sensory organization Flashcards
receptors
filter and transduce energy
photoreceptors: light –> chemical energy
hair cells: air waves –> mechanical energy
visual perception cell organization
ganglion cells –> amacrine cells –> bipolar cells –> horizontal cells –> photoreceptors
visual path: retina to V1
temporal and nasal aspects of each eye are both processing aspects from opposite sides
2 pathways from visual system
- geniculostriate: what are we looking at? - shape, color
2. tectopulvinar: where is the object? - guides head to observe, localization of object
auditory system stimulus
sound waves- movement of molecules in air causing vibrations
function of outer ear
funnel information from environment
function of middle ear
amplify sound
function of inner ear
cochlea- localize and transduce sound information
place theory
depending on localization of stimulation on basilar membrane you will have high or low frequencies
- base is HIGH frequnecy
- apex is LOW frequency
auditory system pathway
decussates in medulla
- some info passes ipsilaterally
synapse in medial geniculate nucleus
auditory cortex
maintains tonotopic organization of cochela
2 somatosensory pathways
temperature and pain - contralateral - antereolateral
touch and proprioception- ipsilateral - posterior columns
motor- contralateral- lateral corticospinal tract
posterior column medial lemniscal pathway
conveys proprioception, vibration and fine touch - up through dorsal column (sensory) - arms: gracilis, legs: cuneates - decussates in caudal medulla - up to VPL of thalamus (sensory) - up to somatosensory cortex primary cells are large, myelinated
antereolateral pathways
convey pain, temperature sense and crude touch - up through dorsal (sensory) - decussates in cervical spinal cord - up to VPL (sensory) - somatosensory cortex primary cells are small, unmyelinated
thalamus
relays sensory info from periphery, motor inputs from cerebellum and basal ganglia
lesion: S1 and thalamus are gone in left side
loss os sensation from right side and proprioception (unsure)
lesion: lateral pons and lateral medullla
lesion of antereolateral pathway: loss of pain and temp sensation on contralateral side of body and ipsilateral side of face
lesion: medial medulla
lesion of medial leminiscal pathway: loss of vibration and joint position sense in contra lateral side of body
lesion: nerve roots or peripheral nerves
peripheral nerves of posterior and column medial lemniscla and antereolateral systems
- distal symmetrical polyneuropathies cause glove and stocking distribution
