Pons Flashcards
Mention the longitudinal fibers
Corticospinal, corticonuclear, corticopontine
The transverse pontine fibers form……
Middle cerebellar peduncle
Function of the basis pontis
Considered a massive relay station, by which impulses from the cerebral cortex are transmitted to contralateral cerebellar hemisphere.
Mention contents of central tegmental tract
A) Descending fibers from the red nucleus in midbrain to the inferior olivary complex
B) ascending fibers from reticular formation of thalamic nuclei
The intermediate acoustic stria arises from…..
Dorsal part of ventral cochlear nucleus
…….runs transversely between basis pontis & tegmentum, derived from…..
Trapezoid
Ventral cochlear nucleus
The cochlear nerve originated from……nerve cells in….of inner ear. Their peripheral process end in relation to…..
Bipolar
Spiral ganglion
hair cells of organ if Corti
In auditory pathway, the axons of…..&……ascend mainly in ipsilateral lateral leminiscus
Superior olive & nuclei of the trapezoid body
Describe the tertiary auditory fibers
Lateral leminiscus ascends in the lateral part of tegmentum , most of its fibers end on inf colliculus some cross to inf colliculus of opposite side, the inf c. gives fibers to medial genifukate body of thalamus then these fibers project to auitory cortex.
The vestibular nerve nerve cells is in……, their peripheral processes recieve impulses from……
Vestibular ganglion
Hair cells of maculae of the utricle and saccules and crista ampularis
Compare 1ry & 2ry vestibular fibers
1ry, 1st order neuron (vestibular nerve) some project directly to cerebellum & remain 1ry
2ry, vestibulo-cerebellar fibers that arise from vestibular nuclei
Describe postion of vestibular nuclei
Floor of 4th ventricle
A) superior & lateral nuclei are at inferior level of pons
B) inferior & medial nuclei are at level of open medulla
Describe efferents of vestibular nuclei
A) cerebellum: from medial & inferior nuclei
B) spinal cord from lateral vestibualr nucleus
C) MLF: from all vestibular nuclei, to motor nuclei of cranial nerves that supply extra-ocular muscles.
Describe components of medial longitudinal fasiculus
1) Ascending fibers: from medial & superior vestibular (crossed & uncrossed), that project to motor nuclei of 3rd, 4th & 6th. 6th connect with 3rd for conjugate eye movements.
2) Descending: vestibuloinal from medial vestibular, reticulospinal, tectospinal (descend to VII nucleus), interstitial nucleus of Cajal.
Describe function of medial longitudinal fasiculus
- Coordination of reflex eye movements (tectospinal) and neck muscles in response to visual & auditory stimuli
- Control of conjugate eye movements
Mention nuclei of facial nerve
- Motor nucleus of facial nerve
- Solitary nucleus
- Spinal nucleipus of V
- Superior salivatory nucleus
Describe function & connections if motor nucleus of facial
Supply msucles of facial expression, posterior belly of digastric, platysma, stapedius, stylohyoid
Dorsal part of nucleus supplies upper face & recieves bilateral corticonuclear while ventral part which supplies lower face recieves contralateral.
Mention role of following nuclei in CN VII:
1. superior salivatiry
2. Spinal n. of trigeminal
3. Solitary nucleus
- Parasymp , gives secretory fibers to submandibular, sublingual, lacrimal, nasal, buccal & palatine glands.
- Exteroceptive impulses from external auditory meatus & skin back to ear
- Gustatory part recives taste of ant 2/3 of tongue
Function of abducent nucleus
Its fibers relay in….
Supply motor innervation to lateral rectus muscle of same side
Nucleus of III
Mention nuclei of trigeminal nerve
- Main sensory nucleus (cont. with spinal nucleus)
- Spinal nucleus of trigeminal
- Mesencephalic nucleus extends from pons to upper midbrain level
- Motor nucleud of trigeminal nerve in cranial part of pons
Describe the descending fibers of trigeminal nerve
The descend in spinal tract of trigeminal to end in spinal nucleus of trigeminal then cross to opposite side & form ventral trigemino-thalamic tract which ascends to VPMN then to sensory cortex.
Describe the ascending fibers of trigeminal nerve
The ascend to end in main sensory nucleus then ascend in same or to opposite side & form dorsal trigemino-thalamic tract forms trigeminal leminiscus which ascends to VPMN then to sensory cortex.
Ascending fibers of proprioception go directly to mesencephalic nucleus (considered 1st order neuron)
Describe connections of mesencephalic nucleus
A) Motor nucleus of trigeminal
B) Trigeminal leminiscus
GR, Motor nucleus of trigeminal in connected to mesencephalic nucleus
To increase force of mastication
