Functional Anatomy Of The Spinal Cord

Question 1

Which two sources do motor neurons receive input?

Answer 1

Local sources - segmental reflexes

Descending tracts from brain - voluntary movement

Question 2

Where does the lateral corticospinal tract decussate?

Answer 2

In the medulla

Question 3

Where does the anterior corticospinal tract decussate?

Answer 3

At the level at which it leaves the spinal cord

Question 4

Where in the white matter does the lateral corticospinal tract travel?

Answer 4

Immediately lateral to the dorsal horn

Question 5

Where in the white matter does the anterior corticospinal tract travel?

Answer 5

Lateral to the anterior median fissure

Question 6

Which two parts of the brain does the corticospinal tract travel through?

Answer 6

Internal capsule

Cerebral peduncle of the midbrain

Question 7

Where do the axons of the corticospinal tract form ventral bulges, and what are they called?

Answer 7

In the medulla oblongata

- known as pyramids

Question 8

What is the difference in function between the lateral and anterior corticospinal tracts?

Answer 8

Anterior - control trunk and proximal limb movement

Lateral - precise, agile and highly skilled movements of hands and feet

Question 9

What is the function of the corticobulbar pathway?

Answer 9

Controls skeletal muscles of the head

Question 10

Which two areas of the brain does the corticobulbar tract pass through?

Answer 10

Internal capsule

Cerebral peduncle of the midbrain

Question 11

Which nine cranial nerve motor nuclei, do axons of the corticobulbar tract terminate in?

Answer 11

Oculomotor 
Trochlear 
Trigeminal
Abducens 
Facial
Glossopharyngeal 
Vagus
Accessory
Hypoglossal

Question 12

What is the function of the tectospinal pathway?

Answer 12

Maintains balance and posture

Question 13

Which neurons does tectospinal modulate the activity of?

Answer 13

Alpha and gamma motor neurons innervation muscles of the neck

Question 14

What is the function of the vestibulospinal pathway?

Answer 14

Maintains balance and posture

Question 15

What are the two parts of the retculospinal tract?

Answer 15

Pontine (extensor)

Medullary (flexor)

Question 16

What is the function of the reticulospinal tract?

Answer 16

Maintains balance and posture

Question 17

What is the function of the rubrospinal tract?

Answer 17

Regulates upper limb muscle tone and movement

Question 18

Where do the upper motor neurons arise in the rubrospinal tract?

Answer 18

The red nuclei of the midbrain

Question 19

Where do upper motor neurons of the rubrospinal tract decussate?

Answer 19

Midbrain

Question 20

Where in the White matter of the spinal cord will you find the dorsal column (medial lemniscus pathway)?

Answer 20

Posterior and medial to the dorsal horn

Question 21

Why is the dorsal column/medial lemniscus path called this?

Answer 21

Dorsal column of the spinal cord

Medial lemniscus of the brainstem

Question 22

Where do first order neurons of the dorsal column arise from and terminate at?

Answer 22

Arises from sensory receptors in limbs, trunk, neck, etc

Travels into the spinal cord, ascends up the ipsilateral side and terminates at the medulla (still ipsilaterally)

Question 23

Where are the cell bodies for the first order neurons of the dorsal column found?

Answer 23

Dorsal root ganglion

Question 24

What are the two dorsal columns in the white matter - and what sensations are carried in each?

Answer 24

Gracile fasciculus
- touch, pressure and vibration from lower limbs
Cuneate fasciculus
- touch, pressure, vibration and conscious proprioception from the upper limbs, trunk and neck

Question 25

Where do first and second order neurons synapse in the dorsal column?

Answer 25

In either the gracilis or cuneate nucleus

Question 26

Where do the second order neurons of the dorsal column arise and terminate?

Answer 26

Arise in the cuneate of gracile nucleus, then decussate (in the medulla still) and enters the medial lemniscus Terminates in the ventral, posterior nucleus of the thalamus

Question 27

Where do tertiary axons of the dorsal column arise and terminate?

Answer 27

Arise in the ventral, posterior nucleus of the thalamus | Terminates in the primary somatosensory area of the cerebral cortex

Question 28

What sensations does the medial lemniscus pathway transmit?

Answer 28

Tactile sensations | Proprioception

Question 29

Where in the white matter is the spinothalamI c tract located?

Answer 29

Anterio-lateral to the ventral horn

Question 30

What sensations does the spinothalamic tract carry?

Answer 30

Pain Temperature Itch Tickle

Question 31

Where do the first order neurons in the spinothalamic tract arise and decussate?

Answer 31

They arise at the receptor (in trunk, limbs, neck, posterior head) They terminate in the dorsal horn on the ipsilateral side

Question 32

Where do the second order neurons in the spinothalamic tract arise and decussate?

Answer 32

They arise in the dorsal horn, and then decussate to the contralateral side They pass up the spinal cord They terminate in the ventral, posterior nucleus of the thalamus

Question 33

Where do the third order neurons in the spinothalamic tract arise and decussate?

Answer 33

They arise in the ventral, posterior nucleus of the thalamus and travel to the primary somatosensory area (on the same side as the thalamus)

Question 34

Where are the pre-ganglionic neurons of the sympathetic nervous system located?

Answer 34

Thoracolumbar region | - T1-L3

Question 35

Where are the pre-ganglionic neurons of the parasympathetic nervous system located?

Answer 35

The brainstem - CN III, VII, IX and X Sacral region - S2-4

Question 36

Where are the ganglia of the sympathetic nervous system located?

Answer 36

In the sympathetic trunk - next to the vertebral column from T1 to the coccyx

Question 37

Where are the ganglia of the parasympathetic nervous system located?

Answer 37

Near the targets organ - in the walls of the viscera they innervate

Question 38

What is the function of the sympathetic nervous system?

Answer 38

Increased heart rate Decreases gut activity Dilates pupils

Question 39

What is the function of the parasympathetic nervous system?

Answer 39

Decreased heart rate Increased gut motility Pupil constriction Increase in secretions

Question 40

What organs are only supplies by the sympathies nervous system?

Answer 40

``` Sweat glands Adrenal medulla Hair follicles Spleen Iris dilator ```

Question 41

What organs are only supplies by the parasympathies nervous system?

Answer 41

Ciliary muscles - focusing the eye | Iris sphincter