Cranial nerves I Flashcards
what are the first order neurons of the of the olfactory pathway?
olfactory receptor cells (bipolar)
olfactory bulbs contain what types of cells?
- second order neurons (mitral, tufted) 2. interneurons
what is the principal central projection of the olfactory system? where does it terminate?
- lateral olfactory stria 2. terminates in primary olfactory cortex and amygdala
where does the primary olfactory cortex project its axons?
- hypothalamus 2. amygdala of limbic system 3. cortical areas 4. olfactory association cortex
what are the first order neurons of the visual system? second order?
- bipolar cells of retina 2. ganglion cells
where do most of the optic tract fibers terminate?
lateral geniculate nucleus of the thalamus (some in superior colliculus, pretectal area, hypothalamus)
where are the third order neurons of the visual system? what do they form?
- lateral geniculate nucleus 2. geniculocalcarine tract (optic radiation)
what is the course of the geniculocalcarine tract?
posterior aspect of internal capsule - corona radiata - primary visual cortex (occipital lobe)
what is unique about the optic nerve?
- it is a tract (part of CNS) 2. myelinated by oligodendrocytes 3. susceptible to MS
lesion of the inferior division of the geniculocalcarine tract leads to what visual defect? superior division?
- inferior - pie in the sky 2. superior - pie on the floor
what is the result of a lesion at the optic chiasm?
heteronymous hemianopia
what is the result of a lesion at the optic nerve?
total blindness in ipsilateral eye
what are the two factors that support macular sparing?
- dual blood supply of visual cortex 2. extensiveness of macular cortical region
the aberrant vagal fibers arise from what nucleus? what do they innervate?
- nucleus ambiguus (medulla) 2. laryngeal muscles
the spinal accessory nerve arises from what nucleus? what does it innervate?
- spinal accessory nucleus 2. trapezius, SCM
