The Central Autonomic Network and Regulation of Bladder Function

Figures

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  FIGURE 1. (A) Efferent innervation of the bladder, ureter, and external urethral sphincter (modified from Fowler et al., 2008). Parasympathetic fibers (green) arise from S2-4 nerve roots. They travel in the pelvic nerve and pass via the pelvic plexus to innervate the bladder detrusor muscle of the bladder. Sympathetic fibers (red) arising from T11-L2 segments, pass via the inferior mesenteric plexus (IMP) and travel in the hypogastric nerve (HGN) to innervate the ureter and the detrusor smooth muscle. Somatic innervation of the external urethral sphincter is via the pudendal nerve, and arises from Onuf’s nucleus at S2-S4. (B) A simplified schematic showing the major nerves and neurotransmitters involved in bladder control. The pudendal nerve causes contraction of the external urethral sphincter via nicotinic receptors (+N); parasympathetic fibers produce contraction of the detrusor muscle by acting at M3 receptors; and sympathetic innervation inhibits detrusor contraction through β3 receptors, and contraction of the internal urethral sphincter by α1 receptor activation.

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  FIGURE 2. Schematic to illustrate some of the key anatomical regions significant for bladder control, including the pons, cerebellum, insula, occipito-parietal cortex, and frontal cortex.

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  FIGURE 3. Summary of some key brain areas demonstrated to be involved in bladder related tasks based on fMRI: supplementary motor area (SMA), mid-cingulate gyrus (A), frontal operculum (B), insula (C), cerebellum.