Overview of Brainstem Organisation

Question 1

What is the brainstem a gateway between?

Answer 1

Spinal cord and higher cortical areas

Question 2

Why do anencephalic babies survive?

Answer 2

Born without forebrain
Have brainstem
- Breathe
- Suckle
- Swallow
- Cry

Question 3

What are the functions of the brainstem?

Answer 3

Reflexive and unconscious behaviour

Modulation of arousal and conscious states

Question 4

What are the parts of the brainstem?

Answer 4

Midbrain
Pons
Medulla oblongata

Question 5

Which part of the brainstem is most rostral and continuous with the structures above it?

Answer 5

Midbrain

Question 6

Which part of the brainstem is most caudal and continuous with the spinal cord?

Answer 6

Medulla

Question 7

In which cranial fossa is the brainstem?

Answer 7

Posterior

Question 8

What is the rostral to caudal boundary of the brainstem?

Answer 8

Mammillary bodies rostrally to pyramidal decussation caudally

Question 9

Describe the dorsal aspect of the midbrain

Answer 9

Two pairs of bumps = superior and inferior colliculi

Question 10

What are the superior colliculi important for?

Answer 10

Eye movement control

Question 11

What are the inferior colliculi important for?

Answer 11

Hearing

Question 12

Describe the dorsal aspect of the pons

Answer 12

Linked with cerebellum via cerebellar peduncles

Limited by 4th ventricle

Question 13

What are the cerebellar peduncles?

Answer 13

White matter tracts

Where cerebellum joins rest of brain

Question 14

Describe the dorsal aspect of the medulla

Answer 14

Caudally, dorsal columns and nuclei:

- Gracile and cuneate fasciculus

Question 15

What happens at the gracile and cuneate fasciculi?

Answer 15

Synapse of spinothalamic tract, carrying somatosensory info

Question 16

Describe the ventral aspect of the midbrain

Answer 16

Cerebral peduncles between interpeduncular fossa

Question 17

What are the cerebral peduncles?

Answer 17

White matter tracts coming down from cerebrum and out carrying corticospinal tracts = motor information

Question 18

Describe the ventral aspect of the pons

Answer 18

Attached to cerebellum dorsolaterally by cerebellar peduncles

• Superior
• Middle
• Inferior

Question 19

Describe the ventral aspect of the medulla

Answer 19

Rostrally, two bulges = inferior olivary nuclei

Pyramids descending to pyramidal decussation

Question 20

What are the inferior olivary nuclei important for?

Answer 20

Hearing

Question 21

What is the tectum?

Answer 21

Roof
Another name for 4 superior and inferior colliculi
Only applies to midbrain

Question 22

What is the tegmentum?

Answer 22

Most of action of brainstem

Continuous with spinal cord

Question 23

Where are the cranial nerve nuclei?

Answer 23

Dorsal tegmentum

Question 24

What is in the basus of the brainstem?

Answer 24

Nuclei and long fibre tracts containing motor control to body

Question 25

Where is the motor control of the body in the brainstem: dorsally or ventrally?

Answer 25

Ventrally

Question 26

Where is the reticular formation?

Answer 26

Tegmentum

Question 27

What do cranial nerves supply?

Answer 27

Somatic and visceral motor and sensory information to head

Question 28

Where else do CN IX and X supply visceral sensory and motor innervation to?

Answer 28

Neck Chest Most abdominal organs

Question 29

From which surface do most cranial nerves exit the brainstem?

Answer 29

Ventral

Question 30

Which cranial nerve doesn't exit the brainstem ventrally?

Answer 30

CN IV

Question 31

Which cranial nerves are exclusively motor?

