Sensory Organization Flashcards
What are the two areas of the visual field?
- nasal and temporal
The nasal part of the retina captures information from?
- the temporal visual field
What occurs at the optic chiasm?
- nasal retina optic nerves cross
Damage to what area could cause the inability to see the upper visual field?
- damage to temporal lobes because neurons wrap around inferior horn to get to visual cortex (Meyer’s loop)
What are the receptors in the eyes?
- rods: process dim light
- cones: process strong light
- bipolar cells: horizontal and amacrine integrate
- ganglion: bundle and form optic nerve
What are the visual subsystems?
- frontal eye fields: eye movements
- suprachiasmatic nucleus: daily rhythms
- pretectum: pupil size in response to light
- pineal gland: long term circadian rhythm
- superior colliculus: head orienting
- accessory optic nucleus: eye movements compensate for head movement
- visual cortex: perception of pattern, depth
What are the areas of the outer ear?
- pinna: filter and direct
- ear canal
What are the areas of the middle ear?
- tympanic membrane
- hammer, anvil and stirrup
What are the areas of the inner ear?
- cochlea
- auditory nerve
What are the parts of the cochlea?
- basilar and tectorial membrane
- place theory: low and high frequencies at different ends
- transduction
Where does decussation of auditory information occur?
- the medulla
What other structures are important for auditory sensory organization?
- thalamus
- medial geniculate nucleus (MGN)
The primary auditory cortex is organized by:
- tonotopic map with columnar organization
What sensory stimuli does the posterior column-medial lemniscal pathway transmit?
- vibration, joint position (proprioception), fine touch
What sensory stimuli does the anterolateral pathway transmit?
- pain, temperature, crude touch
Where does decussation occur in the posterior column-medial lemniscal pathway?
- caudal medulla
What kind of axons are used in the posterior column-medial lemniscal pathway?
- large diameter myelinated axons
Where does decussation occur for the anterolateral pathway?
- cervical spinal cord
what kind of axons are used in the anterolateral pathways?
- small diameter, unmyelinated axons
What is the thalamus’s role in sensory information processing?
- relays sensory information from the periphery, motor inputs from cerebellum and basal ganglia
What do relay nuclei do?
- receive inputs from numerous pathways and project to the cortex
- receive reciprocal connections back from the cortex
What occurs if there is a lesion in the left cortex?
- loss of sensation in right in all sensory modalities
What occurs if there is a lesion in the lateral pons and lateral medulla?
- hard time feeling pain and temperature in opposite side of body and same side of face
What occurs if there is a lesion in the medial medulla?
- loss of vibration and joint position sensation in contralateral side of body
What occurs if there is a lesion in the nerve roots or peripheral nerves?
- loss of pain and temperature and vibration and joint position in hands or feet of area of lesion