Ch. 18: Red Blood Cell Morphology and Approach to Diagnosis Flashcards
What type of cells perform the vital physiologic function of oxygen delivery to the tissues?
Red Blood Cells (RBCs)
What component within the erythrocyte can bind to oxygen in the lungs and then release it appropriately in the tissues?
Hemoglobin
From what Greek word was anemia derived from?
Anaimia
Define anaimia.
Without blood
Dec. in RBCs, or the amount of hemoglobin in the RBCs, results in (increased/decreased) oxygen delivery.
Decreased
The decrease of _____ can lead to tissue hypoxia.
Dec. in RBCs, or the amount of hemoglobin in the RBCs
Give the functional definition of anemia.
It is a decrease in the oxygen carrying capacity of blood
Give the operational definition of anemia.
It is a reduction, from the baseline value,
in the total number of RBCs
in the amount of circulatiing hemoglobin
in RBC mass of a particular patient
Explain why in practice, the operational definition is not applicable.
A patient’s baseline value is rarely known
Give the conventional definition of anemia.
It is a decrease in RBCs, hemoglobin, and hematocrit below the reference range for healthy individuals of the same age, sex, and race, under similar environmental conditions.
Enumerate problems that may occur with the conventional definition.
Definition of normal is different for each of the data sets
(Different reference ranges)
Pools of individuals lack heterogeneity required to be universally applied to all the different populations.
What are the classic symptoms associated with anemia?
Fatigue
Shortness of breath
Iron deficiency can lead to a symptom called _____, wherein a patient can have cravings for unusual substances such as ice (pagophagia), cornstarch, or clay.
Pica
Patients experiencing a rapid fall in hemoglobin concentration typically have _____.
Tachycardia (Fast heart rate)
What is the hemoglobin concentration of a patient with moderate anemia?
7 - 10 g/dL
What is the hemoglobin concentration of a patient with sever anemia?
less than 7 g/dL
The severity of the anemia is gauged by the _____, _____, and the _____
Degree of reduction in RBC mass
Cardiopulmonary adaptation
Rapidity of progression of anemia
Reduced delivery of oxygen to tissues caused by reduced hemoglobin causes an (increase/decrease) in erythropoietin secretion by the kidneys.
Increase
What secretes erythropoietin when there is reduced delivery of oxygen to tissues?
Kidneys
This stimulates the RBC precursors in the bone marrow, which leads to the release of more RBCs into the circuation.
Erythropoietin
With persistent anemia, what physiologic adaptations are done to increase the oxygen-carrying capacity of a reduced amount of hemoglobin.
Increase in:
Heart rate
Respiratory rate
Cardiac output
This condition triggers an increase in RBC 2, 3-bisphosphoglycerate that shifts the oxygen dissociation curve to the right (decreased oxygen affinity of hemoglobin) and results in increased delivery of oxygen to tissues
Tissue hypoxia
The increase in _____ shifts the oxygen dissociation curve to the right (decreased oxygen affinity of hemoglobin) and results in increased delivery of oxygen to tissues
RBC 2, 3-bisphosphoglycerate
What is the lifespan of the RBC in circulation?
120 days
In a healthy individual with no anemia, how many percent of the RBCs are removed from corculation due to senescence?
1%
This releases reticulocytes that mature into RBCs in the peripheral blood circulation.
Bone marrow
Adequate RBC production requires several nutritional factors, such as _____.
Iron
Vitamin B12
Folate
At what conditions should the bone marrow increase RBC production to compensate for the increased RBC loss?
Excessive bleeding
Hemolysis
This is the term used for marrow erythroid proliferative activity.
Erythropoiesis
Normal erythropoiesis occurs in the _____.
Bone marrow
This refers to the production of erythroid progenitor cells that are defective.
Ineffective erythropoiesis
The defective progenitor cells produced during ineffective erythropoiesis are often destroyed in the _____ and released into the _____.
Bone marrow
Peripheral circulation
What conditions are characterized by ineffective erythropoiesis?
Megaloblastic anemia
Thalassemia
Sideroblastic anemia
In anemias characterized by ineffective erythropoiesis, the peripheral blood hemoglobin is (high/low) despite an increase in RBC precursors in the bone marrow
Low
In ineffective erythropoiesis, the effective production rate is considerably (greater/less) than the total production rate, which results in a (increased/decreased) number of normal circulating RBCs.
Less
Decreased
This refers to a decrease in the number of erythroid precursors in the bone marrow.
Insufficient erythropoiesis
Insufficient erythropoiesis results in the following conditions:
Decreased RBC production
Anemia
What factors can lead to decreased RBC production?
Deficiency of iron
(Inadequate intake, malabsorption, excessive loss from chronic bleeding)
Deficiency of erythropoietin
Loss of erythroid precursors due to an autoimmune reaction
(Aplastic anemia, acquired pure red cell aplasia)
Infection
(Parvovirus B19)
Suppression of the erythroid precursors due to infiltration of the bone marrow with granulomas (sarcoidosis) or malignant cells (acute leukemia)
This is the hormone that stimulates erythroid precursor proliferation and maturation.
Erythropoietin
Enumerate intrinsic causes of hemolysis.
Intrinsic defects in:
RBC membrane
Enzyme systems
Hemoglobin
Enumerate extrinsic causes of hemolysis.
Antibody-mediated processes
Mechanical fragmentation
Infection-related destruction