Somatosensory System Flashcards
What is a rapidly adapting receptor and name one type?
Upon stimulation shows an initial increase in action potential firing but with continued stimulation shows a rapid decline in the frequence of action potentials.
Mechanoreceptors.
Give 4 slowly adapting receptor types.
Nociceptors
Baroreceptors
Proprioceptors
Chemoreceptors
Name 3 sensory modalities controlled by the spinothalamic pathway.
Temperature
Pain
Pressure (crude touch)
Vibration
Fine touch
Proprioception
2 point discrimination
What levels does the gracile fasciculus recieve signals from?
T7 and below
Give some causes of damage to dorsal column medial leminiscus pathway.
What test can test the function of this pathway?
B12 deficiency
MS
Tabes dorsalis
Rombergs (proprioception)
What is the initial presentation of B12 deficiency leading to demyelination of the dorsal column?
Sensory ataxia (broad based stomping gait)
Give four receptor types that feed into the DCML pathway.
Pacinian corpuscles
Meisnerr’s corpuscles (light touch)
Ruffini corpuscles
Merckel’s discs
Somatotropically how are the limbs organised in the spinothalamic vs DCML pathways.
Spinothalamic - lower limbs are lateral
DCML - upper limbs are more lateral
What are two types of pain fibres.
Differences in myelination?
Main stimulation?
Which one is more stimulated by cold temperatures?
A fibres
C fibres
A - highly myelinated
C - less myelinated
A - mechanically gated (TRPV channels)
C - chemical signals - BK, H+ histamine, K+
A
What are some causes of brown sequard syndrome?
Trauma (stab wound)
Vertebral bone fracture
Gunshot
Tumour
Name some features of brown sequard syndrome.
Ipsilateral spastic paralysis below the lesion level
Flaccid paralysis at the level
Contralateral spinothalamic modality loss 1-2 segments below level
Ipsilateral DCML modality loss below the lesion
Ipsilateral segmental anaesthesia (at the level)q
