brainstem and cranial nerve nuclei Flashcards
what makes up the brainstem?
medulla oblongata, pons, midbrain
what is the midbrain continuous with rostrally?
diencephalon of the forebrain
the brainstem contains a complex and heterogenous matrix of neurons known as the ______, within which a number of individually identified nuclei exist
reticular formation
functions of the reticular formation
has several functions, including control over the level of consciousness, the perception of pain and regulation of the CV and resp systems
at what level is the 4th ventricle widest?
at the level of the pontomedullary junction
what provides passage for CSF within the 4th ventricle to reach the sub ach out space surrounding the brain?
foramen of Luschka
superior vs inferior colliculus
superior — visual system
inferior — auditory system
where does the trochlear nerve emerge?
immediately caudal to the inferior colliculus
what make up the lateral walls of the rostral part of the 4th ventricle and connect the brainstem with the cerebellum?
superior and inferior cerebellar peduncles
what separates the 2 crura cerebri?
interpeduncular fossa
what is the crus cerebri continuous rostrally with?
the internal capsule of the cerebral hemisphere
what do the crus cerebri contain?
- descending fibres
- contain the corticobulbar and corticospinal fibres that have left the cerebrum via the internal capsule
what are the pyramids of the medulla either side of?
the ventral median fissure
describe the pyramids
- pyramids overlie the pyramidal or corticospinal tract
- consists of descending fibres originating from the ipsilateral cerebral cortex
- 75-90% of these fibres cross over at the decussation of the pyramids — form lateral corticospinal tract of the spinal cord
what does the inferior olivary nucleus lie within and what does it have connections with?
lies within the olive of the medulla — has connections with the cerebellum primarily and is involved in the control of movement
the ________ runs through the rostral medulla, the pons and the midbrain, to terminate upon 3rd order neurons in the _______ of the thalamus
- medial lemniscus
- VP nucleus of the thalamus
what do the motor nuclei contain?
nerve cell bodies of LMNs
what happens in the sensory nuclei?
1st order neurons synapse with 2nd order neurons
list the sensory modalities
GSA - general somatic afferent
SSA - special somatic afferent
GVA - general visceral afferent
SVA - special visceral afferent
list the motor modalities
GSE - general somatic efferent
SVE - special visceral efferent
GVE - general visceral efferent
what is the only nucleus to fall into the GSA category?
trigeminal sensory nucleus
what is the trigeminal nucelus divided into and what do they carry?
- mesencephalic - proprioception
- chief - touch and pressure
- spinal - pain and temperature
associating nerves of the trigeminal nucleus (GSA)
- V
- VII
- IX
- X
what does SSA originate from?
ectoderm
what are the functions of SSA?
hearing, balance
name the nuclei in the SSA category
- vestibular and cochlear nucleus
name the nucleus in the SVA category and the functions of SVA
= taste and smell
- nucleus solitaries
associated nerves of nucleus solitaires (SVA)
- VII
- IX
- X
what nucleus is in the GVA category and function of GVA?
= viscera. PS fibres. (fibres from viscera, baroreceptors, chemoreceptors terminate here)
- nucleus solitaries
associated nerves of the nucleus solitaries (GVA)
- IX
- X
function of GSE
skeletal muscles voluntary innervation (contains NCBs of LMNs which supply skeletal muscle)
associated nerves of GSE
- oculomotor
- trochlear
- abducens
- hypoglossal
SVE function
contain NCBs of motor neurons supplying skeletal muscle derived from pharyngeal arches
— muscles of pharynx, larynx, mastication, facial expression
what nuclei are in the SVE category?
- trigeminal motor nucleus
- facial motor nucleus
- nucleus ambiguous
what does the nucleus ambiguous supply fibres to?
IX and X
associated nerves of SVE
- V
- VII
- IX
- X
what do GVE nuclei contain?
NCBs of preganglionic parasympathetic neurons
what nuclei are in the GVE category?
- Edinger-Westphal
- superior and inferior salivatory
- dorsal motor nuclei of vagus
preganglionic fibres from the EW nucleus synapse in the ______ and post ganglionic fibres innervate the______
- ciliary ganglion
- sphincter pupillae and ciliary muscles
what nerve is the EW nucleus assoicated with?
oculomotor
what nerve is the superior salivatory nucleus associated with?
CN VII
fibres from the inferior salivatory ganglion pass within what nerve? where do their postganglionic fibres project?
- glossopharyngeal
- project to parotid gland
the dorsal motor nucleus of vagus contains fibres of the vagus nerve that supply what?
viscera off the abdomen and thorax (PS)
what modality contains parasympathetic fibres?
GVE
