Difference between revisions of "Micturition - Anatomy & Physiology"
| Line 22: | Line 22: | ||
* The general aim for the '''sympathetic and somatic systems''' is to '''retain urine''' | * The general aim for the '''sympathetic and somatic systems''' is to '''retain urine''' | ||
* The general aim for the '''parasympathetic system''' is to '''void urine''' | * The general aim for the '''parasympathetic system''' is to '''void urine''' | ||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
===Parasympathetic Supply - Bladder Detrusor Muscle=== | ===Parasympathetic Supply - Bladder Detrusor Muscle=== | ||
| Line 50: | Line 43: | ||
* Excitatory action | * Excitatory action | ||
* Function - retain urine through increased urethral tone | * Function - retain urine through increased urethral tone | ||
| + | |||
| + | |||
| + | ===Somatic Motor Supply - External Urethral Sphincter=== | ||
| + | * S1-S2 | ||
| + | * Pudendal Nerve | ||
| + | * No synapse | ||
| + | * Innervates the urethral skeletal muscle - external urethral sphincter | ||
| + | * Function is to retain urine | ||
===Central Connections=== | ===Central Connections=== | ||
There is aspects of control by the Pons and the Cerebral Cortex with possible influences from the cerebellum. | There is aspects of control by the Pons and the Cerebral Cortex with possible influences from the cerebellum. | ||
Revision as of 16:41, 18 August 2008
|
Micturition is the normal process of the passive stoage and active voiding of urine.
Introduction
After entering the renal pelvis the modification of the urine is over in all domestic species other than the horse where mucin is added. The urine passes along the ureters and enters the bladder. It is here that the urine is stored until it is to be voided. Urine is not constantly excreted and it is only when there is a significant amount present in the bladder that the process of voiding occurs. Both the Bladder and the Urethra have smooth muscle and thus receive autonomic influence with regard to their activity. However the urethra also has an element of skeletal muscle giving the animal some degree of concsious control over the voiding of urine.
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 Detrusor Muscle, Internal Urethral Sphincter and the 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
Parasympathetic Supply - Bladder Detrusor Muscle
- S1-S3
- Synapse in pelvice plexus or bladder wall
- Innvervate the detrusor muscle
- Action - excitatory
- Function - empty bladder
Sympathetic Supply - Bladder 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
Somatic Motor Supply - External Urethral Sphincter
- S1-S2
- Pudendal Nerve
- No synapse
- Innervates the urethral skeletal muscle - external urethral sphincter
- Function is to retain urine
Central Connections
There is aspects of control by the Pons and the Cerebral Cortex with possible influences from the cerebellum.