1. Average Bladder Capacity 350-550 cc.
In the elderly, the capacity may decrease to 250 - 300 cc. Approximately 150-250 cc may be stored (less in the elderly) before there is a sensation of bladder pressure. Then the bladder fills to the point at which the individual is uncomfortable and seeks the toilet. Click here for National Institutes of Health information on normal urination
2. Anatomical integrity of the bladder and urethra.
The bladder and the urethra act as a storage unit for urine. The bladder muscle (detrusor) is stable and does not contract until the person relaxes the urethra. Post voided residual is normally less than 50cc. The literature suggests that younger people empty their bladder every 4 to 5 hours and older people empty their bladder every 3 to 4 hours within a 24 hour period.
Instant Feedback:
The bladder tends to increase in capacity with increased age
3. Intact neurological system to provide voluntary and coordinated voiding.
Complex feedback loops involve the frontal lobe of the brain. The sacral reflex center in the spinal cord and the sphincter comprise the voiding cycle. This complex cycle is slowed by age related changes.
Click here for overview of the age-related changes affecting this complex voiding cycle.
4. Physical and mental capacity of the person to perform that associated task of voiding.
- Mental
- Able to identify need to void.
- Can locate an appropriate place to urinate.
- Physical
- Has the mobility to get to toilet.
- Can remove clothing as necessary.
Instant Feedback:
It's normal to have about 100 cc left in the bladder after voiding.
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