**Core Concept**
Sjogren's syndrome is an autoimmune disorder characterized by lymphocytic infiltration and destruction of the exocrine glands, particularly the salivary and lacrimal glands, leading to symptoms of dry mouth (xerostomia) and dry eyes (xerophthalmia).

**Why the Correct Answer is Right**
The disease involves a complex interplay between T cells and autoantibodies, particularly anti-SSA/Ro and anti-SSB/La antibodies, which target the epithelial cells of the exocrine glands. This results in chronic inflammation and destruction of the glandular tissues, impairing their secretory functions. The pathogenesis of Sjogren's syndrome is thought to be multifactorial, involving both genetic predisposition and environmental triggers.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as Sjogren's syndrome is not primarily a disease of the endocrine glands, although some patients may develop secondary endocrine abnormalities.
**Option B:** This option is incorrect as Sjogren's syndrome is not a type of rheumatoid arthritis, although some patients may develop rheumatoid arthritis or other autoimmune diseases concurrently.
**Option C:** This option is incorrect as Sjogren's syndrome is not a disease of the nervous system, although some patients may develop neurological manifestations such as neuropathy.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that Sjogren's syndrome can be associated with other autoimmune diseases, such as rheumatoid arthritis, lupus, and scleroderma, and that patients may present with a range of systemic symptoms, including fatigue, joint pain, and skin rashes.

**Correct Answer:** D. Exocrine glands.