South University - NSG 5003. Question and Answers

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NSG5003 Question and Answers Quiz 1 Question : Why is it possible for potassium to diffuse easily into and out of cells? Student Answer: Potassium has a greater concentration in the ICF. ... Sodium has a greater concentration in the ECF. The resting plasma membrane is more permeable to potassium. An excess of anions is inside the cell. Instructor Explanation: Because the resting plasma membrane is more permeable to K+ than to Na+, K+ can easily diffuse from its area of higher concentration in the ICF to its area of lower concentration in the ECF. Because Na+ and K+ are both cations, the net result is an excess of anions inside the cell, resulting in the resting membrane potential. The remaining options do not correctly identify the process that most easily diffuses K+. Points Received: 0.5 of 0.5 Comments: Question 3. Question : A major determinant of the resting membrane potential necessary for the transmission of nerve impulses is the ratio between: Student Answer: Intracellular and extracellular Na+ Intracellular and extracellular K+ Intracellular Na+ and extracellular K+ Intracellular K+ and extracellular Na+ Instructor Explanation: The ratio of K+ in the ICF to K+ in the ECF is the major determinant of the resting membrane potential, which is necessary for the transmission and conduction of nerve impulses, for the maintenance of normal cardiac rhythms, and for the skeletal and smooth muscle contraction. This is not true of the other options. Points Received: 0.5 of 0.5 Comments: Question 5. Question : What is a consequence of plasma membrane damage to the mitochondria? Student Answer: Enzymatic digestion halts DNA synthesis. Influx of calcium ions halts ATP production. Edema from an influx in sodium causes a reduction in ATP production. Potassium shifts out of the mitochondria, which destroys the infrastructure. Instructor Explanation: The most serious consequence of plasma membrane damage is, as in hypoxic injury, to the mitochondria. An influx of calcium ions from the extracellular compartment activates multiple enzyme systems, resulting in cytoskeleton disruption, membrane damage, activation of inflammation, and eventually DNA degradation. Calcium ion accumulation in the mitochondria causes the mitochondria to swell, which is an occurrence that is associated with irreversible cellular injury. The injured mitochondria can no longer generate ATP, but they do continue to accumulate calcium ions. The remaining options do not accurately describe the consequence of plasma membrane damage to the mitochondria. Points Received: 0.5 of 0.5 Comments: Question 6. Question : Current research supports the belief that after heart muscle injury, the damage: Student Answer: Remains indefinitely because cardiac cells do not reproduce Is repaired by newly matured cardiomyocytes Gradually decreases in size as mitotic cell division occurs Is replaced by hypertrophy of remaining cells Instructor Explanation: The recent discovery that cardiac stem cells exist in the heart and differentiate into various cardiac cell lineages has profoundly changed the understanding of myocardial biology; it is now believed that bone marrow–derived cardiac stem cells or progenitor cells that have the ability to mature into cardiomyocytes may populate the heart after injury. The other options do not accurately describe the process that is believed to occur to address cardiac muscle damage. Points Received: 0.5 of 0.5 Comments: Question 9. Question : Free radicals cause cell damage by: Student Answer: Stealing the cell’s oxygen to stabilize the electron, thus causing hypoxia Stimulating the release of lysosomal enzymes that digest the cell membrane Transferring one of their charged, stabilized atoms to the cell membrane, which causes lysis Giving up an electron, which causes injury to the chemical bonds of the cell membrane Instructor Explanation: A free radical is an electrically uncharged atom or group of atoms having an unpaired electron. Having one unpaired electron makes the molecule unstable; thus to stabilize, the molecule gives up an electron to another molecule or steals one. Therefore it is capable of forming injurious chemical bonds with proteins, lipids, or carbohydrates—key molecules in membranes and nucleic acids. The remaining options do not accurately describe the role played by free radicals in cell damage. Points Received: 0.5 of 0.5 Comments: Question 12. Question : The loss of the ATP during ischemia causes cells to: Student Answer: Shrink because of the influx of calcium (Ca) Shrink because of the influx of potassium chloride (KCl) Swell because of the influx of sodium chloride (NaCl) Swell because of the influx of nitric oxide (NO) Instructor Explanation: A reduction in ATP levels causes the plasma membrane’s sodium-potassium (Na+–K+) pump and sodium-calcium exchange to fail, which leads to an intracellular accumulation of sodium and calcium and diffusion of potassium out of the cell. (The Na+–K+ pump is discussed in Chapter 1.) Sodium and water can then freely enter the cell, and cellular swelling results. The other options do not accurately describe the result of ATP at the cellular level. Points