**Core Concept**
The vagina is a muscular, tubular organ that forms part of the female genital tract. It plays a crucial role in reproduction, including sexual intercourse, micturition, and childbirth.

**Why the Correct Answer is Right**
The correct answer will be the statement that does not accurately describe the vagina. This requires an understanding of the vagina's anatomy, physiology, and functions.

**Why Each Wrong Option is Incorrect**
**Option A:** The vagina is a muscular organ lined with mucous membranes. This statement is true, as the vaginal walls are composed of smooth muscle and mucous membranes that secrete mucus to facilitate intercourse and protect the vaginal lining.

**Option B:** The vagina is a part of the urinary system. This statement is false, as the vagina is part of the female genital tract and is not directly involved in the urinary system, although it does communicate with the urethra through the vaginal vestibule.

**Option C:** The vagina is a highly vascularized organ. This statement is true, as the vagina receives a rich blood supply from the vaginal arteries, which are branches of the internal iliac arteries.

**Option D:** The vagina is a homologous structure to the penis. This statement is true, as the vagina and penis develop from the same embryonic tissue, the genital tubercle.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the vagina's anatomy and physiology can be affected by various factors, including hormonal changes, infections, and age-related changes.

**Correct Answer:** B. The vagina is a part of the urinary system.