Overview of brainstem organization

Question 1

which fossa is brainstem located in and what are its borders?

Answer 1

posterior cranial fossa.
Rostral border is the mammillary bodies.
Caudal border is the pyramidal decussation.

Question 2

characteristic gross dorsal and ventral features of the midbrain?

Answer 2

Dorsal: 2 pairs of bumps, superior and inferior colliculi

Ventral: cerebral peduncles

Question 3

characteristic gross dorsal and ventral features of the pons?

Answer 3

Dorsal:
linked with cerebellum.
limited by 4th ventricle.
facial colliculi at base.

Ventral:
cerebella peduncles attaching it to cerebellum dorsolaterally

Question 4

characteristic gross dorsal and ventral features of the medulla?

Answer 4

Dorsal:
dorsal columns
cuneate tubercle
and gracile nucleus

Ventral:
Rostrally two bulges called Olivary nuclei
Caudally are the pyramids descending to the pyramidal decussation.

Question 5

what term and structures refers to the roof of the brainstem.

Answer 5

The “tectum”. Superior and inferior colliculi at the rostral portion of the midbrain.

Question 6

tegmentum?

Answer 6

sheath covering the brainstem thats continuous with spinal cord.
contains the cranial nerves and reticular formation (reflexes)

Question 7

What is the ‘basis’ of the brain stem important for?

Answer 7

descending motor control. attachments to the Cerebellum.

Question 8

at what verterbra do spinal nerves end?

Answer 8

C2

Question 9

which cranial nerves are exclusively motor?

Answer 9

III (oculomotor), IV (abducens), VI (trochlear), XI (accessory), XII (hypoglossal)

Question 10

which cranial nerves are exclusively sensory?

Answer 10

I (olfactory), II (optic), VIII (vestibulocochlear)

Question 11

Which is the only cranial nerve that exits the brain stem via the dorsal surface?

Answer 11

IV (trochlear)

Question 12

Which nerves are mixed?

Answer 12

V (trigeminal), VII (facial), IX (glossopharyngeal), X (vagus)

Question 13

which cranial nerves exit via the medulla?

Answer 13

IX to XII

Question 14

which cranial nerves exit the pons?

Answer 14

V to VIII

Question 15

which cranial nerves exit above the pons?

Answer 15

III and IV

Question 16

where does the olfactory nerve exit?

Answer 16

cribiform plate of ethmoid bone

Question 17

where does the optic nerve exit?

Answer 17

optic canal

Question 18

which embyrological plate do sensory nuclei develop from?

Answer 18

alar plate (dorsal)

Question 19

which embyrological plate do motor nuclei develop from?

Answer 19

basal plate (ventral)

Question 20

What are the rostral and caudal extents of the reticular formation

Answer 20

continuous with thalamus rostrally and intermediate gray of spinal cord caudally

Question 21

function of the rostral and caudal reticular formation?

Answer 21

rostral: (midbrain and upper pons) maintain alert conscious state
caudal: (pons and medulla) motor reflexes and autonomic functions

Question 22

3 major pathway traversing the brain stem?

Answer 22

ascending:

• anterolateral system
• dorsal column medial lemniscus pathway

descending:
- corticospinal tract

Question 23

dorsal column medial lemniscus: function and location and decussation

Answer 23

ascending pathway through brain stem.
responsible for fine touch-tactile, and vibration.

decussates in medulla (medial lemniscus)

Question 24

anterolateral system: function and location and decussation

Answer 24

ascending pathway through brain stem
responsible for pain.
decussates in spinal cord.

Question 25

corticospinal tract: function and location and decussation

Answer 25

descending pathway through brain stem.
controls motor function.

decussates in medullary pyramids.