Brainstem

Question 1

describe the anatomy of corticospinal (pyramidal) tract

Answer 1

85% cross over at decussation of pyramids to become lateral corticospinal tract. Uncrossed fibers form ventral corticospinal tract

Question 2

composition of the olive

Answer 2

inferior olivary nuclei. Olivocerebellar fibers cross to opposite inferior cerebellar peduncle which climb to cerebellum

Question 3

tuberculum cinereum

Answer 3

spinal tract and nucleus of V.

Question 4

pathway for pain and temp from face

Answer 4

Adelta and C fibers. Descending afferents synapse on second order neurons in nucleus of V. Trigeminothalamic tract crosses to synapse on VPM. third order to postcentral gyrus areas 3,1,2

Question 5

what does a lateral lesion of medulla result in

Answer 5

ipsilateral loss of pain and temp

Question 6

dorsal column-medial lemniscus pathway

Answer 6

Fasc and nuc. gracilis and cuneatus. Decussate. synapse in VPL. Carry touch, proprioception

Question 7

Reticular formation: composition? location? Fxns?

Answer 7

lateral (parvocellular) and medial (magnocellular) areas. Central core of all three areas of brainstem. Lat: eating. Med: arousal and consciousness

Question 8

Two main parts of the pons

Answer 8

basal portion and tegmentum

Question 9

What does the basal portion of the pons consist of?

Answer 9

conticobulbar, corticospinal, corticopontine fibers, pontocerebellar fibers (traversing tracts)

Question 10

describe the corticopontine tract

Answer 10

corticopontine fibers synapse on pontine nuclei. Pontocerebellar fibers enter opposite middle cerebellar peduncle and end in cerebellar cortex

Question 11

Tegmentum of pons and trigeminal lemniscus

Answer 11

main sensory nucleus (in tegmentum) receives 1* afferents for touch, pressure, vibration. 2* cross in trigeminal lemniscus to VPM. 3* to postcentral gyr.

Question 12

four principle parts of midbrain

Answer 12

tectum (not seen in medulla or pons), tegmentum, substantia nigra, crus cerebri

Question 13

parts of the tectum and functions

Answer 13

S and I colliculi and their brachii. Smooth pursuit and cicaidic eye movements. Reflexive response to sound, touch, etc

Question 14

periaqueductal gray: where? fxn?

Answer 14

midbrain. Pain control center. Enkaphalin release activates raphe nucleus in medulla which inhibits pain entering dorsal horn

Question 15

explain proprioception of muscles of mastication, TMJ, and teeth

Answer 15

receptors in muscles have cell bodies in mesencephalic nucleus of V in tegmentum of midbrain. Central processes to retic form. 2* to trigeminal meniscus

Question 16

three nuclei in CNV somatic sensory paths

Answer 16

spinal (pain and temp), principal sensory (touch, pressure, vibration), mesencephalic (proprioception)

Question 17

Red nucleus: associated with? where?

Answer 17

tegmentum of midbrain. Rubrospinal tract descending motor

Question 18

depression b/w crus cerebri on either side

Answer 18

interpeduncular fossa`

Question 19

CN rule of 4s

Answer 19

midbrain and above (I-IV), pons and pontomedullary jxn (V-VIII), medulla and cord (IX-XII)

Question 20

what spinal nerves come out dorsally and ventrally from midbrain

Answer 20

ventral-3, dorsal-4

Question 21

what would cause ipsilateral facial paralysis and hearing and balance loss? Where?

Answer 21

acoustic neuroma of the 8th CN in the cerebellopontine angle