Nokea
Which of the following mechanisms most accurately describes how pseudo-membranous colitis caused by Clostridium difficile is produced?
- A. elaboration of an enterotoxin following colonization of the colon
- B. ingestion of a preformed toxin
- C. invasion and destruction of mucosa by the organism
- D. host immune response to the organism
Correct Answer: A
Rationale: The correct answer is A because Clostridium difficile produces toxins, specifically enterotoxins, which cause damage to the intestinal mucosa leading to pseudo-membranous colitis. The organism colonizes the colon and then elaborates the toxins, which disrupt the mucosal barrier.
Choice B is incorrect as there is no preformed toxin ingested; the toxin is produced by the organism after colonization. Choice C is incorrect as Clostridium difficile does not invade and destroy the mucosa directly. Choice D is incorrect as the host immune response is a consequence of the toxin production, not the primary mechanism of disease.
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The pacemaker signal generated by the SA node spreads to the ventricles by passing through the AV node. What would happen to the contraction of the ventricles if there was a complete block at the AV node?
- A. the ventricles would cease beating
- B. the ventricles would beat very fast and uncontrollably
- C. the ventricles would contract rhythmically, but more slowly
- D. the ventricles would contract at the same rate as the atria
Correct Answer: C
Rationale: Rationale: A complete block at the AV node would prevent the transmission of the pacemaker signal from the SA node to the ventricles. As a result, the ventricles would not receive the signal to contract at their normal rate. Instead, they would rely on their inherent ability to generate impulses, resulting in a slower, but still rhythmic contraction. This scenario is known as an escape rhythm, where a lower pacemaker takes over in the absence of the SA node signal.
Summary:
A: the ventricles would cease beating - Incorrect, as the ventricles have their own intrinsic pacemaker.
B: the ventricles would beat very fast and uncontrollably - Incorrect, as a complete AV block would lead to a slower rhythm.
D: the ventricles would contract at the same rate as the atria - Incorrect, as the ventricles and atria have different intrinsic rates.
An excessive response or activity of T suppressor cells would most likely be associated with
- A. autoimmune disease
- B. cancer
- C. allergies
- D. graft rejection
Correct Answer: B
Rationale: The correct answer is B: cancer. T suppressor cells play a crucial role in regulating the immune response to prevent excessive activation, which can lead to the development of cancer. In cancer, T suppressor cells may become dysfunctional, allowing cancer cells to evade immune surveillance and proliferate. Autoimmune diseases (choice A) are more associated with a breakdown in immune tolerance, leading to an overactive immune response against self-antigens. Allergies (choice C) involve an exaggerated immune response to harmless substances, primarily driven by IgE antibodies and other immune cells, rather than T suppressor cells. Graft rejection (choice D) is typically mediated by T helper cells and cytotoxic T cells targeting foreign antigens present in transplanted tissues, rather than T suppressor cells.
The center of the tooth that is filled with blood vessels and nerves is called the ______ and the cavity within the root of the tooth is called the ______.
- A. clinical crown; root canal
- B. pulp cavity; root canal
- C. pulp cavity; dentin
- D. dentin; root canal
Correct Answer: B
Rationale: The correct answer is B: pulp cavity; root canal. The pulp cavity is the center of the tooth filled with blood vessels and nerves, while the root canal is the cavity within the root of the tooth. This is because the pulp cavity contains the pulp tissue, which includes blood vessels and nerves, providing nourishment and sensation to the tooth. The root canal, on the other hand, is the space within the root where the pulp tissue extends down into. Choices A, C, and D are incorrect because they do not accurately describe the specific structures mentioned in the question.
A client has to undergo a barium enema for a suspected GI disorder. During the test, he experiences a strong urge to defecate and seeks the nurse's advice. Which of the following should the nurse do?
- A. Advise him to clear his bowel immediately
- B. Assure him that most people can retain the urge
- C. Give him analgesics to relieve him of the urge
- D. Instruct him to drink plenty of fluids
Correct Answer: B
Rationale: The correct answer is B: Assure him that most people can retain the urge. The rationale is as follows:
1. Retaining the urge during a barium enema is common due to the pressure from the barium solution.
2. Advising the client to clear his bowel immediately is incorrect because it may disrupt the test.
3. Giving analgesics to relieve the urge is incorrect as it does not address the issue.
4. Instructing to drink plenty of fluids is incorrect as it does not help in managing the urge.
In summary, choice B is correct as it reassures the client and helps maintain the integrity of the test.
Which action will the nurse include in the plan of care for a patient who is being admitted with Clostridium difficile?
- A. Teach the patient about proper food storag
- C. Order a diet without dairy products for the patient.
- D. Place the patient in a private room on contact isolation.
Correct Answer: D
Rationale: The correct answer is D: Place the patient in a private room on contact isolation. This is important because Clostridium difficile is highly contagious, spread through contact with infected feces. Isolating the patient helps prevent the spread. A: Teaching about food storage is irrelevant to managing C. difficile. B: Administering medications is not mentioned in the question. C: Ordering a diet without dairy is not the priority; isolation is key to prevent transmission.