What fluid is secreted by the choroid plexus into the brain's ventricles?

The fluid secreted by the choroid plexus into the brain's ventricles is cerebrospinal fluid (CSF). The choroid plexus is a specialized tissue found in the ventricles of the brain that plays a crucial role in producing and regulating the composition of CSF. This fluid is essential for various functions, including cushioning the brain, providing buoyancy, and maintaining a stable environment for the central nervous system. Additionally, CSF serves as a medium for the transport of nutrients and waste products between the brain and its surroundings.

The other options refer to different types of fluids that serve distinct functions in the body. Interstitial fluid is the fluid that exists in the spaces between cells, playing a role in nutrient and waste exchange at the cellular level. Blood plasma is the liquid component of blood that carries cells, nutrients, hormones, and waste products but is not involved in the direct fluid environment of the brain. Lymphatic fluid, associated with the lymphatic system, helps with immune responses and fluid balance in tissues but is also not related to cerebral function. The distinct roles of these fluids help to clarify why cerebrospinal fluid is the correct answer, highlighting the unique function of the choroid plexus in the central nervous