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level: Level 1 of Chapter 44

Questions and Answers List

level questions: Level 1 of Chapter 44

Question	Answer
Hematologic disorders, often called blood dyscrasias, occur when:	components of the blood are formed incorrectly or either increase or decrease in amount beyond normal ranges.
Blood components originate in the: circulate through: and ultimately are destroyed by the:	Blood components originate in the bone marrow, circulate through blood vessels, and ultimately are destroyed by the spleen
The total volume of blood in the human body is roughly:	proportional to body weight: 85 mL per kg at birth, 75 mL per kg at 6 months of age, and 70 mL per kg after the first year.
function chiefly to transport oxygen to and carry carbon dioxide away from body cells.	Erythrocytes
Erythrocytes are formed in the bone marrow under the stimulation of: a hormone formed by the kidneys that is produced whenever a child has tissue hypoxia.	erythropoietin
Children with kidney disease often have a low number of RBCs because:	erythropoietin secretion is inadequate in diseased kidneys.
Which is displayed as an elevated hematocrit, often occurs when a child has impaired tissue oxygenation and increased erythropoietin.	Polycythemia
Polycythemia, which is displayed as an elevated hematocrit, often occurs when:	a child has impaired tissue oxygenation and increased erythropoietin.
At birth, an infant has approximately how many RBCs per mm3 of blood.	5 million
This concentration (5 million RBCs per mm3 of blood in an infant) diminishes rapidly in the: reaching a low of approximately 4.1 million per mm3 at what months: The number then increases until:	c.) ... diminishes rapidly in the first month b.) ... reaching a low of approximately 4.1 million per mm3 at 3 to 4 months of age. c.) adolescence, when the adult value of approximately 4.9 million per mm3 is reached.
RBCs form first as: (large, nucleated cells), then mature through normoblast and reticulocyte stages to become more mature, nonnucleated erythrocytes.	erythroblasts
An elevated what count indicates that rapid production of new RBCs is occuring.	reticulocyte (immature RBC) count (more than 1% of the total count)
At the end of the lifespan of RBC (a: about how many days?), erythrocytes are destroyed through:	a: 120 days ... through phagocytosis by reticuloendothelial cells, found in the highest proportion in the spleen
The component of RBCs that allows them to carry out the transport of oxygen is:	hemoglobin
Hemoglobin is composed of:	globin, a protein, and heme, an iron-containing pigment.
it is what portion that combines with oxygen and carbon dioxide for transport:	the heme portion