Introduction to the Brainstem

Question 1

Mesencephalon

Answer 1

Midbrain

Question 2

Metencephalon

Answer 2

Pons

Question 3

Myelencephalon

Answer 3

Medulla

Question 4

What are the 4 main components of the brain stem?

Answer 4

1. Cranial nerve nuclei and related structures
2. Long tracts
3. Cerebellar circuitry
4. Reticular formation and related structures

Question 5

What are the 3 main divisions of the brainstem?

Answer 5

Midbrain, pons, and medulla

Question 6

What does the tegmentum do?

Answer 6

Forms a thick covering over the bases of the cerebral penduncles, basal pons, and pyramids

Question 7

What important structures are contained within the tegmentum?

Answer 7

1. Reticular formation
2. Cranial nerve nuclei
3. Most ascending and descending tracts

Question 8

What is the only cranial nerve that comes off posterior side of the brainstem?

Answer 8

Trochlear

Question 9

What are 2 examples of sensory long tracts?

Answer 9

1. Posterior column-medial lemniscus pathway

2. Anterolateral pathway

Question 10

What sensory info does the Posterior column-medial lemniscus pathway provide?

Answer 10

Tactile proprioception

Question 11

What sensory info does the Anterolateral pathway provide?

Answer 11

Pain, temperature, crude touch

Question 12

What is an example of a motor long tract?

Answer 12

Corticospinal pathway (Pyramidal tract)

Question 13

What sensory info does the Spinothalamic tract provide?

Answer 13

Pain and temperature from head

Question 14

What sensory info does the Medial lemniscus pathway provide?

Answer 14

Tactile and proprioceptive info from head

Question 15

What sensory info does the Dorsal trigeminal tract provide?

Answer 15

Sensory info from the oral cavity

Question 16

Describe the Inferior Olivary Nucleus.

Answer 16

Start of climbing fibers; aids cerebellum in coordination of movement

Question 17

Pontine nuclei give rise to axons that travel into the cerebellum via the what?

Answer 17

Middle cerebellar peduncle

Question 18

Input to the cerebellum from the inferior olivary nuclei and spinal cord travel through what?

Answer 18

Inferior cerebellar peduncle

Question 19

Output from the cerebellum travels in the what?

Answer 19

Superior cerebellar peduncles

Question 20

What is the function of the Edinger-Westphal nuclei?

Answer 20

Visceromotor via occulomotor nerve to pupillary sphincter and ciliary muscle

Question 21

What is the function of the occulomotor nerve?

Answer 21

Motor to all eye muscles, except lateral rectus and superior oblique

Question 22

What is the function of the trochlear nerve?

Answer 22

Motor to superior oblique

Question 23

What is the function of the trigeminal nerve?

Answer 23

Motor to muscles of mastication

Question 24

What is the function of the abducens nerve?

Answer 24

Motor to lateral rectus

Question 25

What is the function of the facial nerve?

Answer 25

Motor to muscle of facial expression

Question 26

What is the functions of the salivatory nuclei?

Answer 26

Visceromotor via facial and glossopharyngeal nerves to salivary glands

Question 27

What is the function of the dorsal motor nuclei?

Answer 27

Visceromotor via vagus to thorax and abdomen

Question 28

What is the function of the nucleus ambiguus?

Answer 28

Lower motor neurons to pharynx/larynx, visceromotor to heart

Question 29

What is the function of the accessory nerve?

Answer 29

Motor to sternocleidomastoid and trapezius

Question 30

What is the function of the mesencephalic nuclei?

Answer 30

Mostly cell bodies of muscle spindle fibers from head

Question 31

What is the function of the trigeminal main accessory nuclei?

Answer 31

Touch, proprioception from head

Question 32

What is the function of the cochlear nuclei?

Answer 32

Auditory input

Question 33

What is the function of the vestibular nuclei?

Answer 33

Input from vestibular apparatus

Question 34

What is the function of the nucleus of the solitary tract?

Answer 34

Taste and visceral afferent input from facial, glossopharyngeal, and vagus nerves

Question 35

What is the function of the spinal trigeminal nuclei?

Answer 35

Pain, temperature, crude touch from the head

Question 36

The pathway of the vestibulo-ocular reflex is the response to what?

Answer 36

Rotation to the left

Question 37

Describe the vestibule-ocular reflex.

Answer 37

Excitation of the left horizontal semicircular duct causes increased contraction of the right lateral rectus and left medial rectus by way of excitatory interneurons in the left vestibular nuclei. Simultaneously, motor neurons for the left lateral rectus and right medial rectus are inhibited by way of inhibitory interneurons.

Question 38

What is the reticular formation comprised of?

Answer 38

Numerous relatively small and diverse nuclei scattered throughout the tegmentum

Question 39

What does the various nuclei of the reticular formation do?

Answer 39

Contact all levels of the CNS and are involved in virtually every activity from visceral functions to consciousness.

Question 40

The brainstem does not contain what 2 cranial nerves?

Answer 40

Olfactory and optic

Question 41

What does fine/proprioceptive information enter?

Answer 41

1. Fasciculus gracilis and Tuberculum gracile (below T6) | 2. Fasciculus cuneatus and tuberculum cuneatum (above T6)

Question 42

What is the obex?

Answer 42

floor of 4th ventricle

Question 43

Inferior cerebellar peduncle receives inform the what?

Answer 43

Olive

Question 44

Middle cerebellar peduncle receives input from what?

Answer 44

Pons

Question 45

The Anterolateral pathway include what tract?

Answer 45

Spinothalamic tract

Question 46

Describes the Auditory pathway.

Answer 46

Fibers enter from cochlea to synapse on cochlear nuclei. Fibers then synapse on superior olive. Fibers run up lateral lemniscus and then synapse on inferior colliculus. Fibers then run to medial geniculate body, and then to the primary auditory cortex.

Question 47

In an embryo sensory nuclei are located where?

Answer 47

Dorsal horn

Question 48

In an embryo motor nuclei are located where?

Answer 48

Ventral horn

Question 49

Motor nuclei are located where in relation to the sulcus limitans?

Answer 49

Medial to sulcus limitans

Question 50

Sensory nuclei are located where in relation to the sulcus limitans?

Answer 50

Lateral to sulcus limitans