MIDTERM Week 2: Hematology Flashcards
What % of blood is plasma?
55%
What is plasma composed of?
91% water, 7% proteins and 2% other solutes (like ions, nutrients, waste products, gases, lytes)
What are plasma proteins? (types) Which is most common in the blood?
albumin (60% of plasma proteins)
Globulin
Fibrinogen
Prothrombin
Functions of plasma proteins? (4 broad categories)
Clotting, defense (such as antibodies), transport, regulation
What is serum?
plasma that has been allowed to clot in la to remove fibrinogen & clotting factors
Life span of RBC
80-120 days
Normal range of RBCs
4.2-6.1 x 10^12/L
Life span of WBCs
High varied (unknown, some up to years)
Normal WBC count?
5-10 x 10^9/L
Lifespan of platelets?
8-11 days
Normal platelets blood levels?
150-400 x 10^9/L
Where does hematopoeisis happen?
In the bone marrow
What are the two types of stem cells?
mesenchymal stem cells (MSCs) aka stromal cells that differentiate into osteoblasts, adipocytes and chondrocytes & hematopoietic stem cells (HSCs)
What do hematopoietic stem cells become? (2 types of progenitor cells)
Myeloid & lymphoid progenitor cells
What do lymphoid progenitor cells differentiate into?
T cells, B cells, NK cells
What is a mature B cell called?
Plasma cell
= a fully differentiated B cell that produces a single type of antibody.
What do you call the large cell that breaks into platelets?
Megakaryocyte
What types of cells come from the myeloid progenitor cell?
Megakaryocytes, eosinophils, basophils, erythrocytes, monocytes & neutrophils
(just remember: all blood cells except NK, B & T cells)
What is the last immature form of an RBC called?
Reticulocyte
What % of RBCs should be reticulocytes?
• Reticulocyte count should be 1% of body’s RBCs (useful clinic index of erythropoietin activity
General outline of where WBCs come from/steps of differentiation
Most arise from HSCs in bone barrow
- differentiate to common lymphoid progenitors and common myeloid progenitors
- lymphoid progenitors –> lymphocytes released into bloodstream to go to lymphoid organs for further maturation
- Myeloid progenitor cells further differentiate into progenitors for erythrocytes, megakaryocytes, and mast cells and granulocyte/monocyte progenitors
- Monocytes mature into macrophages 1-2 days after release
General outline of how platelets develop from a megakaryocyte?
Megakaryocyte progenitor undergoes endomitosis (DNA replication but no anaphase and cytokinesis) –> huge nucleus with polyploidy develops & cell develops surface branches that progressively fragment into platelets
• Single megakaryocyte can produce thousands of platelets
• 2/3 enter circulation & 1/3 remain in splenic pool
Which WBCs are granulocytes?
The “PHILS”
Neutrophils, basophils, eosinophils
What types of WBCs are agranulocytes?
Monocytes, macrophages & lymphocytes
T/F all granulocytes are phagocytes?
True!
• Have many membrane-granules in cytoplasm that contain enzymes capable of killing microorganisms & catabolizing debris ingested during phagocytosis; also contain powerful biochemical mediators with inflammatory and immune fx’s
What hormone induces platelet production?
o Regulated by Thrombopoietin (TPO), hormone growth factor – produced by liver & induces platelet production in bone marrow
What is considered “primary hemostasis”?
Formation of a platelet plug at the site of injury
What is secondary hemostasis?
Formation of a fibrin clot
At what factor do the intrinsic and extrinsic clotting pathways converge?
X!
What are the extrinsic and intrinsic pathways named in this way?
Extrinsic is activated by factors in the tissue (extrinsic or outside the blood). Intrinsic is activated by factors already in the blood.
Where do DOACs act?
At factor X
(these re Direct Oral Anticoagulants…such as apixaban and rivaroxaban)
What is considered thrombocytopenia?
Platelets <150
Manifestations/S&S of thrombocytopenia?
When do we expect to see spontaneous bleeding?
• Concern for hemorrhage with small trauma if <50
• Spontaneous bleeding w/t trauma (10-15) skin manifestations (petechiae, ecchymoses, purpura) or frank bleeding from mucous membranes
• Severe spontaneous bleeds if <10 (fatal if GI or resp tract, CNS)
• Heavy/long periods
• Headaches
• Hematuria
• Malaise, fatigue, general weakness
What is hemophilia?
an inherited bleeding disorder in which the individual is deficient in factor VIII (hemophilia A) or factor IX (hemophilia B) or factor XI (hemophilia C)
What role does vitamin K play in coagulation? What causes a deficiency?
- needed for the production and regulation of procoagulant factors (VII, IX, X); and the anticoagulant factors within the liver (proteins C and S).
Vitamin K can either come from food sources (leafy green vegetables) or be naturally produced in the intestinal tract. The causes of Vitamin K deficiency in adults include poor nutrition, bulimia, destruction of normal gut flora by taking antibiotics, and conditions that affect fat malabsorption e.g. cystic fibrosis and warfarin therapy (warfarin inhibits activation of Vitamin K).
Where are most clotting factors made?
Liver
What med is most commonly responsible for thrombocytopenia? What is happening here?
Heparin
• HIT is an immune- mediated, adverse drug reaction caused by IgG antibodies against the heparin–platelet factor 4 complex
• The release of additional platelet factor 4 from activated platelets and activation of thrombin lead to increased platelet consumption and a decrease in platelet counts
How long after initiating heparin does HIT occur?
beginning 5 to 10 days after administration of heparin.
How severe is the change in platelet drop in HIT? Is bleeding common? What other contrary side effect may occur?
50% reduction
Bleeding uncommon
• 30% also at risk of thrombosis: venous or arterial, because a prothrombotic state is caused by antibody binding to platelets, inducing activation, aggregation, and consumption
WHat is idiopathic thrombocytopenia? What do we call it now? Is it acute or chronic?
Immune Thrombocytopenic Purpura (ITP)
Now recognized as immune process
Caused by autoantibodies against platelet antigens
Can be acute or chronic
QUESTIONS FROM HERE ARE FROM LECTURE:
What kind of units (conventional or SI) do we use in Canada?
SI
Which component of CBC will indicate BACTERIAL infection?
Neutrophils (may see a rise in all of the WBCs but most commonly see high neutrophils)