Lecture: Thrombocytes

Question 1

Earliest cell in the megakaryocytic series

Answer 1

BFU-Meg

Question 2

BFU-Meg and CFU-Meg undergo what type of cell division?

Answer 2

Mitosis

Question 3

What precursor/hematopoietic stem cell undergo meiosis/endomitosis?

Answer 3

LD-CFU-Meg

Question 4

Nucleus: fine chromatin; multiple nucleoli that generally stain blue; Begins development of alpha and dense granules

Answer 4

Megakaryoblast / MK-1

Question 5

Cytoplasm: more abundant but less basophilic; granules begin to form; Demarcation Membrane System (DMS) develops – gives rise to membrane bsystem/compartments of platelets

Answer 5

Promegakaryocyte / MK-II

Question 6

Nucleus is intensely indented or lobulated, and the degree of lobulation is imprecisely proportional to ploidy; Cytoplasm: abundant; pinkish-blue; diffusely granular and has an irregular peripheral border

Answer 6

Granular Megakaryocyte / MK-III

Question 7

Cytoplasm: contains coarse clumps of granules aggregating into bundles which bud off from the periphery to become platelets (2000-4000 platelets) known as platelet shedding

Answer 7

Mature Megakaryocyte / Metamegakaryocyte

Question 8

Not a true cell; Size: 1-4 µm; Cytoplasm: light blue to purple; very granular; consists of two parts: chromomere and hyalomere; Cellular/cytoplasmic fragments

Answer 8

Thrombocytes

Question 9

Non-granular pale blue
that surrounds the centromere

Answer 9

Outer hyalomere

Question 10

Resting platelets are in what shape?

Answer 10

Biconvex/discoid

Question 11

Platelets in blood collected using EDTA tend to _

Answer 11

“round up” / spherical

Question 12

Platelets Turnover Rate

Answer 12

35,000 ± 4,300

Question 13

Cytokine that Induces early differentiation of stem cells

Answer 13

IL-3

Question 14

Cytokines that enhances endomitosis,
megakaryocyte maturation

Answer 14

IL-6 and IL-11

Question 15

Platelet Distribution

Answer 15

2/3 in the blood; 1/3 in the spleen

Question 16

Circulating Life Span of Platelets

Answer 16

8-9 days

Question 17

Exterior fluffy coat rich in glycoproteins (Gp) which serves as membrane receptors/adhesion or aggregating agents and physiological agonists

Answer 17

Glycocalyx

Question 18

Von Willebrand’S Factor Receptor

Answer 18

Gp Ib

Question 19

VWF and fibrinogen receptor

Answer 19

Gp IIb and IIIa

Question 20

Thrombin receptor

Answer 20

Gp Va

Question 21

Collagen receptor

Answer 21

Gp VI

Question 22

Phospholipids are the source of ?

Answer 22

Arachidonic acid

Question 23

Structural support; Composed of CHON tubulin which maintains the discoid shape of platelets

Answer 23

Microtubules

Question 24

Composed of actin and myosin which upon stimulation are converted into actomyosin, a contractile CHON important in clotting retraction

Answer 24

Microfilaments

Question 25

Other term for actomyosin

Answer 25

Thrombostenin

Question 26

Intermediate Filaments; Connect with actin at tubules – maintaining shape

Answer 26

Desmin and vimentin

Question 27

α-granules proteins that supports mitosis

Answer 27

PDGF Endothelial GF Transforming GF-Beta

Question 28

α-granules proteins that are adhesion molecules

Answer 28

Fibronectin Thrombospondin

Question 29

α-granules protein that acts in heparin neutralization

Answer 29

Platelet factor 4

Question 30

Protein that is only found in α-granules

Answer 30

β-thromboglobulin

Question 31

α-granules protein that promotes fibrinolysis

Answer 31

Plasminogen

Question 32

α-granules proteins that control fibrinolysis

Answer 32

Plasminogen activator inhibitor-1 alpha 2-antiplasmin

Question 33

α-granules protein that controls coagulation

Answer 33

Protein C inhibitor

Question 34

α-granules stains what color in osmium dye?

Answer 34

Medium gray

Question 35

Delta Granules (δ-granules) stain what color in osmium dye?

Answer 35

Black (opaque)

Question 36

A δ-granule that is a potent vasoconstrictor

Answer 36

5-hdyroxytryptamine – 5-HT-serotonin

Question 37

Hydrolytic enzyme that is for clot lysis

Answer 37

Lysozymes

Question 38

Provides direct communication between intracellular and extracellular environment; Intracellular compounds are released into the external environment

Answer 38

Open Canalicular System

Question 39

Acts as Ca-sequestering pump which maintains cytoplasmic Ca level; Important for arachidonic acid metabolism

Answer 39

Dense Tubular System

Question 40

Serves as a link from platelet to platelet

Answer 40

Fibrinogen

Question 41

Serves as the link from damaged vessel to platelet

Answer 41

Von Willebrand Factor

Question 42

Enhances the binding of platelet to platelet

Answer 42

Pseudopods

Question 43

Irreversible second wave of aggregation by changing conformation of IIb-IIa complex

Answer 43

ADP

Question 44

Promotes ADP release; stimulates ADP-induced secondary aggregation and promotes release of phospholipase

Answer 44

Thrombin

Question 45

Promotes aggregation; Potent vasoconstrictor; End product of arachidonic acid; Main mediator of aggregation

Answer 45

TxA2 – thromboxane A2

Question 46

Large molecule coagulation proteins that participate in secondary hemostasis

Answer 46

α-granule contents

Question 47

Small molecule vasoconstrictor and platelet agonists that amplify primary hemostasis

Answer 47

Dense granules contents

Question 48

GpIb is for platelet _?

Answer 48

Adhesion

Question 49

GpIIb and GpIIIa is for platelet _?

Answer 49

Aggregation

Question 50

If GpIb is absent, what may be the disease that develop?

Answer 50

Bernard-Soulier Syndrome

Question 51

If GpIIb and GpIIIa si absent, what may be the disease that develop?

Answer 51

Glanzman’s Disease or Thrombasthenia

Question 52

Phospholipid is converted into arachidonic acid via?

Answer 52

Phospholipase

Question 53

Prostacyclin is then converted to PGI2 via?

Answer 53

COX1-cyclooxygenase

Question 54

PGI2 is then converted into thromboxane A2 via?

Answer 54

Thromboxane synthase