Marong Fang, PhD. Institute of Anatomy & Cell Biology The autonomic nervous system Introduction: visceral, or vegetative, apart of N.S. distributed in the viscera, cardiovascular system & secretory glands. Compositions: 1. Visceral sensory nerve 2. Visceral motor nerve 3. Centers of visceral nerves The visceral motor nerves: 2 parts: sympathetic and parasympathetic nerves The autonomic nervous system Introduction: visceral, or vegetative, apart of N.S. distributed in the viscera, cardiovascular system & secretory glands. Compositions: 1. Visceral sensory nerve 2. Visceral motor nerve 3. Centers of visceral nerves The visceral motor nerves: 2 parts: sympathetic and parasympathetic nerves

Marong Fang, PhD. Institute of Anatomy & Cell Biology Somatic vs. Autonomic Voluntary Skeletal muscle Single efferent neuron Axon terminals release acetylcholine Always excitatory Controlled by the cerebrum Involuntary Smooth, cardiac muscle; glands Multiple efferent neurons Axon terminals release acetylcholine or norepinephrine Excitatory or inhibitory Controlled by the homeostatic centers in the brain – pons, hypothalamus, medulla oblongata

Marong Fang, PhD. Institute of Anatomy & Cell Biology

Main differences between somatic motor and visceral motor n. SomaticVisceral EffectorsSkeletal muscles Cardiac, smooth muscles and glands Kind of fibersOneTwo: sympathetic and parasympathetic From lower center to effect require Single neuron Two neurons: preganglionic neuron (fiber) and postganglionic neuron (fiber) FibersThick myelinated Preganglionic: thin myelinated postganglionic: unmyelinated Distributive form Nerve trunkNerve plexuses ControlVoluntary (consciousness ) Involuntary (unconsciousness )

Marong Fang, PhD. Institute of Anatomy & Cell Biology Autonomic Nervous System 2 divisions:  Sympathetic “Fight or flight” “E” division  Exercise, excitement, emergency, and embarrassment  Parasympathetic “Rest and digest” “D” division  Digestion, defecation, and diuresis

Marong Fang, PhD. Institute of Anatomy & Cell Biology  The sympathetic nervous system: 1. lower center: in lateral horn of T1(or C8) ~ L3 segments of spinal cord (intermediolateral nucleus) 2. peripheral part: sympathetic trunks sympathetic ganglia(pre/para-vertebral) sympathetic plexuses sympathetic nerves communicating branches  The sympathetic nervous system: 1. lower center: in lateral horn of T1(or C8) ~ L3 segments of spinal cord (intermediolateral nucleus) 2. peripheral part: sympathetic trunks sympathetic ganglia(pre/para-vertebral) sympathetic plexuses sympathetic nerves communicating branches

Marong Fang, PhD. Institute of Anatomy & Cell Biology  The sympathetic trunk: --- paravertebral ganglia and interganglionic branches --- extends from the base of skull to the coccyx --- on the both sides of vertebral column parts: cervical part (superior, middle and inferior cervical ganglia) thoracic part (10~12 pairs of thoracic sympathetic ganglia) lumbar part (3~4 pairs of lumbar sympathetic ganglia) sacral part (4~5 pairs of sacral sympathetic ganglia) coccygeal part (1 unpair of coccygeal ganglion)

Marong Fang, PhD. Institute of Anatomy & Cell Biology  The sympathetic ganglia: 2 types ---- paravertebral ganglia:inf./sup./imf. Cervical ganglia;12 thoraci,3-4lumbar,4-5sacral,coccygeal ganglion ---- prevertebral ganglia: celiac ganglia, aorticorenal ganglia superior mesenteric ganglia inferior mesenteric ganglia  The sympathetic ganglia: 2 types ---- paravertebral ganglia:inf./sup./imf. Cervical ganglia;12 thoraci,3-4lumbar,4-5sacral,coccygeal ganglion ---- prevertebral ganglia: celiac ganglia, aorticorenal ganglia superior mesenteric ganglia inferior mesenteric ganglia

Marong Fang, PhD. Institute of Anatomy & Cell Biology The communicating branches: --link the sympathetic ganglion with the corresponding spinal nerve types: white and gray communicating branches white communicating branches sympathetic preganglionic fiberse arise from the neurons of lateral horn from T1~L3 segments of spinal nerves. about 15 pairs via the anterior roots of corresponding spinal nerves to communicate with the paravertebral ganglia. gray communicating branches: peripheral blood vessels, sweat glands & arrectores pilorum sympathetic postganglionic fiberse arise from the neurons of the paravertebral ganglia and communicate with the 31 pairs of spinal nerves.