Received: 0.5 of 0.5 Comments: Question 14. Question : Which statement is true about eukaryotic cells? Student Answer: They lack a distinct nucleus. They contain compartments called organelles. They lack an encasing nuclear membrane. They are smaller than the typical prokaryote cell. Instructor Explanation: Eukaryotic cells have a characteristic set of membrane-bound intracellular compartments called organelles that include a well-defined nucleus and are larger than prokaryotes. The remaining statements are not true regarding eukaryotic cells. Points Received: 0.5 of 0.5 Comments: Question 15. Question : Which mode of chemical signaling uses local chemical mediators that are quickly taken up, destroyed, or immobilized? Student Answer: Paracrine Autocrine Neurotransmitter Hormone Instructor Explanation: In paracrine signaling, cells secrete local chemical mediators that are quickly taken up, destroyed, or immobilized. The other options do not correctly describe this process. Points Received: 0.5 of 0.5 Comments: Question 19. Question : During cell injury caused by hypoxia, an increase in the osmotic pressure occurs within the cell because: Student Answer: Plasma proteins enter the cell. The adenosine triphosphatase (ATPase-driven pump is stronger during hypoxia. Sodium chloride enters the cell. An influx of glucose occurs through the injured cell membrane. Instructor Explanation: In hypoxic injury, movement of fluid and ions into the cell is associated with acute failure of metabolism and a loss of ATP production. Normally, the pump that transports sodium ions out of the cell is maintained by the presence of ATP and ATPase, the active-transport enzyme. In metabolic failure caused by hypoxia, reduced ATP and ATPase levels permit sodium to accumulate in the cell, whereas potassium diffuses outward. The increase of intracellular sodium increases osmotic pressure, which draws more water into the cell. The remaining options do not accurately describe the cell injury that results in increased osmotic pressure caused by hypoxia. Points Received: 0.5 of 0.5 Comments: Question 20. Question : When a mucous gland cell creates a new substance from previously absorbed material, this process is known as which specialized cellular function? Student Answer: Excretion Metabolic absorption Reproduction Secretion Instructor Explanation: Certain cells, such as mucous gland cells, can synthesize new substances from substances they absorb and then secrete the new substances to serve elsewhere as needed. The other options are not used to describe the function described in the stem. Quiz 2 Question 4. Question : A reduction in an individual’s number of NK cells appears to correlate with an increased risk for the development of: Student Answer: Depression Type 1 diabetes Obsessive compulsive disorder (OCD) Gastroesophageal reflux disorder (GERD) Instructor Explanation: A meta-analysis of studies shows a relationship between depression and the reduction in lymphocyte proliferation and natural killer cell activity. Currently, no research supports the other options. Points Received: 0.5 of 0.5 Comments: Question 6. Question : Which statement concerning exotoxins is true? Student Answer: Exotoxins are contained in cell walls of gram-negative bacteria. Exotoxins are released during the lysis of bacteria. Exotoxins are able to initiate the complement and coagulation cascades. Exotoxins are released during bacterial growth. Instructor Explanation: Exotoxins are proteins released during bacterial growth. The other options are not true of exotoxins. Points Received: 0.5 of 0.5 Comments: Question 7. Question : Which statements are true regarding viruses? (Select all that apply.) Student Answer: Viruses are very complex microorganisms. Viruses are referred to as eukaryotes. Viruses are capable of producing messenger ribonucleic acid RNA (mRNA). Viruses penetrate the plasma membrane via endocytosis. Viruses are capable of uncoating cytoplasmic nucleocapsids. Instructor Explanation: Viruses are extremely simple microorganisms and do not possess any of the metabolic organelles found in prokaryotes (e.g., bacteria) or eukaryotes (e.g., human cells). Once bound, the virus can penetrate the plasma membrane by receptor-mediated endocytosis. Within the cytoplasm, the virus uncoats the protective nucleocapsid and releases viral genetic information. Most RNA viruses directly produce mRNA, which is translated into viral proteins, and genomic RNA, which is eventually packaged into new viruses. Points Received: 0.5 of 0.5 Comments: Question 12. Question : Cytokines are thought to cause fevers by stimulating the synthesis of which chemical mediator? Student Answer: Leukotriene Histamine Prostaglandin Bradykinin Instructor Explanation: Cytokines seem to raise the thermoregulatory set point through stimulation of prostaglandin synthesis and turnover in thermoregulatory (brain) and nonthermoregulatory (peripheral) tissues. The other options do not accurately identify the appropriate chemical mediator. Points Received: 0 of 0.5 Comments: Question 14. Question : Fusion is the step in phagocytosis during which: Student Answer: Microorganisms are killed and digested. An intracellular phagocytic vacuole is formed. Lysosomal granules enter the