Brainstem And Cranial Nerve

Question 1

What is the medulla oblongata?

Answer 1

The medulla oblongata is a part of the brainstem that connects the brain to the spinal cord.

Question 2

What structures are found on the ventral surface of the medulla oblongata?

Answer 2

The structures include:
* Pyramid
* Olive
* Anterolateral sulcus
* Retroolivary sulcus

Question 3

What is the function of the pyramidal tract?

Answer 3

The pyramidal tract (corticospinal tract) is involved in motor control.

Question 4

What occurs at the decussation of the pyramid?

Answer 4

The decussation of the pyramid is formed by crossing fibers of the corticospinal tract.

Question 5

What is produced by the underlying inferior olivary nucleus?

Answer 5

The olive is produced by the underlying inferior olivary nucleus.

Question 6

Which nerves emerge from the anterolateral sulcus?

Answer 6

The rootlets of the hypoglossal nerve emerge from the anterolateral sulcus.

Question 7

Which nerves emerge from the retroolivary sulcus?

Answer 7

The rootlets of the glossopharyngeal, vagus, and accessory nerves emerge from the retroolivary sulcus.

Question 8

What type of nuclei lies medial to the sulcus in the medulla oblongata?

Answer 8

Motor nuclei lie medial to the sulcus.

Question 9

What type of nuclei lies lateral to the sulcus in the medulla oblongata?

Answer 9

Sensory nuclei lie lateral to the sulcus.

Question 10

What structures are located underneath the medulla oblongata?

Answer 10

The fasciculus gracilis and fasciculus cuneatus are located underneath.

Question 11

What is the significance of the pyramidal decussation?

Answer 11

It marks the crossing of 90% of the fibers en route to the spinal cord.

Question 12

What happens to fibers that cross to the contralateral side of the brainstem?

Answer 12

They form the pyramidal decussation.

Question 13

What is the lateral corticospinal tract?

Answer 13

It is the continuation of fibers that descend into the dorsolateral aspect of the lateral funiculus of the spinal cord.

Question 14

What results from damage to the pyramidal tract?

Answer 14

Damage results in upper motor neuron paralysis.

Question 15

What are the characteristics of upper motor neuron lesions?

Answer 15

Upper motor neuron lesions are characterized by:
* Hypertonia
* Spasticity
* Hyperreflexia
* Positive Babinski sign

Question 16

What are the characteristics of lower motor neuron lesions?

Answer 16

Lower motor neuron lesions are characterized by:
* Hypotonia
* Flaccidity
* Muscle atrophy
* Hyporeflexia or areflexia
* Negative Babinski sign

Question 17

What is the spinomedullary transition?

Answer 17

It refers to the area where motor pathways transition from the brainstem to the spinal cord.

Question 18

Name the sensory-related structures in the medulla oblongata.

Answer 18

The sensory-related structures include:
* Fasciculus gracilis
* Fasciculus cuneatus
* Spinothalamic tract
* Spinal trigeminal nucleus
* Spinal trigeminal tract

Question 19

Name the motor-related structures in the medulla oblongata.

Answer 19

The motor-related structures include:
* Corticospinal tract
* Lateral corticospinal tract
* Pyramidal decussation

Question 20

What is the medial lemniscus responsible for?

Answer 20

Mediates somesthetic (fine and proprioceptive senses) impulses from the contralateral body to thalamus

The medial lemniscus carries proprioceptive and discriminative sensation.

Question 21

What structures are located dorsally in the lower part of the floor of the fourth ventricle?

Answer 21

Gracile tubercle and cuneate tubercle

The gracile tubercle is medial to the cuneate tubercle.

Question 22

Fill in the blank: The hypoglossal trigone is adjacent to the _______.

Answer 22

midline

Question 23

What is the function of the internal arcuate fibers?

Answer 23

Cross midline at sensory decussation, becoming medial lemniscus

The internal arcuate fibers are axons of the nucleus gracilis and nucleus cuneatus.

Question 24

True or False: The anterior spinothalamic tract and lateral spinothalamic tract carry light touch sensation.

Answer 24

True

Question 25

What is the location of the accessory cuneate nucleus?

Answer 25

Dorsolateral to cuneate nucleus ## Footnote It mediates proprioceptive sense from the upper limb and neck to the cerebellum via the cuneotocerebellar tract.

Question 26

What is the role of ascending axons from the vestibular nuclei?

Answer 26

Project to pons and midbrain involved in the vestibulo-ocular reflex

Question 27

Fill in the blank: The corticospinal tract decussates at the level of the _______.

Answer 27

pyramid

Question 28

What is the function of the medial vestibulospinal tract?

Answer 28

Adjusts changes in head position in response to vestibular input ## Footnote Involves coordination of head and eye movements.

Question 29

What are the components of the sensory-related structures in the closed medulla?

Answer 29

FG, FC, GN, CN, IAF, ML, SD, ALS, STN, STT ## Footnote FG = fasciculus gracilis, FC = fasciculus cuneatus, GN = gracile nucleus, CN = cuneate nucleus, IAF = internal arcuate fibers, ML = medial lemniscus, SD = sensory decussation, ALS = anterolateral system, STN = spinal trigeminal nucleus, STT = spinal trigeminal tract.

Question 30

What is the significance of the gracile and cuneate tubercles?

Answer 30

They are small elevations on the external dorsal surface of the closed medulla

Question 31

What does the term 'closed medulla' refer to?

Answer 31

The part of the medulla where the fourth ventricle has narrowed to the tiny central canal

Question 32

What areas are found at the lateral corners of the diamond-shaped floor of the fourth ventricle?

Answer 32

Vestibular area and medullary striae