Hypersensitivity and Immune Response, Exams of Pathophysiology

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NSG 5003 WEEK 1 CAT 2023 TERM PRIME

SOLUTIONS GRADED EXAM 98% (South

UNIVERSITY)

1. Hypersensitivity is best defined as a(an): a. Disturbance in the immunologic tolerance of self-antigens b. Immunologic reaction of one person to the tissue of another person c. Altered immunologic response to an antigen that results in disease d. Undetectable immune response in the presence of antigens

CORRECT ANSWER C

Hypersensitivity is an altered immunologic response to an antigen that results in disease or damage to the host. The other options are not accurate definitions of hypersensitivity.

2. Which component of the immune system is deficient in individuals with infections caused by viruses, fungi, or yeast? a. Natural killer cells c. B cells b. Macrophages d. T cells

CORRECT ANSWER D

Of the available options, deficiencies in T-cell immune responses are suggested when certain viruses (e.g., varicella, vaccinia, herpes, cytomegalovirus), fungi, and yeasts (e.g., Candida, Histoplasma) or certain atypical microorganisms (e.g., Pneumocystis jiroveci) cause recurrent infections.

3. In a type III hypersensitivity reaction, the harmful effects after the immune complexes that are deposited in tissues are a result of: a. Cytotoxic T cells c. Complement activation b. Natural killer cells d. Degranulation of mast cells

CORRECT ANSWER C

Complement activation, particularly through the generation of chemotactic factors for neutrophils, causes the harmful effects of immune complex deposition. The neutrophils bind to antibody and C3b contained in the complexes and attempt to ingest the immune complexes. Type III hypersensitivity reactions as described are not the result of any of the

other options.

4. During an IgE-mediated hypersensitivity reaction, which leukocyte is activated? a. Neutrophils c. Eosinophils b. Monocytes d. T lymphocytes

CORRECT

ANSWER C

Of the options provided, only eosinophils are activated during IgE-mediated hypersensitivity reactions.

5. Which primary characteristic is unique for the immune response? a. The immune response is similar each time it is activated. b. The immune response is specific to the antigen that initiates it. c. The response to a specific pathogen is short term. d. The response is innate, rather than acquired. CORRECT ANSWER B

Unlike inflammation, which is nonspecifically activated by cellular damage and pathogenic microorganisms, the immune response is primarily designed to afford long-term specific protection (i.e., immunity) against particular invading microorganisms; that is, it has a memory function. The other options are not unique characteristics of the immune response.

6. Which type of immunity is produced by an individual after either natural exposure to the antigen or after immunization against the antigen? a. Passive-acquired immunity c. Passive-innate immunity b. Active-acquired immunity d. Active-innate immunity

CORRECT ANSWER B

An individual produces active-acquired immunity (active immunity) after natural exposure to an antigen or after immunization, whereas passive-acquired immunity (passive immunity) does not involve the host’s immune response at all. The innate immune system, also known as nonspecific immune system and the first line of defense, is composed of the cells and mechanisms that defend the host from infection by other organisms in a nonspecific manner, which means that the cells of the innate system recognize and respond to pathogens in a generic way.

7. The portion of the antigen that is configured for recognition and binding is referred to as what type of determinant? a. Immunotope c. Epitope b. Paratope d. Antigenitope CORRECT ANSWER C

The precise portion of the antigen that is configured for recognition and binding is called

its antigenic determinant or epitope. The other options are not used to identify this portion of the antigen.

8. Which immunoglobulin is present in blood, saliva, breast milk, and respiratory secretions? a. IgA c. IgG b. IgE d. IgM

CORRECT ANSWER A

9. IgA can be divided into two subclasses, IgA1 and IgA2. IgA1 molecules are predominantly found in the blood, whereas IgA2 is the predominant class of antibody found in normal body secretions. The other options are not found in the substances identified in the question.

