All are true about the trigone on the base of the urinary bladder, except:
**Core Concept**
The trigone of the urinary bladder is a triangular area located at the base of the bladder, formed by the two ureteric orifices and the internal urethral orifice. It plays a crucial role in the normal functioning of the urinary system.
**Why the Correct Answer is Right**
The trigone is a smooth muscle area that is derived from the mesoderm, which is a thickening of the bladder wall. This area is unique in that it is the only region of the bladder that is not lined with transitional epithelium, instead being lined with squamous epithelium. The trigone is also innervated by the pelvic splanchnic nerves, which are responsible for transmitting parasympathetic and sympathetic signals to the bladder.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the trigone is not a region of the bladder that is primarily involved in the storage of urine. Instead, it plays a key role in the normal emptying of the bladder during micturition.
**Option B:** This option is incorrect because the trigone is not a region of the bladder that is primarily involved in the regulation of bladder tone. Instead, it is a region of the bladder that is involved in the normal functioning of the ureterovesical junction.
**Option C:** This option is incorrect because the trigone is not a region of the bladder that is primarily involved in the sensation of pain. Instead, it is a region of the bladder that is involved in the normal functioning of the urinary system.
**Clinical Pearl / High-Yield Fact**
The trigone of the bladder is a region that is particularly susceptible to damage during prostate surgery, which can lead to urinary incontinence and other complications. This is because the trigone is located directly behind the prostate gland and can be easily damaged during surgical procedures.
**Correct Answer: None of the above (Trigone is not listed among the options)**