Somatosensory Systems Flashcards
Are somatosensory systems ascending or descending
Ascending
True or False:
Dorsal root ganglia are pseudounipolar
True
What are located in the dorsal root ganglia
Cell bodies
How many branches does the axon have
2
What are the 2 branches of the axon
One projects to the periphery and the other projects to the spinal cord or brainstem
What do specialized terminals on peripheral branch do
Convert environmental energy into nervous system signals
The distal/peripheral section of the axon may either be what (2)
- Bare nerve ending
2. Encapsulated by a structure that helps relay specific information to nerve
Why can’t you perceive the shirt on your back
Adaption
True or False:
Tactile receptors of the skin exist in different densities in different locations on your body
True
What is the distance between two tactile stimuli at which the two are just discerned to be separate
Simultaneous spatial threshold
True or False:
Pain always adapts
False
What are the 5 types of receptors
- Cutaneous and subcutaneous mechanoreceptors
- Muscle and skeletal mechanoreceptor
- Nociceptors
- Thermal receptors
- Itch receptors
Large diameter myelinated sensory nerve fibers muscles fiber, cutaneous nerve, diameter, and conduction
Muscle fiber: I
Cutaneous nerve: Aa
Diameter: 12-20 um
Velocity: 72-120 m/s
Medium diameter myelinated sensory nerve fibers muscles fiber, cutaneous nerve, diameter, and conduction
Muscle fiber: II
Cutaneous nerve: Ab
Diameter: 6-12 um
Velocity: 36-72 m/s
Small diameter myelinated sensory nerve fibers muscles fiber, cutaneous nerve, diameter, and conduction
Muscle fiber: III
Cutaneous nerve: Ad
Diameter: 1-6 um
Velocity: 4-36 m/s
Unmyelinated sensory nerve fibers muscles fiber, cutaneous nerve, diameter, and conduction
Muscle fiber: IV
Cutaneous nerve: C
Diameter: 0.2-1.5 um
Velocity: 0.4-2 m/s
Type I is the main neuron for what
Proprioception (muscle and joint activity)
Ab is the main neuron for
Touch (mechanoreceptors)
C fibers conduct what (2)
- Poorly localized, dull, aching, pain
2. Itch
What do large diameter myelinated fibers innervate (2)
- Muscle spindle receptors
2. GTO (muscle length and contractile force
What do medium diameter myelinated fiber innervate
Secondary spindle endings and receptors in joint capsules (proprioception)
What do small diameter myelinated and unmyelinated fibers innervate
Muscle and joint pain
What is a sensory region of the skin and deeper tissues innervated by a given nerve root
Dermatome
True or False:
The dermatomes are largely overlapping in the thoracic region
True
Somatotopy is maintained in what (3)
- Spinal cord
- Brainstem relay nuclei
- Cortex