Descending tracts of the spinal cord

Question 1

There are two pyramidal tracts. What are they called?

Answer 1

• The corticobulbar tract
• The corticospinal tract

Question 2

Where are the 1st motorneuron cell body located?

Answer 2

In the fifth layer of motorcortex called the pyramidal layer.

Question 3

What are the typical consecuences of a first motorneuron injury?

Answer 3

Spastic paralysis and brisk reflexes in the contralateral side of the body.

Question 4

In what gyri is motorcentrum located?

Answer 4

The precentral gyri

Question 5

Where does the pyramidal tract go in the middle brain?

Answer 5

Through the anterior 2/3 of the POSTERIOR leg of the internal capsule

Question 6

What regions of the brain most likely lead to paralysis and disorders in initiation of movements?

Answer 6

• VA nuleus of Thalamus
• VL nucleus of Thalamus
• Motorcortex.
  More?

Question 7

What specific spinal tract may be involved in a positive babinski reflex?

Answer 7

The lateral corticospinal tract

Question 8

What type of nerves constitute the anterior fasciculus?

Answer 8

The corticospinal nerves responsible for movement of the axial muscles. They do not decussate in the lower medulla, but instead at the level of their spinal exitpoint and synapse with the corresponding PSN in the anterior horn.

Question 9

What two tracts are part of the pyramidal tract in the spine?

Answer 9

• lateral corticospinal tract
• Anterior corticospinal tract

Question 10

What type of disease is ALS?

Answer 10

UMN disease.

Question 11

where is the pyramidal decussation situated?

Answer 11

In lower medulla oblongata by the level of the bulbo-medullary junction.

Question 12

What brodman area is the motorcortex?

Answer 12

Br4

Question 13

What spinal tract crosses to the opposite side at the level of each spinal sepment?

Answer 13

The anterior corticospinal tract.

Question 14

Från att ha gått i capsula internas bakhorn drar sig corticospinala banan framåt i mellanhjärnan. Var hamnar banan där?

Answer 14

Den ligger då framför Substantia nigra.

Question 15

where are the olivary nuclei situated?

Answer 15

In superior medulla oblongata, just posterior to the cerebrospinal lateral tract.

Question 16

What does the posterior column-medial lemnicus pathway do?

Answer 16

It carries proprioceptive and mechanoreceptive afferent fibres from the body to the somatosensory cortex.

Question 17

How many nerve nuclei are connected in the posterior column- medial lemniscus pathway?

Answer 17

3

Question 18

What are the two fascicles of the posterior column medial lemniscus pathway called and what do they do?

Answer 18

Cuneatus - more lateral and carry info from the upper extremity
Gracile - medial to cuneatus, transfer sensory info from the lower extremities.

Question 19

There is a special point where the medial lemniscus forms. Where is that?

Answer 19

After the second order neurons axons (the internal arcuate fibers) have crossed the midline = the decussation of the PCML.

Question 20

Where does the primary Posterior column medial lemniscus synapse to the second neuron?

Answer 20

In the nucleus of the gracilis and cuneatus in the caudal medulla oblongata on the posterior (dorsal) side.

Question 21

Where does the second order neurons ( the medial lemniscus) of the posterior column medial lemniscus neurons synapse?

Answer 21

In VPL in Thalamus

Question 22

What sensory information does the posterior column medial lemniscus pathway carry?

Answer 22

Fine touch, vibration, proprioception and pressure sensation from skin and joints.

Question 23

What is the difference between exteroceptive and proprioceptive information?

Answer 23

Exteroceptive information comes from the body’s exterior, such as pain and touch. In contrast, proprioceptive information comes from inside of the body, such as the muscles.

Question 24

where are the cellbodies of the first order neurons in the ascending pathways lay?

Answer 24

In the posterior nerve root ganglion.

Question 25

Where are the sensory first order neurons axons send?

Answer 25

To the posterior gray horns of the spinal cord

Question 26

Which two fasciculus make up the dorsal column?

Answer 26

Gracilis- lower extremeties sensation
CUneatus - upper extremities sensation

Question 27

What tracts/fibers/pathways make up the (aschending) lateral column?

Answer 27

• Lateral spinothalamic tract
• Dorsal spinocerebellar tract
• Ventral spinocerebellar tract
• spinotectal tract
• spinoreticular fibers
• spino-olivary pathway
• spinovestibular tract

Question 28

What makes up the ventral column?

Answer 28

The anterior spinothalamic tract.

Question 29

What does the axons from the dorsal root ganglion do, more than achending?

Answer 29

Short deschending branches are send several segments down and split into branches synapsing to posterior horn, internunceal neurons and anterior horn cells.
They are responsible for INTERSEGMENTAL REFLEXES.

Question 30

How many of the Thoracic nerves “belong to” the cuneate fasciculus?

Answer 30

The lower 6 thoracic nerves.

Question 31

there are a few fibres called the external arcuate fibers. What do they do?

Answer 31

They go through the inferior cerebellar peduncle as the cuneocerebellar tract, responsible for carrying muscle joint sense information to the cerebellum.

Question 32

What are the object for the spinothalamic tracts?

Answer 32

They carry pain, temperature, non-discriminative touch and pressure info to the Thalamus.

Question 33

What differs between fibers in the spinothalamic and the posterior column medial lemniscus pathway?

Answer 33

1. The cell bodies of origin are PRESENT IN THE SPINAL GRAY MATTER
2. Fibers cross within the ? gray matter? before aschending to Thalamus.