TEST 2: Hematology Flashcards
$ RBC function and main component
Function: O2 transport from lungs to body and & CO2 transport from tissue to lungs
Main component: hemoglobin (binds O2)
-Catalyzes the reversible reaction between C02 and H20
WBC function and types
Function: Infection defense
Types: several types (neutrophils, lymphocytes, monocytes, eosinophils and basophils) where each type has a specific role
Platelets and main function
Crucial role in blood clotting and wound healing
Main function: aggregate to form a temporary plug at the site of blood vessel injury and release chemicals that activate further clotting processes.
Plasma function and main components
Function: liquid component of blood transports blood cells, nutrients, waste, and other substances throughout the body
Main component: water, electrolytes, protein (albumin, clotting factors), hormones and waste.
$$ Anemia Types (8)
- Iron Deficiency
- Vit B 12 deficiency (Pernicious)
- Folate Deficiency
- Aplastic
- Sickle Cell
- Hemolytic
- Anemia of chronic disease
- Acute blood loss
$Lymphoma definition?
Types (2)
What tissues does it affect?
Def: cancer of lymphatic system
Types:
1. Hodgkin lymphoma (~75% survival)
2. Non-hodgkin lymphoma
Tissues: lymphoid such as spleen, marrow and thymus. Typically starts in lymph nodes.
$Myeloma definition and symptoms
Def: cancer of plasma cells in bone marrow
Sx: bone pain, anemia, renal dysfunction, recurrent infections,
LONG BONE FRACTURE
$$Hemophilia definition, types (2) and symptoms
Def: genetic disorder impairing the body’s ability to make blood clots
Types:
1. Hemophilia A (factor 8 deficiency)
2. Hemophilia B (factor 9 deficiency)
Sx: prolonged bleeding, spontaneous bleeding into joints and muscles
*What is a blood smear
Microscopic exam of stained blood cells to evaluate their morphology
*What is flow cytometry
A test analyzing the physical and chemical characteristics of cells or particles
$$ Hematologic medication treatments (4) and the condition they treat
- Anti-coagulants (prevent clotting)
- Clotting factor concentrates (hemophilia)
- Immunosuppressants (autoimmune anemia)
- Erythropoiesis-stimulating agents (anemia of chronic disease)
What is erythropoiesis
Development of RBCs
*What hormone regulates erythropoiesis? Where is it produced?
Under what conditions (most common one)?
Using what factor?
Hormone: Erythropoietin (Epo)
Where: kidneys
Condition: Hypoxia
Factor: Hypoxia inducible factor-1 (HIF-1)
Bonus Info: hypoxia such as anemia or high altitude the kidneys release Epo, which stimulates the bone marrow to produce more RBCs
*Where are RBCs developed in adults (tissue and location)
Hematopoietic tissue, primarily found in flat bones such as pelvis, vertebrae, cranium, and mandible.
Bonus: these bone house hematopoietic bone marrow
$$ Where are RBCs developed in Infants (prenatal & post natal)
Prenatal: yolk sac in early gestation, then liver in second gestational month
Postnatal & last month of gestation: bone marrow
Marrow of all bones make RBCs until around 5yo
*In cases where additional RBCs are needed what occurs?
Is there a difference in children?
Extra RBC production takes place in extramedullary erythropoiesis outside the bone marrow. Can take place in the liver and spleen.
Children: This entire process is more common in children than adults
*What are Hematopoietic Stem Cells (HSCs)? What (2) types of cell can they become?
Multipotent cells found in the bone marrow that have the unique ability to self-renew and differentiate into all types of blood cells.
Can become:
1. Common lymphoid progenitors (CLPs)
2. Common myeloid progenitors (CMPs)
*What are precursor cells?
Examples?
Immature cells derived from committed progenitor cells that undergo further differentiation and maturation into specific blood cell types.
-BLAST CELLS
Examples: erythroblasts, myeloblasts, monoblasts, and megakaryoblasts
What is the platelet precursor cell?
