Spinal Cord 3

Question 0

Dorsal column-medial lemniscal system

Answer 0

Discriminative touch, proprioception, vibration sense

Question 1

Corticospinal tract

Answer 1

Part of the pyramidal system,

Volitional motor

Question 2

Anterolateral system

Answer 2

Pain, temperature, crude touch

Spinoreticular, spinothalamic, spinomesencephalic, and other tracts.

Question 3

Spinocrebellar tract

Answer 3

Unconscious proprioception, information from muscle (spindles and Golgi tendon organs), to the cerebellum

Question 4

Hypothalamospinal tract

Answer 4

Central control of pre ganglionic autonomic neurons of the spinl cord

Question 5

Pyramidal system

Answer 5

Major Volitional motor control
Neurons originate in the cerebral cortex, primary motor complexioned frontal lobe
Sends projections to the brain stem(corticobulbar) and spinal cord (corticospinal)

Question 6

Upper motor neurons

Answer 6

Cortical neurons of the pyramidal tract

Have origin and termination in the CNS

Question 7

Lower motor neurons

Answer 7

Spinal crd and braistem neurons that directly Innervate muscles are lower motor neurons
Originate in CNS and terminate in the periphery

Question 8

Lateral corticospinal tract

Answer 8

80-90 % of fibers cross at the pyramidal decussation

Question 9

Anterior corticospinal tract

Answer 9

Descends ipsilaterlly as they do not decussate, Innervate motor neurons and interneurons that primarily are axial muscles, some fibers cross at level of Innervation of inter or motor neurons

Lesions do not oresnt significant clinical problems

Question 10

CS tract Innervation

Answer 10

CS axons Innervate some alpha neurons directly but the majority Innervate interneurons that supply alpha neurons, can be excitatory or inhibitory, generally CS neurons activate flex or sand inhibit extensors
This is to control fine skilled movements

Question 11

Other descending tracts that contribute to normal motor fnxn

Answer 11

Reticule spinal, rubrospinal, and vestibulospinal

Question 12

Rubrospinal tract

Answer 12

Other significant flexor biased tract, crosses near its origin in the red nucleus of the midbrain
Involved in flexor movements of arm and firearm doesn’t descend past cspine.
Has some inhibition of extensors

Question 13

Vestibulospinal and reticulospinal tracts

Answer 13

Extensor biased

Fnxn in proximal body muscle tone,and postural muscle activity related to balance

Question 14

Vestibulospinal tract

Answer 14

Vestibular tracts have to main branches that participate in extensor activation and balance special orientation.
Does not receive input from the cerebrum, but from the cerebellum.
The cerebellum maintains posture through sensory input from the soinocerebellar tracts, that convey partly to the vestibulospinal tract to maintain posture.

Question 15

Preganglionic autonomic neurons

Answer 15

Primarily through the Hypothalamospinal tract, neurons of the Intermediolateral cell column
Constitute upper motor neuron influences of viscera motor activity.

Question 16

Ascending tracts

Answer 16

Primarily dorsal columns, ALS, ans spinocerebellar tracts

Question 17

Dorsal columns

Answer 17

Carry fast conducting myelinated axons, t types Ia, Ib, II, A beta, enter the spinal cgord in medial division of the dorsal root entry zone
Carrie info ipsilaterally in the spinal cord in posterior fasiculi, gracilis, and cuneatus.

Question 18

Fasciculus gracilis

Answer 18

Consists of Axons of DRG neurons below t6

Question 19

Fasciculus cuneatus

Answer 19

Consists of axons of DRG neurons above t6

Question 20

Somatotopic arrangement of DC

Answer 20

Information from the legs and feet are found medially while info from the arms and trunk and neck are found laterally.

Question 21

Medial lemniscus

Answer 21

Formed from axons coming from the nucleus gracilis and cuneatus.
Axons that form medial lemniscus cross at the level of the obex. They continue up to the thalamus, thalamic neurons then continue to sensory areas of the cerebral cortex.

Question 22

ALS

Answer 22

Collection of tracts carrying pain temperature and crude touch sensory information, contains lightly and unmyelinated axons, type 111, IV, A-delta and C
Enter SC at lat. div. of dorsal root entry zone.
Tracts run Mostly in lat and partly I he ant funiculi

Question 23

Dorsal root entry zone

Answer 23

Where ALS sensory nerves enter to synapse in the lateral horn of the SC. They then cross over through the ant white commissure to form ALS on the opposite side of entry, these axons also give off collateral nerves

Question 24

Spinothalamic tracts

Answer 24

Direct connection to thalamus of ALS neurons is the first major connection of spinothalamic tract which provides connection then to the somatosensory cortex.

Question 25

Spineoreticular fibers

Answer 25

Indirect rout to thalamus through reticular formations, these form poly synaptic pathway that will eventually reach wide areas of cerebral cortex.

Question 26

ALS resistance to localized lesions

Answer 26

Is occurs as a result of the collateral branches that the ascending ALS tracts give off along the way..

Question 27

Spinocerebellar tracts

Answer 27

Anterior, posterior, and cuneocerebellar tract, A and P carry info from the spindles, joint capsule receptors and skin of the lower limb while C carry this info from the upper limb
Fibers pass through dorsal root gang to cell nuclei in intermediate zone of the sp. gray matter. P and C carry info ipsilaterally and deal primarily with individual muscle coordination while A ascends contra. And deals with entire lower limb muscles coordination in the cerebellum.