Sensory Systems

Question 1

Where do ventral and dorsal rootlets enter the spinal cord?

Answer 1

Ventrolateral and dorsolateral sulcus respectively

Question 2

What does the dorsal and ventral horn of the spinal cord carry?

Answer 2

Dorsal: sensory information from the body to the brain Ventral: motor information from the brain to the body

Question 3

What info does the later horn carry?

Answer 3

ANS information for visceral organs (levels T1-L2, S1-S3)

Question 4

Where is the larges amount of WM found in the spinal cord?

Answer 4

Cervical: most axon tracts pass through to reach the brain

Question 5

What modality does the DCML pathway exhibit?

Answer 5

Proprioception and fine discriminative touch

Question 6

Describe the difference between the DCML and anterolateral pathway?

Answer 6

Question 7

What modality does the anterolateral pathway carry?

Answer 7

Pain, temperature and itch

Question 8

Where does the trigeminal nerve originate and what are it’s three branches? Names its thalamic relay.

Answer 8

• Originates from the pons
• Opthalamic branch: sensory info from the orbit, nose, forehead and scalp
• Maxillary branch: sesnory info from lateral corners of mouth and eye
• Mandibular branch: sensory info from low part of face
• Thalamic relay: ventral posterior medial nucleus

Question 9

List the trigeminal nuclei and their projections

Answer 9

• Main trigeminal nucles
  
  • touch and mechanical sesnsation
  • Travels with medial leminscius to the VMP
• Spinal trigeminal nucleus
  
  • pain, temp and itch
  • project with anterolateral pathway to VMp
• Mesencehpalic trigeminal nucleus
  
  • jaw propiception
  • projects to main and spinal nuceli

Question 10

Difference between rods and cones?

Answer 10

• Rods
  
  • black/white vision –> sensitive to low light
  • Connect to a large number of bipolar cells
    
    • high sesnitivity
    • low acuity
• Cones
  
  • colour vision

Question 11

Describe the lateral geniculate nucleus and retinoganglion cells

Answer 11

• Consists of 6 layers
• M type retinoganglion cells: project to magnocellular layer LGN (ventral 2x)
  
  • movement detection
• P type retinoganglion cells: project to parvocellular layer of LGN (dorsal 4x)
  
  • form and colour
• Intralaminar neurons: located in between the 6 layers, relay colour info

Question 12

What layers of the visual cortex process what information?

Answer 12

• V1;V2 what and where visual pathways
• V4: what its it?
  
  • colour and form
  • projects towards temporal lobe
• V5: where is it
  
  • movement and speed
  • projects towards posterior parietal lobe

Question 13

Name the three relay nuclei in the auditory pathway

Answer 13

• Cochlear nucleus
• supeior olivary complex
• inferior colliculus

Question 14

List the three subdivisions of the cochlear nucelus and the sound it processes. And the role of the supeior olivary complex

Answer 14

• Dorsal
  
  • sound from vertical axis
  • connects directly with inferior colliculus
• Anteroventral
  
  • Sound from horizontal plane
• posteroventral
• Supeior olivary complex
  
  • spatial localisation of horizontal plane
  • compares timing differences between left and right ear

Question 15

Where is the primary olfactory cortex housed?

Answer 15

The uncus