Reflex and UMN/LMN Flashcards
Neurons whose cell bodies are located in the brain and various brain stem nuceli?
Upper motor neurons
Somatic neurons whose cell bodies are located in the spinal cord and specific brain nuclei?
Lower motor neuron
The __________ pathway consists of UMN axons that descend into the spinal cord and synapse directly onto LMN
Pyramidal (i.e. Corticospinal)
The pyramidal pathway regulates?
Fine tuned/Skilled movements
The ____________ pathway consists of UMN that synapse onto interneurons in brain nuclei before continuing to LMN
Extrapyramidal (corticorubrospinal)
The extrapyramidal pathway controls what movements?
Muscle tone and initiation of whole limb movements
What type of neurons are involved in the spinal reflex?
LMN
A spinal reflex can occur without _________ but may result in a exaggerated/abnormal response
UMN
The organization of the spinal cord in a point- for point correspondence with a specific body part is called?
Somatotopy
UMN traveling in the _______________ regulate LMN cell bodies in the more lateral aspect of the ventral horn, which corresponds with what part of the the limb?
Dorsolateral motor system; distal musculature (fine tuned movements)
UMN traveling in the ____________ regulate LMN cell bodies in the medial aspect of the ventral horn. What aspect of the limb does this control?
Ventromedial motor system; proximal musculature (whole limb movement, posture and balance)
Damage to the dorsolateral motor system will have what affect on voluntary movement?
Paretic or paralyzed movement to the fine mortar systems (flexor systems) caudal to the sight of damage
Eg.
Damage at T13 -> decreased/absent fined tuned movements of the distal pelvic limb
Damage at C3 -> decreased/absent fined tuned movements of the distal aspect of the forelimb and hindlimb
Damage to the ventromedial motor system will have what affect on voluntary movements?
Paretic or paralyzed movement of the whole limb (mostly extensor) caudal to site of damage
Damage to afferent sensory pathways in the spinal cord causes?
Loss of sensory information reaching the brain
Loss occurs in increasing predictable and increasing severity by loss of : General proprioception Motor control Superficial pain Deep pain
UMN signs are observed ________ to a spinal lesion or injury
Caudal
LMN signs are seen _________ of the lesion or injury
At the site
If you pinch the dorsal aspect of an animals forelimb and do not observe a reflex, this is a _________ sign indicating damage to what portion of the spinal cord?
LMN; C6-T2 (cervicothoracic)
If you pinch the dorsal aspect of an animals hindlimb and do not observe a reflex, this is a _________ sign indicating damage to what portion of the spinal cord?
LMN; L4-S2 (lumborosacral plexus)
In a dog you observe a normal reflex to pinching of the dorsal forelimb and the dog turns to look at you. When pinching the hindlimb you observe a reflex but the dog doesn’t turn around or growl. With respect to the hind limb, you have _________ signs. Where is the lesion?
UMN; between T3-L3
What nerves are involved in the micturition control
Pudendal - somatic
Pelvic - PSNS
Hypogastric -SNS
Filling of the bladder activates stretch receptors that travel afferently in the ___________ nerve
Pelvic
What reflex pathway allows the filling of the bladder?
Filling activate stretch receptors -> pelvic nerve (afferent) -> ascends in the spinal cord -> synapse to SNS -> hypogastric nerve => inhibit detrussor m and stimulates IUS
When the bladder is full and urine escapes through the IUS what reflex pathway is initiated?
Stretch receptor in urethra -> visceral afferents in pelvic nerve -> synapse to somatic pudendal nerve -> reflexive contraction of EUS
This is so you dont pee in inappropriate places
A lesion to S1-S3 would cause _________ bladder signs. Clinically you see continuous leakage. What pathways are disrupted to cause this?
LMN
Pelvic afferent to the SNS hypogastric is blocked -> lack of tone to detrussor m. and IUS
Somatic efferent -> no tone to EUS
Continuous leakage
