Brainstem & Cranial Nerves Flashcards
name the 12 cranial nerves
- olfactory
- optic
- occulomotor
- trochealar
- trigeminal (ophthalmic, maxillary and mandibular)
- abducens
- facial
- vestibulocochlear/ auditory
- glossopharyngeal
- vagus
- accessory (spinal)
- hypoglossal
name the exit points of the cranial nerves
- olfactory - cribriform plate of ethmoid bone
- optic - optic canal
- occulomotor - SOF
- trochealar - SOF
- trigeminal (ophthalmic - SOF, maxillary - foramen rotandum and mandibular - foramen ovale)
- abducens - SOF
- facial - IAM
- vestibulocochlear/ auditory - IAM
- glossopharyngeal - Jugular foramen
- vagus - JF
- accessory (spinal) - JF
- hypoglossal - hypoglossal canal
what is the function of CN 1-6
- olfactory - smell
- optic - vision
- occulomotor - eye movement, pupillary constriction and accommodation
- trochealar - eye movement
- trigeminal - motor:mastication, sensory: facial sensation (nerves from the head)
- abducens - eye movement
what are the three main components of the brainstem?and what can they be further divided into?
- midbrain
- pons
- medulla oblongata
they can be further divided into dorsal tectum and ventral tegmentum which lie dorsal and ventral to the aqueduct of the midbrain and fourth ventricle respectively
define a pyramid/pyramidal (corticospinal) tract
an elongated eminence marking the position of underlying fibres passing from the cerebral hemispheres to the cord referred to as corticospinal or pyramidal tract
what is the decussation of pyramids?
diagonally orientated bundles of fibres cross the fissure via which 80% of corticospinal tracts cross the midline to enter the opposite lateral white column of SC
what is the tectum and tegmentum made of?
tectum (dorsal to aqueduct) made of collucli
tegmentum (ventral to aqueduct) made of nerve fibres
what is the function of superior collucli and inferior collucli?
superior collucli - part of visual system, concerned with eye reflexes
inferior collucli - part of auditory system, concerned with reflex of looking towards a loud noise
what is the superior cerebellar peduncle?
a fibre bundle passing from the cerebellar to the midbrain
what is pineal gland and its function?
an endocrine gland that synthesises melatonin
which are the 2 important nerve pathways? (MALE)
- inferior branchium - conveys Auditory information from the Medial geniculate body to the inferior collucli
- superior branchium - conveys visual (Eyes) information from the Lateral geniculate body to the superior collucli
which of the cranial nerve nuclei is present in the tegmentum consists of in pons and medulla?
tegmentum of pons - nuclei of CN 5,6,7
tegmentum of medulla - nuclei of CN 9,10,11 and 12
where is gracile and cuneate tubercle?
gracile - a round swelling of on either side of the midline (of medulla)
cuneate - a swelling lateral to the gracile
what is the dorsal column nuclei and its function?
the nuclei underlying the gracile and cuneate nucleus are called dorsal column nuclei and are a major relay site for dorsal column sensory pathway
what is Bell’s palsy? its symptoms and signs?
- it is the acute unilateral inflammation of facial nerve (LMN)
- symptoms (unilateral): pain behind the ear, paralysis of facial muscles and failure to close eyes
- signs: loss of taste on the anterior 2/3 of tongue, absent corneal reflex, hyperacusis (certain sounds heard unpleasantly loudly)
- if caused by herpes zoster (virus that causes shingles), a vesicular rash is present in external auditory canal and on the oropharynx