Lecture 11- Autonomic innervation of the head and neck- Parasympathetics

Question 1

Which cranial nerves carry parasympathetic fibres from the brainstem?

Answer 1

• Oculomotor
• Facial
• Glossopharyngeal
• Vagus

Question 2

each cranial nerve associated with parasympathetic fibres have their own

Answer 2

nuclei - parasympathetic ganglion

Discrete ganglions (no chain- not like symapthetic chain)

Question 4

name the four paraysmapthetic nuceli

Answer 4

• Edinger Westphal (only one you need to remember)
  
  • Think pupillary light reflex
• Superior salivary
• Inferior salivary
• Dorsal motor

Question 5

CNIII isassociated with which nuclei and parasymapthetic ganglion

Answer 5

Edinger westphal

ciliary ganglion (where pre-ganglionic fibre meets the post-ganglionic fibre)

Question 6

The Edinger–Westphal nucleus

Answer 6

hitchhikes on the oculomotor nevre

innervates the iris sphincter muscle and the ciliary muscle

Question 7

outline how parasymapthetic nerves get to their target tissues

Answer 7

• arise from the brainstem from parasympathetic nculei
• hitchkine on one fo the 4 CNs
• parasymapthetic glanglion
• hicth hike on branches fon CNV
  
  • Ciliary (parasympathetic of the oculomotor nerve)
  • Submandibular
  • Pterygopalatine
  • Otic
• target tissues

Question 8

target tissues of hitchhiking parasympathetics

Answer 8

• Target tissue
  
  • Smooth muscle (sphincter pupillae (pupil constrictor) and ciliary muscle (controls lens)
  • Lacrimal gland
  • Mucosal gland in nasal/ oral mucos/resp tract

Question 10

summary pic of hwo parasymapthetic nerve relate to CN and their target tissue

Answer 10

Question 11

outline CN III oculomotor and parasymapthetic pathway

Answer 11

• Comes from midbrain of brainstem
• Edinger Westphal (blue line) nucleus and nucleus of the other motor fibres associated with the oculomotor nerve (pink line) exit the brainstem together and reach inside the orbit with each other
  
  • Parasympathetic fibres run on the outside of the oculomotor nerve
• At the ciliary ganglion (back of orbit) the parasympathetic pre-ganglionic nerve becomes the post-ganglionic nerve
• hitchhikes on the small branches from CN Va
• target tissues
  
  • ciliary muscle- alters shape of lens
  • sphincter pupillae msucle- constrictor of the pupil

Question 12

the pupillary light reflex afferent arm

Answer 12

optic nerve (sensory)–> brighter light

Question 13

the pupillary light reflex efferent arm

Answer 13

oculomotor (parasympathetic part)

Question 14

outline the pupillary light reflex

Answer 14

• Shine light in eye (e.g. left)
• Optic nerve senses light
• Optic nerve reaches the chiasm and becomes the optic tract
• When it is in the brainstem the optic tract transmits info to the Edinger-Westphal nucleus on both sides of the nucleus
• Parasympathetics will leave the Edinger Westphal nucleus carrying this info on both oculomotor nerves CN III to both eyes
  
  • Both pupils should constrict in exactly the same time and amount

Question 15

Answer 15

efferent limb (oculomotor nerve) right eye

Question 16

Parasympathetic: CN VII Facial

Answer 16

Parasympathetic (pre-ganglionic) nerves exit brainstem with other axons forming facial nerve

Question 17

Parasympathetics reach target tissues via two branches of CN VII that arise in petrous bone

Answer 17

• Greater petrosal nerve
• Chorda tympani nerve (also transmits special sense taste from anterior 2/3 tongue)

Question 18

the facial nerve has 3 associatyed parasynapthetic ganglia

Answer 18

• Pterygopalatine ganglion (in the Pterygopalatine fossa)
• Submandibular ganglion (beneath the tongue)
  
  • These ganglia= area of synapse between pre-ganglionic parasympathetic nerves onto cell bodies of post-ganglionic nerves
• Post ganglionic parasympathetics then run with distal branches of trigeminal (lingual nerve)

Question 19

To determine where on the route of facial nerve the lesion may be…

Answer 19

e. g. look if the lacrimal or mucosal gland is working. If you have a lesion right at the beginning = loss of facial nerve completely
* If lesion is on greater petrosal nerve = lack of tears etc.

Question 20

Parasympathetic: CN IX glossopharyngeal

Answer 20

• Parasympathetic fibres arise from brainstem and exit with CN IX
• Exits through jugular foramen but at this point splits into no. of branches

Question 21

branches of the parasymapthetics hitchhiking on the glossopharyngeal

Answer 21

• Tympanic nerve which supplies sensory to middle ear
• Parasympathetic fibres run with the tympanic nerve initially
• Then parasympathetics exit middle ear as lesser petrosal nerve
• Synapses in otic ganglion (in infratemporal fossa)
  
  • Postganglionic parasympathetics then hitch hike on branch of CN Vc-auriculotemporal)
• Parotid gland

Question 23

Parasympathetic: CN X Vagus

Answer 23

Exists at the bottom of the brainstem (medulla) and parasympathetics exit with other axons forming CNX

Question 24

Parasympathetic: CN X Vagus route

Answer 24

• Long journey from brainstem to abdomen
• Pre-ganglionic parasympathetic fibres run within CN X and its branches
• Meet ganglion AT OR IN target tissue
  
  • Mucosal glands in pharynx/larynx and smooth muscle of oesophagus and trachea
  • Smooth muscle and mucosal glands within rest of resp and GI tract
  • Heart

Question 25

origin of parasymapthetic nuclei

Answer 25

brainstem

Question 26

parasympathetics hitchhike on whcih CNs

Answer 26

• oculomotor
• facial
• glossopharangeal
• vagus

but all psot ganglionic fibres (except CNX) reach effector rogans vis the distal branches of CNV

Question 27

parasympathetic ganglia

Answer 27

ciliary

pterygopalatine

submandibular

otic

Question 28

effector tissue

Answer 28

• eye (sphincter pupillae and ciliary muscles)
• lacrimal glands
• mucosal glands
• salivary glands
• parotid gland

Question 29

parasympathetic rest and dugest responses

Answer 29

• consrtrict pupil
• accomodation reflex (lens shape)
• glandular (salivary and mucosal secretions
• cardiac muscle and smooth msucle in resp and digestive system