phagocytes. Microorganisms are ingested. Instructor Explanation: Fusion occurs with lysosomal granules entering the phagocyte (phagolysosome). The remaining options do not accurately describe fusion as a step in phagocytosis. Points Received: 0 of 0.5 Comments: Question 15. Question : The main functions of NK cells include: (Select all that apply.) Student Answer: Recognizing virus-infected cells Eliminating virus-infected cells Recognizing bacteria-infected cells Eliminating bacteria-infected cells Eliminating previously identified cancer cells Instructor Explanation: The main functions of NK cells are recognizing and eliminating cells infected with viruses, not bacteria. They are also somewhat effective at eliminating other abnormal host cells, specifically cancer cells. Points Received: 0.3 of 0.5 Comments: Question 19. Question : Which cytokine is needed for the maturation of a functional Th cell? Student Answer: IL-1 IL-2 IL-4 IL-12 Instructor Explanation: Of the options provided, IL-2 production is critical for the Th cell to mature efficiently into a functional helper cell. Points Received: 0 of 0.5 Comments: Question 20. Question : Which disease is an example of a rickettsial infection? Student Answer: Cholera Candida Sleeping sickness Rocky Mountain spotted fever Instructor Explanation: Rocky Mountain spotted fever is a result of a rickettsiae. Cholera is a bacterial infection, candida is a fungal infection, and sleeping sickness is a protozoal infection. Quiz 3 Question : Which characteristic among women correlates with a high morbidity of cancer of the colon, uterus, and kidney? Student Answer: Women older than 45 years of age Women who have never had children Women who have a high body mass index (BMI) Woman who have smoked for more than ten years Instructor Explanation: A recent hypothesis states that the observed increased incidence of such cancers as breast, endometrium, colon, liver, kidney, and adenomas of the esophagus may be associated with obesity. No current research supports the remaining options. Points Received: 0 of 0.5 Comments: Question 2. Question : A carcinoma refers to abnormal cell proliferation originating from which tissue? Student Answer: Blood vessels Epithelial cells Connective tissue Glandular tissue Instructor Explanation: Only cancers arising from epithelial cells are called carcinomas. Points Received: 0 of 0.5 Comments: Question 16. Question : The ras gene converts from a proto-oncogene to an oncogene by: Student Answer: Designating a chromosome that has a piece of one chromosome fused to a piece of another chromosome Duplicating a small piece of a chromosome, repeatedly making numerous copies Altering one or more nucleotide base pairs Promoting proliferation of growth signals by impairing tumor suppressor genes Instructor Explanation: A point mutation is the alteration of one or a few nucleotide base pairs. This type of mutation can have profound effects on the activity of proteins. A point mutation in the ras gene converts it from a regulated proto-oncogene to an unregulated oncogene, an accelerator of cellular proliferation. The remaining options do not describe point mutation as it affects the conversion of a ras gene. Points Received: 0 of 0.5 Comments: Question 18. Question : Which statement concerning benign tumors is true? Student Answer: The resulting pain is severe. Benign tumors are not encapsulated. Benign tumors are fast growing. The cells are well differentiated. Instructor Explanation: A benign tumor is well-differentiated with its tissue appearing similar to the tissue from which it arose. The other options are characteristic of a malignant tumor. Points Received: 0 of 0.5 Comments: Question 19. Question : Which aberrant change causes the abnormal growth in a retinoblastoma? Student Answer: Proto-oncogenes are changed to oncogenes. The tumor suppressor gene is turned off. Genetic amplification causes the abnormal growth. Chromosomes 9 and 21 are fused. Instructor Explanation: One of the first discovered tumor-suppressor genes, the retinoblastoma (Rb) gene, normally strongly inhibits the cell division cycle. When it is inactivated, the cell division cycle can proceed unchecked. The Rb gene is mutated in childhood retinoblastoma. The remaining options do not describe the abnormal growth in retinoblastoma. Points Received: 0 of 0.5 Comments: Question 20. Question : Which cancers pose the highest risk for radiologists? Student Answer: Thyroid Breast Blood Brain Instructor Explanation: Ionizing radiation exposure places radiologists at risk for the development of leukemia, lymphoma, and skin cancers. Points Received: 0 of 0.5 Comments: Quiz 4 Question : Individuals being effectively managed for type 2 diabetes mellitus often experience a healthy decline in blood pressure as a result of which intervention? Student Answer: Managed carbohydrate intake Appropriate exercise Insulin-sensitivity medication therapy Introduction of minimal doses of insulin Instructor Explanation: Many people with type 2 diabetes mellitus, who are treated with drugs that increase insulin sensitivity, experience a decline in their blood pressure without taking antihypertensive drugs. Although the other medications may be included in the management plan, the other options