Marong Fang, PhD. Institute of Anatomy & Cell Biology

Once a preganglionic axon reaches the chain ganglion, it may: …synapse with a ganglionic neuron … the same chain ganglion. …ascend or descend in the trunk to synapse within another chain ganglion. …pass through the chain ganglion and emerge from the chain … splanchnic nerve.. synapsing.

Marong Fang, PhD. Institute of Anatomy & Cell Biology

Three fates of postganglionic fibers Back to a spinal nerve along gray communicating branches ( 31 pairs ) to terminate in blood vessels, arrectores pilorum and sweat glands of head, neck, trunk and limbs The fibers from their networks around blood vessels passing to visceral end organs Terminate directly in certain organs

Marong Fang, PhD. Institute of Anatomy & Cell Biology Distribution of sympathetic nerve Preganglionic fibersPostganglionic fibers T1~T5Head, neck, upper limb and thoracic viscera T5~T12Abdominal viscera L1~L3Pelvic viscera and lower limb

Parasympathetic part Lower center: located in four pairs parasympathetic nuclei in brain stem and in sacral parasympathetic nucleus of spinal cord segments S2~S4 Parasympathetic ganglia: terminal ganglia are near or within the wall of a visceral organ  Para-organ ganglia ： Ciliary ganglion Pterygopalatine ganglion Submandibular ganglion Otic ganglion  Intramural ganglia

Marong Fang, PhD. Institute of Anatomy & Cell Biology Parasympathetic Division 4 of 12 pairs of cranial nerves contain preganglionic parasympathetic fibers. Preganglionic fibers are long, postganglionic fibers are short. Vagus:  Innervate heart, lungs esophagus, stomach, pancreas, liver, small intestine and upper half of the large intestine.

Marong Fang, PhD. Institute of Anatomy & Cell Biology Parasympathetic Division Preganglionic fibers originate in midbrain, medulla, and pons; and in the 2-4 sacral levels of the spinal cord. Preganglionic fibers synapse in ganglia located next to or within organs innervated. Do not travel within spinal nerves.  Do not innervate blood vessels, sweat glands,and arrector pili muscles.

Marong Fang, PhD. Institute of Anatomy & Cell Biology Parasympathetic Effects Stimulation of separate parasympathetic nerves. Release ACh. Relaxing effects:  Decrease heart rate (HR).  Dilate blood vessels.  Increase GI activity.

Cranial portion Ⅲ accessory oculomotor nucleus 〈 ○ sphincter pupillae and ciliary muscles ciliary ganglion pterygopalatine ganglion Ⅶ 〈 ○ lacrimal gland superior salivatory nucleus 〈 ○ sublingual gland submandibular ganglion submandibular gland Ⅸ inferior salivator nucleus 〈 ○ parotid gland otic ganglion Ⅹ heart, lungs, liver, spleen, dorsal nucleus of vagus n. 〈 ○ kidneys,alimentary tract terminal ganglia as far as left colic flexure

Marong Fang, PhD. Institute of Anatomy & Cell Biology  E-W nucleus----parasympathetic preganglionic fibers (via oculomotor nerve)----ciliary ganglion (relay)---- parasympathetic postganglionic fibers (short ciliary nerves)---- supply the ciliary m. and sphincter pupillae  superior salivatory nucleus----parasympathetic preganglionic fibers(via the facial nerve )----greater petrosal nerve---- pterygopalatine ganglion (relay)----parasympathetic postganglionic fibers (via the maxillary—zygomatic – lacrimal nerves)---- supply the lacrimal gland

Marong Fang, PhD. Institute of Anatomy & Cell Biology

 superior salivatory nucleus----parasympathetic preganglionic fibers (via facial n.– chorda tympani – lingual n.)---- submandibular ganglion(relay)----parasympathetic postganglionic fibers----supply the submandibular and sublingual glands

Marong Fang, PhD. Institute of Anatomy & Cell Biology superior salivatory nucleus- Facial n.

Marong Fang, PhD. Institute of Anatomy & Cell Biology  Inferior salivatory nucleus----parasympathetic preganglionic fibers (via glossopharyngeal n.– tympanic n. – lesser petrosal n.) ---- otic ganglion (relay) ---- parasympathetic postganglionic fibers(via auriculotemporal n.) ---- supply parotid gland

Marong Fang, PhD. Institute of Anatomy & Cell Biology

 dorsal nucleus of vagus n parasympathetic preganglionic fibers (via the vagus n. and it’s branches) ---- ganglia in organs (relay) ---- parasympathetic postganglionic fibers ---- supply the organs of neck, thorax and abdomen (above the left colic flexure).

