Autonomic Nervous System

• What does the autonomic NS innervate?

  Motor innervation of smooth muscle, cardiac muscle & glands

  Split into sympathetic & parasympathetic
• How many pairs of spinal nerves do we have?

  31
• How many pairs of cervical spinal nerves are there?

  8
• How many pairs of thoracic spinal nerves are there?

  12
• How many pairs of lubar spinal nerves are there?

  5
• How many pairs of sacral spinal nerves are there?

  5
• How many pairs of coccygeal spinal nerves are there?

  1
• What is the innervation of the adrenal medulla?

  Preganglionic sympathetic neurons

  • no post-ganglionic neuron
  • no parasympathetic innervation
• What is found only in thoracic & lumbar spinal segments?

  Lateral horn - where sympathetic efferent originates
• What neurotransmitter is released within sympathetic ganglion (between pre- and post-ganglionic fibres)?

  Acetylcholine
• What neurotransmitter is released by post-ganglionic sympathetic fibres at their target tissue?

  Noradrenaline
• What do parasympathetic neurons release?

  Acetylcholine (always acetylcholine, in ganglion & at target tissue)
• What do splanchnic nerves target?

  Viscera
• Are splanchnic nerves sympathetic or parasympathetic?

  Can be either
• What cranial nerves are parasympathetic?

  CN III - oculomotor

  CN VII - facial nerve

  CN IX - glossopharyngeal

  CN X - vagus nerve
• What are the 4 ganglia that cranial parasympathetic nerves can synapse in?

  Ciliary ganglion

  Otic ganglion

  Pterygopalatine ganglion

  Submandibular ganglion
• What are the nuclei for the oculomotor nerve?

  Pre-ganglionic fibres arise from Edinger-Westphal nucleus (midbrain)

  Oculomotor nucleus gives rise to all other fibres in nerve
• What is the ganglia for the oculomotor nerve?

  Ciliary ganglion
• What do post-ganglionic fibres of the oculomotor nerve target?

  Ciliary muscles

  Sphincter pupillae
• What is Horner's syndrome?

  Sympathetic nerves reach eye (travel along internal carotid & opthalmic arteries) Lesion along pathway -> Horner's
• What are the symptoms of Horner's syndrome?

  Miosis - permanently constricted pupil

  Ptosis - eyelid drooping

  Anhydrosis - inability to sweat

  Enophthalmos - sunken appearance to eye
• What is oculomotor nerve palsy?

  Impairment of the oculomotor nerve, which controls eye movement and pupil constriction.
• Visceral afferents can be…

  Reflexive OR nociceptive
• Reflexive afferents?

  Fibres do not reach consciousness

  Project to spinal cord, brainstem or hypothalamus
• Nociceptive afferents?

  Reach consciousness, but poorly localised

  Due to visceral afferents being less densely packed than somatic afferents
• Where do sympathetic nerves arise from?

  Only thoracic & lumbar spinal segments

  Thoracolumbar outflow
• Where do parasympathetic nerves arise from?

  Only from brainstem & sacral spinal segments

  Craniosacral outflow
• Fill in the blanks

  A) Spinal cord

  B) Dorsal root

  C) Ventral root

  D) Spinal nerve

  E) Spinal ganglion

  F) Sympathetic ganglion and trunk

  G) Dorsal ramus

  H) Ventral ramus

  I) Grey

  J) white

  K) rami communicantes

  
• What is the pathway of a sympathetic efferent?

  Pre-ganglionic fibre originates in lateral horn

  Neuron travels through ventral root -> spinal nerve -> into white ramus communicans ('white' as fibres are myelinated)

  Pre- and post-ganglionic neurons synapse in sympathetic ganglion

  Post-ganglionice fibre exits grey ramus communicans & travel to target tissue ('grey' as fibres are unmyelinated)
• What is the sympathetic trunk?

  A bundle of nerves that runs along the vertebral column.

  Fibres can travel up or down the sympathetic trunk to different vertebral levels before passing through grey ramus communicans
• Fill in the blanks

  A) Superior vena cava

  B) Descending thoracic aorta

  C) Diaphragm

  D) Sympathetic trunk

  
• What is the pathway of a parasympathetic efferent?

  Efferent runs from ventral horn -> through ventral root -> spinal nerve -> along ventral/dorsal ramus -> synapses within ganglion before reaching target tissue

  Parasympathetic ganglia lie near to, or even within lining of target organ
• What is the route of splanchnic nerves?

  Synapse in prevertebral ganglia that lie beside blood vessels that supply target organ

  Post-ganglionic fibres then 'hitch a lift' with vessels
• What are the nuclei for the facial nerve?

  Pre-ganglionic parasympathetic fibres arise from Salivatory Lacrimal (Superior Salivatory) Nucleus of pons

  Facial nucleus gives rise to all other fibres in nerve
• What ganglia does the facial nerve synapse in?

  EITHER

  Pterygopalatine ganglion OR

  Submandibular ganglion
• What do post-ganglionic pterygopalatine facial nerve fibres target?

  Lacrimal glands
• What do post-ganglionic submandibular facial nerve fibres target?


  Sublingual & submandibular glands
• What are the nuclei for the glossopharyngeal nerve?

  Pre-ganglionic parasympathetic fibres arise from Salivatory Lacrimal (Inferior Salivatory) Nucleus (medulla)

  Nucleu ambiguus gives rise to other fibres in nerve
• What is the ganglion for the glossopharyngeal nerve?

  Otic ganglion
• What do post-ganglionic fibres of the glossopharyngeal nerve target?


  Parotid gland