3. Primary site of hematopoietic stem cells: Bone marrow ("myeloid tissue")
4. Difference between red and yellow bone marrow: Red marrow produces
RBCs, yellow marrow does not produce
RBCs
5 Active bone marrow sites:
pelvic bones vertebrae
cranium mandible
sternum
ribs
humerus
femur
5. Factors that increase hematopoiesis:
(1) conversion of yellow bone marrow, which does not produce blood cells, to
hematopoietic red marrow by the actions of erythropoietin (a hormone that
stimulates erythrocyte production)
(2) faster differentiation of progenitor cells
(3) faster proliferation of stem cells into progenitor cells
6. Erythropoiesis: production of RBCs
7. Sequence of erythropoiesis: Pluripotent hematopoietic stem cell -->
committed Proerythroblast/Pronormoblast --> Erythroblast/Normoblast
(Hgbsynthesis begins)
Reticulocyte (nucleus is lost; 3 days spent in bone marrow, about 1 day in blood)
--> Erythrocyte
, NURS 8022 Exam 2 2024
** aprox. 1% of RBCs are reticulocytes **
In each step the quantity of hemoglobin increases and the nucleus decreases in
size
8. Erythropoietin: A hormone produced and released by the kidney that stimulates
the production of red blood cells by the bone marrow Always present in plasma
Released in response to low renal oxygenation
- NOT the # of RBCs but rather oxygen delivery
- e RBC production increases within 24 hours; life span 4-12 hours; increased
RBC # in 5 days
- Given to dialysis and chemo patients
9. Reticulocytes: Last immature form of erythroblast
Contains polyribosomes (globin synthesis) and mitochondria (heme synthesis)
24-48 hours after leaving bone marrow for circulation, matures into erythrocyte
- Loses polyribosomes and mitochondria
-Make up 1-2% of RBCs
- Last about 2 days in bone marrow and 1 day in blood continuing to mature-
During time of low HCT time in marrow decreased to as little as 1 day
Reticulocyte count -- Indicates whether new RBCs are being produced; good
indicator of erythropoiesis
10. Renal oxygenation negative feedback loop:
11. Hemoglobin and its structure: Oxygen-carrying protein of the erythrocyte -->
may carry up to 300 hgb molecules Reversible deformity to be abvle to
squeeze through the tiniest of capillaries
Each Hgb molecule has 2 pairs of different globin chains and 4 complexes of iron
+ heme
, NURS 8022 Exam 2 2024
Heme: large, flat, iron-protoporphyrin disk that is synthesized in the
mitochondria and can carry one molecule of oxygen Each Hgb can carry 4
molecules of oxygen
12. Heme vs Globin: Heme: Synthesized in mitochondria of reticulocyte - Carries
Oxygen
Globin: Polyribosomes in reticulocytes
- 2 pairs of globin chains on each Hgb molecule
- Combo of pair determines type of globin chain
Most common hgb A: 2 alpha chains and 2 beta chains - hgb F (fetal): 2 alpha, 2
gamma
13. Red blood cell structure: Sac of Hgb, no nucleus or mitochondria, only
hemoglobin & enzymes surrounded by membrane
-Lack mitochondria, rely on glycolysis for energy --> "aerobic metabolism"
Deficiencies of 2 enzymes result in anemia
• Pyruvate kinase - necessary for glycolysis - no glycolysis results in RBC damage
and death
• G6PD - involved in protecting the RBC against oxidative stress
14. Anisocytosis
Poikilocytosis: Variation in RBC size
Variation in RBC shape
15. Hereditary vs Acquired Hemolysis: Hereditary hemolysis: sickle cell disease
MCV: 78-100 (related to size)
MCH: 27-34 (related to hgb content)
Reticulocytes: new RBC formation - low suggest issues in production
, NURS 8022 Exam 2 2024
17. Microcytic-Hypochromic Anemias: Characterized by red cells that are
abnormally small and contain reduced amounts of hemoglobin
Iron Deficiency Anemia (IDA)
Sideroblastic
Thalassemia
18. Iron Deficiency Anemia (IDA): Type of Microcytic-Hypochromic Anemia
- Most common type of anemia
- Highest risk: older adults, women, infants, poverty
- Associated with cognitive impairment in children
- Causes: inadequate dietary intake; excessive blood loss (GI bleed most common
pathophysiologic cause); chronic parasite infestations; metabolic or functional
iron deficiency; menorrhagia (most common physiologic cause)
** Good sign of malignancy for postmenopausal women and men **
19. IDA Diagnostic Manifestations: Low MCV, low MCH
High RDW
Low initial reticulocyte count - elevated once treatment and iron supplementation
begin
Ferritin low - #1 test for IDA
Low serum iron; TIBC high - not enough iron to bind transferrin
20. IDA Clinical Manifestations: Mild (hgb 10-12): likely no symptoms
Moderate (hgb 7-11): palpitations, dyspnea, exercise intolerance, angular
stomatitis, glossitis, pallor, koilonychia (pitting nails), pica (eating disorder in which
a person eats things not usually considered food)
Severe (hgb <7): postural hypotension, dizziness, weakness, gastritis,
paresthesias, lethargy
Elderly: lethargy and confusion
21. Sideroblastic Anemia: Type of Microcytic-Hypochromic Anemia
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