Week 3 (Spinal Cord)

Red arrows

Pyramids

How many neurons are involved in the somatosensory ascending pathways?

3

How many neurons are involved in the motor descending pathways?

2

Where are the nuclei of the sensory neurons located in the somatosensory ascending pathways?

First order neuron?

Dorsal root ganglion

Where are the nuclei of the sensory neurons located in the somatosensory ascending pathways?

Third order neuron?

VPL/thalamus

Where are the nuclei of the sensory neurons located in the somatosensory ascending pathways?

Which is their destination?

Somatosensory cortex

Sensations of pain and temperature are transited to the brain by the _____ pathway (be specific)?

Spinothalamic tract (anterolateral system/pathway)

Two point discrimination is a sensation transmited to the brain by the _____ pathway

Dorsal Column/ Medial Lemniscus (DCML)

Spinothalamic tract (Anterolateral System/ ALS) decussates at the level of:

Spinal cord

Dorsal Column/ Medial Lemniscus (DCML) decussates at the level of:

Medulla

List the characteristics of pain/temperature receptors:

Free nerve endings, small diamater, unmyelinated, low conduction velocity

What is the name of the main descending pathway?

Corticospinal tract

Where is the origin of the main descending pathway?

Motor cortex

Where does the main descending pathway decussate?

Pyramids medulla

How many neurons are involved in the main descending pathway?

2

What is the final target of the main descending pathway?

Motoneurons spinal cord/ Lower motor neuron

In the ALS, where are 2nd order neurons located?

Cuneatus and Gracilus fasciculus

In the DCML, where are 2nd order neurons located?

in the spinal cord

How many neurons are involved in the spinocerebellar tracts?

2

Does the proprioceptive info. (from golgi tendon organs and muscle spindles) ascend ipsilaterally or contralaterally?

Ipsilateral

Which is the final destination of the spinocerebellar pathway?

Cerebellum

What is the babinski sign a characteristic of?

Upper motor neuron lesion