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Micturition - Anatomy & Physiology (view source)
Revision as of 10:58, 10 July 2008
, 10:58, 10 July 2008no edit summary
<big><center>[[Urinary System - Anatomy & Physiology|'''BACK TO URINARY - ANATOMY & PHYSIOLOGY''']]</center></big>
<big><center>[[Urinary System - Anatomy & Physiology|'''BACK TO URINARY - ANATOMY & PHYSIOLOGY''']]</center></big>
Micturition is the normal process of the passive stoage and active voiding of urine.
==Storage and Voiding==
===Under neurological control===
* [[Bladder - Anatomy & Physiology| Bladder]]
** Smooth muscle
* [[Urethra - Anatomy & Physiology| Urethra]]
** Smooth muscle
** Skeletal muscle
==Innervation Involved in the Reflex==
===Sensory===
The fullness of the bladder is detected by stretch sensitive nerve endings in the bladder wall
===Motor===
The motor components of the reflex are the [[Bladder - Anatomy & Physiology #Detrusor Muscle| Detrusor Muscle]], [[Bladder - Anatomy & Physiology #Internal Urethral Sphincter| Internal Urethral Sphincter]] and the [[Bladder - Anatomy & Physiology #External Urethral Sphincter| External Urethral Sphincter]]. They former two are supplied by the autonomic nervous system with the latter being of somatic innvervation.
* The general aim for the '''sympathetic and somatic systems''' is to '''retain urine'''
* The general aim for the '''parasympathetic system''' is to '''void urine'''
===Somatic Motor Supply===
* S1-S2
* Pudendal Nerve
* No synapse
* Innervates the urethral skeletal muscle - external urethral sphincter
* Function is to retain urine
===Parasympathetic Supply - Bladder===
* S1-S3
* Synapse in pelvice plexus or bladder wall
* Innvervate the detrusor muscle
* Action - excitatory
* Function - empty bladder
===Sympathetic Supply - Detrusor Muscle===
* L1-L4
* Syanpse in caudal mesenteric ganglion - bladder wall
* Receptor - beta
* Inhibitory action
* Allows bladder filling
===Sympathetic Supply - Internal Urethral Sphincter===
* L1-L4
* Synapse in caudal mesenteric ganglion
* Receptor - alpha
* Excitatory action
* Function - retain urine through increased urethral tone
===Central Connections===
There is aspects of control by the Pons and the Cerebral Cortex with possible influences from the cerebellum.