Which of the following mediates humoral immunity?

Correct Answer: C

Rationale: In the context of pharmacology and pathophysiology, understanding the components of the immune system is crucial. In this question, the correct answer is C) B cells, which mediate humoral immunity. B cells are responsible for producing antibodies that target specific antigens, forming the basis of humoral immune responses. This is important in defending the body against extracellular pathogens such as bacteria and viruses. Option A) Natural killer cells are part of the innate immune system and are responsible for detecting and killing infected or cancerous cells, not mediating humoral immunity. Option B) T cells are involved in cell-mediated immunity, not humoral immunity. T cells directly kill infected cells or help other immune cells respond to specific pathogens. Option D) Neutrophils are a type of white blood cell involved in the innate immune response, particularly in phagocytosis of pathogens, but they do not mediate humoral immunity. Educationally, understanding the roles of different immune cells helps pharmacology students comprehend how various medications target specific components of the immune system to treat diseases. Knowing the functions of B cells in humoral immunity is essential for developing therapies like vaccines that stimulate antibody production. This knowledge is foundational for pharmacological interventions in immune-related disorders.

Correct Answer: D

Rationale: A rash from poison ivy is an example of a type IV hypersensitivity reaction. Type IV hypersensitivity reactions are delayed cell-mediated immune responses involving T cells. This type of reaction is characterized by a delayed onset, typically occurring 48-72 hours after exposure to the antigen. Choice A, Type I hypersensitivity reactions, are immediate hypersensitivity reactions mediated by IgE antibodies. Choices B and C, Type II and Type III hypersensitivity reactions, involve antibody-mediated cytotoxicity and immune complex deposition, respectively, which are not characteristic of poison ivy-induced rashes.

Correct Answer: A

Rationale: The correct answer is A: Levonorgestrel (Plan B). Levonorgestrel is the most commonly prescribed medication for emergency contraception within 72 hours of unprotected intercourse. It is effective when taken within 72 hours after intercourse, with better efficacy the sooner it is taken. Choice B, Mifepristone (RU-486), is not indicated for emergency contraception but is used for medical abortion. Choice C, Ulipristal acetate (ella), is another option for emergency contraception that is effective up to 120 hours after unprotected intercourse. Choice D, Estradiol (Estrace), is not used for emergency contraception.

Correct Answer: A

Rationale: When a patient taking an oral contraceptive misses one pill, the correct action is to take two pills as soon as they remember and then continue the regular schedule. Option A is the correct answer because doubling up the dose helps maintain the effectiveness of the contraceptive. Option B is incorrect because taking only one pill after missing one may decrease contraceptive effectiveness. Option C is wrong as skipping the missed pill can also reduce effectiveness. Option D is inaccurate because taking two pills immediately is not necessary; the patient should take the missed pill as soon as remembered and then resume the regular dosing schedule.

Correct Answer: A

Rationale: The correct answer is A. Medroxyprogesterone acetate (Provera) can cause breakthrough bleeding or spotting, which is a common side effect of this medication. Choices B, C, and D are incorrect because weight gain, increased risk of diabetes, and increased risk of breast cancer are not commonly associated side effects of medroxyprogesterone acetate. Therefore, the nurse should focus on educating the patient about the potential for breakthrough bleeding or spotting.