Neuro I, Unit 3, Lec 1 (Sss)

Front 1

Pic 1 Flash

Back 1

Pic 1 Flash

Front 2

Somatosensory System:

How many Neurons in the pathways of SS System?

What are the general names of the 3 Neurons?

Back 2

3 Neuron Chain

1st Order Neuron,
2nd Order Neuron,
3rd Order Neuron

Front 4

SSS:

Describe the Components of a generic SSS Pathway?

Back 4

1st ON Periph Process -->
Sensory Ganglion -->
1st ON Cell Body -->
1st ON Central Process -->

SYNAPSE ON 2nd ON Cell Body in BS or SC

2nd ON Fiber Crosses Midline -->

SYNAPSE on 3rd ON Cell Body in VPN of Thalamus

3rd ON Fiber SYNAPSE in Lam 4 of Prim SS Cortex in Postcentral Gyrus

Front 5

Pic 2 -
Whole BodyFine Discriminatory Touch & Vibratory Sense

Upper Body Proprioception

Back 5

Pic 2 -
Whole BodyFine Discriminatory Touch & Vibratory Sense

Upper Body Proprioception

Front 6

Pic 2-
Pathway for Fine, Discriminatory Touch & Vibratory Sensation for Upper Body

Back 6

1st ON Periph Process -->
Dorsal Root Ganglion -->
1st ON Cell Body -->
1st ON Central Process -->
Fasciculus Cuneatus
OR
descending collats forming fasc interfasciularis
& fascicularis septomarginalis

1st ON Central Proc in FC -->
SYNAPSE on 2nd ON in Nucleus Cuneatus

2nd ON Fibers in NC Form Int Arc Fibers That Cross Midline -->
Form ContralLat Medial Lemniscus

SYNAPSE on 3rd ON in VPN of Thalamus

3rd ON Fibers in VPN of Thalamus Synapse in Lam 4 of Prim SS Cortex in Postcentral Gyrus

Front 7

Pic 2-
Pathway for Fine, Discriminatory Touch & Vibratory Sensation for Lower Body

Back 7

1st ON Periph Process -->
Dorsal Root Ganglion -->
1st ON Cell Body -->
1st ON Central Process -->
Fasciculus Gracilis
OR
descending collats forming fasc interfasciularis
& fascicularis septomarginalis

1st ON Central Proc in FG -->
SYNAPSE on 2nd ON in Nucleus Gracilis

2nd ON Fibers in NG Form Int Arc Fibers That Cross Midline -->
Form ContraLat Medial Lemniscus

SYNAPSE on 3rd ON in VPN of Thalamus
3rd ON Fibers in VPN of Thalamus Synapse in Lam 4 of Prim SS Cortex in Postcentral Gyrus

Front 8

Pic 2-
Proprioception for Upper Body
(SAME PATH AS Fine, Discriminatory Touch & Prop & Vibratory Sense for Upper Body)

Back 8

1st ON Periph Process -->
Dorsal Root Ganglion -->
1st ON Cell Body -->
1st ON Central Process -->
Fasciculus Cuneatus
OR
descending collats forming fasc interfasciularis
& fascicularis septomarginalis

1st ON Central Proc in FC -->
SYNAPSE on 2nd ON in Nucleus Cuneatus

2nd ON Fibers in NC Form Int Arc Fibers That Cross Midline -->
Form ContraLat Medial Lemniscus

SYNAPSE on 3rd ON in VPN of Thalamus

3rd ON Fibers in VPN of Thalamus Synapse in Lam 4 of Prim SS Cortex in Postcentral Gyrus

Front 9

Pic 2-
The Descending Collaterals - fasciculus interfascicularis & fascicularis septomarginalis serve what function?

Back 9

Spinal Cord Reflexes

Front 10

Pic 3 - Proprioception for Lower Body

Give Pathway for Proprioception for Lower Body

***NOTE - Unique 4 NEURON CHAIN***

Back 10

1st ON Periph Process -->
Dorsal Root Ganglion -->
1st Order Neuron Cell Body -->
1st Order Neuron Central Proc

1st ON Central Proc -->
SYNAPSE on 2 ON in
Ipsilat Nucleus Dorsalis of Clark

2nd ON in Nucleus Dorsalis of Clark Fibers-->
Ipsilat Dorsal Spinocerebellar Tract

Fibers in Dorsal SCT give Collats -->
SYNAPSE on 3rd ON in Nucleus Z

3rd ON in Nucleus Z Cross Fibers Midline -->
Form Medial Lemniscus

3rd ON Fibers -->
SYNAPSE on 4th Order Neurons in VPN of Thalamus

4th ON in VPN of Thal Fibers Synapse in Lam 4 of Prim SS Cortex in Postcentral Gyrus

Front 11

Pic 4 - Simple/Crude Touch & Pressure

Back 11

1st ON Periph Proc -->
DRG -->
1st ON Cell Body -->
1st ON Central Process -->
Dorsolat Fasciculus

1st ON Central Proc in DLF -->
SYNAPSE on many 2nd ON in Nulceus Prop (Lam 4-6 - Dorsal Horn) in
2-3 spinal cord segs