are not associated with a decrease in hypertension. Points Received: 0 of 0.5 Comments: Question 4. Question : Which factor can trigger an immune response in the bloodstream that may result in an embolus? Student Answer: Amniotic fluid Fat Bacteria Air Instructor Explanation: Of the options available, only amniotic fluid displaces blood, thereby reducing oxygen, nutrients, and waste exchange; however, it also introduces antigens, cells, and protein aggregates that trigger inflammation, coagulation, and the immune response in the bloodstream. Points Received: 0 of 0.5 Comments: Question 8. Question : An infant has a continuous machine-type murmur best heard at the left upper sternal border throughout systole and diastole, as well as a bounding pulse and a thrill on palpation. These clinical findings are consistent with which congenital heart defect? Student Answer: Atrial septal defect (ASD) Ventricular septal defect (VSD) Patent ductus arteriosus (PDA) Atrioventricular canal (AVC) defect Instructor Explanation: If pulmonary vascular resistance has fallen, then infants with PDA will characteristically have a continuous machine-type murmur best heard at the left upper sternal border throughout systole and diastole. If the PDA is significant, then the infant also will have bounding pulses, an active precordium, a thrill on palpation, and signs and symptoms of pulmonary overcirculation. The presentations of the other congenital heart defects are not consistent with the described the symptoms. Points Received: 0 of 0.5 Comments: Question 9. Question : When endothelia cells are injured, which alteration contributes to atherosclerosis? Student Answer: Toxic oxygen radicals that oxidize low-density lipoproteins (LDLs) are released. Cells are unable to make the normal amount of vasodilating cytokines. Cells produce an increased amount of antithrombotic cytokines. Cells develop hypersensitivity to homocysteine and lipids. Instructor Explanation: Injured endothelial cells become inflamed and cannot make normal amounts of antithrombotic and vasodilating cytokines. This selection is the only option that accurately identifies the factor that contributes to atherosclerosis. Points Received: 0 of 0.5 Comments: Question 11. Question : Which cardiac pathologic condition contributes to ventricular remodeling? Student Answer: Left ventricular hypertrophy Right ventricular failure Myocardial ischemia Contractile dysfunction Instructor Explanation: Of the options available, myocardial ischemia contributes to inflammatory, immune, and neurohumoral changes that mediate a process called ventricular remodeling. Points Received: 0 of 0.5 Comments: Question 13. Question : What is the effect of oxidized low-density lipoproteins (LDLs) in atherosclerosis? Student Answer: LDLs cause smooth muscle proliferation. LDLs cause regression of atherosclerotic plaques. LDLs increase levels of inflammatory cytokines. LDLs direct macrophages to the site in the endothelium. Instructor Explanation: Oxidized LDLs are toxic to endothelial cells, cause smooth muscle proliferation, and activate further immune and inflammatory responses. This selection is the only option that accurately identifies the effects of LDLs. Points Received: 0 of 0.5 Comments: Question 14. Question : What is the trigger for angina pectoris? Student Answer: Atherosclerotic lesions Hyperlipidemia Myocardial necrosis Myocardial ischemia Instructor Explanation: Angina pectoris is chest pain caused by myocardial ischemia. None of the other options are considered triggers for angina pectoris. Points Received: 0 of 0.5 Comments: Question 15. Question : When does systemic vascular resistance in infants begin to increase? Student Answer: One month before birth During the beginning stage of labor One hour after birth Once the placenta is removed from circulation Instructor Explanation: The low-resistance placenta is removed from circulation, which causes an immediate increase in systemic vascular resistance to approximately twice of that before birth. Points Received: 0 of 0.5 Comments: Question 16. Question : Which inflammatory cytokines are released when endothelial cells are injured? Student Answer: Granulocyte-macrophage colony-stimulating factor (GM-CSF) Interferon-beta (IFN-β), interleukin 6 (IL-6), and granulocyte colony-stimulating factor (G-CSF) Tumor necrosis factor–alpha (TNF-α), interferon-gamma (IFN-γ), and interleukin 1 (IL-1) Interferon-alpha (IFN-α), interleukin 12 (IL-12), and macrophage colony-stimulating factor (M-CSF) Instructor Explanation: Numerous inflammatory cytokines are released, including TNF-α, IFN-γ, IL-1, toxic oxygen radicals, and heat shock proteins. This selection is the only option that accurately identifies which inflammatory cytokines are associated with endothelial cell injury. Points Received: 0 of 0.5 Comments: Question 17. Question : Which statement is true concerning the cells’ ability to synthesize cholesterol? Student Answer: Cell production of cholesterol is affected by the aging process. Cells produce cholesterol only when dietary fat intake is low. Most body cells are capable of producing cholesterol. Most cholesterol produced by cells is converted to the low-density form. Instructor Explanation: Although cholesterol can