An individual is more susceptible to infections of mucous membranes when he or she has a seriously low level of which immunoglobulin antibody? a. IgG c. IgA b. IgM d. IgE

CORRECT ANSWER C

The IgA molecules found in bodily secretions are dimers anchored together through a J-chain and secretory piece. This secretory piece is attached to the IgA antibodies inside the mucosal epithelial cells and may function to protect these immunoglobulin antibodies against degradation by enzymes also found in the secretions, thus decreasing the risk of infections in the mucous membrane. The other options do not accurately identify the immunoglobulin antibody involved in mucous membrane infections.

10. 1. Which action is a purpose of the inflammatory process? a. To provide specific responses toward antigens b. To lyse cell membranes of microorganisms c. To prevent infection of the injured tissue d. To create immunity against subsequent tissue injury

CORRECT ANSWER C

If the epithelial barrier is damaged, then a highly efficient local and systemic response (inflammation) is mobilized to limit the extent of damage, to protect against infection, and to initiate the repair of damaged tissue. The other options do not accurately identify a purpose of the inflammatory process.

11. Which bacterium grows in the intestines after prolonged antibiotic therapy? a. Lactobacillus c. Clostridium difficile b. Candida albicans d. Helicobacter pylori CORRECT ANSWER C

Prolonged antibiotic treatment can alter the normal intestinal flora, decreasing its

protective activity and leading to the overgrowth of other microorganisms, such as the yeast C. albicans or the bacterium C. difficile. The other options do not accurately identify intestinal bacterium whose growth is a result of prolonged antibiotic therapy.

12. What occurs during the process of repair after tissue damage? a. Nonfunctioning scar tissue replaces destroyed tissue. b. Regeneration occurs; the original tissue is replaced. c. Resolution occurs; tissue is regenerated. d. Epithelialization replaces destroyed tissue.

CORRECT ANSWER A

Repair is the replacement of destroyed tissue with scar tissue. Scar tissue is primarily made up of collagen, which fills in the lesion and restores tensile strength but cannot carry out the physiologic functions of the destroyed tissue. The other options do not accurately describe the process of repair after tissue damage.

13. Which solution is best to use when cleaning a wound that is healing by epithelialization? a. Normal saline c. Hydrogen peroxide b. Povidone-iodine d. Dakin solution

CORRECT ANSWER A

Normal saline is the most innocuous solution that can be used to cleanse or irrigate a wound that is primarily healing by epithelialization and is the only correct answer for this question.

14. When cellular damage occurs and regeneration is minor with no significant complications, the process of returning the cells to preinjury function is referred to as: a. Restoration c. Regrowth b. Resolution d. Replacement

CORRECT ANSWER B

If damage is minor with no complications and destroyed tissues are capable of regeneration, then returning the injured tissues to an approximation of their original structure and physiologic function is possible. This restoration is called resolution. The other terms are not used to describe this process.

15. A patient’s blood gases reveal the following findings: pH, 7.3; bicarbonate (HCO3) 27 mEq/L; carbon dioxide (CO2), 58 mm Hg. What is the interpretation of these gases? a. Respiratory alkalosis c. Respiratory acidosis b. Metabolic acidosis d. Metabolic alkalosis

CORRECT ANSWER C

The values provided in this question characterize only acute uncompensated respiratory

acidosis.

16. During acidosis, the body compensates for the increase in serum hydrogen ions by shifting hydrogen ions into the cell in exchange for which electrolyte? a. Oxygen c. Potassium b. Sodium d. Magnesium

CORRECT ANSWER C

In states of acidosis, hydrogen ions shift into the cells in exchange for intracellular fluid potassium; hyperkalemia and acidosis therefore often occur together. This is not true of the other options.

17. Increased capillary hydrostatic pressure results in edema because of: a. Losses or diminished production of plasma albumin b. Inflammation resulting from an immune response c. Blockage within the lymphatic channel system d. Sodium and water retention

CORRECT ANSWER D

Increased capillary hydrostatic pressure can result from venous obstruction or sodium and water retention. The other options do not accurately describe the cause of edema related to increased capillary hydrostatic pressure.

