Somatosensory and Proprioception Flashcards
What is meant by the terms
1) proprioception
2) kinaesthesia
1 = detection of a limb in space 2 = detection of movement
What are the somato-senses?
Touch Pain Temperature Proprioception Kinaesthesia
Which pathways do not decussate?
Kinaesthesia and proprioception
Where does pain decussate?
Around the spinal cord segment
What is a nociceptor?
Neuron that detects pain
What is the name of the touch/sensory receptors in the skin?
Pacinian corpuscles
What are the 5 types of sensory receptor?
- Meissner
- Merkel disc
- Pacinian
- Ruffini
- Free nerve ending
How do slowly adapting primary afferents fire action potentials?
When a force is applied to a receptor the response is slower and then action potentials continually fire
Where are large receptive fields found?
Hairy skin
Viscera
What is a mechanoreceptor and what is its function?
Ion channel that sits in the neuronal membrane and when it detects a chemical, temperature or movement it registers a depolarisation and fires
Which types of nerve fibres is the fastest?
Aa fibres = 72-120m/s
Which type of nerve fibres is the slowest?
C-fibres = 0.4-2m/s
Where do pain and temperature pathways cross over?
in spinal cord
Where do touch and proprioception pathways cross over?
Medulla
What is the medial lemniscus?
A collection of nerve pathways that runs through the midbrain
Which pathway is most involved with pain?
Ventrolateral pathway
What does the ventrolateral pathway include?
Spinothalamic tract & spinoreticular tract
Where does the spinocervical tract cross over and travel through?
Crosses just below the midbrain and travels through the medial lemniscus
Where does a somatosensory reflex have to travel through before we are consciously aware of it?
The thalamus
Where is gait generated?
In the spinal cord - each limb has a central pattern generator
How is speed calculated?
stride frequency x stride length
What is the role of proprioceptors?
Proprioceptors inform CNS of body position, strength and speed of movement, so motor output can be modified as needed.
When can an animal demonstrate normal proprioception?
If they have normal motor function
What is the difference between conscious and sub-conscious proprioception?
Conscious – fine detailed movement
Subconscious – larger movements e.g. position of arms and legs
Does conscious or sub-conscious proprioception decussate?
Conscious
What deficits are shown by damage to conscious proprioception?
Stumbling, knuckling, intention tremor
What deficits are shown by damage to sub-conscious proprioception?
Ataxia = Alteration in the rate, range and force of movements
- swaying of the body
- wide/narrow stance
- non-intention tremor
Where are conscious and subconscious tracts located?
Conscious = dorsal funiculus Subconscious = lateral funiculus
Which type of proprioception is the cerebellum involves with?
Sunconscious
What is mentation?
Behaviour, reactions, etc