easily be obtained from dietary fat intake, most body cells can also manufacture cholesterol. This selection is the only option that accurately describes the cellular role in cholesterol synthesis. Points Received: 0 of 0.5 Comments: Question 18. Question : What is the usual source of pulmonary emboli? Student Answer: Deep venous thrombosis Endocarditis Valvular disease Left heart failure Instructor Explanation: Pulmonary emboli originate in the venous circulation (mostly from the deep veins of the legs) or in the right heart. This selection is the only option that accurately identifies the usual source of pulmonary emboli. Points Received: 0 of 0.5 Comments: Question 19. Question : Amyloidosis, hemochromatosis, or glycogen storage disease usually causes which form of cardiomyopathy? Student Answer: Infiltrative Restrictive Septal Hypertrophic Instructor Explanation: Restrictive cardiomyopathy may occur idiopathically or as a cardiac manifestation of systemic diseases, such as scleroderma, amyloidosis, sarcoidosis, lymphoma, and hemochromatosis, or a number of inherited storage diseases. This characterization is not true of the other forms of cardiomyopathy. Points Received: 0 of 0.5 Comments: Question 20. Question : Which condition is consistent with the cardiac defect of transposition of the great vessels? Student Answer: The aorta arises from the right ventricle. The pulmonary trunk arises from the right ventricle. The right ventricle pumps blood to the lungs. An intermittent murmur is present. Instructor Explanation: Transposition of the great arteries refers to a condition in which the aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle. A transposition of the great vessels is not associated with any of the other options. Quiz 5 Question : Which statement is true regarding hypoxemia? Student Answer: Hypoxemia results in the increased oxygenation of arterial blood. Respiratory alterations cause hypoxemia. Hypoxemia results in the decreased oxygenation of tissue cells. Various system changes cause hypoxemia. Instructor Explanation: Hypoxemia, or reduced oxygenation of arterial blood (PaO2), is caused by respiratory alterations, whereas hypoxia, or reduced oxygenation of cells in tissues, may be caused by alterations of other systems as well. Points Received: 0 of 0.5 Comments: Question 16. Question : Which statement about the advances in the treatment of RDS of the newborn is incorrect? Student Answer: Administering glucocorticoids to the mother in preterm labor accelerates the maturation of the fetus’s lungs. Administering oxygen to the mother during preterm labor increases her arterial oxygen before the birth of the fetus. Treatment includes instillation of an exogenous surfactant down an endotracheal tube in an infant weighing less than 1000 g. Using continuous positive airway pressure (CPAP) supports the infant’s respiratory function. Instructor Explanation: Administering oxygen to the mother is not a valid treatment of RDS. The other statements provide correct information regarding RDS. Points Received: 0 of 0.5 Comments: Question 17. Question : The collapse of lung tissue caused by a lack of collateral ventilation through the pores of Kohn is referred to as which type of atelectasis? Student Answer: Compression Perfusion Absorption Hypoventilation Instructor Explanation: Absorption atelectasis is a result of the gradual absorption of air from obstructed or hypoventilated alveoli or from inhalation of concentrated oxygen or anesthetic agents. The other forms of atelectasis are not a result of the described mechanism. Quiz 6/Midterm 1. Question : What pathologic change occurs to the kidney’s glomeruli as a result of hypertension? Student Answer: Compression of the renal tubules Ischemia of the tubule Increased pressure from within the tubule Obstruction of the renal tubule Instructor Explanation: In the kidney, vasoconstriction and resultant decreased renal perfusion cause tubular ischemia and preglomerular arteriopathy. This selection is the only option that accurately identifies the pathologic change to the kidney that occurs as a result of hypertension. Points Received: 0 of 5 Comments: Question 2. Question : Which structure is not associated with any lymphatic vessels? Student Answer: Trachea Bronchi Acinus Terminal bronchioles Instructor Explanation: No lymphatic structures are located in the acinus. The other options are associated with lymphatic vessels. Points Received: 0 of 5 Comments: Question 4. Question : What is an example of compensatory hyperplasia? Student Answer: Hepatic cells increase cell division after part of the liver is excised. Skeletal muscle cells atrophy as a result of paralysis. The heart muscle enlarges as a result of hypertension. The size of the uterus increases during pregnancy. Instructor Explanation: Compensatory hyperplasia is an adaptive mechanism that enables certain organs to regenerate. For example, the removal of part of the liver leads to hyperplasia of the remaining liver cells (hepatocytes) to compensate for the loss. The other options do not accurately describe the term compensatory hyperplasia. Points Received: 0 of 5 Comments: Question 10. Question : Which is an example of an endogenous antigen? Student Answer: Yeast Cancer cells