Thoracic anatomy

Autonomic nervous system

Thoracic Anatomy 3.G.1.1 James Mitchell (December 24, 2003) Autonomic nervous system

Division by direction Visceral efferent Preganglionic myelinated, postganglionic unmyelinated Synapse in ganglia Visceral afferent Similar to somatic afferent Cell body in CNS, peripheral processes travel with autonomic and somatic fibres Division by outflow Sympathetic Thoracolumbar outflow: T1-L3 Synapse in sympathetic trunk ganglia or other ganglia near CNS Preganglionic cholinergic, postganglionic predominantly noradrenergic (also adrenergic, cholinergic sudomotor and purinergic) Parasympathetic Craniosacral outflow: III, VII, IX, X, S2-4 Synapse adjacent to end-organs Cranial nerve parasympathetic ganglia are traversed by other fibres but contain only parasympathetic synapses Parasympathetic anatomy III Edinger-Westphal nuclei → oculomotor n. → n. to inferior oblique → ciliary ganglion → short ciliary nn. → ciliary muscle and sphincter pupillae VII Superior salivatory nucleus → nervus intermedius → facial n. → chorda tympani → lingual n. → submandibular ganglion → submandibular and sublingual glands Geniculate ganglion → greater petrosal n. → pterygopalatine ganglion → zygomatic and lacrimal nerves to lacrimal gland and nasal and palatine branches to nasal mucosa XI Inferior salivatory nucleus → glossopharyngeal nerve → tympanic plexus → lesser petrosal n. → otic ganglion → auriculotemporal n. → parotid gland and oral mucosa X Dorsal nucleus of vagus → vagus n. → minute ganglia in respiratory tract, heart, kidneys and gastrointestinal viscera from oesophagus to mid transverse colon. Most vagal fibres are afferent, there is a very large ratio of postganglionic to preganglionic efferent fibres. S2-4 Anterior rami → sacral spinal nerves → pelvic viscera and pelvic plexus → bladder, erectile tissue, gonads, uterus and uterine tubes, hindgut from mid transverse colon to rectum Sympathetic anatomy Preganglionic efferent Lateral column cell body → ventral root → white ramus communicans → sympathetic trunk → synapse in trunk or other ganglia or adrenal Postganglionic May ascend or descend in the trunk, rejoin all spinal nerves via grey rami communicantes or leave in direct branches to vessels or viscera Distribution Cranial Internal carotid plexus arises from superior cervical ganglion and

Thoracic Anatomy 3.G.1.2 James Mitchell (December 24, 2003) accompanies carotid into the cranium and along anterior and middle cerebral arteries and ophthalmic artery Cervical Sympathetic chain condenses usually into three ganglia on each side: superior (C2-3), middle (C6) and cervicothoracic (stellate, T1) cervical ganglia Cardiac plexus Derived from T1-4 (and X) via cervical and thoracic ganglia Surrounds heart, great vessels and coronaries Pulmonary plexuses Coeliac plexus Two ganglia opposite T12-L1 with large condensation of autonomic fibres Gives rise to phrenic, splenic, hepatic, left gastric, intermesenteric, suprarenal, renal, gonadal, superior and inferior mesenteric plexuses which accompany arteries to their target organs Superior hypogastric plexus Inferior hypogastric plexus Supplies hindgut, ureter, bladder, gonads, sex organs

Somatic levels of visceral afferents

Organ Sympathetic Parasympathetic Heart T1-5 X Lungs T2-4 X Oesophagus T5-6 X Stomach T6-10 X Liver, gallbladder T6-10 X Pancreas, spleen T6-10 X Small bowel T9-10 X Large bowel T11-12 X to mid transverse Kidney, ureter T10-L2 X, S2-4 Adrenal T8-L1 none Gonads T10-11 S2-4 Bladder T11-L2 S2-4 Prostate T11-L1 S2-4 Uterus T10-L1 S2-4

Thoracic Anatomy 3.G.1.3 James Mitchell (December 24, 2003)