Sensory Organization

Question 1

What are the two areas of the visual field?

Answer 1

• nasal and temporal

Question 2

The nasal part of the retina captures information from?

Answer 2

• the temporal visual field

Question 3

What occurs at the optic chiasm?

Answer 3

• nasal retina optic nerves cross

Question 4

Damage to what area could cause the inability to see the upper visual field?

Answer 4

• damage to temporal lobes because neurons wrap around inferior horn to get to visual cortex (Meyer’s loop)

Question 5

What are the receptors in the eyes?

Answer 5

• rods: process dim light
• cones: process strong light
• bipolar cells: horizontal and amacrine integrate
• ganglion: bundle and form optic nerve

Question 6

What are the visual subsystems?

Answer 6

• 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

Question 7

What are the areas of the outer ear?

Answer 7

• pinna: filter and direct

- ear canal

Question 8

What are the areas of the middle ear?

Answer 8

• tympanic membrane

- hammer, anvil and stirrup

Question 9

What are the areas of the inner ear?

Answer 9

• cochlea

- auditory nerve

Question 10

What are the parts of the cochlea?

Answer 10

• basilar and tectorial membrane
• place theory: low and high frequencies at different ends
• transduction

Question 11

Where does decussation of auditory information occur?

Answer 11

• the medulla

Question 12

What other structures are important for auditory sensory organization?

Answer 12

• thalamus

- medial geniculate nucleus (MGN)

Question 13

The primary auditory cortex is organized by:

Answer 13

• tonotopic map with columnar organization

Question 14

What sensory stimuli does the posterior column-medial lemniscal pathway transmit?

Answer 14

• vibration, joint position (proprioception), fine touch

Question 15

What sensory stimuli does the anterolateral pathway transmit?

Answer 15

• pain, temperature, crude touch

Question 16

Where does decussation occur in the posterior column-medial lemniscal pathway?

Answer 16

• caudal medulla

Question 17

What kind of axons are used in the posterior column-medial lemniscal pathway?

Answer 17

• large diameter myelinated axons

Question 18

Where does decussation occur for the anterolateral pathway?

Answer 18

• cervical spinal cord

Question 19

what kind of axons are used in the anterolateral pathways?

Answer 19

• small diameter, unmyelinated axons

Question 20

What is the thalamus’s role in sensory information processing?

Answer 20

• relays sensory information from the periphery, motor inputs from cerebellum and basal ganglia

Question 21

What do relay nuclei do?

Answer 21

• receive inputs from numerous pathways and project to the cortex
• receive reciprocal connections back from the cortex

Question 22

What occurs if there is a lesion in the left cortex?

Answer 22

• loss of sensation in right in all sensory modalities

Question 23

What occurs if there is a lesion in the lateral pons and lateral medulla?

Answer 23

• hard time feeling pain and temperature in opposite side of body and same side of face

Question 24

What occurs if there is a lesion in the medial medulla?

Answer 24

• loss of vibration and joint position sensation in contralateral side of body

Question 25

What occurs if there is a lesion in the nerve roots or peripheral nerves?

Answer 25

• loss of pain and temperature and vibration and joint position in hands or feet of area of lesion