18. Free radicals play a major role in the initiation and progression of which diseases? a. Cardiovascular diseases such as hypertension and ischemic heart disease b. Renal diseases such as acute tubular necrosis and glomerulonephritis c. Gastrointestinal diseases such as peptic ulcer disease and Crohn disease d. Muscular disease such as muscular dystrophy and fibromyalgia

CORRECT ANSWER A

Emerging data indicate that reactive oxygen species play major roles in the initiation and progression of cardiovascular alterations associated with hyperlipidemia, diabetes mellitus, hypertension, ischemic heart disease, and chronic heart failure. No current research connects the disorders mentioned in the other options to the effects of free radicals.

19. The loss of the adenosine triphosphate (ATP) during ischemia causes cells to: a. Shrink because of the influx of calcium (Ca). b. Shrink because of the influx of potassium chloride (KCl). c. Swell because of the influx of sodium chloride (NaCl). d. Swell because of the influx of nitric oxide (NO).

CORRECT ANSWER C

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.

20. During cell injury caused by hypoxia, an increase in the osmotic pressure occurs within the cell because: a. Plasma proteins enter the cell. b. The adenosine triphosphatase (ATPase)–driven pump is stronger during hypoxia. c. Sodium chloride enters the cell. d. An influx of glucose occurs through the injured cell membranes.

CORRECT ANSWER C

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. (Transport mechanisms are described in Chapter 1.) The remaining options do not accurately describe the cell injury that results in increased osmotic pressure caused by hypoxia.

21. What is the single most common cause of cellular injury? a. Hypoxic injury c. Infectious injury b. Chemical injury d. Genetic injury

CORRECT ANSWER A

Hypoxia, or lack of sufficient oxygen, is the single most common cause of cellular injury (see Figure 2-8). The other options are not a commonly observed as is the correct option.

22. Which mode of chemical signaling uses local chemical mediators that are quickly taken up, destroyed, or immobilized? a. Paracrine c. Neurotransmitter b. Autocrine d. Hormone

CORRECT ANSWER A

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.

23. Which mode of chemical signaling uses blood to transport communication to cells some

distance away? a. Paracrine c. Neurotransmitter b. Autocrine d. Hormonal

CORRECT ANSWER D

Chemical signaling can be classified into three categories: (1) local-chemical mediator, (2) hormone, and (3) neurotransmitter. In the local-chemical mediator model, the secreted chemical acts on the cells in the immediate environment. Hormones are used for communication with distant target cells. For example, cells can secrete a chemical and rely on the blood system to deliver the signal to a distant cell. Finally, neurotransmitters are secreted by neurons to stimulate an adjoining cell. For example, a neuron might secrete acetylcholine to stimulate the movement of a muscle cell.

24. Under anaerobic conditions, what process provides energy for the cell? a. Oxidative phosphorylation c. Lactolysis b. Glycolysis d. Passive transport

CORRECT ANSWER B

Glycolysis produces a net of two molecules of ATP per glucose molecule through the process of oxidation or the removal and transfer of a pair of electrons. The other options do not correctly identify an anaerobic process that provides energy to the cell.

25. What is the mechanism by which the energy produced from carbohydrates, proteins, and lipids is transferred to adenosine triphosphate (ATP)? a. Anaerobic glycolysis c. Oxidative phosphorylation b. Oxidative cellular metabolism d. Tricarboxylic acid phosphorylation

CORRECT ANSWER C

Oxidative phosphorylation occurs in the mitochondria and is the mechanism by which the energy produced from carbohydrates, fats, and proteins is transferred to ATP. The other options do not correctly identify the mechanism described in the question.

26. A patient who has diarrhea receives a 3% saline solution intravenously to replace the sodium and chloride lost in the stool. What effect will this fluid replacement have on cells? a. Become hydrated c. Shrink b. Swell or burst d. Divide

CORRECT ANSWER C

A hypertonic solution has a concentration of greater than 285 to 294 mOsm/kg. An example of a hypertonic solution is 3% saline solution. Water can be pulled out of the cells by a hypertonic solution; therefore the cells shrink. The remaining options do not correctly describe the effect identified in the stem.