Library · Anatomy
Urinary bladder
Make it clearer
Urine is not made in the bladder: it is produced by the nephrons of the kidney and reaches the bladder already formed. Every drop travels down one of the two tubes that leave the kidneys, the ureters, and ends up in the urinary bladder, a sac where urine is stored until it leaves through the urethra, the channel you urinate through. Storing and emptying: that is what it is there for.
The bladder is not a rigid bag. Its wall is made of bands of muscle that cross in every direction, and that interlacing network is called the detrusor muscle. That is why the bladder is so distensible, so easy to stretch: as urine flows in, its upper part, the dome, bulges upward, the same way a grocery bag bulges as you load things into it.
In brief
The urinary bladder is a sac that serves as a reservoir for urine: it collects what the two ureters deliver and holds it until it leaves through the urethra.
It is a highly distensible organ: its irregular, interlacing bands of smooth muscle make up the detrusor muscle, and its dome stretches upward as it fills.
Its two main jobs are storing urine and emptying it; urine is made by the nephrons of the kidney and reaches the bladder already formed.
Sources (2)
- National Center for Biotechnology InformationHistology, Bladder. StatPearls
- OpenStax, Rice UniversityAnatomy and Physiology 2e, 25.2 Gross Anatomy of Urine TransportPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated