Spinal Cord: Ascending tracts & sensation Flashcards
List 5 types of receptors in the hand.
Meissner corpuscle
Pacinian corpuscle
Ruffini ending
Merkel discs
Free nerve endings
What do Meissner corpuscles detect?
Discriminative touch
What do Pacinian corpuscles detect?
Deep pressure & vibration
What 2 things do Ruffini endings detect?
Touch
Sheer stress / forces
What do Merkel discs detect?
Light, sustained touch
What do free nerve endings detect?
Pain & temperature
Which brain area is responsible for integration of sensory inputs, sensory memory, perception of contralateral self/ world
Superior parietal lobe
What does the anterior limb of the internal capsule contain?
Descending fibres (frontopontine + frontothalamic)
What 2 things does the genu and posterior limb of the internal capsule contain?
Motor fibres to the head, arm, leg
Sensory fibres
What 2 things does the retrolenticular part of the internal capsule contain?
Visual input
Auditory input
Describe the route of each neuron in the 3 neuron ascending sensory pathway.
1st order neuron – enters spinal cord via dorsal root, ascends ipsilaterally
2nd order neuron – decussates + ascend to the thalamus
3rd order neurons – leave thalamus to ascend to cortex via internal capsule
What are the 2 main nuclei in the thalamus for sensory input?
Ventral posterior lateral nucleus (VPL)
Ventral posterior medial nucleus (VPM)
The VPL nucleus in the thalamus receives sensory input from what?
Body
The VPM nucleus in the thalamus receives sensory input from what?
Face
What are the 4 sensory tracts?
Dorsal column pathway
Spinothalamic tract
Spinocerebellar tract
Trigeminothalamic tract
The dorsal column pathway receives sensory input from which 5 receptors?
Meissner’s
Merkel’s
Pacinian
Ruffini
Joint proprioceptors
The dorsal column pathway receives which 2 kinds of sensory input?
Discriminative touch & vibration
Conscious proprioception
The spinothalamic tract receives sensory input from which receptors?
Free nerve endings
The spinothalamic tract receives which 3 kinds of sensory input?
Pain + temperature
Simple touch
The spinocerebellar tract receives sensory input from which 2 receptors?
Muscle spindles
Golgi tendon organs
The spinocerebellar tract receives which kind of sensory input?
Unconscious proprioception
What are the 2 sections of the dorsal column pathway and from which vertebral levels do they receive fibres from?
Fasciculus gracilis – from below T6
Fasciculus cuneatus – from above T6
Where do 2nd order neurons in the dorsal column pathway decussate?
Medulla
What are 2nd order neurons in the dorsal column pathway called after they decussate?
Which nucleus do they ascend to?
Medial lemniscus – which ascends to VPL nucleus of the thalamus