Ascending & Descending Tracts

Question 0

Tracts

Answer 0

Bundles of axons with similiar origins and terminations
Similiar
Fasiculus
Lemniscus

Question 1

Ganglia

Answer 1

Structure containing cell bodies, generally outside of the cns
Mass of grey matter within the cns (basal ganglia)

Question 2

Ascending & descending tracts

Answer 2

Ascending-related to sensory systems-brings sensory information UP to the brain
Descending-associated with motor system , brings motor command DOWN to muscles

Question 3

Thalamus

Answer 3

“Grand central station”
➡️deep within the cortex
➡️many nuclei receive all sensory information, peripheral and visual and vestibular
➡️transmit to all locations within the cortex
➡️ventral posteriolateral nucleus VPL

Question 4

Brodmans areas

Answer 4

➡️Brodman divided the brain into 53 different areas
➡️primary somatosensory cortex (1,2,3)
Secondary somatosensory corex (40,43)
➡️posterior parietal cortex (5,7)

Question 5

Column

Answer 5

Dorsal column-only ascending tracts
Myelinated, very fast
Newer system, proprioception, vibration , touch
Antero-lateral column 
Un myelinated,-slower
Older system-pain, crude touch, temp

Question 6

Descending tracts (3)

Answer 6

1) corticospinal tract
2) vestibulospinal tract
3) reticulospinal tract

Question 7

Corticospinal tract

Answer 7

• descending tract
• transmits voluntary motor commands to the SC
• motor cortex associated with Contralateral muscles, so axons must desiccate
• important In controlling skilled movements
• begins in the motor cortex , through the internal capsule

Question 8

Vestibulo spinal tract

Answer 8

-descending tract
-beings in the vestibular nuclei, and controls ipsilateral muscle
-transmits subconscious motor commands to extensor muscles to maintain balance
2 tracts
Medial VS tract:controls neck muscles
Lateral VS tract:descends directly to ipsilateral extensor muscles

Question 9

Reticulospinal tract

Answer 9

Coordinates automatic movements (locomotion and posture)
-originate in the reticular formation (pons and medulla)
-travel ipsilateral, terminate at all sc segments
2 tracts
1)pontine reticulospinal tract : medial. Excites ipsilateral extensor muscles. (Helps support our weight)
2)medullary reticulospinal tract:lateral, inhibits ipsilateral extensor muscles , let’s us relax

Question 10

Ascending tracts (3)

Answer 10

1) medial lemniscal system
2) anterolateral spinothalamic tract
3) spinocerebellar tract

Question 11

Medial lemniscal tract

Answer 11

-transmits proprioception, fine touch and Vibration
Transcends from dorsal column
-axons are most myelinated, fastest
-sensations from one side of the body, associated with Contralateral somatosensory cortex

Question 12

Spinothalamic tract

Answer 12

• transmits pain, temperature and crude touch from periphery to areas within the cortex
• receptors on one side of the body associated with Contralateral cortex
• lateral spinothalamic tract- pain and temperature
• anterior spinothalamic tract-crude touch and pressure

Question 13

Spinocerebellar tract

Answer 13

• Transmits information from skin receptors, gtos, spindles to the cerebellum for integration
• ascends in dorsal column via the dorsal and ventral spinocerebellar tracts
• receptors on one side of the body associated with ipsilateral cerebellum