The urinary tract is the system through which urine is produced, transported, stored, and eliminated from the body.
The anatomy of the urinary tract can be divided into upper and lower parts.
Here's a description of each part:
Upper urinary tract:
1. Kidneys:
Function: Filter blood and produce urine.
Structure: A pair of bean-shaped organs located on either side of the spine, below the ribcage.
Nephrons: Each kidney contains about 1 million nephrons, which perform filtration, reabsorption, secretion, and excretion.
2. Ureters:
Function: Transport urine from the kidneys to the bladder.
Structure: Two muscular tubes, each about 10-12 inches (25-30 cm) long.
Mechanism: Use peristalsis (involuntary muscular contractions) to move urine along their length.
Lower urinary tract:
3. Urinary Bladder:
Function: Acts as a reservoir for storing urine.
Location: In the pelvic cavity, behind the pubic symphysis.
Structure: Made of detrusor muscle that contracts during urination.
Capacity: Typically holds 400-600 mL of urine.
2. Urethra:
Function: Carries urine from the bladder to the outside of the body.
Control: Has two sphincters, the internal and external urethral sphincters, that control urine release.
Structure: Varies in length between males and females.
In males, the urethra is about 8 inches (20 cm) long and passes through the prostate gland, the urogenital diaphragm, and the penis. The male urethra has three sections: the prostatic urethra, the membranous urethra, and the spongy (penile) urethra.
In females, the urethra is much shorter, approximately 1.5 inches (4 cm) long, and extends from the bladder to the vaginal vestibule. The female urethra has a single section called the urethral meatus.