Hematology and Immune Physiology - Theoretical Questions Flashcards Preview

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Flashcards in Hematology and Immune Physiology - Theoretical Questions Deck (124)
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How much RBCs and WBCs are forming relatively out of 10^11 daily ? Why?

75% - WBC (Shorter life span)
25% - RBC (120, Longer life span)


Hematopoiesis: where? In fetus and Adult
Forms of production site?

Fetus - Liver
Adult - Bone marrow:
Yellow Bone marrow - Inactive (fatty)
Red Bone Marrow - Active or Hyperplastic (HSC, HC and Stromal cells)


Hematopoietic stem cells:
Markers, potency, function

c-Kit and CD34
Omnipotent to Oligopotent to Multipotent
Self renewing asymmetrical divisions


What is special about Multipotent progenitor cells (MPP) ?

The first cell formed in hematopoiesis unable of self renewal. From it the formation pathway divides to Myeloid and Lymphoid Lineages


What are the synonyms for the the Progenitor cells and Hematopoietic growth factors?

Progenitor cells - colony forming units (CFU)
Hematopoietic growth factors - Colony stimulating Factors (CSF)


What are CLPs? what are their outcomes?

CLP -Common lymphocyte precursors: Lymphoid lineage - Forming T and B-Cells (naive) and NK cells


What are CMPs? what are their outcomes?

CLP -Common Myeloid precursors: Myeloid lineage - Forming Monocytes, Mast cells and Megakaryocytes and Erythrocytes


What determines the life span of the blood elements?

RBCs - Rigidity of old cells cause clearing in hepatic circulation.
Platelets - Used up continuously by micro injuries
WBC - Used up continuously by Immune functions


What causes the Stress Hematopoiesis?

Hypoxia - HIF1-Alpha - EPO - Erythrocytes↑
Infection - Granulocytes↑


What Cytokines? Examples for Hematopoietic CSF?

Glycoproteins that cause transcription through TyrK mechanism. IL3 is a CSF for Myeloid Line.
EPO- Erythrocytes↑


What is the general principle for the Hematopoiesis regulation?

Early stage - Many factors (Overlapping)
Late stage - Fewer specific factors


What is an Hematopoietic Niche ?

Cell to cell interaction in the bone marrow for differentiation signaling - Causes the Divisional Asymmetry . Chemokines - Regulate the movement of Stem cells through these.


How are Thrombocytes formed?

Budding off the the Megakaryocytes into the vessels lumen. Cell Fragments.


What are the Reticulocytes?

Final RBCs progenitor still containing RNA for Hemoglobin synthesis (After nucleus removed)


Why are the kidney responsible for the EPO secretion ? (Mostly, Some is from liver)

They have the smallest AVDO2, Meaning their JG cells can sense with the greatest resolution the changes in O2 supply.


what ae the derivatives of the Monocytes developing course ?

Osteoclasts, Dendritic Cells, Macrophages, Kupffer cells and Alveolar Macrophages.


What regulates the Formation of Platelets?

Thrombopoietin from Liver.


What is necessary for Erythropoetin?
What could happen in shortage of each?

Folic Acid, B12 and Iron.
Iron↓ - Microlytic Anemia
Folic Acid and B12↓ -Megaloblastic Anemia


What are the steps of Primary hemostasis?

2)Platelet adhesion
3)Platelet Activation and Aggregation


What are the steps of Secondary Hemostasis?

Activation of Coagulation factors and Fibrin


What are the steps of Fibrinolysis?

Activation of Fibrinolysis and Lysis of Plug


What causes Vasoconstriction in Injury?

Endothelin released from raptured Endothelial cells and Neurogenic Intermediates also released: TH5, K, THX2


What causes Platelets Adhesion?

vWF binding them to Collagen of Subendothelial tissue.. With GP4 and GP2b binding proteins.


What causes Activation of Platelets (6)?

Collagen - Subendothelial Tissue (Gq)
TXA2 - from other platelets
5HT - from other platelets
Adrenaline - Blood and from other platelets
Thrombin - Formed in clotting
PAF - from WBCs


What happens to activated platelets?

They form lamellipodia for interactions with other platelets and They release ADP and THX2 to cause other platelets to adhere. They also have a negative phosphatidylserine surface allowing for Coagulation factors activation.


What prevents Platelets aggregation?

NO and PGI2 coming from Uninjured Endotheliales


What is the role of Vitamin K in Hemostasis?

Gla proteins formation: Vit K in its reduced form is a cofactor for Carboxylases in the liver that react to form the Gamma-Carboxyglutamic acids residues (Gla) essential for binding to phosphatidylserine surface of Platelets and Coagulation.


Extrinsic Pathway of Coagulation:

Factor VII forms a complex with Ca and Tissue factor (F3) which is then able to cleave and Activate Factor X.


Intrinsic Pathway of Coagulation:

Factor XII is conformationally changed and activated by Activated Platelets which Cleaves Factor XI which with Ca Cleaves Factor IX which forms a complex with factor VIII and Ca to Cleave Factor X.


Common Pathway of Coagulation:

Factor X activated by Intrinsic or Extrinsic Pathway Cleavage. With Factor V and Ca forms Prothrombinase complex which is able to Cleave thousands of Prothrombins and form Active Thrombins (Amplification)