Chapter 19 Clinical Questions, Plus One Tortora Question – Flashcards
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Cancer patients being treated with chemotherapeutic drugs designed to destroy rapidly dividing cells are monitored closely for changes in their red and white blood cell counts. Why so?
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Hemopoiesis is a process involving fairly rapid cell production. Because chemotherapeutics simply target cells exhibiting rapid turnover (rather than other specific properties of cancer cells), hemopoiesis is a target of chemotherapeutic drugs and must be carefully monitored.
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Mary Healy, a young woman with severe vaginal bleeding is admitted to the emergency room. She is three months pregnant, and the physician is concerned about the volume of blood she is losing. (a) What type of transfusion will be probably be given to this patient? (b) What blood tests will be performed before starting the transfusion?
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a. The woman would probably be given a whole blood transfusion. It is essential that she maintain sufficient O2-carrying capacity to serve fetal needs and blood volume to maintain circulation. b. The blood tests that would be performed include tests for ABO and Rh group antigen and cross matching.
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Alan Forsythe, a middle-aged college professor from Boston, is in the Swiss Alps studying astronomy during his sabbatical leave. He has been there for two days and plans to stay the entire year. However, he notices that he is short of breath when he walks up steps and tires easily with any physical activity. His symptoms gradually disappear, and after two months he feels fine. Upon returning to the United States, he has a complete physical exam and is told that his erythrocyte count is higher than normal. (a) Attempt to explain this finding. (b) Will his RBC count remain at this higher-than-normal level? Why or why not?
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a. Polycythemia accounts for his higher erythrocyte count because of the need to produce more RBCs to increase his O2 binding and transport ability in the high-altitude (thinner air) environment of the Alps. Enhanced production of RBCs was prompted by an increased production of erythropoietin. b. His RBC count will not stay higher than normal because the excess production of RBCs will depress erythropoietin production by the kidneys when adequate levels of O2 are being transported in the blood.
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A young child is diagnosed as having acute lymphocytic leukemia. Her parents cannot understand why infection is a major problem for Janie when her WBC count is so high. Can you provide an explanation for Janie's parents?
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Janie's leukocytes are immature or abnormal and are incapable of defending her body in the usual way.
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Mrs. Ryan, a middle-aged woman, appears at the clinic complaining of multiple small hemorrhagic spots in her skin and severe nosebleeds. While taking her history, the nurse notes that Mrs. Ryan works as a rubber glue applicator at a local factory. Rubber glue contains Benzene, which is known to be toxic to red marrow. Using your knowledge of physiology, explain the connection between the bleeding problems and Benzene.
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Red bone marrow is the site of hemopoiesis, and if it is destroyed by benzene, hemocytoblasts will not be produced, which will reduce the production of megakaryocytes (the progenitor cells of platelets, which are involved in clotting).
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A reticulocyte count indicated that 5% of Tyler's red blood cells were reticulocytes. His blood test also indicated he had polycythemia and a hematocrit of 65%. Explain the connection between these three facts.
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Tyler is turning out a high rate of reticulocytes (immature red blood cells), which accounts for his high hematocrit.
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In 1998, the U.S. Food and Drug Administration approved the nation's first commercial surgical glue to control bleeding during certain surgeries. Called Tinsel, it forms a flexible mesh over an oozing blood vessel to help stem bleeding within five minutes. This sealant is made from two blood proteins that naturally cause blood to clot when they latch together. Name these proteins.
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An analysis of the clotting process described in the text should reveal that the two blood proteins are thrombin and fibrinogen.
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Jenny, a health young woman, had a battery of tests during a physical for her new job. Her RBC count was at the higher end of the normal range at that time, but four weeks later it was substantially elevated beyond that. When asked if any circumstance has changed in her life, she admitted to taking up smoking. How might her new habit explain her higher RBC count?
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An elevated RBC count could be related to smoking, due to the frequent hypoxia that results from inhalation of oxygen-poor cigarette smoke.
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Mr. Chu has been scheduled for surgery to have his arthritic hip replaced. His surgeon tells him he must switch from aspirin to acetaminophen for pain control before his surgery. Why?
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Aspirin is a mild anticoagulant, which could cause excessive bleeding during or after surgery.
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Tortora Question: List and briefly describe the major functions of blood.
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1) Transportation of oxygen, carbon dioxide, nutrients, wastes, hormones and heat. 2) Regulation of pH via buffers, body temperature via properties of water in plasma, and water balance via osmotic pressure created by plasma proteins. 3)Protection via clotting, antibodies, phagocytosis, and complement.
