Rather than going into exaggerated details... I will only point the important
facts.
1. When urine starts collecting within
the bladder. The detrusor muscle is stretched. This is detected via stretch
receptors and is carried by the sensory nerve to the spinal cord.
2. The reflex arc root value is S2 to S4,
from these parasympathetic fibers arise, which causes contraction of the detrusor
muscle.
3. This arc is under the control of the
higher centers ( frontal lobe and pons), which can either FACILITATE or
INHIBIT this reflex arc.
1. Atonic bladder- This happens when only
the sensory pathway is destroyed. For example, the posterior cord lesions where all
sensory tracts are involved like tabes dorsalis.
The bladder stretches to its maximum
(because of the absence of stretch sensation) and suddenly there is an overflow of
urine.
2. Automatic bladder- Think of this
bladder like that of an infant. The child voids urine without any conscious
control. The micturition reflex is intact..but the higher centers are not
active! Hence as soon as the stretch reflex becomes strong enough the person
voids urine irrespective of the social setting.
Example- cord lesions above the level of
S2.
http://medicowesome.blogspot.in/2014/11/remembering-autonomic-innervation-of.html
-M-
Thanks for good information! Can I use the picture with resource?
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