Somatosensation Flashcards
(15 cards)
How are sensory receptors classified?
By location (e.g. interoceptors, exteroceptors), stimulus (e.g. mechanoreceptors), structure (e.g. free endings, encapsulated)
What are the main ascending sensory pathways and their functions?
Dorsal columns (fine touch, proprioception), Spinothalamic (pain, temperature, non-discriminative touch), Spinocerebellar (unconscious proprioception)
Why does spinal cord injury result in sensory loss, brisk reflexes, and weakness?
Interrupts sensory/motor pathways; removes brain modulation of reflexes → hyperreflexia
What’s the difference between complete and incomplete spinal cord injury?
Complete: total loss below lesion; Incomplete: partial preservation of function
Which receptor detects vibration?
Pacinian corpuscle.
Which sensory pathway crosses in the medulla?
The dorsal column-medial lemniscus pathway.
What is the function of the spinocerebellar tract?
It carries unconscious proprioception.
What sensory loss occurs in a dorsal column lesion?
Loss of fine touch, vibration, and proprioception.
What is a dermatome?
An area of skin supplied by a single spinal nerve.
Which tract carries pain and temperature?
The spinothalamic tract.
How do mechanoreceptors differ from nociceptors?
Mechanoreceptors detect pressure/vibration; nociceptors detect pain.
What does a positive Babinski reflex suggest in sensory exams?
Upper motor neuron lesion affecting motor-sensory integration.
Dorsal Column Pathway
Fasciculus (Gracilis/Cuneatus) -> Nucleus (Gracilis/Cuneatus) -> Medial Leminicus -> Thalamus -> Sensory Cortex
Spinothalamic Tract
Dorsal Root (Spinal Cord) + Decussates -> Thalamus
Spinocerebellar Tract’s special trait
Doesn’t Decussates!
