RBC path Flashcards
\_\_\_\_ system Blood cell forming system Lymph tissue Bone Marrow Red bone marrow Yellow bone marrow Circulating blood
Hematopoietic System
Process in which red and white blood cells are
produced
Red bone marrow
Hematopoiesis
Erythropoiesis Regulated by kidneys Erythropoietin 1% of RBCs replaced daily Life span 120 days (4 months)
Erythrocytes
Immature red blood cells
Reticular network of RNA in cytoplasm
Normal range: 0.5% to 1.5%
Indicator of bone marrow activity
Reticulocytosis – elevated number of reticulocytes in blood
Reticulocyte count should be appropriate to the clinical situation
Reticulocytes
Heme – non-protein portion
Iron porphyrin - 4 pyrrole rings + iron
Globin – protein portion
HbA (Adult Hb) – 2 alpha, 2 beta
HbF (Fetal Hb) – 2 alpha, 2 gamma
Normal adult red cells contain mainly HbA
Hemoglobin
A reduction in the erythron – a reduction in the total red cell mass
below normal limits
Reduction in the oxygen carrying capacity of the blood leading to
tissue hypoxia
Usually diagnosed based on:
Inadequate numbers of erythrocytes (low hematocrit - the ratio
of packed red cells to total blood volume)
Inadequate level of hemoglobin – the hemoglobin concentration
of the blood
Anemia
The lifespan of a red blood cell is about ____ days
120 days
Increased RBC destruction
Decreased RBC production
Blood loss
Anemia
Clinical Features of \_\_\_\_\_: Pallor – pale skin and mucosa Lethargy – lack of energy, fatigue, weakness Dyspnea – labored breathing, SOB Tachycardia, arrhythmia, chest pain Koilonychia - spoon-shaped nails Atrophic glossitis Cognitive problems, dizziness Cold extremities Headache
Anemia
A hemoglobinopathy
Inherited, mis-sense mutation of beta chain
A single AA substitution of valine for glutamic acid
Forms a new, abnormal hemoglobin, Hemoglobin S - HbS
Sickle cell disease – homozygous HbS
Sickle cell trait - heterozygous, a less serious condition
Sickle cell anemia
Individuals with sickle cell trait (heterozygous for HbS) have a survival
advantage in malaria-endemic areas
Homozygous normal – increased mortality due to malaria
Heterozygous – survival advantage
Homozygous – increased mortality due to sickle cell disease
About 8% of African Americans are heterozygous (sickle cell trait)
1 in 600 African Americans are homozygous (sickle cell disease)
HbS
Clinical Consequences of \_\_\_\_\_\_\_ Increased susceptibility to infection with encapsulated organisms Pneumococcus pneumoniae Hemophilus influenzae
Splenectomy
“Mediterranean” anemia Group of inherited diseases Quantitative problem - too few globins synthesized Underproduction of normal globin proteins due to mutations in regulatory genes Ineffective production of globin chains Alpha globin chains (α Thalassemia) Beta globin chains (β Thalassemia) Regular transfusions – iron overload – organ damage Bone deformities – expansion of marrow space Splenomegaly - splenectomy Impaired growth Bone marrow transplantation
Thalassemia
Two genes involved in making beta chain (one from
each parent)
Severity depends on number of affected beta chain
genes
One gene – beta-thalassemia minor - beta-thalassemia
trait
Mild disease
Two genes – beta-thalassemia major (Cooley’s anemia)
Severe disease
Beta Thalassemia
Four genes involved in making alpha chain (two from each parent)
Severity depends on number of affected alpha chain genes
One gene – asymptomatic carrier
Two genes – alpha-thalassemia minor - alpha-thalassemia trait
Mild disease
Three genes – hemoglobin H disease
Moderate to severe disease
Four genes – alpha-thalassemia major – (lethal)
Alpha Thalassemia