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Blood: RBC Physiology
Red Blood Cells, Anemia, and Polycythemia
45
Physiology
Graduate
03/27/2012

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Term
What is the average hemoglobin content per deciliter of blood in an adult man? A woman? What is the maximum per deciliter of RBCs? How much oxygen can 1g of hemoglobin carry?
Definition
1. about 15g/dL
2. about 14g/dL
3. 34 g/dL
4. 1.34 ml
Term
In early embryological development, where are RBCs made? What about the middle of embryological development? What about adult life?
Definition
1. the yolk sac
2. the liver
3. the bone marrow
Term
What bones produce the most RBCs in an adult? How do children differ in this respect?
Definition
1. flat bones and vertebrae
2. children can produce significant quantities in their long bones, but adults have most of those cavities filled with fatty marrow
Term
What is MCV? MCH? MCHC? RDW? What are the average values for these?
Definition
1. mean cell volume (the average volume of the RBCs); average is 90 fL
2. mean cell hemoglobin (the average amount of Hb per cell); average is 32 pg
3. mean cell hemoglobin concentration; average is 33% of cell volume
4. RBC distribution weight (the population of RBCs in the blood); average is 42 fL
Term
What is the average diameter of an RBC? The average thickness?
Definition
1. 8 μm
2. 2.5 μm
Term
About how many RBCs are made per day? About how many are destroyed per day?
Definition
1. about 1%
2. about 1%
Term
What hormone regulated RBC production? Where is it produced? What other hormonal stimuli exist? What are some stimuli for erythropoiesis (non-hormonal)? Hematopoiesis?
Definition
1. erythropoietin
2. the peritubular interstitial cells of the kidneys (90%) and in the liver (10%)
3. testosterone
4. prolonged low O2
5. infection, cancer, hypoxia
Term
What is PHSC?
Definition
1. pluripotent hematopoietic stem cell
Term
What stimulates PHSC to become the following cells: T-lymphocytes, B-lymphocytes, erythrocytes, granulocytes?
Definition
1. IL-3; then IL-2, 3, and 4
2. IL-3; then IL-3, 5, 6, and 7
3. IL-3 and GM-CSF; then IL-3, GM-CSF, and EPO; then EPO
4. IL-3 and GM-CSF; then IL-3 and GM-CSF
Term
What stimulates PHSC to become the following cells: monocytes, macrocytes, megakaryocytes, platelets?
Definition
1. IL-3 and GM-CSF; then IL-3 and GM-CSF
2. IL-3 and GM-CSF; then IL-3 and GM-CSF
3. IL-3 and GM-CSF; then IL-3, IL-11, GM-CSF, and EPO; then IL-6, GM-CSF, and EPO
4. IL-3 and GM-CSF; then IL-3, IL-11, GM-CSF, and EPO; then IL-6, GM-CSF, and EPO
Term
What is the first stage of blood cell differentiation that can be recognized as an RBC? What is the first stage without a nucleus?
Definition
1. proerythroblast
2. reticulocyte
Term
Describe the abnormalities associated with each of the following: microcytic hematochromatic anemia, sickle cell anemia, megaloblastic anemia, and erythroblastosis fetalis
Definition
1. small and pale cells
2. abnormally shaped cells
3. large cells (may or may not have other abnormalities
4. several abnormalities, most notably the presence of nuclei in several cells
Term
How quickly does erythropoietin increase RBC production? How quickly does it increase RBC count? How long is its life span?
Definition
1. 24 hours
2. 5 days
3. 4-12 hours
Term
What stimuli stimulate the release of erythropoietin?
Definition
prostaglandins, norepinephrine, hypoxia, anemia, and high altitude
Term
What is the life span of an RBC? How are they is their iron disposed of?
Definition
1. about 120 days
2. when they get old, they become less flexible and either lyse or are bound by IgG and targeted for destruction by macrophages in the spleen; hemoglobin is ingested by the macrophages in the spleen and iron is released to transferrin or to ferritin for storage
Term
What are the two essential vitamins in RBC production? What do they do? What does their deficiency cause?
Definition
1. folic acid and B12
2. they help in the formation of DNA and nucleotides
3. anemia and maturation failure; the latter means that large, immature, fragile cells will be synthesized
Term
What is a hemoglobin molecule composed of?
Definition
4 hemoglobin chains loosely bound together and an iron-based heme group in the middle of each chain
Term
What factors inhibit iron metabolism? What promotes its absorption? Where is it absorbed?
Definition
1. carbonates, tannate (tea), oxalate (spinach and rhubarb), phosphates (vegetables), and clay
2. HCl
3. duodenum and jejunum, mostly
Term
How much iron is lost per day for males? For females?
Definition
1. about 1 mg/day
2. about 1 mg/day, except about 14 mg per period
Term
Where is iron typically used in the body?
Definition
in order of most iron: Hb, hepatocytes (in storage), myoglobin, and cytochromes
Term
What is transferrin? What is its function?
Definition
1. a protein
2. iron + apotransferrin = transferrin, which is an iron transport; it can bind to two iron atoms at once and the blood transferrin is usually 30% saturation
Term
What is ferritin and what is its function? What is hemosiderin and what is its function?
Definition
1. a protein used to store iron; it stores iron in dispersed clusters
2. a protein used to store iron; it stores iron in large clusters for use when ferritin stores are inadequate to provide sufficient supplementary iron
Term
How is iron absorption rate regulated?
Definition
when the body's apoferritin is saturated, absorption decreases; when it is depleted of iron, absorption increases
Term
What abnormality does sickle cell anemia cause?
Definition
it substitutes valine for glutamic acid in the β hemoglobin chains, causing a deformation of the cellular structure; crystals form inside the cell when it is exposed to low oxygen and the cell is unable to fit in small spaces and may rupture
Term
What are the types of hemoglobin and what chains are they composed of? Which one is found in embryos?
