Which body substance is not included in the definition of body fluids according to healthcare standards?

The correct answer is muscle tissue, as it is not classified as a body fluid. In healthcare, body fluids typically refer to liquid substances present in the body that are involved in various physiological processes. This includes blood, which transports oxygen and nutrients; urine, which is a waste product filtered by the kidneys; and saliva, often referred to as spit, which aids in digestion and oral health.

Muscle tissue consists of the cells responsible for movement and does not fall under the category of fluids. Instead, it is considered a solid tissue that plays a critical role in bodily functions. Understanding these classifications is essential for tasks related to patient care, hygiene practices, and infection control in nursing. Recognizing what constitutes body fluids helps healthcare workers in maintaining safety protocols when handling different types of biological materials.