Megakaryloblasts
Bonus Info: when megakaryocytes are mature they release small fragments of their cytoplasm into the blood stream as platelets.
$$ What are the (5) triggers for RBC production?
- Anemia/Hypoxemia
- Low blood volume
- Poor blood flow
- Pulmonary Disease
- Increased androgens
**How does an increase in androgens trigger erythropoiesis?
Androgens including testosterone have been shown to upregulate erythropoiesis by modulating erythropoietin productions.
Bonus: elevated androgens, either due to medical conditions or testosterone supplementation, can enhance RBC production.
$$ How does the Kreb’s cycle influence hematopoiesis?
Krebs plays a role in the synthesis of Succinyl Co-A (an intermediary in cellular energy)-> Binds with glycine -> pyrrole
-4 pyrroles bind to make protoporphyrin IX that combine with Iron to make a HEME
ADDITIONAL ORGANIZER INFO: Krebs is not directly involved in hemoglobin synthesis it does play a role in generating components essential for cellular metabolism indirectly supporting the energy requirements for hematopoiesis, including the production of hemoglobin.
$$ What are the 4 polypeptide chains that comprise ADULT hemoglobin?
- Alpha globulins (x2)
- Beta globulins (x2)
Bonus: the four polypeptide chains are arranged as two pairs of identical chains. The chains are proteins known as globulins and consist of two alpha globin chains and two beta globin chains.
-The combination of alpha and beta globin chains is crucial for the structural integrity and proper function of the hemoglobin molecule, enabling it to effectively bind and release O2 as needed.
$$ What are Iron-Protoporphyrin Complexes (hemes)
For each hemoglobin there are 4 iron-protoporphyrin complexes known as hemes, with each group associated with a polypeptide chain.
Bonus: It is a critical component of hemoglobin that can bind one molecule of oxygen facilitating O2 transport.
$$ What does a heme group consist of?
-Protoporphyrin ring with a centrally bound ferrous iron (Fe2+ OR Fe3+) depending on O2 status.
Heme combines with globin to make HEMOGLOBIN
BONUS: When oxygen binds to the heme group the ferrous iron (Fe2+) is oxidized to the ferric state (Fe3+) leading to the formation of oxyhemoglobin which enhances O2 transport.
$What is the STRUCTURAL ROLE of alpha and beta globin chains in the hemoglobin molecule?
alpha and beta globin chains are integral components of the hemoglobin tetramer, which consists of two alpha chains and two beta chains. This quaternary structure is essential for the stability and proper functioning of hemoglobin as an oxygen carrying protein.
-composition and arrangement influence the O2 binding affinity of hemoglobin.
$What is the OXYGEN BINDING ROLE of alpha and beta globin chains in the hemoglobin molecule?
alpha and beta globin chains contain heme groups, each within an iron atom at its core. The heme groups bind to and transport O2.
-There are 4 Iron molecules meaning up to 2 molecules of O2 can be transported.
Bonus: the cooperative binding and release of O2 by hemoglobin depends on the interaction between the heme groups and globin chains.
$What is the effect of alterations to the alpha and beta globin genes?
What does this cause?
Vatiations in the sequences can lead to the production of different hemoglobin variants that affect the STRUCTURE AND FUNCTION of the alpha or beta globin chains.
-the balanced production of alpha and beta are CRITICAL for the proper assembly of functional hemoglobin molecules.
Results: sickle cell anemia or thalassesmias (can be alpha or beta) that both affect the shape and function of RBCs.
What is the Bohr Effect?
Refers to the phenomenon where low pH and high CO2 in the tissues enhance the release of O2 from hemoglobin. It supports O2 unloading in active tissues.
What is the Haldane Effect?
Describes how deoxygenation of blood in tissues results in an increased capacity to carry CO2 and H2CO3 back to the lungs. This assist in the removal of CO2 and waste products of cellular metabolism from tissues.
$$ What is Fetal Hemoglobin (HbF) composition and function?