Bacteria Fungus Instructor Explanation: Of the options provided, endogenous antigens include only those uniquely produced by cancerous cells. Points Received: 0 of 5 Comments: Question 11. Question : Which factor contributes to the production of mucus associated with chronic bronchitis? Student Answer: Airway injury Pulmonary infection Increased goblet cell size Bronchospasms Instructor Explanation: Continual bronchial inflammation causes bronchial edema and increases the size and number of mucous glands and goblet cells in the airway epithelium. Thick, tenacious mucus is produced and cannot be cleared because of impaired ciliary function. The lung’s defense mechanisms are therefore compromised, increasing a susceptibility to pulmonary infection, which contributes to airway injury. Frequent infectious exacerbations are complicated by bronchospasm with dyspnea and productive cough. Points Received: 0 of 5 Comments: Question 13. Question : Which type of cell adaptation occurs when normal columnar ciliated epithelial cells of the bronchial lining have been replaced by stratified squamous epithelial cells? Student Answer: Hyperplasia Metaplasia Dysplasia Anaplasia Instructor Explanation: Metaplasia is the reversible replacement of one mature cell by another, sometimes a less differentiated cell type. The best example of metaplasia is the replacement of normal columnar ciliated epithelial cells of the bronchial (airway) lining by stratified squamous epithelial cells. The other options do not accurately describe the event in the question. Points Received: 0 of 5 Comments: Question 18. Question : Some older adults have impaired inflammation and wound healing because of which problem? Student Answer: The circulatory system cannot adequately perfuse tissues. Complement and chemotaxis are deficient. Underlying chronic illnesses exist. The number of mast cells is insufficient. Instructor Explanation: In some cases, impaired healing is not directly associated with aging, in general, but can instead be linked to a chronic illness such as cardiovascular disease or diabetes mellitus. The other problems are not related to the aging process. Points Received: 0 of 5 Comments: Question 27. Question : Which statement is true for the process of cellular reproduction? Student Answer: The process often takes months or years to complete. Cellular reproduction typically has a short interphase. Two diploid cells, called daughter cells, have been formed. The process involves the interaction of male and female cells. Instructor Explanation: During telophase, the final stage, a new nuclear membrane is formed around each group of 46 chromosomes, the spindle fibers disappear, and the chromosomes begin to uncoil. Cytokinesis causes the cytoplasm to divide into roughly equal parts during this phase. At the end of telophase, two identical diploid cells, called daughter cells, have been formed from the original cell. Points Received: 0 of 5 Comments: Question 28. Question : During an Immunoglobulin E (IgE)-mediated hypersensitivity reaction, the degranulation of mast cells is a result of which receptor action? Student Answer: Histamine bound to H2 Chemotactic factor binding to the receptor Epinephrine bound to mast cells Acetylcholine bound to mast cells Instructor Explanation: Histamine bound to H2 results in the degranulation of mast cells during an IgE-medicated hypersensitivity reaction. The other options do not cause this reaction. Points Received: 0 of 5 Comments: Question 33. Question : Vaccines against viruses are created from: Student Answer: Killed organisms or extracts of antigens Live organisms weakened to produce antigens Purified toxins that have been chemically detoxified Recombinant pathogenic protein Instructor Explanation: Most vaccines against viral infections (e.g., measles, mumps, rubella, varicella [chickenpox], rotavirus) contain live viruses that are weakened (attenuated) to continue expressing the appropriate antigens but are unable to establish more than a limited and easily controlled infection. The other options are not used in virus-focused vaccines. Points Received: 0 of 5 Comments: Question 36. Question : Why is osmolality preferred over osmolarity as the measurement of osmotic activity in the clinical assessment of individuals? Student Answer: Plasma contains sodium and chloride, which influence the volume of solution. Volume affects perfusion more than the weight of solutes. More of the weight of plasma is influenced by solutes, such as protein and glucose, rather than by water. Osmotic activity depends on the concentration of the solutes present in plasma, such as proteins and glucose. Instructor Explanation: In plasma, less of the plasma weight is water; therefore the overall concentration of particles is greater. The osmolality will be greater than the osmolarity because of the smaller proportion of water. Osmolality is thus the preferred measure of osmotic activity in clinical assessment of individuals. Points Received: 0 of 5 Comments: Question 38. Question : In addition to osmosis, what force is involved in the movement of water between the plasma and interstitial fluid spaces? Student Answer: Oncotic pressure Buffering Net filtration Hydrostatic pressure Instructor Explanation: Water