1C. Proprioception Flashcards
Participates in local, segmental, and regional communication
Reflex Activity
Information sent to higher levels of the Nervous System
Relay Activity
What type of reflex does the following describe?
- Limbs and trunk via spinal nerves
- may need to coordinate over several cord segments to reach appropriate lower motor neurons that contract body/limb muscles
Spinal Reflexes
What type of reflex does the following describe?
- head and face via Cranial nerves
- may need to travel through different adult brain divisions to reach appropriate lower motor neurons that contract face muscles
Brainstem Reflexes
Reflex where there’s going to be one synapse in our reflex arc, are also relatively rare in the body
Monosynaptic Reflex
List the components of the Monosynaptic Reflex:
- Stimulus receptor synapse
- Motor Cell
- Neuromuscular Junction (NMJ)
- Muscle (effector)
List the components of the Polysynaptic reflex:
- multiple synapses (for proper effect); usually incorporates Interneurons
Name an example of a Monosynaptic Reflex:
Knee jerk = patellar tendon reflex (causes stifle to extend)
Help spread the effect of the stimulus a long a few localized segments so that the proper muscle unit can be recruited in order to cause a full contraction of the muscle
Interneurons
Formed by interconnections of interneurons to recruit appropriate segments of the spinal cord for totality of response
Fasciculus Proprius Pathway
What is a good example of a clinical application of the Fasciculus Proprius?
Skin twitch reflex
It is a strip of skin that is innervated by one spinal nerve
Dermatomes
Location of motor neurons (__________) for lateral thoracic nerve that innervates cutaneous trunci muscle
C8, T1
It is the awareness of body position, knowing where both the trunk and the limbs are located in space
Proprioception
The proprioceptive system is active when the animal is standing still (limbs at rest)
Conscious Proprioceptive System
The proprioceptive system is active when the animal is actually walking
Subconscious Proprioceptive system
The modified nerve ending, a receptor in general, but it is designed to detect changes as the body relates to the external environment
Exteroceptor
The pathway for conscious proprioception (pelvic limb):
Fasciculus Gracilis
The Fasciculus gracilis conscious proprioception pathway is:
contralateral
Fasciculus Gracilis - Pelvic Limb
- spinal ganglion or dorsal root ganglion (DRG)
- Axons ascend ipsilaterally forming fasciculus gracilis
1st neuron
Fasciculus Gracilis - Pelvic Limb
- nucleus gracilis
- axons cross midline as deep arcuate fibers, form contralateral medial lemniscus and ascend through the brainstem
2nd neuron
Fasciculus Gracilis - Pelvic Limb
- ventral caudal lateral nucleus (VCL) of the thalamus
- axons contribute to the formation of the internal capsule, and terminate in the appropriate part of the sensory cortex (somesthetic cortex) in the parietal lobe
3rd neuron
Dorsal Spinocerebellar Tract - Pelvic Limb (1 of 2 Subconscious Proprioception)
- Spinal ganglion or dorsal root ganglion
1st neuron
Dorsal Spinocerebellar Tract - Pelvic Limb (1 of 2 Subconscious Proprioception)
- dorsal gray column in Clarke’s Nucleus (also known as thoracic nucleus)
- axons ascend ipsilaterally in lateral funiculus forming DSCT, pass through superficial arcuate fibers, enter caudal cerebellar peduncle, terminate in the appropriate area of the cerebellum
2nd neuron
Ventral Spinocerebellar Tract - Pelvic Limb (2 of 2 Subconscious Proprioception)
- spinal ganglion or dorsal root ganglion
1st neuron
Ventral Spinocerebellar Tract - Pelvic Limb (2 of 2 Subconscious Proprioception)
- dorsal gray column
- axons cross in ventral white commissure, ascend contralateral in lateral funiculus forming VSCT, enter rostral cerebellar peduncle, recross to terminate in appropriate area of cerebellum
2nd neuron
Clinical Signs
1. Conscious Deficit:__________________
2. Unconscious Deficit: ________________
- Wide stance, wobbly
- Limbs swing out wide while moving
3. detected by testing postural reactions such as placing, hopping, and hemiwalking
- detect signs of knuckling
- Sensory Ataxia (lesion in one of these subconscious sensory pathways)
Conscious Proprioception
Fasciculus Cuneatus - Thoracic Limb
- DRG
- Axons ascend ipsilaterally forming fasciculus cuneatus
1st neuron
Conscious Proprioception
Fasciculus Cuneatus - Thoracic Limb
- medial cuneate nucleus
- axons cross midline as deep arcuate fibers, form contralateral medial lemniscus and ascend through the brainstem
2nd neuron
Conscious Proprioception
Fasciculus Cuneatus - Thoracic Limb
- ventral caudal lateral nucleus (VCL) of the thalamus
- axons contribute to the formation of the internal capsule and terminate in the appropriate part of the sensory cortex (somesthetic cortex) in the parietal lobe
3rd neuron
Subconscious Proprioception (1 of 2)
Cuneocerebellar Tract - Thoracic Limb
- spinal ganglion or dorsal root ganglion (DRG)
- axons ascend ipsilaterally in most lateral part of fasciculus cuneatus
1st neuron
Subconscious Proprioception (1 of 2)
Cuneocerebellar Tract - Thoracic Limb
- lateral cuneate nucleus
- axons ascend ipsilaterally through the brainstem, enter the caudal cerebellar peduncle, terminate in the appropriate area of the cerebellum
2nd neuron
Subconscious Proprioception (2 of 2)
Rostral Spinocerebellar tract - Thoracic Limb
- DRG
1st neuron
Subconscious Proprioception (2 of 2)
Rostral Spinocerebellar Tract - Thoracic Limb
- dorsal gray column
- axons ascend ipsilaterally in lateral funiculus as RSCT, enter caudal and rostral cerebellar peduncle, terminate in the appropriate area of the cerebellum
2nd neuron
