Midterm 2: Sensory Systems (Ben)

Question 1

What are the 3 types of general sensory systems we have discussed?

Answer 1

1. Proprioception
2. Epicritic Sensibility (fine touch/vibration)
3. Protopathic Sensibility (pain/heat)

Question 2

Where do sensory neurons of proprioceptive sensibility from the lower half of the body above L4 synapse in the spinal cord?

Answer 2

on multipolar neurons in the Clark-Stilling (Dorsal) Nucleus (T9 - L3)

Question 3

What spinal cord white matter does proprioceptive information travel through after leaving the Clark-Stilling nucleus?

Answer 3

enters the lateral funiculus of the same side and ascends in the dorsal spinocerebellar (Flechsig) tract

Question 4

Through what structure does the dorsal spinocerebellar tract finally reach the cerebellum?

And which part of the cerebellum?

Answer 4

through the Inferior Cerebellar Peduncle

to the Paleocerebellum

Question 5

Where do sensory neurons of proprioceptive sensibility from the lower half of the body below L3 synapse in the spinal cord?

Answer 5

in the intermediate zone and ventral horn

Question 6

What is the path of proprioceptive information from below L3 after its synapse in the spinal grey matter?

Answer 6

it decussates in the anterior white commissure, then…

ascends via the Ventral Spinocerebellar Tract (of Gowers) in the Lateral Funiculus

Question 7

What is the pathway for proprioceptive sensation from below L3 once it is in the brain?

Answer 7

after traveling through the ventral spinocerebellar (Gower’s) tract…

…crosses again in the superior medullary velum, then…

…enters the spinocerebellum via the superior cereberellar peduncle

Question 8

What is the pathway in the spinal cord for proprioceptive sensation from the upper body?

Answer 8

(Burdach’s) Cuneate Fascicle

an uncrossed** pathway in the **dorsal funiculus

Question 9

Once in the brainstem, where does proprioceptive sensation from the upper body synapse first?

Answer 9

in the accessory/external cuneate nucleus (just lateral to cuneate nucleus)

Question 10

How does proprioceptive sensation originating from the upper half of the body get from the brainstem to its final destination?

Answer 10

after leaving the accessory cuneate nucleus…

it courses through the cuneocerebellar tract** in the **inferior cerebellar peduncle

Question 11

How is epicritic information first sensed?

Answer 11

via Meissner’s Corpuscles in dermal CT papillae

Question 12

Where does epicritic information from the lower half of the body travel in the spinal cord?

Answer 12

Gracile Fascicle (of Goll)

in the dorsal funiculus on the same side as the stimulation

Question 13

Where does epicritic information from the upper half of the body travel in the spinal cord?

Answer 13

Burdach’s Cuneate Fascicle

• in the dorsal funiculus on the same side as the stimulation

Question 14

Once epicritic information has reached the medullary nuclei (gracile/cuneate), what happens to its fibers (still within the medulla)?

Answer 14

they cross as the internal arcuate fibers forming the lemniscal decussation

Question 15

Where does epicritic information go from the medulla and how does it get there?

Answer 15

it travels to the thalamus VPL via the medial lemniscus

Question 16

Where does epicritic sensation travel from the thalamus?

And how?

Answer 16

since it is sensory information…

it goes to the Post-central Gyrus…

via the Internal Capsule

Question 17

Where does protopathic information from the body go after entering the spinal grey matter?

Answer 17

it decussates** via the **anterior white commissure** and ascends in the **spinothalamic tract

Question 18

Where are the 2nd order neurons conveying protopathic information from the body found?

Answer 18

Substantia Gelatinosa

Question 19

Depending on the type of protopathic sensation, information will travel in different parts of the spinothalamic tract.

What type travels in which part?

Answer 19

Anterior Spinothalamic = crude touch, pressure

Lateral Spinothalamic = heat, pain

Question 20

To where does protopathic information from the body travel via its spinal cord tract?

Answer 20

the spinothalamic tract takes protopathic information the the Thalamus VPL

Question 21

Where does protopathic information go from the thalamus?

Answer 21

thalamus VPL > post-central gyrus

Question 22

In what structure does the first neuron carrying epicritic sensation from the head have its perikaryon?

And where is it?

Answer 22

in the Trigeminal Ganglion (of Gasser)

found in Meckel’s Cave

Question 23

Where is the perikaryon of the second neuron carrying epicritic information from the head?

Answer 23

Pontine/Principle Trigeminal Nucleus

Question 24

What course does epicritic sensation from the head take from its 2nd neuron in the principle trigeminal nucleus?

Answer 24

it decussates** and ascends in the **trigeminal lemniscus

(Agota said “dorsal trigeminal lemniscus” but the handout seems to say otherwise on pg. 43)

Question 25

Where the 2nd order neuron carrying epicritic information from the head synapse?

Answer 25

Thalamus VPM

Question 26

Where does the first neuron carrying protopathic information from the head have its perikaryon?

Answer 26

trigeminal ganglion

Question 27

Where does the 2nd neuron carrying protopathic information from the head have its perikaryon?

Answer 27

in the spinal trigeminal nucleus

located in the lateral portion of the medulla

Question 28

Where does protopathic sensation from the head go after it has left the medulla?

Answer 28

it decussates** and ascends via the **spinal trigeminal lemniscus

Question 29

To what part of the thalamus does protopathic information from the head go?

Answer 29

it goes to the Thalamus VPM via the spinal trigeminal lemniscus