Urology is the specialty of medicine concerned with the study of the genito-urinary system along with the treatment of its associated problems and diseases.
 
The function of the urinary system can be affected by ageing, hereditary factors, injury, infection, underlying illnesses, or hormonal imbalances that can lead to wide-ranging symptoms such as excessive urine production, prostate cancer restricted urinary flow, frequent, urgent or involuntary urination as well as pain. 

Problems related to nocturnal urine production and emptying are very common. Generally, the bulk of the body’s 24-hour urine output is generated during the day, with less than a third being produced during sleep.  To facilitate this balance the kidneys normally concentrate the urine produced during sleep, reducing the volume needed to be stored in the bladder. When this balance is upset problems begin.

Nocturia
Nocturia is the disorder where an individual has to wake up one or more times a night to void (urinate).

Bedwetting - Primary Nocturnal Enuresis - PNE
Bedwetting is the involuntary passing of urine during sleep.