A valve at the bladder outlet.
D000818:Animals; D002417:Cattle; D004285:Dogs; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement; D010828:Physiology, Comparative; D012756:Sheep; D013552:Swine; D001743:Urinary Bladder / Q000502:physiology*; D014549:Urinary Incontinence / Q000209:etiology; D014554:Urination