2 ON Fibers from Nuc Prop Cross Midline -->
Form ContraLat Vent Spinothalmic Tract of Spinal Cord

Fibers of Vent Spinothal Tract of Spinal Cord -->
BS Spinal Lemniscus

2nd ON Fibers of Spinal Lem -->
SYNAPSE on 3rd ON in VPN of Thal

3rd ON Fibers in VPN of Thal SYNAPSE in Lam 4 of Prim SS Cortex in Postcentral Gyrus

Front 12

Pic 5 - Pain & Temp

Path for Pain & Temp

Back 12

1st ON Periph Proc -->
DRG -->
1st ON Cell Body -->
1st ON Central Process -->
Dorsolat Fasciculus

1st ON Central Proc in DLF -->
SYNAPSE on many 2nd ON in Nulceus Prop (Lam 4-6 - Dorsal Horn) in
2-3 spinal cord segs VIA SUBSTANTIA GELATINOSA

2 ON Fibers from Nuc Prop Cross Midline -->
Form ContraLat Lat Spinothalmic Tract of Spinal Cord

Fibers of Vent Spinothal Tract of Spinal Cord -->
BS Spinal Lemniscus

2nd ON Fibers of Spinal Lem -->
SYNAPSE on 3rd ON in VPN of Thal

3rd ON Fibers in VPN of Thal SYNAPSE in Lam 4 of Prim SS Cortex in Postcentral Gyrus

Front 13

Spinal Cord Destruction -->
Neurological Loss

1. Unilateral Segmental Sensory SIGNS result of damage to what?

2. 2 Examples of these Unilateral Segmental Sensory SIGNS?

Back 13

1. Dorsal Root Ganglion & Spinal Nerves

2. Pain along spinal nerve distribution
Anesthesia / Paresthesia along dermatome

Front 14

Spinal Cord Destruction -->
Neurological Loss

1. Expansion of Spinal Cord Central Canal Is Called What?

2. Syringomelia only occurs where?

3. Disrups what fiber types?

4. Describe the location of the pain and temperature loss?

Back 14

1. Syringomyelia

2. Spinal Cord before Decussation in BS

3. Pain and Temp fibers that CROSS OVER in SC

4. Bilateral, "girdle" type loss of pain & Temp

Front 15

Spinal Cord Destruction -->
Neurological Loss

1. Hemisection of the spinal cord is called what?

2. Brown-Sequard Only Occurs Where?

3. Where will you lose Fine Discriminatory Touch & Prop?

4. Will you lose Pain & Temp Sensation on the same or opposite side of lesion?

Back 15

1. Brown-Sequard Syndrome

2. In Spinal Cord Before Decussation in BS

3. Same Side, bc Brown-Sec only occurs before decus in BS
Below level of the hemisection

4. Opposite, bc Pain & Temp decussates @ level which the input is received
Below level of the section

Front 16

Pic 6: Fine Discriminatory Touch, Simple/Crude Touch, Pain & Temp for Head

Give Generic Pathway for FSP for Cranial Nerves

Back 16

1st ON Periph Proc -->
Semilunar (Trig) Ganglion
Geniculate Gang of VII
Sup Ganglion of IX
Sup Ganglion on X -->
1st ON Cell Body -->
1st ON Central Proc -->
Spinal Tract of V

1st ON Central Proc in Spinal Tract of V -->
SYNAPSE on 2nd ON in
Chief Sensory Nucleus (FDT) &
Spinal Nucleus of V (FDT, ST, PT)

2nd ON Fibers from Chief Sensory Nuc & Spinal Nuc of V -->
SYNAPSE on 3rd ON in Infero-medial part of VPN (VMPN) of Thal

3rd ON Fibers in VPN of Thal Synapse in Lam 4 of Prim SS Cortex in Postcentral Gyrus

Front 17

MAKE A PATH FOR BITE FORCES VIA MESENCEPHALIC NUC OF V p. 8

Back 17

MAKE A PATH FOR BITE FORCES VIA MESENCEPHALIC NUC OF V p.8

Front 18

Pic 7:
When Pathways Project to VPN --> Primary SS Cortex

1. Do Any of the preceding pathways not cross over @ some point?

2. Therefore, they will all eventually synapse on the what?

3. Where specifically in the VPN of the Thal, will the fibers which innervate the ContraLat face project to?

4. Where specifically in the VPN of the Thal, will the fibers which innerv the ContraLat body project to?

5. Where in the Ventrolateral Post Nucleus Will the fibers which innerv the foot project to?

6. Fibers from VPN of Thalamus project to where?

Back 18

1. No

2. Contralat VPN of the Thalamus

3. The Inferomedial part of the VPN of thalamus called the Ventromedial Post Nucleus

4. The Lateral part of the VPN of thalamus called the Ventrolateral Post Nucleus

5. Superolateral part of the Lateral part of the VPN

6. Lam 4 of Prim SS Cortex in Postcentral Gyrus

Front 20

Pic 7:
When Pathways Project to VPN --> Primary SS Cortex

1. Do the prev pathways project to the Ipsilateral or contralateral Lam 4 of Prim SS Cortex in Post-central gyrus?

2. Where do sensory fibers from the foot project to?

3. Where do sensory fibers from face project to?

4. Where does every body part in b/t project to?

5. Which parts of the body have the largest part of the post-central gyrus dedicated to them?

Back 20

1. Contralateral

2. Superomedial part of paracentral lobule

3. Inferomedial part near lateral fissure

4. The space in between

5. Face & Hand