Asc and Desc Tracts

Question 1

What kind of information does the asc pathway carry and from where to where

Answer 1

It carries sensory information from body to brain

Question 2

What kind of information does the desc pathway carry and from where to where

Answer 2

It carries with motor information from brain to muscles / glands

Question 3

In the asc pathway, where do the impulses come from?

Are they cortico or spino

Answer 3

Comes from pain, thermal, tactile, muscle and joint receptors
Spino

Question 4

Is the desc pathway cortico or spino

Answer 4

Cortico

Question 5

What is contralateral decussation

Answer 5

Pathways cross to the opposite side

Question 6

What is ipsilateral decussation

Answer 6

Pathways ascend on the same side

Question 7

How many sensory neurons are involved in the asc pathway

Answer 7

3 ( Primary, Secondary, Tertiary )

Question 8

How many neurons are involved in the motor pathways

Answer 8

Upper Motor Neuron

Lower Motor Neuron

Question 9

Sensory pathways are ascending pathways that conduct information about ( 5 )

Answer 9

Limb position
Sensations of Touch 
Temperature 
Pressure 
Pain 
...... to the brain

Question 10

What are the three types of somatosensory pathways

Answer 10

Posterior column - medial lemniscus
Spinothalamic
Spinocerebellar

Question 11

There are two kinds of corticospinal tracts. What are they and what kind of information do they carry

Answer 11

Lateral Corticospinal Tract
Anterior Corticospinal Tract
They conduct motor information

Question 12

Wheat fascicles are present in Post Column - Medial Lemniscus ( 2 )

Answer 12

Fasciculus Gracilis

Fasciculus Cuneatus

Question 13

Were do you find the fasciculus gracilis ( in terms of SC )

Answer 13

Present throughout cord length ( Sacral, Lumbar, and lower 6 Thoracic spinal Nerves )

Question 14

Where do you find fasciculus cuneatus

Answer 14

Present in T6 and cervical cord segments

Question 15

What are the tracts collectively called in the spinal cord

Answer 15

Posterior Funiculus

Question 16

What are the tracts within the brainstem called

Answer 16

Medial Lemniscus

Question 17

Describe the pathway of Posterior Column Medial Lemniscus Pathway

Answer 17

1) Fibers will ascend ipsilaterally
2) They synapse w neurons in the gracile and cuneate nucleus of the medulla
3) Sensory decussation of second order neurons occur in the medulla oblongata.
3) Medial Lemniscus ascends to pons, midbrain and synapse at VPL of thalamus

Question 18

What is composed of the Spinothalamic Pathway ( 2 )

Where is the anterior and lateral white funiculi of SC located ?

Answer 18

Anterior and Lateral Spinothalamic Tract

Located in the whit funiculi of spinal cord, anteriorly and laterally

Question 19

What kind of stimuli does the
1) Anterior
2) Lateral
Spinothalamic tracts carry

Answer 19

1) Light / Crude touch and pressure

2) Pain and Temperature

Question 20

Describe the pathway of spinothalamic pathway

Answer 20

1) Primary neuron synapses w cells of posterior gray matter
2) Secondary neurons decussate in the spinal cord before ascending the brainstem
3) Synapses w third order neurons in VPL nucleus of thalamus

Question 21

What kind of information does the spinocerebellar pathway conduct ?

Answer 21

Proprioceptive information to the cerebellum as it helps coordinate body movement

Question 22

Describe the pathway of the spinocerebellar pathway

Answer 22

1) Axons enter the posterior tray column and synapses with the secondary neuron
2) Axons ascend ipsilaterally to the medulla

Question 23

What do the motor pathways do

Answer 23

It regulates skeletal muscle activity

Question 24

Where is the upper motor neuron found?

Answer 24

Located in the cerebral cortex or a nucleus within the brainstem

Question 25

Where is the lower motor neuron found?

Answer 25

Located either within anterior grey matter of spinal cord

Or within brainstem cranial nerve nucleus

Question 26

Where does the corticospinal tract ( pyramidal pathway ) originate

Answer 26

Originates in the cerebral cortex

Question 27

Where do the axons descend through ?

Answer 27

Descends through the internal capsule, enters cerebral peduncles forming descending motor tracts and will form thick anterior bulges in medulla oblongata called pyramids

Question 28

Where does synapse occur in the corticospinal tract

Answer 28

Synapses in the anterior grey matter of the spinal cord

Question 29

Where does the lateral corticospinal tract decussate and what do the axons of LMN innervate

Answer 29

It decussates within the pyramids of the medulla oblongata

Axons innervate the skeletal muscles that control skilled movements

Question 30

Where does decussation occur in the anterior corticospinal tracts

Answer 30

Decussates with interneurons or lower motor neurons in the anterior grey matter of SC

Question 31

What does the LMN of the anterior corticospinal tracts innervate

Answer 31

It innervates the axial skeletal muscle