Order: 10 mg. Available: 5 mg per 1 mL. How many mL will the nurse administer?

Choice B rationale

A fever of 38.9 degrees Celsius is a classic systemic manifestation of inflammation. This occurs when inflammatory mediators, such as cytokines (interleukin-1 and tumor necrosis factor), enter the bloodstream and travel to the hypothalamus. The hypothalamus then resets the body's internal thermostat to a higher level. Unlike localized signs, a fever affects the entire body and indicates that the inflammatory process is no longer confined to the initial site of injury, involving a coordinated physiological response across multiple systems.

Choice A rationale

Erythema and warmth are part of the classic cardinal signs of inflammation, which also include swelling, pain, and loss of function. However, when these findings are confined strictly to the incision site, they represent a localized inflammatory response. This local reaction is caused by hyperemia from vasodilation and increased blood flow to the injured area to facilitate tissue repair. It does not indicate that the inflammatory mediators have triggered the systemic responses typically seen in widespread or severe inflammation.

Choice C rationale

Serous drainage is a normal finding during the early stages of wound healing and represents the inflammatory exudate that leaks from capillaries during the phase of increased permeability. This fluid contains proteins and white blood cells needed for repair. Since this drainage is noted specifically at the wound edges, it is a localized clinical finding. It provides information about the status of the specific tissue injury but does not provide evidence that the patient is experiencing a body-wide systemic response.

Choice D rationale

Edema and tenderness surrounding the affected tissue are localized symptoms resulting from increased capillary hydrostatic pressure and the release of chemical mediators like bradykinin and prostaglandins that sensitize local nerve endings. While these symptoms can be distressing, they are restricted to the area of injury. A systemic response would require manifestations such as leukocytosis (WBC count > 11,000/mm), malaise, or the aforementioned fever, which demonstrate that the entire organism is reacting to the presence of inflammation or infection.

Choice A rationale

The activation of macrophages is primarily a function of T helper cells, specifically the Th subset. These T cells release cytokines such as interferon-gamma, which enhances the phagocytic and microbicidal activity of macrophages. While B cells are part of the adaptive immune system and can act as antigen-presenting cells, their primary specialized role in the immune hierarchy is not the direct stimulation of macrophage effector functions but rather the transition into antibody-secreting plasma cells.

Choice B rationale

The recognition of Major Histocompatibility Complex I molecules is a specific function of CD8+ cytotoxic T lymphocytes. Every nucleated cell in the human body expresses MHC I to display endogenous antigens. Cytotoxic T cells use their T-cell receptors to scan these molecules for viral or tumor proteins. B cells, conversely, recognize intact, soluble antigens through their membrane-bound immunoglobulin receptors, which do not require the antigen to be presented on an MHC I molecule for initial binding.

Choice C rationale

The direct killing of infected or cancerous cells is performed by cytotoxic T cells and Natural Killer cells through the release of perforins and granzymes. These substances induce apoptosis in the target cell. B cells do not possess these cytolytic granules and do not engage in cell-to-cell combat. Instead, they provide humoral immunity, which involves the systemic distribution of proteins that neutralize pathogens remotely, rather than requiring the B cell to physically destroy the infected host cell.

Choice D rationale

The hallmark function of B lymphocytes is their differentiation into plasma cells, which are specialized factories for the production of antibodies or immunoglobulins. These antibodies circulate in the blood and lymph, binding specifically to antigens on the surface of pathogens like bacteria and viruses. This binding can neutralize the pathogen, opsonize it for easier phagocytosis by neutrophils, or activate the complement system. This humoral response is essential for long-term immunity and the effectiveness of vaccinations.