Brain Stem

Question 1

3 parts of the midbrain

Answer 1

midbrain, pons and medulla

Question 2

Features inside the brainstem

Answer 2

• All ascending sensory pathways pass the brain stem on route to the thalamus and some like the dorsal columns ( nucleus gracilis & nucleus cuneatus) synapse in the brain stem
• Descending motor systems (e.g. corticospinal tracts) pass through brain stem
• The red nucleus (rubrospinal pathway)
• Vestibular nuclei ( vestibulospinal pathway)
• Reticular formation (reticulospinal pathway/ reticular activating system)
• Pontine nuclei, cranial nerve nuclei, substantia nigra
• Periaqueductal grey matter

Question 3

Tegmentum

Answer 3

Area lying behind the ventral structures and is marked by the ventricular system posteriorly.
Fourth ventricle which extends into the cerebral aqueduct above. Most of the tegmentum running throughout length of brainstem is occupied by the reticular formation.

Question 4

Tectum

Answer 4

posterior to the aqueduct at level of midbrain/ ‘roof of the midbrain’. Within the tectum is four small bumps (2 superior and 2 inferior) known as calculi which are associated with the visual and auditory system

Question 5

substantia Nigra

Answer 5

area in the anterior tegmentum of midbrain which contains several pigmented neurones that use dopamine as a neurotransmitter

Question 6

Red Nucleus

Answer 6

connected to both the cortex and the cerebellum and it marks the origins of the rubrospinal pathway

Question 7

Vestibular Nuclei

Answer 7

Occupies a prominent position in the dorsal pons and the medulla. They receive information from the vestibular labyrinth, cerebellum and from visual systems. They integrate lots of sensory information and gives rise to the vestibulospinal tracts

Question 8

Fasciculus cuneatus and fasciculus gracilis

Answer 8

present on the posterior aspect of the medulla. Structures are associated with the dorsal columns, the ascending sensory pathways that convey fine touch and proprioceptive information

Question 9

Cranial Nerve I name and function

Answer 9

olfactory
Function: Limbic system

Question 10

Cranial Nerve II

Answer 10

Optic

Function: Visual system

Question 11

Cranial nerve III

Answer 11

Oculomotor

Function: Eye movements

Question 12

Cranial Nerve IV

Answer 12

Trochlear

Function: eye movements

Question 13

Cranial nerve V

Answer 13

Trigeminal

Function: Somatosensation

Question 14

Cranial Nerve VI

Answer 14

abducens

function: Eye movements

Question 15

Cranial Nerve VII

Answer 15

Facial

Function: Somatic motor system

Question 16

Cranial Nerve VIII

Answer 16

Vestibulocochlear

Function: The ear

Question 17

Cranial Nerve IX

Answer 17

Glossopharyngeal

Function: somatosensation, brainstem reflexes

Question 18

Cranial Nerve X

Answer 18

vagus nerve

Function: Somatosensation

Question 19

Cranial nerve XI

Answer 19

Accessory

function: Spinal accessory nerve

Question 20

Cranial Nerve XII

Answer 20

Hypoglossal

Function: somatic motor system

Question 21

Descending influences: motor control

Answer 21

Reticular nuclei give rise to reticulospinal tracts which project into the spinal motor neurones which influence control of posture

Question 22

Descending influences pain modulation

Answer 22

Raphe nuclei ( in the caudal medulla and receive input from area of grey matter that immediately surrounds the cerebral aqueduct known as the periaqueductal grey matter (PAG). Raphe nuclei project into the spinal cord to inhibit transmission of nociceptive information. Raphe nuclei acting at a spinal level to modulate or partially block transmission of pain to the brain

Question 23

Ascending influences: Arousal

Answer 23

Reticular activating system: Neurones that project into the cerebral cortex and thalamus and increase our responsiveness to responsive stimuli. Damage to this pathway impairs consciousness and can result in a coma. Important for interaction with external environment

Question 24

Ascending influences: Sleep

Answer 24

Raphe Nuclei: within pons and midbrain and projects onto the 4 brain structures to regulate sleeping patterns. Play important roles in cardiovascular and thermoregulatory control

Question 25

Ascending influences: Stress response

Answer 25

Locus Cerules: lies at the midbrain-pontine border and projects extensively into the cerebral cortex. Allows us to maintain vigilance and responsiveness particularly to unexpected stimuli. Uses noradrenaline as a neurotransmitter which mediates the sympathetic response to stress -> increases heart rate and blood pressure (stress response)