brainstem and cranial nerves Flashcards
all ascending and descending pathways pass through the…
brainstem
and they synapse here in relay nuclei or arise directly from or synapse in other brainstem nuclei
how is the cerebellum connected to the brainstem
3 cerebellar penduncles (white fibre tracts)
how many nuclei of cranial nerves are found in the cerebellum and which ones
9 cranial nerves are found here
3-12 except 11 (spinal accessory nerve)
brainstem organisation in terms of tectum/tegmentum and bases
tectum (roof) - behind the central canal or ventricular system
the tegmentum is anterior to the tectum
the base of the brainstem is anterior to the tegmentum
posterior view of the midbrain, pons and medulla contains..
pineal gland (small blob on top of the 4 blobs)
the upper 2 blobs are the superior colliculus
the lower 2 blobs are the inferior colliculus
the trochlear nerve runs under inferior colliculus
dorsal columns in medulla oblongata
the anterior view of the midbrain, pons and medulla contains…
optic chiasm (weird line thingy at the very top) under it is this tiny circle = pituitary stalk underneath that are 2 blobs stuck together = mamillary body the thing around the mamillary body which looks like a jacket = cerebral penduncle the medulla has medullary pyramids at the very top of the medulla where the line of the pyramids stop = pryamidal decussation
what are the descending tracts of the cerebral penduncles
corticospinal and coticobulbar
the posterior surface of the medulla divides into…
open and closed
what does the closed surface of the medulla have
extension of the central canal of spinal cord
what does the canal widen to form
4th ventricle to open medulla
what fibres cross between the open and closed medulla
corticospinal fibres
where are upper motor neurones found
motor cortex
where are lower motor neurones found
the anterior horn of the spinal cord
what 2 arterial systems does the CNS blood supply come from
anterior and posterior
what is the anterior arterial system
derived from internal carotid system (supplying most of the cerebral hemispheres)
what is the posterior arterial system
derived from vertebrobasilar vessels (supplies brainstem)
what does the circle of Willis contain
anterior cerebral artery carotid artery middle cerebral artery posterior communicating artery posterior cerebral artery
what does the vertebrobasilar system include
superior cerebellar artery basilar artery anterior inferior cerebellar artery posterior inferior cerebellar artery anterior spinal artery posterior spinal artery vertebral artery
what are general somatic afferent fibres (GSA)
fibres that carry general sensation from skin, muscles, joints of head and neck
what are general somatic efferent fibres (GSE)
fibres that innervate skeletal muscle
what are general visceral afferent fibres (GVA)
fibres that carry sensation from viscera of head, neck, thorax and abdomen
what are general visceral efferent (GVE)
fibres that are preganglionic parasympathetic neurones to cranial, thoracis and abdominal viscera
what are special somatic afferent fibres (SSA)
fibres that carry special senses of hearing and balance
what are special visceral afferent (SVA)
fibres that carry taste sensation
what are special visceral efferent (SVE)
innervate skeletal muscles of the jaw, face, larynx and pharynx
function of cranial nerve 3 - occulomotor
motor to levator palpebrae superioris, superior rectus, inferior rectus, medial rectus
parasympathetic : motor to sphincter pupillae, cilliary muscles for acommodation
function of cranial nerve 4 - trochlear
motor to superior oblique
function of cranial nerve 5 - trigeminal
proprioception from muscles of mastication
discriminative touch and vibration from head
pain and temparature from the head
motor to muscles of mastication
function of cranial nerve 6 - abducens
motor to lateral rectus
function of cranial nerve 7 - facial
motor to muscles of facial expression
sensory from external auditory meatus and skin posterior to ear
parasympathetic motor to lacrimal, submandibular, sublingual glands and mucous glands of mouth and nose
taste from anterior 2/3 of tongue
function of cranial nerve 8 - vestibulocochlear
balance
hearing
function of cranial nerve 9 - glossopharyngeal
general sensation from posterior 1/3 tongue, tonsil, skin of external, internal surface of tympanic membrane, pharynx
chemoreceptors and baroreceptors in the carotid body, visceral afferent info from tongue and pharynx (gag)
taste from posterior 1/3 of tongue
motor to stylopharyngeaus
parasympathetic to parotid gland
function of cranial nerve 10 - vagus
sensory from posterior meninges, external acoustic meatus and skin posterior to ear
sensory from larynx, trachea, oesophagus, thoracic and abdominal viscera, stretch receptors in aortic arch, chemoreceptors in aortic bodies adjacent to arch
sensory from taste buds in the epiglottis
motor to pharyngeal muscles and intrinsic muscles of larynx
parasympathetic to smooth muscles and glands of pharynx, larynx and thoracic and abdominal viscera
cardiac muscles
function of cranial nerve 12 - hypoglossal
hyoglossus, genioglossus, styloglossus and all intrinsic muscles of the tongue
what cranial nerves emerge from midbrain
2 and 4
what cranial nerves emerge from pons
5-8
what cranial nerves emerge from medulla
9, 10 and 12