Composition: HbF is composed of 2 alpha globin chains and two gamma globin chains giving it the formula: α₂γ₂
(Alpha, beta, gamma, delta and fetal globins possible types)
Function: HbF has a higher affinity for O2 than adult hemoglobin, which facilitates O2 transfer from mother to fetus across the placenta.
Bonus: levels increase in beta thalassemia
What is polycythemia and what causes it?
What: increase in RBC count, hemoglobin and hematocrit.
Cause: Can occur as a normal response in fetuses and newborns due to the lower oxygen environment in utero which stimulates erythropoiesis.
$$ What INCOMPATIBILITY causes hemolytic disease of the newborn?
What is the effect on hemoglobin?
Incompatibility of blood types between mother and baby, such as Rh incompatibility.
Effect: hemolysis of fetal RBCs leads to increase in erythropoiesis, raising Hb levels initially. However, severe cases can lead to anemia.
$$The effect of lower testosterone in men (aging) on erythropoiesis?
Decrease in testosterone levels lead to decreased stimulation of erythropoiesis.
Unlike other physiologic changes this reduction is not considered a normal physiological variation but rather a consequence of hormonal decline associated with aging.
$$ What is the lifespan of RBCs.
90- 120 days
-With aging membrane becomes fragile and rbcs can lyse
$What are the (3) steps in RBC destruction at the end of their lifespan?
- Globin breakdown: broken down into amino acids, which are reused.
- Heme breakdown: Iron is recycled from heme, is oxidized to form methemoglobin and eventually recycled into new RBCs.
- Porphyrin ring breakdown: broken down into unconjugated bilirubin. The liver conjugates the bilirubin to make it water soluble and it is then excreted into the bile.
*What role do mononuclear phagocytes have in iron management?
They can store iron within tissues
$$ What role do hepatic cells have in iron management?
liver is primary storage site for iron in the body
$$ What two forms can iron be stored?
- Ferritin
- Hemosiderin
$$ What is Ferritin?
Primary form of stored iron within cells. Ferritin is a protein complex that can store up to 4,500 iron atoms, making it a key iron reservoir. It released iron in a controlled fashion according to need.
$$ What is Hemosiderin?
a form of stored iron that is formed when there is an excess of iron. It is less readily available than ferritin and can be seen in conditions of iron overload.
*What ways can iron be lost?
- Urine: very minor amounts
- Seat: some
- Bile: can contain small amounts of iron
- Sloughing of epithelial cells: like those lining the GI tract and skin. They die and are shed naturally removing some iron.
CLINICAL GEM: THERE IS NO ACTIVE EXCRETORY PATHWAY TO REMOVE EXCESS IRON IN THE BODY!!!
What is Iron Toxicity? Why is it a problem?
What? Without a excretory pathway excess iron can become toxic in large quantities.
Problem? It can cause damage to organs and tissues by catalyzing the formation of free radicals, which can result in oxidative stress and cellular damage.
What is Hemochromatosis?
a genetic disorder that causes the body to absorb an excessive amount of iron from the diet.
Overtime this can lead to iron accumulation in organs such as the liver, heart, and pancreas causing damage.
How does frequent blood transfusions affect iron balance?
Can lead to iron overload if not properly managed.
Example: thalassemia or sickle cell anemia where frequent transfusions are required.
What 2 tests help monitor iron status?
- Serum ferritin
- transferrin saturation
What is Chelation therapy?
a therapy that can be used to bind excess iron and facilitate its removal from the body in cases of iron overload.
-Can be used for other heavy metals as well (lead, mercury, or arsenic)
NOT needed for test but relevant to our practice: can be oral or IV. Oral takes several days to weeks with doses taken at regular intervals. IV given over 1-4 hrs depending on the agent being used. Frequency and duration of treatment based on iron levels.
Rough on kidneys.
What are the (4) clinical implications that require understanding the oxygen-hemoglobin dissociation curve?
- Respiratory conditions: alter breathing and can change the shape of the curve and affect O2 delivery.
- Anemia: Hgb concentration impact on O2 carrying capacity
- CO poisoning: CO binds to Hgb with much greater affinity than O2 shifting the curve to the LEFT and making it difficult for O2 to unload at the tissues.