Marong Fang, PhD. Institute of Anatomy & Cell Biology

Sacral portion Preganglionic fibers from sacral parasympathetic nucleus leave spinal cord with anterior roots of the spinal nerves S2~S4, Then leave sacral nerves and form pelvic splanchnic nerve and travel by way of pelvic plexus to terminal ganglia in pelvic cavity Postganglionic fibers terminate in descending and sigmoid colon, rectum and pelvic viscera

Marong Fang, PhD. Institute of Anatomy & Cell Biology  The sacral portion of parasympathetic nervous system: sacral parasympathetic nucleus ----parasympathetic preganglionic fibers (via corresponding sacral nerves pelvic splanchnic nerves ---- pelvic plexus and it’s branches ) --- ganglia in organs (relay) ---- supply the pelvic organs, descending and sigmoid colons and rectum.

Marong Fang, PhD. Institute of Anatomy & Cell Biology Parasympathetic Division Preganglionic fibers from the sacral level innervate the lower half of large intestine, the rectum, urinary and reproductive systems.

Main differences between sympathetic and parasympathetic

SympatheticParasympathetic Lower centerLateral gray horn of spinal cord segments T1~L3 Four pairs parasympathetic nuclei and sacral parasympathetic nucleus GangliaParavertebral, prevertebral Terminal Preganglionic f.ShorterLonger Postganglionic f.LongerShorter Pre: Postganglionic1: many more1: a few DistributionsThroughout the bodyLimited primarily to head and viscera of thorax, abdomen, and pelvis Different actionPrepares for emergency situation (fight or flight) Conserve and restore body energy (rest and relaxation)

Visceral plexuses Cardiac plexuses  Superficial, below aortic arch  Deep, anterior to bifurcation on trachea Pulmonary plexus Celiac plexus Abdominal aortic plexus Hypogastric plexus  Superior hypogastric plexus  Inferior hypogastric plexus (pelvic plexus)

Visceral sensory nerves Enteroceptors Ⅶ，Ⅸ, Ⅹ Nucleus of solitary tract Sympathetic nerve Pelvic splanchnic nerve Posterior horn Thalamus Hypothalamus Cerebral cortex Somatic motor neurons visceral motor neuclei Effectors

Marong Fang, PhD. Institute of Anatomy & Cell Biology Visceral pain BRAIN sensory fibres in visceral nerves Visceral sense is conveyed by visceral nerves 1

Marong Fang, PhD. Institute of Anatomy & Cell Biology Referred pain (reflective pain) is a term used to describe the phenomenon of pain perceived at a site adjacent to or at a distance from the site of an injury's origin. One of the best examples of this is during ischemia brought on by a heart attack where pain is often felt in the neck, shoulders, and back rather than in the chest, the site of the injury.

Marong Fang, PhD. Institute of Anatomy & Cell Biology The cardiac general visceral sensory pain fibers follow the sympathetics back to the spinal cord and have their cell bodies located in thoracic dorsal root ganglia.Also, the dermatomes of this region of the body wall and upper limb have their neuronal cell bodies in the same dorsal root ganglia. and synapse in the same second order neurons in the spinal cord segments (T1-5) as the general visceral sensory fibers from the heart. The CNS does not clearly discern whether the pain is coming from the body wall or from the viscera

Marong Fang, PhD. Institute of Anatomy & Cell Biology BRAIN HEART T1 - T5 Visceral pain How is pain felt? 2 Case: A 50-year- old man with a history of high cholesterol presents with retrosternal pain, which later radiates to the chest, armpit and shoulder on the left. 1) Pain may be felt from the affected organ phrenic also to pericardium, for retrosternal pain PERICARDIUM phrenic C3,4,5

Marong Fang, PhD. Institute of Anatomy & Cell Biology T1 - T5 BRAIN HEART How is pain felt? Visceral pain 3 Case: A 50-year- old man with a history of high cholesterol presents with retrosternal pain, which later radiates to the chest, armpit and shoulder on the left. 2)Pain may be 'referred' to nearby dermatomes CHEST & ARM

Marong Fang, PhD. Institute of Anatomy & Cell Biology BRAIN HEART How is pain felt? Visceral pain 4 Case: A 50-year- old man with a history of high cholesterol presents with retrosternal pain, which later radiates to the chest, armpit and shoulder on the left. 3)Pain may be 'referred' to distant dermatomes T1 - T5 HEART T1 - T5C3, 4, 5 PERICARDIUM phrenic NECK and SHOULDE R

Referred pain