Hematology 2 Lecture: Megakaryopoiesis Introduction

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Questions and Answers

What is the main function of thrombocytes?

Producing megakaryocytes

Maintaining blood vessel shape

Initiating vessel wall repairs (correct)

Differentiating into blood cells

What is the process by which platelets are produced from megakaryocytes?

Budding

Cytoplasmic division

Endomitosis (correct)

Nuclear division

Which growth factor is involved in megakaryopoiesis?

Pluripotential hematopoietic stem cell

FLT3 ligand

KIT ligand

CSF-GM (correct)

What is the size range of mature megakaryocytes?

40-120 µm in diameter Signup and view all the answers

What is the N:C ratio of promegakaryocytes?

4:1 to 7:1 Signup and view all the answers

Which cell stage exhibits nucleoli that are not visible?

Mature megakaryocyte Signup and view all the answers

What characterizes the open canalicular system in platelets?

Exchange of substances in and out of the platelet Signup and view all the answers

Which component acts as a physical and chemical barrier between intra and extracellular environment in platelets?

Plasma membrane Signup and view all the answers

What is the normal life span of platelets?

7-10 days Signup and view all the answers

What is the function of the submembrane area in platelets?

Contributes to the discoid shape of platelets Signup and view all the answers

Which component is involved in the exchange of substances in and out of the platelet?

Open canalicular system Signup and view all the answers

What regulates the arrangement of internal organelles in platelets?

Sol-gel zone Signup and view all the answers

What is one of the functions of alpha granules in platelets?

Release serotonin Signup and view all the answers

Which factor is involved in blood coagulation and platelet adhesion?

Factor VIII Antihemophilic Factor Signup and view all the answers

What contributes to the discoid shape of an inactivated platelet?

Microtubules and microfilaments Signup and view all the answers

What is the main function of megakaryocytes?

Production of platelets Signup and view all the answers

Which growth factor is NOT involved in megakaryopoiesis?

IL-6 Signup and view all the answers

What type of cell can further differentiate into megakaryocytes?

Totipotential hematopoietic stem cell Signup and view all the answers

What is the size range of promegakaryocytes?

20 - 60 µm in diameter Signup and view all the answers

Which factor acts as a stable gel component to regulate the arrangement of internal organelles in platelets?

Factor XIII Fibrin Stabilizing Factor Signup and view all the answers

What is the main function of the open canalicular system (OCS) in platelets?

To exchange substances in and out of the platelet Signup and view all the answers

What characterizes the mature megakaryocyte stage?

Nucleoli: Multiple; Presence of coarse clumps of aggregated granules Signup and view all the answers

Which growth factor is involved in platelet production?

Platelet factor 4 Signup and view all the answers

What contributes to the normal discoid shape of platelets?

Microtubules and Thrombostenin (actomyosin) Signup and view all the answers

Which component of platelets prevents contact between organelles and the cell membrane?

Dense tubular systems (DTS) Signup and view all the answers

What is the main function of the submembrane area in platelets?

To prevent contact between organelles and the cell membrane Signup and view all the answers

Study Notes

Thrombocytes (Platelets)

The main function of thrombocytes is to participate in blood coagulation and hemostasis.

Megakaryocyte Development

Megakaryocytes produce platelets through a process involving the fragmentation of their cytoplasm.
Thrombopoietin (TPO) is the primary growth factor involved in megakaryopoiesis.

Megakaryocyte Characteristics

Mature megakaryocytes have a size range of 50-100 μm in diameter.
Promegakaryocytes have a nucleocytoplasmic (N:C) ratio of 1:1-1:2.
The nucleoli of promegakaryocytes are not visible.
Mature megakaryocytes are characterized by multiple lobes and a high nuclear-to-cytoplasmic ratio.

Platelet Structure and Function

The open canalicular system (OCS) is a network of membranous tubules and channels that characterizes platelets.
The OCS acts as a physical and chemical barrier between the intra- and extracellular environments.
The submembrane area is involved in the exchange of substances in and out of the platelet.
The submembrane area also regulates the arrangement of internal organelles in platelets.
Alpha granules are involved in blood coagulation and platelet adhesion.
The normal life span of platelets is 7-10 days.

Platelet Shape and Structure

The discoid shape of inactivated platelets is contributed to by the spectrin-based membrane skeleton.
The spectrin-based membrane skeleton also prevents contact between organelles and the cell membrane.

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Description

This quiz covers the introduction and definition of terms related to megakaryopoiesis, including the production of megakaryocytes and thrombocytes (platelets) in the context of hematology. It also explores the growth factors involved in megakaryocyte maturation and platelet production.