Brainstem and Cranial Nerves III-VIII

Question 1

external features of anterior midbrain

What is the anterior and posterior components of the midbrain called

Answer 1

Anterior: tegmentum
Posterior: tectum

Question 2

external features of anterior midbrain

Question 3

external features of anterior midbrain

Where are cerebral peduncles located and what are they also known as

Answer 3

• located in tegmentum
• AKA crus cerebri

Question 4

external features of anterior midbrain

What are the cerebral peduncles

Answer 4

• bundles of white matter in tegmentum predominantly made of desceding motor nerve fibres travelling from the cerebral cortex

Question 5

midbrain: cross-sectional anatomy

What are 3 key internal structures of the midbrain

Answer 5

• periaqueductal grey
• substantia nigra
• Red nuclei

Question 6

midbrain: cross sectional anatomy

What cranial nerves nuclei does the midbrain contain?

Answer 6

CN III-X and CN XII

Question 7

what is the function of the substantia nigra

Answer 7

control of movement

Question 8

what is the function of the periaqueductal grey

Answer 8

propagation and modulation of pain

Question 9

what is the function of the red nuclei

Answer 9

involved in motor coordination

Question 10

what type of neurons does CNIII have and where does it supply?

Answer 10

Motor neurones that supply:

• most of skeletal muscels controlling the eye movement
• parasympathetic innervation to involuntary muscles for constriction of pupil and lens shape change

Question 11

what does the oculomotor nuclei do?

Answer 11

• sends off somatic motor fibres to most of the extraocular muscles that move to eye

Question 12

What muscle does CN IV send motor fibres to and what direction does this move the eye?

Answer 12

• sends motor fibres to superior oblique muscle
• superior oblique muscle moves eye laterally and downward

Question 13

Pons

What is the key external structure of the Pons

Answer 13

middle cerebellar peduncles

Question 14

pons

What cranial nerves are associated with the pons

Answer 14

• V
• VI
• VII
• VIII

Question 15

pons: posterior

What is found in the superior, middle and inferior cerebellar peduncles of the Pons when looking at the pons posteriorly?

fibres to places

Answer 15

superior: fibres running from cerebellum to red nuclei of the midbrain

middle: fibres to the cerebellum

inferior: fibres from spinal cord and medulla oblongata to cerebellum

Question 16

Pons: CN V

What 2 types of fibres does CN V have and where do they supply?

Answer 16

Motor fibres (Less than Sensory), supplying muscles of mastication (chewing)

Sensory fibres (more than motor fibres), supplying:

• skin of face and anterior section of scalp
• Inside of mouth (eg teeth, gums) and nose

Question 17

CN VI (abducens)

What type of fibres does the CN VI have, where does it supply and what does this muscle do in the eye?

Answer 17

• motor fibres
• supplies lateral rectus
• allows for abduction of the eye

Question 18

Pons: CN VII (Facial)

What are the 4 different types of fibres in the CN VII and where do they supply

Answer 18

Motor fibres supplying muscles for facial expressions

parasympathetic fibres supplying:
- lacrimal gland
- sublingual and submandibular salivary glands

Sensory fibres from:
- skin behind ear

Special sensory fibres from:
- taste from anterior 2/3 of the tongue

Question 19

Pons: CN VIII

what 2 nerves form the Vestibulocochlear cranial nerve

Answer 19

• vestibular nerve
• cochlear nerve

Question 20

PONS: CN VIII

what special sensory fibres does the vestibular nerve and cochlear nerve have in the vestibulochochlear cranial nerve

Answer 20

vestibular: balance
cochlear: Hearing