(Test Bank) Understanding Pathophysiology

Huether,Mccance, 6

Medicine

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6th Edition

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Author(s): Huether, Mccance

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Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM Chapter 01: Cellular Biology Huether & McCance: Understanding Pathophysiology, 6th Edition MULTIPLE CHOICE 1. A student is observing a cell under the microscope. It is observed to have supercoiled DNA with histones. Which of the following would also be observed by the student? a. A single circular chromosome b. A nucleus c. Free-floating nuclear material d. No organelles ANS: B The cell described is a eukaryotic cell, so it has histones and a supercoiled DNA within its nucleus; thus, the nucleus should be observed. A single circular chromosome called a prokaryote contains free-floating nuclear material but has no organelles. REF: p. 2 2. A nurse is instructing the staff about cellular functions. Which cellular function is the nurse describing when an isolated cell absorbs oxygen and uses it to transform nutrients to energy? a. Metabolic absorption b. Communication c. Secretion d. Respiration ANS: D NURSINGTB.COM The cell’s ability to absorb oxygen is referred to as respiration while its communication ability involves maintenance of a steady dynamic state, metabolic absorption provides nutrition, and secretion allows for the synthesizing of new substances. REF: p. 2 3. A eukaryotic cell is undergoing DNA replication. In which region of the cell would most of the genetic information be contained? a. Mitochondria b. Ribosome c. Nucleolus d. Nucleus Cytoplasm ANS: C The region of the cell that contains genetic material, including a large amount of ribonucleic acid, most of the DNA, and DNA -binding proteins, is the nucleolus, which is located within the cell’s nucleus. Mitochondria is associated with cellular respiration, while ribosomes are involved with protein manufacturing. Cytop lasm is a fluid filling that is a component of the cell. REF: p. 2 Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM U S N T O 4. Which of the following can remove proteins attached to the cell’s bilayer by dissolving the layer itself? a. Peripheral membrane proteins b. Integral membrane proteins c. Glycoproteins d. Cell adhesion molecules ANS: B Proteins directly attached to the membrane bilayer can be removed by the action of integral membrane proteins that dissolve the bilayer. Peripheral membrane proteins reside at the surface while cell adhesion molecules are on the outside of the membrane. Glycoprotein marks cells and does not float. REF: p. 7 5. Which of the following can bind to plasma membrane receptors? a. Oxygen b. Ribosomes c. Amphipathic lipids d. Ligands ANS: D Ligands are the only specific molecules that can bind with receptors on the cell membrane. REF: p. 9 6. A nurse is reviewing a report from a patient with metastatic cancer. What alternation in the extracellular matrix wou ld suNppoRrt thIe dGiagnBo.siCs ofMmetastatic cancer? a. Decreased fibronectin b. Increased collagen c. Decreased elastin d. Increased glycoproteins ANS: A Only a reduced amount of fibronectin is found in some types of cancerous cells, allowing them to travel or metastasize. REF: p. 10 7. Which form of cell communication is used to relate to other cells in direct physical contact? a. Cell junction b. Gap junction c. Desmosome d. Tight junction ANS: A Cell junctions hold cells together and permit molecules to pass from cell to cell. Gap junctions allow for cellular communication between cells. Neither desmosomes nor tight junctions are associated with cellular communication. REF: p. 11 Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM 8. Pancreatic beta cells secrete insulin, which inhibits secretion of glucagon from neighboring alpha cells. This action is an example of which of the following signaling types? a. Paracrine b. Autocrine c. Neurohormonal d. Hormonal ANS: A Paracrine signaling involves the release of local chemical mediators that are quickly taken up, destroyed, or immobilized, as in t he case of insulin and the inhibition of the secretion of glucagon. None of the other options involve signaling that is associated with a local chemical mediator like insulin. REF: p. 12 9. In cellular metabolism, each enzyme has a high affinity for a: a. solute. b. substrate. c. receptor. d. ribosome. ANS: B Each enzyme has a high affinity for a substrate, a specific substance converted to a product of the reaction. Cellular metabolism is not dependent on an attraction between an enzyme and any of the remaining opt ions. REF: p. 16 NURSINGTB.COM 10. An athlete runs a marathon, after which his muscles feel fatigued and unable to contract. The athlete asks the nurse why this happened. The nurse’s response is based on the knowledge that the problem is result of a deficiency of: a. GTP b. AMP c. ATP d. GMP ANS: C When ATP is deficient, impaired muscle contraction results. None of the other options are involved in muscle contraction. REF: p. 16 11. Which phase of catabolism produces the most ATP? a. Digestion b. Glycolysis c. Oxidation d. Citric acid cycle ANS: D While some ATP is produced during the oxidation and glycolysis phases, most of the ATP is generated during the citric acid cycle. Digestion does not produce any ATP. Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM REF: p. 16 12. A nurse is teaching the staff about the phases of cellular catabolism. Which phases should the nurse include? a. Digestion, glycolysis, oxidation, and the citric acid cycle b. Diffusion, osmosis, and mediated transport c. S phase, G phase, and M phase d. Metabolic absorption, respiration, and excretion ANS: A Only digestion, glycolysis, oxidation, and the citric acid cycle are the phases of cellular catabolism. REF: p. 16 13. A runner has depleted all the oxygen available for muscle energy. Which of the following will facilitate his continued muscle performance? a. Electron -transport chain b. Aerobic glycolysis c. Anaerobic glycolysis d. Oxidative phosphorylation ANS: C When no oxygen is available, anaerobic glycolysis occurs. The electron -transport chain is part of the citric acid cycle. Aerobic glycolysis involves the presence of oxygen. Oxidative phosphorylation is the mechanism by which the energy produced from carbohydrates, fats, and proteins is transferred to ATP. It is not part of muscle performance. REF: p. 16 NURSINGTB.COM 14. A faculty member asks a student to identify the appropriate term for the movement of a solute from an area of greater to lesser concentration. Which answer indicates the nursing student understood the teaching? a. Osmosis b. Diffusion c. Hydrostatic pressure d. Active transport ANS: B Diffusion is the movement of a solute molecule from an area of greater solute concentration to an area of lesser solute concentration through a permeable membrane. Osmosis is the movement of water across a semipermeable membrane from a region of higher water concentration to one of lower concentration. Hydrostatic pressure is the force of fluid against a cell membrane. In active transport, molecules move up a concentration gradient. REF: p. 19 15. Which description accurately describes electrolytes? a. Small lipid-soluble molecules b. Large protein molecules c. Micronutrients used to produce ATP Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM d. Electrically charged molecules ANS: D Electrolytes are electrically charged molecules. They are not lipid soluble, they are not made up of protein, and they do not play a role in ATP production. REF: p. 18 16. A nurse is reading a chart and sees the term oncotic pressure. The nurse recalls that oncotic pressure (colloid osmotic pressure) is determined by: a. the concentration of sodium. b. plasma proteins. c. hydrostatic pressure. d. the availability of membrane transporter proteins. ANS: B Oncotic pressure is determined by the effect of colloids or plasma proteins. The concentration of sodium plays a role in tonicity. Hydrostatic pressure is the force within a vessel. Membrane transporter proteins are involved in active transport within a concentration gradient. REF: p. 20 17. A patient has a body fluid of 300 mOsm/kg. This lab result is measuring: a. osmolality. b. osmolarity. c. osmotic pressure. d. oncotic pressure. ANS: A NURSINGTB.COM Osmolality measures the number of milliosmoles per kilogram of water, or the concentration of molecules per weight of water, while osmolarity measures the number of milliosmoles per liter of solution, or the concentration of molecules per volume of solutio n. Osmotic pressure is the amount of hydrostatic pressure required to oppose the osmotic movement of water. Oncotic pressure is from plasma proteins, not body fluids. REF: p. 19 18. A nurse is discussing the movement of fluid across the arterial end of capillary membranes into the interstitial fluid surrounding the capillary. Which process of fluid movement is the nurse describing? a. Hydrostatic pressure b. Osmosis c. Diffusion d. Active transpo rt ANS: A Blood reaching the capillary bed has a hydrostatic pressure of 25 –30 mm Hg, which is sufficient force to push water across the thin capillary membranes into the interstitial space. Osmosis involves the movement of fluid from an area of higher concentration to an area of lower concentration. It does not involve pressure or force. Diffusion is the passive movement of a solute from an area of higher solute concentration to an area of lo wer solute concentration. Active transport involves movement up a concentration gradient. Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM REF: p. 19 19. How are potassium and sodium transported across plasma membranes? a. By passive electrolyte channels b. By coupled channels c. By adenosine triphosphate enzyme (ATPase) d. By diffusion ANS: C The transporter protein ATPase is directly related to sodium and potassium transport via active transport. Electrolyte movements require energy and do not move passively, nor are they transported by diffusion. Enzymes, not electrolytes, are passed via coupled channels. REF: p. 21 20. The ion transporter that moves Na+ and Ca2+ simultaneously in the same direction is an example of which of the following types of transport? a. Biport b. Uniport c. Antiport d. Symport ANS: D When ions are transported in one direction, it is termed symport. There is no such term as biport. Uniport refers to the movement of a single molecule. Antiport refers to the movement of molecules in the opposite direction. REF: p. 19, Figure 1-22 NURSINGTB.COM 21. During which process are bacteria engulfed for ingestion? a. Endocytosis b. Pinocytosis c. Phagocytosis d. Exocytosis ANS: C Phagocytosis (cell eating) involves the ingestion of large particles, such as bacteria, through the formation of large vesicles. Endocytosis involves the formation of vesicles to facilitate movement into the cell. Pinocytosis is a type of endocytosis in which fluids and solute molecules are ingested through the formation of small ve sicles. Exocytosis occurs when coated pits invaginate and internalize ligand -receptor complexes in coated vesicles. REF: p. 22 22. Some cancer drugs work during the cell cycle phase where nuclear and cytoplasmic divisions occur. What is this cell cycle phase called? a. G1 b. S c. M d. G2 Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM ANS: C The M phase includes both nuclear and cytoplasmic divisions. The G 1 phase includes the period between the M phase and the start of DNA synthesis. The S phase includes synthesis of DNA in the cell nucleus. The G2 phase includes RNA and protein synthesis. REF: pp. 25-26 23. Which causes the rapid change in the resting membrane potential that initiates an action potential? a. Potassium gates open, and potassium rushes into the cell, changing the membrane potential from negative to positive. b. Sodium gates open, and sodium rushes into the cell, changing the membrane potential from negative to positive. c. Sodium gates close, allowing potassium into the cell to change the membrane potential from positive to negative. d. Potassium gates close, allowing sodium into the cell to change the membrane potential from positive to negative. ANS: B When the threshold is reached, the cell will continue to depolarize with no further stimulation. The sodium gates open, and sodium rushe s into the cell, causing the membrane potential to reduce to zero and then become positive (depolarization). Sodium is involved in creating the action potential, not potassium. The sodium gate and channel must be open, not closed. The action potential is not affected by a change in the potassium gate. REF: pp. 24 -25 24. A cell is isolat ed, and electroNphUyRsiSolIogNyGstTuBdi.esCreOvMeal that the resting me mbrane potential is 70 mV. The predominant intracellular ion is Na+, and the predominant extracellular ion is K+. With voltage change, which of the following would result in an action potential? a. K+ rushing into the cell b. Na+ rushing into the cell c. Na+ rushing out of the cell d. K+ rushing out of the cell ANS: A With voltage change, potassium rushes into, not out of, the cell. Sodium movement is not related to this process. REF: pp. 24 -25 25. A nurse teaching the staff about platelet -derived growth factor includes information that platelet -derived growth factor (PDGF) stimulates the production of: a. platelets. b. epidermal cells. c. connective tissue cells. d. fibroblast cells. ANS: C Different types of cells require different growth factors; for example, PDGF stimulates the production of connective tissue cells, but not platelets, epidermal cells, or fibroblast cells. Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM U S N T O REF: p. 27 26. The phase of the cell cycle during which the centromeres split and the sister chromatids are pulled apart is referred to as: a. anaphase. b. telophase. c. prophase. d. metaphase. ANS: A Anaphase begins when the centromeres split and the sister chromatids are pulled apart. During telophase, a new nuclear membrane is formed around each group of 46 chromosomes, the spindle fibers disappear, and the chromosomes begin to uncoil. During prophase, the first appearance of chromosomes occurs. Metaphase occurs when two centrioles located at opposite poles of the cell pull the chromosomes to opposite sides of the cell. REF: p. 26 27. What is the role of cytokines in cell reproduction? a. Provide growth factor for tissue growth and development. b. Block progress of cell reproduction through the cell cycle. c. Restrain cell growth and development. d. Provide nutrients for cell growth and development. ANS: A Cytokines play a major role in the regulation of tissue growth and development but do not restrain it. Cytokin es help ovNercoRmeIintrGaceBllu.laCr brMaking m echanism s that restrain cell growth and promote cell growth, but they do not provide nutrients. REF: p. 26 28. A biopsy of the lung bronchi revealed ciliated epithelial cells that are capable of secretion and absorption. These cells are called columnar epithelium. a. simple b. ciliated simple c. stratified d. pseudostratified ciliated ANS: B Ciliated simple columnar epithelium is found in the lungs. Simple columnar epithelium is found from the stomach to the anus. Stratified columnar epithelium is found in the lining of the epiglottis, part of the pharynx, the anus, and the male urethra. Pseud ostratified ciliate columnar epithelium is found in the lining of the large ducts of some glands (parotid, salivary), male urethra, respiratory passages, and Eustachian tubes of the ears. REF: p. 30, Table 1 -6 29. A student is reviewing functions of the cell. The student would be correct in identifying a chief function of the nerve cell as: a. sensory interpretation. b. conductivity. Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM c. maintenance of homeostasis. d. communication. ANS: B Conductivity, not sensory interpretation, homeostasis, or communication, is one of the eight chief functions of nerve cells. REF: p. 2 MULTIPLE RESPONSE 1. A nurse recalls that the basic types of tissues are: (select all that apply) a. nerve. b. epithelial. c. mucosal. d. connective. e. skeletal. f. muscle. ANS: A, B, D, F The basic tissue types include nerve, epithelial, connective, and muscle. Mucosal is a type of epithelial cell, while skeletal is a type of connective tissue. REF: p. 27 2. Characteristics of prokaryotes include which of the following? (select all that apply) a. They contain no organelles. b. Their nuclear material is NnoUt RenScIasNedGbTyBa.nuCcOleMar memb rane. c. They contain a distinct nucleus. d. They contain histones. e. They contain a cellular membrane. ANS: A, B The prokaryotes lack a cellular membrane that encases nuclear material, thus they have no distinct nucleus; organelles and histones are also missing. REF: p. 1 Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM Chapter 02: Genes and Genetic Diseases Huether & McCance: Understanding Pathophysiology, 6th Edition MULTIPLE CHOICE 1. A nurse recalls the basic components of DNA are: a. pentose sugars and four phosphate bases. b. a phosphate molecule, deoxyribose, and four nitrogenous bases. c. adenine, guanine, and purine. d. codons, oxygen, and cytosine. ANS: B The three basic components of DNA are deoxyribose; a phosphate molecule; and four types of nitrogenous, not phosphate, bases. DNA does not contain condone. REF: p. 38 2. Which of the following mutations have the most significant effect on protein synthesis? a. Base pair substitutions b. Silent mutations c. Intron mutations d. Frameshift mutations ANS: D The frameshift mutation involves the insertion or deletion of one or more base pairs of the DNA molecule. This greatly alters the amino acid sequence, which affects protein synthesis. The base pair subst itution is Na tUypReSoIf NmGutTatBio.n CinOwMhich one base pair replaces another. Silent mutations do not change amino acids or protein synthesis. Intron mutations are part of RNA sequencing. REF: p. 39 3. The base components of DNA are: a. A, G, C, and U. b. P, G, C, and T. c. A, G, C, and T. d. X, XX, XY, and YY. ANS: C The four base components of DNA are cytosine, thymine, adenine, and guanine, and are commonly represented by their first letters (A, C, T, and G) and not components identified as P or U. X, XX, XY, and YY are components of human chromosomes. REF: p. 38 4. A DNA strand has a region with the sequence ATCGGAT. Which of the following would be a complementary strand? a. CGATACGT b. TAGCCTAG c. TUGCCTUG Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM d. UAGCCUAG ANS: B The consistent pairing of adenine with thymine and of guanine with cytosine is known as complementary base pairing; thus, A complements to T and C to G and vice versa throughout