question 17

MPV (mean platelet volume ref range)

Answer 17

6.8 to 10.2 fL

Question 18

EDTA effect on platelet volume

Answer 18

Causes 20% increase in MPV within the first hour

Question 19

MPV measurement timing

Answer 19

Should be based on EDTA specimens 1 to 4 hours old

Question 20

MPV result issue if examined immediately

Answer 20

Falsely increased

Question 21

Small platelets associated with

Answer 21

Wiskott-Aldrich Syndrome (X-linked recessive), TORCH infections

Question 22

TORCH infections

Answer 22

Toxoplasma, Other agents, Rubella virus, Cytomegalovirus, Herpesvirus

Question 23

Large/Giant platelets associated with

Answer 23

Bernard-Soulier Syndrome, GPS, MYH9 gene mutations

Question 24

Bernard-Soulier Syndrome and Gray Platelet Syndrome (GPS) inheritance

Answer 24

Autosomal recessive

Question 25

MYH9 gene mutations examples

Answer 25

Fechtner syndrome, Sebastian syndrome, Epstein syndrome, May-Hegglin Anomaly

Question 26

May-Hegglin Anomaly features

Answer 26

Leukopenia, variable thrombocytopenia, giant platelets, Dohle body-like inclusions

Question 27

Shape of resting and circulating platelets

Answer 27

Biconvex or disk shaped

Question 28

Shape of activated platelets

Answer 28

Spherical with pseudopods

Question 29

Cytoplasm of platelets (Wright-stained PBS)

Answer 29

Lavender and granular

Question 30

Two general parts of platelets

Answer 30

Chromomere/granulomere (centrally granular), Hyalomere (peripherally non-granular)

Question 31

Process by which megakaryocytes develop

Answer 31

Megakaryocytopoiesis (megakaryopoiesis)

Question 32

Major regulator of platelet production, produced primarily by the liver

Answer 32

Thrombopoietin (TPO)

Question 33

Alternate name for thrombopoietin

Answer 33

MGDF (megakaryocyte growth and development factor)

Question 34

TPO molecular weight

Answer 34

70,000 Dalton

Question 35

TPO homology with erythropoietin (EPO)

Answer 35

23% homology

Question 36

TPO receptor site

Answer 36

MPL receptor, present at all maturation stages (BFU-Meg to platelets)

Question 37

TPO concentration and platelet mass relationship

Answer 37

Inversely proportional; membrane binding and removal by platelets control platelet count

Question 38

Some functions of TPO

Answer 38

Stimulates megakaryocytopoiesis, induces proliferation and maturation of megakaryocytes, induces thrombocytopoiesis

Question 39

Largest cells in the bone marrow, multilobulated nucleus, abundant granular cytoplasm

Answer 39

Megakaryocyte; size 30-160 µm

Question 40

Percentage of megakaryocytes of all bone marrow cells

Answer 40

<0.5%

Question 41

Megakaryocytes per 10x low-power field

Answer 41

36926

Question 42

3 megakaryocyte lineage-committed progenitor stages

Answer 42

BFU-Meg, CFU-Meg, LD-CFU-Meg

Question 43

Least mature megakaryocyte progenitor, participates in normal mitosis

Answer 43

BFU-Meg

Question 44

Participates in normal mitosis

Answer 44

CFU-Meg

Question 45

Most mature megakaryocyte progenitor, loses capacity to divide, performs endomitosis

Answer 45

LD-CFU-Meg

Question 46

Endomitosis

Answer 46

Nuclear division without cytoplasm division

Question 47

Terminal megakaryocyte differentiation stages are recognized in

Answer 47

Wright-stained morphology in bone marrow or H and E in bone marrow biopsy section

Question 48

Least differentiated, indistinguishable from myeloblasts, develops cytoplasmic ultrastructure (α-granules, dense granules, DMS)

Answer 48

MK-I stage

Question 49

Identified by nuclear lobularity

Answer 49

MK-II stage

Question 50

Most abundant, 10X magnification (30-160 µm), platelet shedding (thrombopoiesis)

Answer 50

MK-III stage

Question 51

MK-III shedding platelet amount

Answer 51

Sheds 2000-4000 platelets

Question 52

MK-I stage nucleus shape

Answer 52

Round

Question 53

MK-II stage nucleus shape

Answer 53

Indented

Question 54

MK-III stage nucleus shape

Answer 54

Multilobed

Question 55

MK-I NC ratio

Answer 55

3:1

Question 56

MK-II NC ratio

Answer 56

1:2

Question 57

MK-III NC ratio

Answer 57

1:4

Question 58

Endomitosis in MK-I

Answer 58

Present

Question 59

Endomitosis in MK-II

Answer 59

Ends

Question 60

Endomitosis in MK-III

Answer 60

Absent

Question 61

Demarcation system in MK-I, II, III

Answer 61

Present

Question 62

Demarcation system function

Answer 62

Delineates individual platelets during thrombopoiesis