sensory and motor Flashcards
The dorsal column-medial leminscus pathway transports:
Fine touch, vibration and proprioception
Information from the ……body (…T…) travels in the …fasiculus to the …. nucleus.
Upper, above T6, cuneate
or
Lower, below T6, gracile
VPL stands for
Ventral posterolateral nucleus of the thalamus
Which sensory pathways have 3 order neurones
Dorsal column
spinothalamic/ aka anterolateral (close to ventral root)
Pain, temperature and course touch are sensed by which sensory pathway?
spinothalamic/ aka anterolateral
Which order neurones synapse at the VPL
2 order neurons from Dorsal column
spinothalamic/ aka anterolateral
Define Adaption
how neurones react to a maintained stimulus
NociceptorsandThermoreceptors are innervated by….fibres
Type III (Aδ) Type iv (c fibres)
Type I and II sensory fibers innervate?
Proprioceptors
Which sensory organs pick up vibration and pressure
Pacinian corpuscle
Meissner’s (or tactile) corpuscles senses
Light touch and low frequencey vibration
What is this:
Found in stratum basale of epidermis
Role in light touch, discrimination of shapes and textures.
Merkel Cells
The role of gamma motoneurones
controlls the sensitivity of muscle spindles
What does the Crossed extensor reflex do:
Helps to keep the body balanced/ in equilibrium
for example if someone grabs arm, it will flex- but the other arm will extend to keep balance.
Which reflex controls muscle tension
Golgi tendon reflex
Name the 3 different sources that the alpha motor neuron receives input from.
- Sensory neurones
- Interneurones
- Upper motor neurones
Conditioning just before eliciting the myotatic reflex causes:
A greater/ exaggerated reflex
The… reflex causes…of a part of a body in response to a painful stimuli
The FLEXOR/ WITHDRAWAL reflex causes WITHDRAWL of a part of a body in response to a painful stimuli
A motor unit is?
Alpha motor neuron and muscle fibres it innervates
All alpha motor neurons innervating a muscle is:
motor neuron pool
Proprioception is sensed by which sensory pathway?
information from muscle and joint receptors
Spinocerbellar tract- from spinal cord to the cerebellum
Name the nuclei that does not receive bilateral innervation from the Corticobulbar fibres
Hypoglossal nucleus and motor nuclei controlling facial muscles below the eye.
Which tract maintains Head stabilisation and the upright posture?
Vestibulospinal tract- Bilateral innervation of muscles
Activation of what can increase excitability of motor neurons?
Locus Coeruleus- these are noradrenergic neurons project to brain and spinal cord
Decorticate posture is due to?
(Arms abducted and flexed; wrists and fingers flexed on the chest; legs stiffly extended and internally rotated; plantar flexion of feet)
Upper motor lesion that separates the cerebrum from the upper brainstem
What is Spinal prep
flaccid paralysis- loss of both voluntary and muscle tone
Due to lower motor neuron lesion between c1 spinal cord and CNS
Which disease causes progressive degeneration of upper and lower motor neurons
Amyotrophic lateral sclerosis
Describe what the phenomenon of WINDUP (in pain)
This phenomenon is found in the Dorsal horn neurons
Stimulation of C-fibres: each stimulus leads to more evoked APs in WDRecptor neurons
Where is the choroid layer found
Between the retina and sclera
What is the function of the choroid layer
Contains melanin which absorbs the excess light..preventing excess reflection
In the dorsal column-ML tract 1st order neuron synapses where? Does it decussate before synapsing?
It synapses at the Gracile or Cuneate nuclei depending on origin and doesn’t decussate beforehand.
Where does the 1st order neuron synapse in the spinocerebellar tract?
Clarke’s nucleus at the level of entry
Where does the 1st order neuron of the spinothalamic tract synapse
It synapses immediately at the dorsal horn
Explain the route of the 2nd order spinothalamic neuron
It decussates to the contralateral Spinothalamic tract and travels up to the Ventral posterolateral nuclei of the thalamus
How does the 3rd order neuron of the Dorsal Column-ML and Spinothalamic tract travel
It travels from the VPL through the internal capsule to the Somatosensory cortex
How does the Posterior spinocerebellar 2nd order neuron reach the cerebellar cortex?
Via the inferior cerebellar peduncle of the pons
How does the Anterior spinocerebellar 2nd order neuron reach the cerebellar cortex?
Via the SUPERIOR cerebellar peduncle of the pons
In which spinocerebellar tract do the 2nd order neurons travel ipsillaterally?
POSTERIOR spinocerebellar tract
What is the pathway for the corticobulbar tract
Motor cortex to cranial nerves nuclei found in the brainstem
What is the function of the corticobulbar tract
Control movement of face, head and neck
The rubrosprinal tract originates from where? and where does it travel
Red nucleus of midbrain
Travels in the lateral corticospinal tract
Lateral corticospinal tract decussates where?
At the medullary cervical junction.
What is the function of the corticospinal tract
Innervation of the lower motor neurones
What is the function of the basal ganglia
Basal ganglia acts to inhibit the motor functions