the strand. A complements to T; thus, the firs t letter must be a T. U does not represent a complement in the sequence. REF: p. 39 5. A biologist is explaining how RNA directs the synthesis of protein. Which process is the biologist describing? a. Termination b. Transcription c. Translocation d. Translation ANS: D In translation, RNA directs the synthesis of a polypeptide, interacting with transfer RNA (tRNA), a cloverleaf -shaped strand of about 80 nucleotides. Termination does not involve synthesis of protein. Transcription is the process by which DNA specifies a s equence of messenger RNA (mRNA). Translocation is the interchange of genetic material between nonhomologous chromosomes. REF: p. 41 6. What is the result of homologous chromosomes failing to separate during meiosis? a. Neurofibromatosis b. Nondisjunction c. Polyploidy d. Conjoined twins ANS: B NURSINGTB.COM Nondisjunction is an error in which homologous chromosomes or sister chromatids fail to separate normally during meiosis or mitosis. Neurofibromatosis is not due to chromosome failure during meiosis. Polyploidy occurs when a euploid cell has more than the diploid number of chromosomes. Conjoined twins are not due to chromosome failure during meiosis. REF: p. 45 7. A cell that does not contain a multiple of 23 chromosomes is called a cell. a. diploid b. euploid c. polyploid d. haploid ANS: C A polyploid cell is one in which a euploid cell has more than 23 pairs of chromosomes. A diploid cell is when the somatic cell nucleus has 46 chromosomes in 23 pairs. A euploid cell is a cell with multiples of the normal number of chromosomes. A haploid cell has only one member of each chromosome pair, for a total of 23 chromosomes. Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM U S N T O REF: p. 42 8. A 20 -year-old pregnant female gives birth to a stillborn child. Autopsy reveals that the fetus has 92 chromosomes. What term may be on the autopsy report to describe this condition? a. Biploidy b. Triploidy c. Tetraploidy d. Aneuploidy ANS: C Tetraploidy is a condition in which euploid cells have 92 chromosomes. Biploidy is a euploid cell with two times more chromosomes, or 46. Triploidy is a zygote that has three copies of each chromosome, rather than the usual two. Aneuploidy is when an aneuploid cell does no t contain a multiple of 23 chromosomes. REF: p. 42 9. The condition in which an extra portion of a chromosome is present in each cell is called: a. reciprocal translocation. b. partial trisomy. c. inversion. d. Down syndrome. ANS: B Partial trisomy is a condition in which only an extra portion of a chromosome is present in each cell. A reciprocal translocation occurs when breaks take place in two different chromosomes and the material is exchanged. An inversion occurs when two breaks take place on a chromosome, followed bNy thRe rIeinsGertioBn.oCf thMe missing fragment at its origin al site, but in inverted order. Down syndrome is an aneuploidy of the twenty -first chromosome. REF: p. 46 10. After a geneticist talks to a patient about being a chromosomal mosaic, the patient asks the nurse what that means. How should the nurse respond? You may genetic disease(s). a. only be a carrier of the b. have a mild form of the c. have two d. be sterile as a result of the ANS: B A chromosomal mosaic means the body has two or more different cell lines, each of which has a different karyotype; thus, the person has a mild form of the disease. Mosaics are not only carriers; they have the disease; they have two different lines but not two different diseases; and they are not necessarily sterile. REF: p. 46 11. What is the most common cause of Down syndrome? a. Paternal nondisjunction b. Maternal translocations c. Maternal nondisjunction Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM d. Paternal translocations ANS: C The most common cause of Down syndrome is maternal, not paternal, nondisjunction. Translocation is not a cause of this syndrome. REF: p. 46, Table 2 -1 12. A patient wants to know the risk factors for Down syndrome. What is the nurse’s best response? a. Fetal exposure to mutagens in the uterus. b. Increased paternal age. c. Family history of Down syndrome. d. Pregnancy in women over age 35. ANS: D The primary risk for Down syndrome is pregnancy in women over 35. Down syndrome is a trisomy and not due to fetal exposure or paternal age. Down syndrome is a chromosomal abnormality and is not related to family history. REF: pp. 46 -47 13. A 13 -year-old girl has a karyotype that reveals an absent homologous X chromosome with only a single X chromosome present. What medical diagnosis will the nurse observe on the chart? a. Down syndrome b. Cri du chat syndrome c. Turner syndrome