Põis

Põis is the Estonian term for the urinary bladder, a hollow, muscular organ in the pelvis that stores urine produced by the kidneys before it is expelled through the urethra. In humans, the bladder sits behind the pubic bone and, in females, is located anterior to the uterus and vagina, while in males it lies anterior to the rectum and superior to the prostate.

Anatomically, the bladder consists of a mucous lining called the urothelium, a thick muscular wall known as the detrusor, and a base called the trigone where the ureters enter and the urethra exits. The detrusor muscle contracts to expel urine during voiding, while the internal urethral sphincter and, in part, the external urethral sphincter regulate urine flow. The bladder’s capacity in adults typically ranges from about 300 to 500 milliliters, though it can accommodate more with gradual stretching.

Functionally, the bladder receives urine from the kidneys via the ureters and stores it until a voluntary or reflexive voiding reflex initiates urination. Autonomic nervous system inputs coordinate storage and release: parasympathetic activity promotes detrusor contraction, while sympathetic and somatic pathways help maintain storage.

Common clinical topics include cystitis (bladder inflammation), urinary incontinence (loss of bladder control), overactive bladder, bladder stones, and bladder cancer. Diagnostics commonly involve urinalysis, ultrasound, and cystoscopy, while treatments range from behavioral therapy and medications to catheterization or surgical options for severe cases. Developmentally, the bladder originates from the urogenital sinus and functions as a key component of the lower urinary tract.