Definition
1. hemoglobin A (α2β2), A2 (α2δ2), and F (α2γ2)
2. F
Term
What is RI, in terms of blood? How can you find RI? What is a normal RI?
Definition
1. reticulocyte index; the relative percent of cells that are reticulocytes
2. RI = reticulocyte % X hematocrit/normal hematocrit
3. 1-2%
Term
What would an RI of under 2% mean? How about over 2%?
Definition
1. decreased production of RBCs
2. increased production of RBCs
Term
What are pertinent data for a history of a hematology patient?
Definition
present illness, recent infections (fevers, chills)/antibiotic use, bleeding, abdominal fullness, pica (a craving for non-food items like clay), skin coloration, alcoholism, nutrition, neurological issues (headaches, mental deficits, itching), medical history (cancer, HIV, hepatitis, pregnancy, venous thrombosis), and family history (bleeding disorders, anemia)
Term
What can a peripheral smear tell you? What are common abnormalities?
Definition
1. color, shape, and size of the cells
2. acanthocytes (spicules), schistocytes (fragments), spheroctes (round, dense cells), tear drops, rouleaux (stacked coins), malaria, crenated (short, evenly spaced spies), bite cells (lack of glucose-6-phosphate dehydrogenase), and nucleated RBCs
Term
What are possible causes of normocytic normochromic anemia? Macrocytic normochromic anemia? Microcytic hypochromic anemia?
Definition
1. bone marrow failure, renal disease, hemolytic anemia
2. megaloblastic anemia
3. iron deficiency, chronic diseases
Term
What are possible causes of microcytic anemias? Normocytic anemias? Macrocytic anemias?
Definition
1. iron deficiencies, sideroblastic anemias, lead poisoning, anemia caused by a chronic disease, thalassemias
2. chronic inflammation, endocrine disorders, renal failure, leukemias
3. B12 deficiency, folate deficiency, nucleotide analog drugs
Term
What are possible causes of hypoproliferative anemias? Maturation disorders? Hemolytic anemias? Are the RI values for each high or low?
Definition
1. marrow damage, problems with stimulation (renal disease, inflammation, metabolic disease), iron deficiency; low RI
2. cytoplasmic defects, nuclear maturation defects; low RI
3. blood loss, intravascular hemolysis, autoimmune, metabolic membrane, hemoglobolinopathy; high RI
Term
What are possible causes for primary aplastic anemia? Secondary?
Definition
1. idiopathic
2. drugs (chemotherapy, antibiotics, antidepressants, ethanol), chemicals (benzene), radiation, immune suppression of stem cells, malignancy (non-hematopoietic tumors and transformation of hematopoietic stem cells)
Term
What can reduce erythropoietin response?
Definition
acute inflammatory state, acute and chronic infections (AIDS, renal disease), hypometabolic state (protein deficiency, hypothyroidism, hypopituitarism)
Term
What is thalassemia? How is it treated?
Definition
1. a defect in hemoglobin synthesis
2. high doses of folic acid and transfusions
Term
What are siderophores? What are the different kinds?
Definition
1. enteric bacteria that can bind to Fe3+ to make iron available for use
2. E. Coli, anthrax, V. Cholera
Term
What are the types of sickle cell anemia? What are the symptoms of sickle cell anemia?
Definition
1. HbSS (sickle cell disease), HbSC (sickle cell trait), and sickle β thalessemia
2. production of HbS, pain, vaso-occlusion, and hemolytic anemia
Term
How common in HbSS in African-Americans? HbSC? What are appropriate treatments?
Definition
1. 1:350
2. 1:500
3. physician visits every 3-6 months, updated vaccines (flu and pneumococcal), possible transfusions, hydroxyurea
Term
What is the effect of hydroxyurea?
Definition
it increases HbF expression, decreases stickiness of erythrocytes, and makes RBCs more flexible
Term
Define: epistaxis, ecchymosis, menorrhagia
Definition
1. nose bleeds, large/perfuse bruising, excessive bleeding during periods
Term
Describe and mention the cause of: bite cells, schistocytes, rouleaux
Definition
1. a genetic defect in RBCs causes some areas to not switch between oxygenated and deoxygenated forms, so macrophages may take small bites out of the RBCs
2. fragments of cells; may occur in mitral valve prolapse
3. stacked cells; cells become sticky
Term
What is sideroblastic anemia? What is a very noticeable characteristic of it?
Definition
1. anemia caused by chronic gut bacterial infection; may also be genetically related;
2. rings of mitochondria form around the nucleus
Term
How might the heart compensate for anemia? How can this be dangerous during exercise?
Definition
1. anemia often causes blood to lose viscosity, which means much more blood can be pumped through the vessels at a given time; which the reduction in oxygen, the heart may respond as it would with exercise and increase cardiac output; this may supply some of the oxygen deficiency in anemia
2. if the heart is already working on increased cardiac output, requiring more output by exercising may overload the heart and cause acute cardiac failure
Term
What is hemoglobin SC disease?
Definition
a glutamic acid is substituted by lysine in hemoglobin, resulting in similar problems as sickle cell anemia
Term
Compare and contrast polycythemia vera and secondary polycythemia.
Definition
1. polycythemia vera is a stem cell disorder that includes a problem with the feedback mechanism to stop production of RBCs (and other blood cells) when the quantities are enough; hematocrit, WBCs, and BV are often greatly increased; EPO may be normal or even low; this may require phlebotomy treatment
2. secondary polycythemia involves tissue hypoxia or renal or hepatic disease causing increased EPO, causing polycythemia; only hematocrit is increase while EPO is high; no treatment is required
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