Which of the following mechanisms is responsible for the phenomenon of immunological memory, wherein the immune system mounts a faster and more robust response upon re-exposure to a previously encountered pathogen?

Correct Answer: A

Rationale: Immunological memory is primarily maintained by the clonal expansion of memory B cells. Memory B cells are a type of long-lived immune cell that originates from previously activated B cells during an immune response to a pathogen. When the immune system encounters the same pathogen again, memory B cells can quickly recognize and respond to it by undergoing rapid clonal expansion and differentiation into plasma cells that produce specific antibodies. This quick and robust response leads to the more efficient elimination of the pathogen during secondary exposure, resulting in the faster and stronger immune response characteristic of immunological memory.

Correct Answer: C

Rationale: Cryptosporidium parvum is a protozoan parasite that commonly causes waterborne illness characterized by watery diarrhea, abdominal cramps, and nausea. This parasite is often transmitted through contaminated water sources such as streams or lakes. Laboratory tests identifying oocysts in the stool sample are indicative of Cryptosporidium infection. Giardia lamblia can also cause similar symptoms, but the presence of oocysts points more towards Cryptosporidium in this case. Entamoeba histolytica causes amoebic dysentery with bloody diarrhea and is usually associated with fecal-oral transmission through contaminated food or water. Cyclospora cayetanensis typically causes prolonged watery diarrhea and is associated with the ingestion of contaminated food or water.

Correct Answer: C

Rationale: The most appropriate nursing action when a postpartum client presents with persistent, severe headache, photophobia, and altered mental status is to notify the healthcare provider immediately. These symptoms could be indicative of serious conditions such as postpartum preeclampsia or postpartum eclampsia, both of which require prompt medical evaluation and intervention. Delaying medical attention in such cases can lead to severe complications for the mother. Therefore, it is crucial to prioritize the client's safety and well-being by quickly involving the healthcare provider for further assessment and management.

Correct Answer: A

Rationale: The clinical presentation of recurrent episodes of epistaxis, gum bleeding, and easy bruising, along with laboratory findings of prolonged bleeding time, normal platelet count, and normal coagulation studies (PT and aPTT) are highly suggestive of Von Willebrand disease. Von Willebrand disease is the most common inherited bleeding disorder and is characterized by a deficiency or dysfunction of von Willebrand factor (vWF), which plays a key role in platelet adhesion and aggregation. The prolonged bleeding time is due to impaired platelet adhesion to the damaged vessel wall in the absence of functional vWF. Normal platelet count and normal PT/aPTT help differentiate Von Willebrand disease from other bleeding disorders such as hemophilia and platelet function disorders like Glanzmann thrombasthenia and Bernard-Soulier syndrome.

Correct Answer: A

Rationale: Opsonization refers to the process by which antibodies bind to the surface of pathogens, marking them for destruction by phagocytes or complement proteins. This coating of antibodies enhances the ability of the immune system to recognize and eliminate the pathogens effectively. Phagocytes (such as macrophages and neutrophils) are better able to engulf and digest pathogens that have been opsonized, as the antibodies attached to the pathogen surface signal to the phagocytes that they are foreign invaders. This process is crucial in the body's immune response to infections and helps in clearing pathogens from the system.

Correct Answer: C

Rationale: The initial step of delegation is to determine the competency level of the staff for the task being given. Before delegating a task, a nurse must assess the knowledge, skills, and abilities of the staff member to ensure that they are competent and capable of performing the task safely and effectively. This step is crucial in ensuring that tasks are delegated appropriately and that quality patient care is maintained. By determining the competency level of the staff, Nurse Gayle can make informed decisions about delegation, provide appropriate support and resources, and facilitate effective communication throughout the delegation process.

Correct Answer: B

Rationale: The patient's presentation of severe headache, blurred vision, and fatigue, along with the laboratory findings of elevated white blood cell count, thrombocytosis, and JAK2 V617F mutation, are characteristic of essential thrombocythemia. This is a myeloproliferative neoplasm characterized by the clonal proliferation of megakaryocytes, leading to an increased platelet count. The JAK2 V617F mutation is commonly found in essential thrombocythemia and other myeloproliferative disorders. The symptoms of essential thrombocythemia can be related to the increased blood viscosity and risk of thrombosis due to the elevated platelet count. Polycythemia vera would present with elevated red blood cell count, hemoglobin, and hematocrit, along with other features such as pruritus after a hot bath. Chronic myeloid leukemia (CML

Correct Answer: A

Rationale: Utilizing communication and social media responsibly is an indicator that models personal and professional behavior and values. Responsible use of communication and social media demonstrates a commitment to maintaining a positive online presence, interacting respectfully with others, and upholding professional standards in digital communication. This behavior reflects integrity, accountability, and respect for oneself and others, which are essential qualities in both personal and professional settings. Additionally, demonstrating responsible behavior in the digital sphere can help build trust, enhance reputation, and foster valuable relationships with colleagues, clients, and the community.

Correct Answer: B

Rationale: The pharynx is the structure responsible for transporting food from the oral cavity to the esophagus during swallowing. When food is chewed and mixed with saliva in the oral cavity, it forms a bolus that is propelled to the pharynx by the tongue. The pharynx serves as a common passageway for both air and food, allowing the bolus to pass into the esophagus while preventing it from entering the trachea. The epiglottis, although important in preventing food from entering the airway, is not directly involved in the transportation of food from the oral cavity to the esophagus.