Question

The urinary bladder is muscular and is under control.
A. Muscular
B. Mechanical
C. Nervous
D. Hormonal

Answer 1

The discharge of urine stored in the bladder by the urethra can be controlled by specialized sphincters. The urinary bladder is an organ of the urinary system which has two primary functions: It stores the urine temporarily and also assists in the expulsion of urine when necessary.

Complete answer: The structure of the bladder varies largely depending on the amount of urine getting stored. When the bladder is full, it exhibits a characteristic oval shape, and when it becomes empty it appears to be flattened by the overlying bowel. Urine enters the bladder through the help of two tubes i.e. the left and the right ureters and exits the bladder through a structure called the urethra. In order to aid the discharge of the urine (a process called micturition), the bladder wall is made up of highly specialized smooth muscles, called ‘detrusor muscle’. The fibres of these muscles remain orientated in multiple directions, in order to retain the structure built even when the bladder is stretched. It receives signals from both the sympathetic and parasympathetic nervous systems. Additionally, there are also two separate muscular sphincters located in the urethra namely:
-Internal urethral sphincter: In males, it is made of smooth circular fibres, which remain under autonomic control. This prevents seminal regurgitation during male ejaculation. In females it is formed by the anatomy of the bladder neck and proximal urethra.
-External urethral sphincter: It has the same structure in both males and females. It is essentially made up of skeletal muscles and therefore is under voluntary control.

So, the correct answer is C, i.e., Nervous.

Note: Normally, the range of the amount of urine that the urinary bladder can store is approximately 400 to 600 mL. The entire musculature of the bladder plays a crucial role in proper functioning.