Which of the following is NOT a disease of the nervous system?

Hypertension, commonly known as high blood pressure, is primarily a cardiovascular condition that affects the heart and blood vessels rather than being classified as a disease of the nervous system. While hypertension can have indirect effects on the nervous system and is often related to other neurological issues, it does not originate within the nervous system itself. Instead, it is primarily concerned with the regulation of blood flow and pressure within the circulatory system.

In contrast, Parkinson's disease, CVA (stroke), and multiple sclerosis (MS) are all directly associated with neurological functioning. Parkinson's disease is a progressive disorder that affects movement due to the degeneration of dopamine-producing neurons in the brain. A CVA or stroke occurs when there is an interruption of blood supply to a part of the brain, leading to neurological deficits. Multiple sclerosis is an autoimmune condition that affects the central nervous system, where the immune system attacks the protective covering of nerves. Each of these conditions is classified specifically as a disease affecting the nervous system, highlighting their direct impact on neurological health and function.