Overview
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All parts gut and its derivatives are innervated by Parasympathetic and Sympathetic nerves
- Nerves travel along gut arteries to reach their destination
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Most come from the Coeliac Plexus and connected Plexuses on the Abdominal Aorta
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Parasympathetic fibres to the Hindgut come from the Inferior Hypogastric Plexus in the Pelvis
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Nerve cells and fibres from the Middle 1/3rd of the Oesophagus to the Rectum that supply muscle, blood vessels and glands in the GI tract are concentrated in two plexuses
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Myenteric Plexus of Auerbach
- Situated between the two muscle layers of the gut
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Submucous Plexus of Meissner
- Situated in the submucosa
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Together, these form the Enteric Nervous System
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System receives:
- Post-Ganglionic Sympathetic (Inhibitory) Fibres
- Pre-Ganglionic Parasympathetic (Excitatory) Fibres Fibres do not pass directly to the gut muscle – enteric system always intervenes
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System able to function without the extrinsic efferent supplies
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Afferent fibres connect with the spinal cord (by the Sympathetic Trunks) and to the brainstem (by the Vagus)
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Pain impulses transmitted by Sympathetic and Parasympathetic Fibres
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Sensation of distension transmitted in Parasympathetic Fibres