Innervation of the Urinary System Flashcards
How does information get from the bladder to the brain?
Mechanoreceptors
Stretch in the urethra is transmitted through which nerve?
Pudendal nerve
Which nerve controls the external urethral sphincter?
Pudendal nerve
Somatic innervation of the external urethral sphincter is controlled by which nerve?
Pudendal nerve
Voluntary motor system
Somatic
Which nerve controls the sympathetic nervous portion of the bladder?
Hypogastric nerve
Where do axons from the hypogastric nerve synapse?
Pelvic plexus, detrusor muscle, internal urethral sphincter
Does relaxation or contraction of the detrusor muscle encourage urinary retention?
Relaxation
Where do parasympathetic preganglionic nerve cells live?
End of spinal cord in the sacral segments
Where do axons from the pelvic nerve synapse?
Pelvic plexus ganglion or bladder wall glanglion
Which nerve controls parasympathetic innervation of the bladder?
Pelvic nerve
Which nerve causes contraction of the detrusor muscle?
Pelvic nerve (parasymathetic)
Which nerve causes relaxation of the detrusor muscle?
Hypogastric nerve (sympathetic)
Which system help to retain urine?
Sympathetic
Which systems help with micturition?
Parasympathetic
Inability of the body to control the evacuative functions
Incontinence
What are common forms of incontinence?
UMN, LMN, hormone sensitive, and congenital
What happens when you lose UMN input to the bladder (UMN disease/UMN bladder)?
Paralysis, incr. tone, full bladder difficult to express
Animal cannot voluntarily open external urethral sphincter
UMN bladder
Squirts of urine
UMN bladder
How do you relax somatic/voluntary muscles (external urethral sphincter)?
Sedatives (like valium)
How do you relax autonomic/involuntary muscles (internal urethral sphincter)?
Block alpha receptors in urethra (phenoxybenzamine, prazosin)
What is a common side effect of phenoxybenzamine and prazosin?
Hypotension
What happens when you lose LMN input to the bladder (LMN disease/LMN bladder)?
Paralysis w/decr tone, flaccid sphincter, prone to UTI b/c urine never completely clears the bladder
