Bladder

Bladder

The bladder is a hollow muscular organ in humans and other vertebrates that collects and stores urine from the kidneys before disposal by urination. The bladder is a part of the urinary system, which also includes the ureters, urethra, and the kidneys.

Anatomy

The bladder is located in the pelvis, just above and behind the pubic bone. In males, it is situated in front of the rectum and above the prostate gland. In females, it is positioned in front of the uterus and the vagina.

Structure

The bladder wall is composed of several layers:

• The innermost layer is the urothelium, a type of transitional epithelium that is highly elastic and can stretch to accommodate varying volumes of urine.
• Beneath the urothelium is the lamina propria, a layer of connective tissue.
• The detrusor muscle is the thick, muscular layer that contracts to expel urine.
• The outermost layer is the adventitia, a layer of connective tissue.

Capacity

The average adult bladder can hold between 400 to 600 milliliters of urine. The urge to urinate typically begins when the bladder contains about 150 to 200 milliliters of urine.

Function

The primary function of the bladder is to store urine until it is ready to be expelled from the body. The process of urination involves the coordinated contraction of the detrusor muscle and the relaxation of the internal urethral sphincter and external urethral sphincter.

Bladder Disorders

Several conditions can affect the bladder, including:

• Cystitis: Inflammation of the bladder, often caused by a urinary tract infection.
• Bladder cancer: A type of cancer that begins in the cells of the bladder.
• Overactive bladder: A condition characterized by a sudden, involuntary contraction of the muscle in the bladder wall.
• Interstitial cystitis: A chronic condition causing bladder pressure, bladder pain, and sometimes pelvic pain.

Diagnosis and Treatment

Bladder conditions are diagnosed using various methods, including urinalysis, cystoscopy, and imaging studies such as ultrasound and CT scan. Treatment options vary depending on the condition and may include medication, surgery, and lifestyle changes.

See Also

• Urinary system
• Kidney
• Ureter
• Urethra
• Prostate gland
• Urinary tract infection