Sensory Pathway I Flashcards
Signal pathways
-involve a sequence of neurons
-excitability is transmitted from one neuron to the next sequence
Pathway types
1.ascending- carrying information from receptors to the brain (sensory)
2.descending- conveying information from the brain to spinal cord neurons (motor)
Somatic sensations
1.proprioreception
2.exteroception
3.nociception
Proprioreception
-sense of the location and movement of the body segments in space (position sense, kinesthesia)
**without proprioreception, animal will have uncoordinated gait= ATAXIA
Receptors of proprioreception
-Muscle spindles (muscle stretch)- 1a fibres
-Golgi tendon organs (muscle force)-1b fibres
-joint capsule stretch receptors
Brain regions for proprioreception
1.conscious proprioreception
2.subconscious proprioreception
Conscious proprioreception
-awareness of body movements
- CEREBRAL CORTEX
Subconscious Proprioreception
-“involuntary” control of proprioreception= not conscious/aware
- CEREBELLUM
**not easily tested
Spinal pathway for conscious proprioreception (getting to brain)
- collateral branch from sensory neuron will travel in white matter tract (myelinated axon) through dorsal funiculus to the cerebral cortex of brain
- constant when animal is standing or moving so that body is aware or body positioning
Signal pathway for conscious proprioreception (within the brain)
- synpase on nuclei on medulla, then travels to contralateral side of brain (crossing over to other side of brain)
- interneuron from medulla to thalamus
- neuron from thalamus will synapse on somtosensory cortex
Dorsal vs. lateral and ventral funiculus
-Dorsal: only sensory tracts running through them
-Ventral and Lateral: will have both sensory and motor tracts running through them
Spinal pathway for subconscious proprioreception
-collateral axon sent to cerebellum in brain (spinocerebellar tracts)
>will have one through both left and right side of lateral funiculus
