Lecture 8 Flashcards
A first order neuron starts at the ____ and goes to the _____
Periphery
Brainstem/SC
A second order neuron starts at the ____ and goes to the _____
SC/Brainstem
Thalamus
A Third order neuron starts at the ____ and goes to the _____
Thalamus
Somatosensory Cortex
Where is the cell body of a 1st order neuron found?
Dorsal root ganglion
How are spinal tracts named?
Origin and end of their 2nd order neuron
Concious vs Divergent pathways
Concious- Discriminitive information (example: pin point sharp pain)
Divergent- Not discriminitive (Example: achey pain in the entire limb)
Nonconcious relay pathways provide ______ information to cerebellum
nonconcious proprioceptive information
The dorsal tract is considered (Concious and/or divergent)
Whereas the Anteriolateral pathway is (Concious and/or divergent)
Dorsal- Concious
A/L - Both
For crude awareness, sensory info must get to ________
For concious awareness it must get to the _________
Thalamus
Somatosensory cortex
What are the 2 concious relay pathways
Dorsal columns and Anteriolateral columns
Senses of the dorsal column?
Concious Proprioception, light touch
Senses of the anterolateral column?
Discriminitive pain, temperature
What tract handles stereognosis?
Dorsal column
The dorsal column crosses sides in the ________
Internal arcuate fibers in the Medulla
The dorsal column travels from the medulla to the thalamus as Nucleus Gracilis OR Cuneatus
Gracilis is for ____ wherewas Cuneatus is for _________
Gracilis - lower body sensation
Cuneatus - upper body sensation
The Dorsal column crosses in the _________ whereas the anteriolateral column crosses in the ___________
Medulla
Spinal Cord (same level it enters)
What is the difference between the anterior spinothalamic tract and the lateral?
Anterior- Crude touch
Lateral- Fast nocioception and temperature
True or false: The anterior and the lateral spinothalamic pathways ascend seperately in the spinal cord
False. they only seperate inside of the brain
In the anteriolateral tract, A-Delta fibers handle….
Fast nocioceptive sensation
In the anteriolateral tract, A-delta and C fibers both handle…..
Temperature
In the anteriolateral tract, C fibers handle…..
Crude touch
What is the region of the spinal cord called where the Anteriolateral tract crosses?
Anterior Commissure
If someone has a lesion on the R side of their spinal cord, their sense of crude touch will be effected (Contralaterally/Ipsilaterally) whereas their sense discrimitive touch will be effected (Contralaterally/Ipsilaterally)
Crude touch- Contralaterally; Anterior Spinothalamic
DIscrimitive touch- Ipsilaterally
Note: this has to do with where it crosses
If a slow nociceptive signal reaches concious awareness, it goes through what pathway?
Spino-emotional
Slow medial nociceptive pathways are: (Divergent/Concious/Non-concious)
Divergent
What spinal tract deals with you looking at an injury after it happens?
Spinomesencephalic (slow-medial nociception)
Goes to the superior colliculus and periaqueductal grey - the former deals with vision and is in the posterior midbrain while the latter deals with control pain sensations
Spinomesencephalic tract plays a role in inhibiting or controlling pain sensations
Slow-Medial Nociception 1st order neurons are always what kind of fibers?
C fibers
Slow-Medial Nociception pathways cross where?
Immediately in the spinal cord
What is the only spinocerebellar tract that crosses?
Anterior/ventral spinocerebellar
Where does the dorsal spinocerebellar and the cuneocerebellar tract cross?
They dont cross.
Where is the clarks nucleus for 1st order neurons in the dorsal spinocerebellar tract found?
C8/T1-L2
Note: because this tract is only for the Lower body!
The posterior spinocerebellar tract is for _____
whereas the cuneocerebellar tract is for ______
Posterior Spinocerebellar: Carrying unconscious proprioceptive information from the lower extremity and trunk
Cuneocerebellar: Carrying unconscious proprioceptive information from the upper extremity
What spinal tracts are responsible for unconcious regulation of posture?
Spinocerebellar
The dorsal spinocerebellar and the cuneocerebellar go through the _____ peduncle whereas the Anterior spinocerebellar tract goes through the _____ peduncle
Inferior Peduncle
Superior Peduncle
Describe the crossing that happens at the anterior spinocerebellar tract
Most fibers cross twice to end up on same side, whereas some fibers go to contralateral side. Each side of brain receives fibers from BOTH sides of body to assist in coordination.
The anterior/ventral spinocerebellar tract is for what part of your body?
Lower Body
Where does the anterior/ventral spinocerebellar tract’s cross?
First in spinal cord immediately, then again in cerebellum
True or false: The Rostrospinocerebellar tract crosses in the spinal cord
False, it does not cross!
Where does the rostrospinocerebellar tract relay information from?
From cervical spinalcord + T1 to cerebellum at both inferior AND superior peduncles
What do projection fibers connect?
Connect cortex with other areas of CNS
What do association fibers connect?
Connect nearby parts of the brain within the same hemisphere
What do commissural fibers connect?
Connect identical parts of the R and L cortex to eachother
Motor tracts that originate in the cortex are _______ whereas if they originate in the brainstem they are __________
Pyramidal
Extrapyramidal
(extrapyramidal=outside cortex)
In the cortex, Posture/gross movements synapse (medially/laterally)
Whereas fine movements synapse (medially/Laterally)
Gross = medially
Fine = Laterally
The Pyramidal Corticospinal tract does what?
Lateral- Fractional limb movements
Medial- automatic/proximal trunk movememts
What does the pyramidal (descending) corticobulbar tract do?
Motor control at the face
What are the two extrapyramidal tracts called?
Reticulospinal and Vestibulospinal tract
What does the reticulospinal tract control?
Posture
What does the vestibulospinal tract control?
Head control
What is the purpose of the premotor cortex?
Prepares for movement (especially movement that involves multiple joints)
What is the purpose of the supplementary motor cortex?
Active prior to initiating movments that require specific sequence
Identify this part of the brain
Supplementary motor cortex
Identify this part of the brain
Premotor cortex
