The tube that carries urine from the bladder to the
outside of the body is the
a. nephron.
b. urethra.
c. meatus.
d. ureter.
The correct answer and explanation is:
The correct answer is b. urethra.
Explanation:
The urethra is the tube responsible for transporting urine from the bladder to the outside of the body. It plays a vital role in the urinary system by serving as the final passageway for urine excretion.
Structure and Function:
- Location and Anatomy:
- In males, the urethra is longer (approximately 20 cm or 8 inches) and has dual functions: it carries urine and semen. It passes through the prostate gland and the penis.
- In females, the urethra is much shorter (about 4 cm or 1.5 inches) and is located above the vaginal opening.
- Process of Urination:
- Urine is formed in the kidneys, travels down the ureters, and is stored in the bladder. When the bladder reaches its capacity, the detrusor muscle contracts, and the sphincter muscles of the urethra relax, allowing urine to pass through the urethra and exit the body.
- Role in the Urinary System:
- The urethra works in coordination with other urinary organs to ensure proper waste elimination. It prevents urine leakage by maintaining sphincter control until urination is consciously initiated.
Comparison with Other Structures:
- The nephron (a) is the functional unit of the kidney that filters blood to produce urine but does not carry it outside the body.
- The meatus (c) refers to the external opening of the urethra where urine exits the body, not the tube itself.
- The ureter (d) is a tube that transports urine from the kidneys to the bladder, not from the bladder to the outside.
The urethra’s health is critical for proper urinary function, and issues like infections (e.g., urinary tract infections) or blockages can significantly affect its function, underscoring its importance in the urinary system.