- Exercise physiology: during exercise, factors like increased CO2 production and body temp shift the curve to the RIGHT, facilitating O2 unloading into muscles.
$$ What is Mean Corpuscular Volume (MCV)? How is it calculated and what units is it reported?
What: MCV measures the average volume or size of a single RBC.
Calculation: MCV= (Hct% x10)/RBC count (in Millions/μL)
Reported Units: fL (femtoliters) or (one quadrillionth of a L)
$$ What is the interpretation of MCV (Mean Corpuscular Volume)?
-CYTIC
LOW (MCV < 80fL)= MICROCYTIC anemia: smaller than normal RBCs
NORMAL (MCV 80-100 fL) = NORMOCYTIC anemia: normal RBCs
HIGH (MCV > 100fL)= MACROCYTIC anemia: larger than normal RBCs. Seen in Vit B12 deficiency, folate deficiency, and certain types of liver disease or hypothyroidism.
$$ What is Mean corpuscular hemoglobin concentration (MCHC)? How is it calculated and what units is it reported?
What: MCHC measures the average concentration of Hgb in a given volume of packed RBCs.
Calculation: MCHC- (Hgb (g/dL) x 100)/Hct%
Reported Units: g/dL (grams per deciliter)
$$ What is the interpretation of MCHC (mean corpuscular hemoglobin concentration)?
-CHROMIC
LOW (MCHC < 32 g/dL)= HYPCHROMIC: RBCs with less Hgb (paler color). Common in iron deficiency anemia and thalassemia.
NORMAL (MCHC 32-36 g/dL)= NORMOCHROMIC: Normal Hgb concentration. Normocytic anemias like anemia of chronic disease or acute blood loss.
HIGH (MCHC > 36 g/dL)= HYPERCHROMIC: Rare! indicates spherocytosis or other RBC membrane disorders where cells are densely packed with Hgb.
$$ What is Red Cell Distribution Width (RDW)? How is it calculated and what units is it reported?
What: measures the variation in the size (volume) of RBCs.
NEW ARE BIGGER get smaller over time
Calculation: RDW= (Standard deviation of MCV/Mean MCV) x 100
Reported Units: Percent %
$$ What is the interpretation of RDW (red cell distribution width)?
HIGH (RDW > 14.5%): indicated larger variation in RBC size (anisocytosis). Often seen in mixed anemias (such as iron deficiency anemia combined with Vit B12 or folate deficiency) and conditions where RBCs are being created and destroyed at uneven rates.
NORMAL (RDW 11.5%-14.5%)= uniform size of RBCs, typical in chronic anemia without significant variation in cell size.
What is Anisocytosis?
Presence of RBCs of varying size
$$ What lab values would be consistent with microcytic, hypochromic anemia? What are common causes?
MCV LOW
MCHC LOW
RDW High IF combined with another anemia
Causes: iron deficiency, thalassemia
$$ What lab values would be consistent with normocytic, normochromic anemia? What are common causes?
MCV NORMAL
MCHC NORMAL
RDW NORMAL OR HIGH
Causes: acute blood loss, hemolytic anemia, anemia of chronic disease, aplastic anemia.
What lab values would be consistent with macrocytic anemia? What are common causes?
MCV HIGH
MCHC NORMAL OR HIGH
DRW OFTEN HIGH
Causes: Vit B12 or folate deficiency, liver disease, hypothyroid
$ What studies (3) appropriate to evaluate for suspected iron deficiency anemia?
Serum iron, ferritin, TIBC (total iron binding capacity)
What studies (2) are appropriate to evaluate for suspected macrocytic anemia?
Vit B12 and folate levels
$$ What studies (3) are appropriate to evaluate for suspected hemolytic anemia?
LDH
Haptoglobin
Bilirubin
$$What studY is appropriate to evaluate for suspected aplastic anemia? What would the common studies show?
Bone marrow biopsy
Normal studies: pancytopenia, normal iron studies.
What does serum iron assess?
Amount of circulating iron bound to transferrin