Nervous System Flashcards
Posterior column-medial lemniscus Pathway - 1st order neuron
- Receive input from peripheral receptor and deals with touch and pressure senses
Upper body sensory nerve receptors
Travel through cervical spinal region
Lower body sensory nerve receptors
Travel through lumbar spinal region
Cuneate fasiculus
Upper body sensory input from receptors travels through and passes through Cuneate nucleus
Gracile fasiculus
Lower body sensory input from receptors travels through and passes through Gracile nucleus
Posterior column-medial lemniscus Pathway - 2nd order neuron
The sensory neurons decussate and travels upwards passing through medial lemniscus in mid brain to the thalamus
Posterior column-medial lemniscus Pathway - 3rd order neuron
Passes sensory input from thalamus to primary somatosensory cortex
Spinothalamic pathway - 1st order neuron
Receives pain and temperature sensory input from trunk, limbs, neck and posterior head. Passes through posterior grey horn
Spinothalamic pathway - 2nd order neuron
Decussates in spinal cord to spinothalamic tract and travels upwards through medulla and midbrain.
Body parts occupying large portions on sensory homunculus map means:
They have a large amount of sensory receptors within the body part.
Size on map does not correlate with actual body part size.
What is the posterior column?
Consists of two tracts - cuneate (upper body) and gracile (lower body) fasciculus
Lower motor neurons in brain stem
Extend through cranial nerve to innervate skeletal muscle of head and face
Lowe motor neurons in spinal cord
Extend through spinal nrves and innervate muscles of lims and trunk.
Upper motor neurons
Send output to LMN. UMN from brainstem regulate muscle tone, control postural muscles and help maintain balance and orientation of head and body.
Basal nuclei
Assist movement by providing input to upper motor neurons. Help initiate and terminate movements, suppress unwanted movements and establish normal level of muscle tone.
