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The discharge of urine from the bladder. Also known as micturition.



(also called micturition), the reflex act of excreting urine from the body.

Uropoiesis—the production of urine—is a constant process, but urination occurs only intermittently, as the urinary bladder fills. Humans urinate four to six times daily. Urine is prevented from escaping from the bladder by two ring-shaped layers of muscle fibers: an internal sphincter, which consists of smooth muscle fibers, and an external one, which consists of striated fibers. When the pressure within the bladder reaches 2–2.66 kN/m2 (kilonewtons per square meter), or 15–20 mm Hg (millimeters of mercury), stimulation of the mechanoreceptors (the nerve endings of sensory neurons) in the wall of the bladder elicits the urge to urinate. In man, this critical pressure is achieved when 300–350 ml of urine accumulate in the bladder. During urination, the external sphincter relaxes reflexively as the muscles of the bladder wall contract.

Urination is regulated by the nerve centers in the spinal cord and brain; these centers are controlled, in turn, by the cerebral cortex. The filling of the urinary bladder arouses the cerebral cortex to elicit the urge to urinate. Certain neurological diseases, as well as injuries to the muscles of the urinary bladder, impair urination.


What does it mean when you dream about urination?

Urination in a dream has several interpretations that range from inhibited sexual desires to the outpouring of emotional feelings that have been repressed.


Releasing bodily wastes in a dream suggests a need to release repressed emotions and/or anxiety. At times, urination may have sexual connotations. Many people dream about the need to urinate, which wakes them up, and then they realize that they need to use the bathroom. At times, the dream triggers the physical sensation and other times the physical sensation may become a part of the dream.
References in periodicals archive ?
McGrath ends the poem irreverently, with strong alliteration and a comically heavy-handed pun, as he refers to Papa pissing: "The force of my miction makes the mighty Gulf Stream.
Must rapidly absorb urine during the miction and subsequently transfer the urine within the absorbent structure.
Les complications, observees chez certains patients, comprennent des symptomes d'irritation a la miction, la contracture du col de la vessie, les hemorragies necessitant des transfusions, les infections urinaires, l'hematurie et le dysfonctionnement sexuel.
Lorsque l'enfant eprouve des emotions plus intenses en raison de sa faim douloureuse, d'une miction difficile, irritante, d'un inconfort penible, l'enfant fait l'experience de la douleur et de la personne encore indifferenciee qui en prend generalement soin, qui satisfait sa faim, soulage sa douleur, console sa peine efficacement.
These layers (in some diapers there are two layers of different material, in others only one) are a receiving layer for the transferred miction through the topsheet.