urination

[u″rĭ-na´shun]

the discharge of urine from the bladder; urine from the kidneys is passed in spurts every few seconds along the ureters to the bladder, where it collects and later is passed to the outside via the urethra. Called also micturition and voiding.

The Urinary Process. Urination is a complex process controlled by muscles of the bladder and sphincter mechanism and by modulatory centers in the central and peripheral nervous systems. The detrusor muscle is a complex meshwork of interlaced smooth muscle bundles that contract in a way that squeezes urine from the bladder vesicle. The sphincter mechanism consists of smooth muscle in the bladder neck and proximal urethra, a striated muscle sphincter consisting of slow twitch muscle fibers in the urethral wall, and periurethral muscles that are a component of the pelvic floor muscles. The detrusor relaxes during bladder filling to accommodate increasing volumes at a low pressure, and the sphincter remains tightly closed. During urination, the detrusor contracts and the sphincter mechanism relaxes, allowing smooth outflow of urine.

As the bladder fills, modulatory centers in the brain prevent the occurrence of contractions. Meanwhile, the sphincter mechanism remains closed under autonomic and somatic nervous system control. During urination, the inhibition of contractions is removed and a reflex originates in the pontine micturition center. That causes the detrusor muscle to contract and the sphincter mechanism to relax. The location of the final output of central nervous system impulses to and from the bladder and sphincter is the sacral micturition center, located in spinal segments 2, 3, and 4, which must be intact for contraction to occur. Injury to the pontine micturition center will compromise the smooth coordination between sphincter mechanism and detrusor muscle, and injury to the brain will affect the volitional control of urine (bladder stability). See also urinary incontinence.

u·ri·na·tion

(yūr'i-nā'shŭn),

The passing of urine.

Synonym(s): miction, micturition (1) , uresis

Farlex Partner Medical Dictionary © Farlex 2012

u·ri·na·tion

(yūr'i-nā'shŭn)

The passing of urine.
Synonym(s): miction, micturition (1) , uresis.

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

Patient discussion about urination

Q. protien in urine what are the causes and preventions

Q. How you stop urinating frequently? I don't have any conditions that make me urinate often. I simply drink lots of water... Is there some trick I can employ so that I can still drink lots of water but not have to go to the bathroom so frequently?

A. I only drink water and green tea, Thanks.

Q. Today doctor removed my stunt of kidney. It inflamate while urination.. till How long i will feel like this?

A. You should consult your doctor, since instruments in the kidney and urinary tracts can cause infections (even after removing them), that may cause symptoms like you describe.

More discussions about urination

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References in periodicals archive

If you take diuretics or other medications that promote urination, taking them earlier in the day instead of at night can make a big difference.

Nocturia: Stay in Bed, Not in the Bathroom

Whether that means physio consults to help women train their muscles for standing urination or standard supply provision of products like 'Shewee'--all soldiers still need a chance for rest and food and urination.

LET'S TALK ABOUT WOMEN IN THE MILITARY: Military Woman

'Then there is a group of drugs that act on the bladder to reduce the frequency of urination and urgency.'

Prostate problems can make life awkward for men over 50

Increased drinking, increased urination, and chronic urinary-tract infections are all signs of Cushing's and can lead to incontinence.

When Leaks Happen: Most cases of canine incontinence have a medical cause that usually responds to treatment

Avoiding alcohol and coffee late at night can help reduce night-time urination, as can drinking fluids earlier in the day rather than later.

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found that fifty percent of patients with BOO had overactive bladder (OAB).1 OAB, a clinical syndrome caused by abnormal afferent signals and detrusor overactivity, used to be called unstable bladder, the main symptoms of which were urgent urination, uroclepsia, frequent micturition, increased urination at night, and it would seriously influence patients' life quality.2,3 Study showed that the more obvious prostatic median lobe hyperplasia was and more serious BOO symptoms were,4 the severer OAB symptoms were; the reason why OAB occurred was secondary changes of stability, elasticity and sensitivity of bladder which was caused by BOO.

Tamsulosin and Solifenacin in the treatment of Benign Prostatic Hyperplasia in combination with overactive bladder

There may be a burning dysuria, a burning urethral pain independent of urination, urinary frequency, and a sense of incomplete bladder emptying.

Kidney Stone Disease and Its Management Using Homeopathy

Before considering Noctiva, health care providers should evaluate each patient for possible causes for the nocturia, and optimise the treatment of underlying conditions that may be contributing to the night-time urination.

US FDA approves Noctiva Nasal Spray as Treatment for Frequent Urination at Night

The present study revealed that nighttime urination was common among patients with OSAS and that patients with OSAS and nocturia tended to be older and have more severe OSAS (compared to patients with OSAS and without nocturia).

Obstructive sleep apnea syndrome should be considered as a cause of nocturia in younger patients without other voiding symptoms

The bogus enforcement officer hit mums and dads with a "public urination notice" and a PS75 penalty charge when he spotted little ones spending a penny.

Potty fines con man is on the loos

Overall, Mary states she is not sure what has caused this sudden thirst, hunger, and urination problems.

Excessive hunger and weight loss in a healthy teen