moves between the plasma and interstitial fluid through the forces of only osmosis and hydrostatic pressure, which occur across the capillary membrane. Buffers are substances that can absorb excessive acid or base to minimize pH fluctuations. Net filtration is a term used to identify fluid movement in relationship to the Starling hypothesis. Oncotic pressure encourages water to cross the barrier of capillaries to enter the circulatory system. Points Received: 0 of 5 Comments: Question 40. Question : Why does tissue damage occur in acute rejection after organ transplantation? Student Answer: Th1 cells release cytokines that activate infiltrating macrophages, and cytotoxic T (Tc) cells directly attack the endothelial cells of the transplanted tissue. Circulating immune complexes are deposited in the endothelial cells of transplanted tissue, where the complement cascade lyses tissue. Receptors on natural killer (NK) cells recognize antigens on the cell surface of the transplanted tissue, which releases lysosomal enzymes that destroy tissue. Antibodies coat the surface of the transplanted tissue to which mast cells bind and liberate preformed chemical mediators that destroy tissue. Instructor Explanation: The recipient’s lymphocytes interacting with the donor’s dendritic cells within the transplanted tissue usually initiate sensitization, resulting in the induction of recipient Th1 and Tc cells against the donor’s antigens. The Th1 cells release cytokines that activate infiltrating macrophages, and the Tc cells directly attack the endothelial cells in the transplanted tissue. The other options do not accurately describe how acute rejection after organ transplantation results in tissue damage. Quiz 8 Question 2. Question : Compared to a younger individual, how is the specific gravity of urine in older adults affected? Student Answer: The specific gravity of urine in older adults is increased. The specific gravity of urine in older adults is considered high normal. The specific gravity of urine in older adults is considered low normal. The specific gravity of urine in older adults is decreased. Instructor Explanation: The specific gravity of the urine in older individuals tends to be on the low side of normal. Points Received: 0 of 0.5 Comments: Question 6. Question : What effects do exercise and body position have on renal blood flow? Student Answer: They activate renal parasympathetic neurons and cause mild vasoconstriction. They activate renal sympathetic neurons and cause mild vasoconstriction. Both activate renal parasympathetic neurons and cause mild vasodilation. They activate renal sympathetic neurons and cause mild vasodilation. Instructor Explanation: Exercise and change of body position activate renal sympathetic neurons and cause mild vasoconstriction. The other options do not have these effects on renal blood flow. Points Received: 0 of 0.5 Comments: Question 8. Question : What causes vesicoureteral reflux to occur in children? Student Answer: Children do not ask for help in urinating in a timely manner, and urine is forced up into the ureters. The submucosal segment of a child’s ureter is short, making the antireflux mechanism inefficient. The trigone lying between the opening to the ureters and the urethra is underdeveloped in children. As the bladder fills in infants and children, it pulls the smooth lining of the transitional epithelium away from the ureters, making the reflux valves ineffective. Instructor Explanation: Although reflux is considered abnormal at any age, the shortness of the submucosal segment of the ureter during infancy and childhood renders the antireflux mechanism relatively inefficient and delicate. The other options are not considered reasons for this reflux. Points Received: 0 of 0.5 Comments: Question 14. Question : Detrusor hyperreflexia develops from neurologic disorders that originate where? Student Answer: Spinal cord between C2 and S1 Spinal cord between S2 and S4 Above the pontine micturition center Below the cauda equina Instructor Explanation: Neurologic disorders that develop above the pontine micturition center result in detrusor hyperreflexia, also known as an uninhibited or reflex bladder. This selection is the only option responsible for detrusor hyperreflexia. Points Received: 0 of 0.5 Comments: Question 16. Question : Which statement is false about the causes of enuresis? Student Answer: A maturational lag may cause enuresis. Enuresis may be related to increased light sleep. Obstructive sleep apnea may be a symptom of enuresis. Excessive nocturnal levels of vasopressin may cause enuresis. Instructor Explanation: Children who do not have the normal nocturnal elevation of vasopressin produce a higher volume of urine with a lower osmolality. The other options are accurate statements regarding enuresis. Points Received: 0 of 0.5 Comments: Question 18. Question : Which effect do natriuretic peptides have during heart failure when the heart dilates? Student Answer: Stimulation of antidiuretic hormones (ADH) Inhibition of ADH Stimulation of renin and aldosterone Inhibition of renin and aldosterone Instructor Explanation: Natriuretic peptides inhibit renin and aldosterone during heart failure when the heart dilates. These make up a group of peptide