Answer 31

``` III IV VI XI XII ```

Question 32

Which cranial nerves are exclusively sensory?

Answer 32

I II VIII

Question 33

Which cranial nerves are mixed?

Answer 33

V VII IX X

Question 34

What is the rule of 4s?

Answer 34

4 cranial nerves exit medulla 4 cranial nerves exit pons 4 exit above pons

Question 35

What determines the location of motor and sensory columns?

Answer 35

Development

Question 36

What do cranial nerve nuclei lie adjacent to during embryological development?

Answer 36

Ventricular system

Question 37

Which nuclei develop from the alar plate?

Answer 37

Sensory

Question 38

Which nuclei develop from the basal plate?

Answer 38

Motor

Question 39

What is the relationship of the alar and basal plates in the spinal cord?

Answer 39

Alar plate becomes dorsal horns | Basal plate becomes ventral horns

Question 40

What does the fourth ventricle do to the dorsal nuclei during development?

Answer 40

Pushes them laterally

Question 41

How are nuclei positioned in the brainstem?

Answer 41

In columns

Question 42

How are cranial nerve nuclei grouped?

Answer 42

Based on similar functions

Question 43

Where are motor nuclei located?

Answer 43

Closer to midline

Question 44

Where are sensory nuclei located?

Answer 44

Laterally

Question 45

How many motor columns are there, and what are they?

Answer 45

3 - General somatic motor - Branchial motor - General visceral

Question 46

How many sensory columns are there, and what are they?

Answer 46

3 - General and special visceral - General somatic - Special somatic

Question 47

Which columns are closer to the midline?

Answer 47

Motor

Question 48

Which columns are located laterally?

Answer 48

Sensory

Question 49

What is the reticular formation continuous with?

Answer 49

Rostrally, with certain nuclei in thalamus | Caudally, with intermediate grey of spinal cord

Question 50

What are the rostral functions of the reticular formation?

Answer 50

Higher cortical function | - Maintain alert conscious state

Question 51

Where is the rostral reticular formation?

Answer 51

Midbrain and upper pons

Question 52

What are the caudal functions of the reticular formation?

Answer 52

Many tasks of spinal cord but with greater complexity | Work together with cranial nerve nuclei and spinal cord to carry out important motor reflexes and autonomic functions

Question 53

Where is the caudal reticular formation?

Answer 53

Pons and medulla

Question 54

How does the reticular formation modulate forebrain activity rostrally?

Answer 54

Via - Ascending reticular activating system - Long projection systems

Question 55

What are long projection systems defined by?

Answer 55

Neurotransmitter

Question 56

What are some long projection systems?

Answer 56

Noradregernic from locus ceruleus Dopaminergic from substantia nigra Serotonergic via dorsal raphe nucleus Cholinergic

Question 57

What does a lesion in the midbrain mean?

Answer 57

Coma

Question 58

What does the ventrolateral medullary reticular formation do?

Answer 58

Regulate visceral functions CN X - GI responses - Swallowing - Vomiting - Respiratory activities - Rhythm - Coughing - Hiccupping - Sneezing - Cardiovascular responses

Question 59

What are the lateral medullary anf pontine reticular formations important for?

Answer 59

Chewing

Question 60

What is the region surrounding facial nucleus important for?

Answer 60

Crying | Smiling

Question 61

Which major pathways traverse the brainstem?

Answer 61

Dorsal column-medial lemniscus system Anterolateral system Corticospinal system

Question 62

What are the ascending pathways in the brainstem?

Answer 62

Dorsal column-medial lemniscus system | Anterolateral system

Question 63

What are the descending pathways in the brainstem?

Answer 63

Corticospinal system

Question 64

Describe the dorsal column-medial lemniscus system

Answer 64

``` 3 neurons Fine touch - Tactile - Vibration Crosses in medulla Travels medially for the most but veers laterally in midbrain ```

Question 65

Describe the anterolateral system

Answer 65

``` 3 neurons Pain Crosses in spinal cord Travels laterally Gets close to dorsal column-medial lemniscus pathway in midbrain ```

Question 66

Describe the corticospinal tract

Answer 66

2 neurons Motor control Crosses at pyramidal decussation at boundary of brainstem Upper motor neuron synapses with lower motor neuron in spinal cord

Question 67

What do the dorsal aspects of the brainstem contain?

Answer 67

Cranial nerve nuclei | Reticular formation

Question 68

What do the ventral aspects of the brainstem contain?

Answer 68

``` Corticospinal tracts Midbrain - Cerebral peduncles - Substantia nigra - Red nuclei Pons - Cerebellar nuclei - Middle cerebellar peduncle Medulla - Inferior olivary nuclei ```