d. Fragile X syndrome ANS: C NURSINGTB.COM A condition with the presence of a single X chromosome and no homologous X or Y chromosome, so the individual has a total of 45 chromosomes, is known as Turner syndrome. Down syndrome is a change in one arm of a chromosome. Cri du chat syndrome is due to a chromosome deletion. Fragile X syndrome is due to a break or a gap in a chromosome. REF: p. 47 14. What genetic disorder is the result if an individual possesses an XXY ch romosome configuration? a. Turner b. Klinefelter c. Down d. Fragile X ANS: B Individuals with at least two X chromosomes and one Y chromosome in each cell (47 XXY karyotype) have a disorder known as Klinefelter syndrome. A condition with the presence of a single X chromosome and no homologous X or Y chromosome, so the individual has a total of 45 chromosomes, is known as Turner syndrome. Down syndrome is a trisomy. Fragile X syndrome is due to a break or a gap in a chromosome, not an extra chromosome. Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM U S N T O REF: p. 47 15. A patient demonstrates severe mental retardation caused by a deletion of part of chromosome 5. What genetic disorder will the nurse see documented in the chart? a. Prader -Willi syndrome b. Down syndrome c. Cri du chat syndrome d. Trisomy X ANS: C Cri du chat syndrome means ―cry of the cat‖ and describes the characteristic cry of the affected child. Another symptom of the disorder is mental retardation. The disease is caused by a deletion of part of the short arm of chromosome 5. Prader -Willi syndro me is characterized by short stature, obesity, and hypogonadism. Down syndrome does cause mental retardation but is due to chromosome 21, not chromosome 5. Trisomy X can result in mental retardation but is due to an extra X chromosome. REF: p. 48 16. An aide asks the nurse why people who have neurofibromatosis will show varying degrees of the disease. Which genetic principle should the nurse explain to the aide? a. Penetrance b. Expressivity c. Dominance d. Recessiveness ANS: B Expressivity is the extent of vNariRatioIn inGpheBno.tCypeMassoci ated with a p articular genotype. For neurofibromatosis, a variety of manifestations occur among individuals. The penetrance of a trait is the percentage of individuals with a specific genotype who also exhibit the expected phenotype. Dominance refers to observable traits and risk of transmission. Recessiveness refers to silent strains with reduced risk of occurrence. REF: p. 51 17. Cystic fibrosis is caused by what gene abnormality? a. X-linked dominant b. X-linked recessive c. Autosomal dominant d. Autosomal recessive ANS: D Cystic fibrosis is an autosomal recessive disorder. It is not a result of X links or dominant pathology. REF: p. 52 18. A 15 -year-old female is diagnosed with Prader -Willi syndrome. This condition is an example of: a. genomic imprinting. b. an autosomal recessive trait. Understanding Pathophysiology 6th Edition Huether Test Bank NURSINGTB.COM c. an autosomal dominant trait. d. a sex-linked trait. ANS: A Prader -Willi, an example of gene imprinting, is not associated with any autosomal sex -linked abnormality. REF: p. 52 19. A patient, age 9, is admitted to a pediatric unit with Duchenne muscular dystrophy. When planning care the nurse recalls the patient inherited this condition through a trait that is: a. X-linked dominant. b. X-influenced. c. X-limited. d. X-linked recessive. ANS: D Duchenne muscular dystrophy is a relatively common X -linked recessive, not dominant, disorder. While it is sex linked, it is not X -limited or X-influenced. REF: p. 55 20. A child is diagnosed with cystic fibrosis. History reveals that the child’s parents are siblings. Cystic fibrosis was most likely the result of: a. X-inactivation. b. genomic imprinting. c. consanguinity. d. obligate carriers. ANS: C NURSINGTB.COM Consanguinity refers to the mating of two related individuals, and the offspring of such matings are said to be inbred . Consanguineous matings produce a significant increase in recessive disorders and are seen most often in pedigrees for rare recessive disorders. X-inactivation occurs when one X chromosome in the somatic cells of females is permanently inactivated. Genomic imprinting is related to methylation and other changes. Obligate ca rriers are those who have an affected parent and affected children and, therefore, must themselves carry the mutation. REF: p. 54 21. A 12-year-old male is diagnosed with Klinefelter syndrome. His karyotype would reveal which of the following? a. XY b. XX c. XYY d. XXY ANS: D A person with Klinefelter syndrome has an XXY karyotype. An XY is a normal male. An XX is a normal female. An XYY is an aneuploid karyotype. REF: p. 47