In the floor of the urinary bladder is a small triangular muscle called
A serosa
B hexagon
C detrusor
D trigone
E mucosa
The correct answer and explanation is:
The correct answer is D. Trigone.
The trigone is a small triangular area located at the floor of the urinary bladder. It is formed by three points: the two openings of the ureters (where urine enters the bladder) and the internal urethral orifice (where urine exits the bladder). The trigone is important because it remains smooth, unlike the rest of the bladder, which is lined with folds called rugae. This smooth structure of the trigone helps ensure that urine can flow in and out of the bladder efficiently.
The trigone is crucial for the functioning of the urinary system because it helps direct urine from the ureters into the bladder and also prevents the backflow of urine into the ureters, a condition known as vesicoureteral reflux, which could lead to infections or kidney damage. Additionally, the trigone is surrounded by muscle tissue that contributes to the contraction of the bladder during urination, ensuring that the process is controlled and efficient.
The other options listed are related to different parts of the bladder or surrounding structures but do not describe the triangular muscle at the floor of the bladder:
- A. Serosa is a membrane covering the outer layer of some organs, including the bladder.
- B. Hexagon refers to a six-sided geometric shape, not a biological structure.
- C. Detrusor is the muscle that makes up the wall of the bladder and helps expel urine but is not a triangular structure.
- E. Mucosa is the inner lining of the bladder that secretes mucus but does not form a triangular muscle.
Understanding the structure of the trigone is essential for appreciating the complex mechanics of the urinary system and how the body ensures proper urinary function.