ANA300 - Motor and Sensory Pathways

Pathways consist of ______

a series of neurons which communicate at synapses

Number of ____/____ varies

neurons/pathway

Neuronal cell bodies located in ____ or ______

ganglia, nuclei

____, _____ occurs within ganglia or nuclei at synaptic relays

processing, modulation

Axons group to form ____ in the PNS and ____ in the CNS

nerves, tracts

In the CNS, pathways are ______ while in the PNS, pathways are arranged _____

functionally segregated, regionally

Pathways are _______, usually _____

bilaterally paired, usually crossed

Somatic motor pathways control ______ and consist of a _____ and ______

Skeletal muscle, upper motor neuron, lower motor neuron

Upper motor neuron cell body usually at _____, and axon usually _____, projecting onto LMN

higher centres, decussates

LMN cell body resides in the ________ or in the _________. The axon travels through either a ____ or _____

motor nucleus of a cranial nerve, ventral horn of the spinal cord, cranial, spinal nerve

In the ____ for control of skeletal muscles in the body, cell bodies of LMNs are located in the _____

spinal cord, ventral horn

Axons of the LMN reach their target muscle by travelling in the ____, _____, _____ to NMJ

ventral root, spinal nerve, peripheral nerve

In the _____ for control of skeletal muscle in the face, cell bodies of the LMN are located in ___________

brainstem, cranial nerve nuclei

Axons of LMNs reach their target muscle by travelling in a ____ to the NMJ

cranial nerve

The ____ os the only neuron that contacts the muscle and can therefore influence it, ()

LMN, “final common pathway”

LMNS are typically _____ with ______ that receive and integrate all incoming signals

large neurons, extensive dendritic trees

In the brainstem, LMNs form a series of _____ associated with certain _____

Motor nuclei, cranial Ns

In the spinal cord, LMNs form _____

ventral horns

LMNs controlling ______ located at ______, innervating ______ controlling posture and balance

axial musculature, all spinal levels, ipsilateral muscles,

LMNs controlling _____ found in _____ and _____ only, forming the ______ portion of the ventral horn (C5-T1, L2-S2)

distal limb muscles, cervical, lumbosacral levels

LMNS are innervated by ________ consisting of _____

Descending pathways, upper motor neurons

In the lateral pathway, UMNS descend in the _______; include the __________

lateral funiculus, lateral corticospinal tract

In lateral pathways, UMNs innervate LMNs of the ______ to control _____

lateral ventral horn, distal limb muscles

The lateral corticospinal tract allows for ________

skilled, asymmetric limb movement

The corticospinal tract originates in _____ of the _____ which contains cell bodies of UMNs

primary motor cortex, precentral gyrus

Axons of the UMN traverse the ________ of the cerebral hemispheres and brainstem

subcortical white matter

At the junction of the _____ and ____, most fibres of the CST ____ and descend ____ in the lateral funiculus. The remainder descend _______ as the _____

medulla, spinal cord, decussate, contralaterally, ipsilaterally, MCST

Axons of the LCST synapse on LMNs in the _____ which innervate _______ for discrete, skilled movement

lateral ventral horn, distal limb musculature

_______ concern themsleves with our internal environment

interoceptors

______ concern themselves with our external environment such as ____ and ____

exteroceptors, special senses, somatosensation

Conscious sensation is the small fraction of sensory input that reaches _________________ in the _________, determining the ____ and ____ of sensation

modality-specific primary sensory cortex, contralateral cerebral hemisphere, location, nature

Somatosensory pathways consist of a ______—

3 neuron chain

The primary neuron is ________, with its cell body located in a ______ of the PNS

pseudounipolar, ganglion,

For a somatosensory pathway in the body, the axon travels in a ________, _____, and ____ and its cell body is located in a _____

peripheral nerve, spinal nerve, dorsal root, DRG

The cell body of the secondary neuron is either in a ______ of the spinal cord or a _____. It’s axon projects to the ______

dorsal horn, brainstem nucleus, contralateral thalamus

In somatosensory pathways, the axon of the _____ decussates

secondary neuron

The cell body of the tertiary neuron is in the ______ of the thalamus. Its axon projects to the ____

VP nucleus, Primary SS cortex

In the dorsal columns, the _______ and _______ sense touch, vibration, and conscious proprioception ____ and ____ T6 respectively

fasciculus gracilis, fasciculus cuneatus, below, above

Spinothalamic tract in the _______ senses  _____, _____, and _____

Ventral lateral fasciculus, pressure, pain, temperature

In the spinothalamic tract, primary neuron cell bodies lie in _____ in the PNS and project to CNS via _____

dorsal root ganglia, dorsal roots

In the spinothalamic tract, secondary cell bodies lie in the ____ of the spinal cord

dorsal horn

Axons of the secondary neurons in the spinothalamic tract ____ and ascend to become the ______ in the brainstem

decussate, spinal lemniscus

Cell bodies lie in the _____ of the thalamus and project to _________

VP nucleus, primary SS in post central gyrus

As you ascend in the spinal cord, more and more ____ are added to the STT

axons

Left-Right

• Cervical

• Thoracic

• Lumbar

• Sacral/coccygeal

Left and right, top to bottom

• C7 Dorsal rootlets

• Dorsal column

• Dorsal median

• Dorsal intermediate

• Dorsal lateral

• Fasciculus gracilis

• Faciculus cuneatus

In dorsal columns/medial lemniscus system, primary neurons lie in ________ and project to the CNS via ___

dorsal root ganglia, dorsal roots

For the lower body, primary neurons of the ____ ascend in the _______

dorsal columns, ipsilateral fasciculus gracilis

The secondar neuron cell bodies are in the ___ of the medulla, and axons ____, ascending _____ as the ______ through the brainstem

nucleus gracilis, ducussate, contralaterally, medial lemniscus

Tertiary neruonal cell bodies in the ____ and project to _____ in the _____

VP thalamus, 1 SS cortex, postcentral gyrus

For the upper body, pimrary neuronal cell bodies lie in _____ and project to the CNS via ___

dorsal root ganglia, dorsal roots

For the upper body, primary neurons ascend in the _________

ipsilateral fasciculus cuneatus

Secondary neurons of of dorsal columns in the upper body: cell bodies in the _____. Axons _____ and ascend ______ in the _____ through the brainstem

Nucleus cuneatus, decussate, contralaterally, medial lemniscus

For tertiary neurons sensing from the upper body, cell bodies in the _____ and project to ________ in the postcentral gyrus

VP thalamus, primary SS cortex

Motor cortex

Spinothalamic tract

Dorsal column system