spinal organisation and proprioception

Question 1

what are the general principles of spinal cord organisation

Answer 1

• similar fibres arranged in tracts
• afferent vs. efferent regions (like a highway)
• somatopic organisation (position of fibres with relation to others follow organisation = small lesions can take out entire functions)
• fibres run in white matter (more efficient)
• poly-synaptic
• decussation (crosses midline all except vestibulospinal tract
• sensible nomeclature
• species variations

Question 2

what is proprioception

Answer 2

• the system responsible for detecting changes in the position of the trunk, limbs and head (lots of inputs = multimodal)
• a sense of where your limbs are in space
• the reason you can close your eyes and touch your nose

Question 3

where do you find proprioceptive receptors

Answer 3

• muscle spindles
• golgi tendon organs
• joint capsule
• ligaments
• skin

sensory nerve endings provide proprioceptive information

Question 4

where are proprioceptive receptions projected to and what do these locations tell us about their perception

Answer 4

• projection to cerebellum = unconcious
• projection to somesthetic cortex = concious

Question 5

what are the fibres involved in proprioception in order of largest to smallest

Answer 5

• large myelinated proprioception (fastest transmission)
• medium myelinated motor
• small myelinated/unmyelinated
• sensory/pain (used first)