Uriinieritys

Uriinieritys is a term in Finnish that refers to the physiological process of urine excretion. In medical English, the equivalent terms are urination or micturition. The process comprises urine production in the kidneys, transport and storage in the urinary tract, and the voluntary or reflexive expulsion of urine through the urethra.

Urine production begins with filtration of blood in the kidneys, followed by selective reabsorption and secretion that concentrate waste products and water. Urine travels from the kidneys via the ureters to the urinary bladder, a muscular sac that stores urine at low pressure. The detrusor muscle of the bladder wall accommodates increasing volumes, while the internal urethral sphincter provides involuntary closure.

Voiding is initiated by a complex neural reflex involving parasympathetic, sympathetic, and somatic pathways. When the bladder fills to a threshold, afferent signals trigger a reflex that stimulates detrusor contraction and relaxation of the internal sphincter. Voluntary control over the external urethral sphincter, mediated by the pudendal nerve, allows initiation or postponement of urination. Higher brain centers can inhibit or facilitate voiding to suit social and environmental contexts.

Variations in urination are common and may indicate health issues. Normal urine output in a healthy adult is around 0.5 to 2.0 liters per day, depending on fluid intake. Disorders include urinary incontinence, urinary retention, dysuria, nocturia, and infections of the urinary tract. Accurate terminology and understanding of uriinieritys aid medical communication and patient education.