Spinal cord anatomy and physiology

Question 1

Central gray matter consists of

Answer 1

two anterior (ventral) and two posterior (dorsal) horns united by gray commissure with central canal

Question 2

Central gray matter - anterior (ventral) horns contain cell bodies that give rise to

Answer 2

efferent (motor) neurons
alpha motor neurons to affect muscles
gamma motor neurons to affect muscle spindles

Question 3

Central gray matter - posterior (dorsal) horns contain cell bodies that give rise to

Answer 3

afferent (sensory neurons)

Cells bodies located in DRG

Question 4

White matter - Ascending fiber systems

Answer 4

SENSORY PATHWAYS
Dorsal columns/medial lemniscal system
Spinothalamic tracts
Spinocerebellar tracts
Spinoreticular tracts

Question 5

White matter - Descending fiber systems

Answer 5

MOTOR PATHWAYS
Corticospinal tracts 
Vestibulospinal tracts
Rubrospinal tracts
Reticulospinal tracts
Tectospinal tracts

Question 6

White matter - Ascending fiber systems - DCML - conveys what

Answer 6

sensation of prop, vibration, tactile discrimination

Question 7

White matter - Ascending fiber systems - DCML - divided into what

Answer 7

fasciulus cuneatus - UE tracts laterally located

fasciulus gracilis - LE tracts medially located

Question 8

White matter - Ascending fiber systems - DCML - neurons ascend to where

Answer 8

medulla where fibers cross to form medial lemniscus - ascend to thalamus and then to somatosensory cortex

Question 9

White matter - Ascending fiber systems - Spinothalamic tracts convey what

Answer 9

sensations of pain and temp (lateral spinothalamic tract)

sensations of crude touch (anterior spinothalamic tract)

Question 10

White matter - Ascending fiber systems - Spinothalamix tracts ascend where

Answer 10

Ascend one or two ipsilateral spinal cord segments (lissauer’s tract) synapse, and cross in spinal cord to opposite side and ascent in ventrolateral spinothalamic system

Question 11

White matter - Ascending fiber systems - Spinocerebellar tracts convey what

Answer 11

prop info from muscle spindles, GTOs, and touch and pressure receptors to cbm for control of voluntary movements

Question 12

White matter - Ascending fiber systems - spinocerebellar tract - dorsal spinocerebellar tract ascends to

Answer 12

ipsilateral inferior cerebellar peduncle

Question 13

White matter - Ascending fiber systems - spinocerebellar - ventrospinocerebellar tract ascends to

Answer 13

contralateral and ipsilateral superior cerebellar peduncle

Question 14

White matter - Ascending fiber systems - spinoreticular tracts convey

Answer 14

deep and chronic pain to reticular formation of bainstem via diffuse, polysynaptic pathways

Question 15

White matter - Descending fiber systems - Corticospinal tracts arise from

Answer 15

primary motor cortex, descend to brainstem, cross in medulla to ventral gray matter (ant horn cells)
10% of fibers do not cross and travel to anterior corticospinal tract to cervical and upper thoracic segments

Question 16

White matter - Descending fiber systems - Corticospinal tracts are important for

Answer 16

voluntary motor control

Question 17

White matter - Descending fiber systems - Vestibulospinal tracts arise from

Answer 17

vestibular nucleus and descend to spinal cord in lateral (uncrossed) and medial (crossed and uncrossed) vestibulospinal tracts

Question 18

White matter - Descending fiber systems - vestibulospinal tracts important for

Answer 18

control of muscle tone, antigravity muscles, and postural reflexes

Question 19

White matter - Descending fiber systems - Rubrospinal tracts arise from

Answer 19

contralateral red nucleus and descend in lateral white columns to spinal gray

Question 20

White matter - Descending fiber systems - Rubrospinal tracts assist in

Answer 20

motor function

Question 21

White matter - Descending fiber systems - Reticulospinal tracts arise in

Answer 21

reticular formation of brainstem and descend in ventral and lateral columns, terminates both on dorsal and ventral gray

Question 22

White matter - Descending fiber systems - Tectospinal tracts arise from

Answer 22

Superior colliculus (midbrain) and descends to ventral gray

Question 23

White matter - Descending fiber systems - Tectospinal tracts assist in

Answer 23

head turning responses to visual stimuli

Question 24

Autonomic NS - two divisions

Answer 24

sympathetic and parasympathetic

Question 25

Autonomic NS - sympathetic does what

Answer 25

fight or flight
thoracolumbar division T1-L2
Inc HR, BP, VC to redistribute blood, inhibit peristalsis

Question 26

Autonomic NS - parasympathetic does what

Answer 26

craniosacral division, CN III, VII, IX, X, pelvic nerves
Conserves and stores homeostasis
Slows HR, BP, inc peristalsis and glandular activity