10 Ascending pathways Flashcards
Hair follcile receptors:
- modality
- features
- touch
- rapidly adapting
Merkel endings:
- modality
- features
- pressure, low freq vibration
- slowly adapting
Meissner corpuscles:
- modality
- features
- light touch
- rapdily adapting
Pacinian corpsucles:
- modality
- features
- vibration, JPS
- rapidly adapting
Ruffini endings:
- modality
- features
- skin stretch, pressure, JPS
- slowly adapting
Nociceptors:
- modality
- features
- pain
- free nerve endings
Muscle spindles:
-modality
-muscle length, proprioception
Golgi tendon organs:
- modality
- features
- JPS
- slowly adapting
Aα axons (from skin):
- axons from muscles
- diameter (μm)
- speed (m/sec)
- sensory receptors
- group I
- 13-20
- 80-120
- proprioceptors of skeletal muscle
Aβ axons (from skin):
- axons from muscles
- diameter (μm)
- speed (m/sec)
- sensory receptors
- group II
- 6-12
- 35-75
- mechanoreceptors of skin
Aδ axons (from skin):
- axons from muscles
- diameter (μm)
- speed (m/sec)
- sensory receptors
- group III
- 1-5
- 5-30
- pain, temp
C axons (from skin):
- axons from muscles
- diameter (μm)
- speed (m/sec)
- sensory receptors
- group IV
- 0.2-1.5
- 0.5-2
- temp, pain, itch
What is the concept of lateral inhibition?
- each sensory neuron has a receptive field
- dendrites are dense at the centre and diffuse at the periphery
- situmuli at the cneter of the field activate more dendrites thatn at the periphery and so cause faster firing
How does lateral inhibition relate to sensation?
sharpens discrimination between 2 points
Clinical sensory testing for joint position sense
- why test
- other
- exclusively dorsal columns
- stabilise joint
Clinical sensory testing for pain and temp
- why test
- other
- exclusively lateral spinothalamic tracts
- sharp/dull or cold tuning fork
Clincial sensory testing for light touch
- why test
- other
-localises lesion (not one pathway)
Clinical sensory testing for vibration sense
- why test
- other
- good screening for several pathologies
- 125Hz tuning fork