hormones, including atrial natriuretic peptide (ANP), secreted from myocardial cells in the atria and brain natriuretic peptide (BNP) secreted from myocardial cells in the cardiac ventricles. When the heart dilates during volume expansion or heart failure, ANP and BNP inhibit sodium and water absorption by kidney tubules, inhibit the secretion of renin and aldosterone, vasodilate the afferent arterioles, and constrict the efferent arterioles. The result is increased urine formation, leading to decreased blood volume and blood pressure. Points Received: 0 of 0.5 Comments: Question 19. Question : Which statement is false concerning the skeletal alterations caused by chronic renal failure when the glomerular filtration rate (GFR) declines to 25% of normal? Student Answer: Parathyroid hormone is no longer effective in maintaining serum phosphate levels. The parathyroid gland is no longer able to secrete sufficient parathyroid hormone. The synthesis of 1,25-dihydroxyvitamin D3, which reduces intestinal absorption of calcium, is impaired. The synthesis of 1,25-dihydroxyvitamin D3, which impairs the effectiveness of calcium and phosphate resorption from bone by parathyroid hormone, is impaired. Instructor Explanation: Bone and skeletal changes develop with alterations in calcium and phosphate metabolism. These changes begin when the GFR decreases to 25% or less. The combined effect of hyperparathyroidism and vitamin D deficiency can result in renal osteodystrophies (e.g., osteomalacia, osteitis fibrosa with increased risk for fractures). Other consequences of secondary hyperparathyroidism include soft-tissue and vascular calcification, cardiovascular disease, and, less commonly, calcific uremic arteriolopathy. The other options are true Quiz 9 Question 5. Question : A blunt force injury to the forehead would result in a contrecoup injury to which region of the brain? Student Answer: Frontal Temporal Parietal Occipital Instructor Explanation: The focal injury produces a contrecoup (on the pole opposite the site of impact) injury. The frontal portion of the brain is opposite of the site of impact. Objects striking the back of the head usually result in both coup and contrecoup injuries because of the irregularity of the inner surface of the frontal bones. A contrecoup injury is not nearly as likely when other portions of the brain are affected. Points Received: 0 of 0.5 Comments: Question 11. Question : The link between major depression and cortisol secretion is that individuals with depression: Student Answer: Show suppression of plasma cortisol when given dexamethasone. Have a decreased plasma cortisol level, despite the administration of exogenous corticosteroids. Show that persistently elevated plasma cortisol levels can result in inflammation that is believed to trigger depression. Have normal plasma cortisol levels throughout the day when they take antidepressant medication, as prescribed. Instructor Explanation: Persistent elevations in cortisol may also induce immunosuppression that compromises the body’s immune systems to contain inflammation and infectious diseases. Increasing evidence suggests that inflammation is another risk factor that triggers the onset of depression. The options related to dexamethasone and exogenous corticosteroids are not true as they apply to depression and cortisol secretion. Points Received: 0 of 0.5 Comments: Question 15. Question : Which person is at the greatest risk of developing delirium? Student Answer: An individual with diabetes, celebrating his or her seventieth birthday A depressed Hispanic woman An individual on the second day after hip replacement A man diagnosed with schizophrenia Instructor Explanation: Delirium is associated with autonomic nervous system overactivity and typically develops in 2 to 3 days, most commonly in critical care units, postsurgically, or during withdrawal from CNS depressants (e.g., alcohol, narcotic agents). Age, gender, and chronic illnesses are not generally associated with delirium triggers. Points Received: 0 of 0.5 Comments: Question 19. Question : Posthyperventilation apnea (PHVA) ceases and rhythmic breathing is resumed when levels of arterial: Student Answer: Carbon dioxide increase Carbon dioxide become normal Oxygen increase Oxygen decrease Instructor Explanation: Rhythmic breathing returns when the PCO2 level returns to normal. None of the remaining options would affect normal rhythmic breathing after PHVA. Points Received: (not graded) Comments: Question 20. Question : Which intracerebral disease process is capable of producing diffuse dysfunction? Student Answer: Closed-head trauma with bleeding Subdural pus collection Neoplasm Infarct embolus Instructor Explanation: Disorders within the brain substance (intracerebral)—bleeding, infarcts emboli, and tumors—primarily functioning as masses may cause diffuse dysfunction. Such localized destructive processes directly impair functioning of the thalamic or hypothalamic activating systems. Disorders outside the brain but within the cranial vault (extracerebral), including neoplasms, closed-head trauma with subsequent bleeding, and subdural empyema (accumulation of pus), can cause similar dysfunction. [Show More]

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