Which of the following cell types is primarily responsible for presenting antigens to T cells during the immune response?

Correct Answer: C

Rationale: The correct answer is C: Macrophages. Macrophages are antigen-presenting cells that engulf pathogens and present their antigens to T cells, initiating an immune response. They express major histocompatibility complex (MHC) molecules necessary for T cell recognition. B cells also present antigens but primarily to B cells for antibody production. NK cells are involved in killing infected cells, not antigen presentation. Eosinophils are mainly involved in allergic responses and defense against parasites, not antigen presentation.

Correct Answer: A

Rationale: The correct answer is A: Hashimoto's thyroiditis. This autoimmune disorder results in chronic inflammation of the thyroid gland, leading to thyroid nodules and hypothyroidism. The colloid-filled spaces seen in the biopsy are characteristic of Hashimoto's. Choice B: Graves' disease is an autoimmune disorder causing hyperthyroidism, not hypothyroidism. Choice C: Diabetes mellitus is a metabolic disorder unrelated to the thyroid. Choice D: Thyroid nodules is a general term and does not explain the presence of colloid-filled spaces.

Correct Answer: D

Rationale: The correct answer is D: Ventricular tachycardia. Ventricular tachycardia is a serious arrhythmia that can lead to palpitations, dizziness, and syncope due to the rapid and abnormal heart rhythm originating in the ventricles. This arrhythmia can be life-threatening if not promptly treated. A: Stable angina is characterized by chest discomfort or pain due to reduced blood flow to the heart muscle, usually during physical exertion or stress. It does not typically present with palpitations, dizziness, or syncope. B: Unstable angina is a more severe form of angina where symptoms occur even at rest. While it can lead to serious complications like heart attack, it does not commonly present with palpitations, dizziness, or syncope. C: Atrial fibrillation is a common arrhythmia originating in the atria, leading to an irregular and often rapid heartbeat. While it can cause palpitations and dizziness,

Correct Answer: D

Rationale: The correct answer is D because confirming the insertion site and direction using imaging guidance ensures precise placement of the chest tube, minimizing the risk of complications. Imaging guidance allows the nurse to visualize the exact location of the pneumothorax and guide the tube insertion accurately. A: Positioning the patient in a semi-Fowler's position with arms elevated may be beneficial for comfort but does not directly ensure proper chest tube placement. B: Marking the insertion site with a pen may help as a reference point but does not guarantee accurate placement. C: Administering analgesia is important for the patient's comfort but does not impact the placement of the chest tube. In summary, choice D is the most critical step to ensure the chest tube is correctly placed and effectively treats the pneumothorax.

Correct Answer: A

Rationale: The correct answer is A: Loss of self-tolerance. This is because autoimmune diseases result from a breakdown in the immune system's ability to distinguish between self and non-self antigens, leading to the production of antibodies against self-antigens. When self-tolerance is lost, immune cells mistakenly target the body's own tissues, causing tissue damage and inflammation. Choice B (Failure of innate immunity) is incorrect because autoimmune diseases are primarily driven by adaptive immunity rather than innate immunity. Choice C (Defective T cell activation) is incorrect as T cells play a critical role in the immune response to self-antigens in autoimmune diseases. Choice D (Impaired phagocytosis) is incorrect as phagocytosis is a mechanism primarily involved in the removal of pathogens, not in the development of autoimmune diseases.

Correct Answer: D

Rationale: The correct immediate action for the nurse is to notify the anesthesia provider immediately (Option D). This is crucial because a sudden change in the patient's level of consciousness during surgery could indicate a serious issue related to anesthesia administration. Notifying the anesthesia provider promptly allows for quick assessment and intervention to address the underlying cause, potentially preventing complications or even saving the patient's life. Administering a reversal agent (Option A) without proper evaluation by the anesthesia provider could be dangerous. Documenting the change in the patient's chart (Option B) is important but not the most immediate action. Checking the patient's vital signs (Option C) is also important but may not provide immediate insight into the cause of the change in consciousness.

Correct Answer: D

Rationale: The correct answer is D: Teeth. Teeth are responsible for the initial mechanical breakdown of food during mastication. Step 1: Teeth use their hard surfaces to chew and grind food into smaller pieces. Step 2: This process increases the surface area of the food, making it easier for digestive enzymes to break down. Step 3: The tongue aids in moving the food around the mouth but does not break down the food mechanically. Pharynx is responsible for swallowing, not mastication. Salivary glands produce saliva that helps in the lubrication and digestion of food, but they do not directly participate in the mechanical breakdown of food.

Correct Answer: B

Rationale: The correct answer is B: Cleanse the bite with soap and running water. This is the first nursing intervention because it is crucial to prevent infection. Cleaning the bite area helps remove bacteria and debris, reducing the risk of infection. Injecting with rabies immune globulin (choice A) and rabies vaccine (choice C) should be done later as per protocol after assessing the situation. Administering pain reliever (choice D) is important but not the first priority in this scenario.

Correct Answer: A

Rationale: The correct answer is A: Pulmonary embolism. This is the most likely cause of the symptoms based on the presentation of chest pain, dyspnea, hemoptysis, and a mismatched defect on the V/Q scan. A pulmonary embolism occurs when a blood clot travels to the lungs, causing a blockage in the pulmonary artery. This can lead to symptoms like chest pain, shortness of breath, and coughing up blood. The V/Q scan showing a mismatched defect indicates a ventilation-perfusion mismatch, which is a classic finding in pulmonary embolism. Pericarditis (B), acute myocardial infarction (C), and aortic dissection (D) typically present with different sets of symptoms and do not match the V/Q scan findings in this case.