Hematology & Disorders Flashcards
What is true about all blood cells and platelets?
Derived from multipotential precursor cells (stem cells) in the bone marrow
What does the blood cell production rates depend on?
Several growth factors; interleukin (IL)-3, erythropoietin, thrombopoietin, and granulocyte-macrophage colony-stimulating factor (GM-CSF)
What is the most numerous blood cells?
RBC or erythrocytes
Lacking nuclei and other organelles, these are small, highly flexible biconcave discs that function to carry large amounts of hemoglobin throughout the bloodstream for oxygen delivery to tissues.
What is made up of hemoglobin?
Four protein chains with four iron-containing heme groups. The iron is the site of oxygen binding
What are the different forms of anemia?
Anemia is the most common blood disorder.
iron-deficiency (the most common), macrocytic, hemolytic, and anemias due to abnormal red cell proteins.
How to identify the subdivisions of anemia diagnosis?
Along with history and physical examination, complete blood count (CBC) and peripheral blood smear provide critical information for diagnosing anemia.
What is a Iron-deficiency anemia?
Result from inadequate iron intake or absorption, or from chronic blood loss that accelerates body iron requirements. Due to lack of hemoglobin production, cells are microcytic (small) and hypochromic (pale).
- Common lifespan
- Tx is iron supplementation, either oral or parenteral depending on disease severity.
What is true about iron-deficiency anemia in infancy and childhood?
Iron-deficiency anemia is a prominent red cell disorder in infancy and childhood, primarily due to increased iron requirements during growth and development.
What is a macrocytic anemia?
vitamin B12 or folate deficiency, leading to slowing of DNA synthesis and delayed cell maturation.
- Cells are large and fragile, exacerbating the anemia because they have a shorter life span.
- A distinguishing characteristic of vitamin B12 deficiency is its neurological sequelae that co-occur with hematological abnormalities.
What are the several causes of anemia due to increased rate of hemolysis?
(a) Cells can be abnormally shaped due to abnormal hemoglobin (sickle cell disease [SCD]).
(b) Cells can be vulnerable to oxidative stress due to enzyme deficiency (G6PD deficiency).
(c) Cells can be abnormally fragile due to cytoskeletal mutations (spherocytosis).
(d) Cells can be targeted by antibodies for destruction.
(e) Cells can be destroyed by intravascular clots in a microangiopathic hemolytic process (HELLP [hemolysis, elevated liver enzymes, low platelets] syndrome, thrombotic thrombocytopenia).
What is abnormal hemoglobin of SCD ion polymerizes?
in response to oxidative stress or cellular dehydration, leading to sickling of cells, occlusion of blood vessels, and rapid cell destruction. Tissue ischemia due to blood vessel occlusion produces severe pain and organ damage.
What is hemostatis?
the ability to stop bleeding when a blood vessel is damaged, involves a tightly regulated sequence of events.
What are the steps for hemostatis?
First, the cut blood vessel constricts, reducing blood flow.
Second, platelets become activated and aggregate to form a plug.
Third, the plasma protein clotting cascade is activated and deposits a mesh of fibrin strands in and around the platelet plug.
Finally, the clot retracts, squeezes out excess fluid, and becomes a compact plug.
What does platelets produce to assist the clotting cascade?
Activated platelets synthesize and release adenosine diphosphate (ADP) and thromboxane A2, as well as serotonin (stored in granules). These factors and others recruit more platelets to become activated in a positive feedback system.
- Platelets also provide phospholipids as cofactors for the clotting cascade, and platelets are activated by thrombin as the clotting cascade occurs around the platelet plug.
What is an important contributors to the clotting process?
Platelet membrane glycoproteins (GPs)
Why is the clotting cascade carefully controlled?
controlled series of enzymes that, when activated, split target proteins, resulting in products that are, themselves, activated protease enzymes. This chain reaction rapidly accelerates and amplifies the clotting signal so that bleeding can be stopped quickly.
What does the clotting cascade process depends on?
protein cofactors (proteins VIII and V), and on calcium and phospholipids.
How does anticoagulant factors work?
To prevent clotting when it is not appropriate or to reduce the spread of clotting once it has started.
- Important signals include prostaglandin I2 (prostacyclin), antithrombin III, thrombomodulin, and proteins C and S, each of which works by a different mechanism of action.
When clots are no longer needed, what happen?
When no longer needed, clots are broken down by plasmin, a protein split from the precursor plasminogen by the action of tissue plasminogen activator (tPa) and other compounds.
What are the factors for states of excess bleedings?
can occur from genetic deficiencies in clotting proteins and factors. Among these heritable states are von Willebrand factor (vWF), factor VIII, and factor IX deficiencies.
What is a common genetic disorder that promotes abnormal clot formation?
mutation causing the production of factor V Leiden (FVL). This mutation causes factor V to resist cleavage and inactivation by protein C. This condition is also referred to as activated protein C (aPC) resistance.
What is the consequences of genetic disorders RBC and bleedings?
Genetic disorders of red blood cells and bleeding also typically manifest early in life, with lifelong consequences including SCD, von Willebrand disease (vWD), and hemophilia.
What are the changes of hematology in older adults?
Healthy older adults have few changes in blood and clotting. However, given the prevalence of chronic diseases among older adults, there is an increased prevalence of anemia (prominently, nutritional anemia and anemia of inflammation, as well as unexplained anemia) in this demographic.
- This high prevalence of chronic disease also manifests as hypercoagulability, which is promoted by chronic inflammation.
- Consequently, risks of myocardial infarction, stroke, and thromboembolic disorders occur more commonly with aging.
How long does RBCs have a finite life span up to?
120 days
RBC accounts for 80% of body cells and are produced rate of 200 billion/day and destroyed rate of 200 billion/day
