Overview of Brainstem Organisation Flashcards

1
Q

What is the gateway between the spinal cord and higher cortical areas?

A

Brainstem

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2
Q

What are the two major functions of the brainstem?

A

Reflexive and unconscious behaviour

Modulation of various arousal and conscious states

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3
Q

Where is the brainstem located?

A

In the posterior cranial fossa, extending from the mammillary bodies to the pyramidal decussation caudally.

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4
Q

What are the 3 divisions of the brainstem?

A

Midbrain, pons and medulla

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5
Q

What are the two pairs of characteristic bumps on the dorsal aspect of the midbrain?

A

The superior and inferior colliculi

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6
Q

Which part of the brainstem does the cerebellum attach to?

A

Pons

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7
Q

What is the pons limited by?

A

The 4th ventricle

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8
Q

Which parts of the pons form the floor of the 4th ventricle?

A

The facial colliculi

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9
Q

What forms the facial colliculi

A

Abducens nucleus and fibres of CNVII (facial nerve)

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10
Q

What forms the dorsal aspect of the caudal medulla?

A

Dorsal columns and nuclei, forming the gracile and cuneate tubercles

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11
Q

What can be seen on the ventral aspect of the midbrain?

A

Cerebral peduncles with the interpeduncular fossa in between.

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12
Q

What can be seen on the ventral aspect of the pons?

A

The superior, middle and inferior cerebellar peduncles dorsolaterally attaching to the cerebellum.

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13
Q

What can be seen on the ventral aspect of the medulla?

A

Rostral: Inferior olivary nuclei

Pyramids descending to the pyramidal decussation

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14
Q

What is the tectum?

A

The “roof” of the midbrain - the dorsal part. It refers solely to the colliculi of the midbrain.

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15
Q

What forms the roof of the 4th ventricle?

A

The 4 colliculi, i.e. the tectum.

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16
Q

What is the tegmentum?

A

Where the spinal cord continues up into the brainstem - continous with the spinal cord.

Structures within the tegmentum go to the spinal cord.

These include the cranial nerves and reticular formation.

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17
Q

What is the basis?

A

The basillar pons - the anterior portion of the pons.

Important for descending motor control, e.g. attachments to cerebellum, from cerebellum to other nuclei and tracts important for motor systems.

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18
Q

Which part of the brainstem only applies to the colliculi and midbrain?

A

The tectum

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19
Q

Which part of the brainstem is a continuation of the spinal cord that travels throughout the entire brainstem?

A

Tegmentum

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20
Q

What does the tegmentum occupy?

A

Middle part of the midbrain

Dorsal part of the pons and medulla

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21
Q

What does the tegmentum contain?

A

Nuclei for the cranial nerves and the reticular formation.

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22
Q

What is the sole focus of the basis?

A

Motor control

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23
Q

Where do the spinal nerves end?

A

C2

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24
Q

Which spinal cord segment lacks a dermatome?

A

C1

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25
Q

What do the spinal nerves supply?

A

The body

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26
Q

What do the cranial nerves supply?

A

Somatic and visceral motor and sensory information to head

27
Q

Which cranial nerves also supply visceral sensory and motor innervation to neck, chest and most abdominal organs?

A

CNIX and X

28
Q

Which side of the brainstem do most cranial nerves exit?

A

Ventral

29
Q

Which cranial nerve does not exit the brainstem on the ventral surface?

A

CNIV

30
Q

Which cranial nerves are exclusively motor?

A

CNIII, IV and VI (control the eye) CNXI and XII

31
Q

Which cranial nerves are exclusively sensory?

A

CNI, II and VIII

32
Q

Which cranial nerves are mixed?

A

CNV, VII, IX and X

33
Q

What is the rule of 4 for the cranial nerves?

A

4 cranial nerves exit the medulla: CNIX-XII

4 exit the pons: CNV, VI, VII, VIII

4 exit above the pons: CNIII, IV

34
Q

Where do the cranial nerve nuclei lie during embryological development?

A

Adjacent to the ventricular system

35
Q

Which plate do the sensory nuclei develop from?

A

Alar plate

36
Q

Which plate do the motor nuclei develop from?

A

Basal plate

37
Q

How are the positions of the cranial nerve nuclei determined?

A

As the 4th ventricle develops, the alar plate (sensory nuclei) is pushed to the side, now sitting more lateral to the basal plate (motor nuclei).

38
Q

How are cranial nerve nuclei grouped?

A

Based on function

39
Q

Which nuclei are closer to the midline?

A

Motor nuclei (motor column)

40
Q

Which nuclei are positioned laterally?

A

Sensory nuclei (sensory column)

41
Q

How are the sensory and motor nuclei grouped within the brainstem?

A

Into 3 medial motor columns and 3 lateral sensory columns.

42
Q

What are the 3 motor columns (medial to lateral)?

A

General somatic motor

Branchial motor

General visceral

43
Q

What are the 3 sensory columns (medial to lateral)?

A

General and special visceral

General somatic

Special somatic

44
Q

Which nucleus is this?

A

Spinal trigeminal

45
Q

What is the tegmentum continuous with rostrally?

A

Certain nuclei in the thalamus

46
Q

What is the tegmentum continuous with caudally?

A

Intermediate grey of the spinal cord

47
Q

What is the function of the tegmentum rostrally (midbrain and upper pons)?

A

Mantains alert conscious state.

48
Q

What is the function of the tegmentum caudally (pons and medulla)?

A

Work together with cranial nerve nuclei and spinal cord to carry out a variety of important motor reflex and autonomic functions. Closer to spinal cord, therefore more spinal cord-like actions.

49
Q

What is the ascending reticular activating system?

A

Long projection systems from the rostral tegmentum.

50
Q

What 4 different systems does the ascending reticular activating system use?

A

Noradrenergic (locus cereleus)

Dopaminergic (e.g. substantia nigra)

Serotonergic (dorsal raphe nucleus)

Cholinergic

51
Q

What functions does the caudal reticular formation serve crucial functions in?

A

Motor reflex and autonomic functions

52
Q

What does the ventrolateral medullary (VLM) reticular formation do?

A

Regulates the visceral functions of CNX (Vagus): G

I responses (swallowing, vomiting)

Respiratory activities

Rhythm, coughing, hiccupping, sneezing

Cardiovascular responses

53
Q

What is the lateral medullary pontine reticular formation important for?

A

Chewing

54
Q

What is the region of the reticular formation surrounding the facial nucleus important for?

A

Crying and smiling

55
Q

What are the 3 major pathways traversing the brainstem?

A

Ascending pathways:

  1. Dorsal column-medial lemniscus system
  2. Anterolateral system

Descending pathways:

  1. Corticospinal tract
56
Q

Which sensory modality is the dorsal column-medial lemniscus system for?

A

Fine touch-tactile, vibration

57
Q

Where does the dorsal column-medial lemniscus system decussate?

A

In the medulla, at the medial lemniscus

58
Q

Which sensory modality is the anterolateral system for?

A

Pain and temperature

59
Q

Where does the anterolateral system terminate?

A

In 3 different regions: thalamus, midbrain and reticular formation.

60
Q

What is the function of the corticospinal tract?

A

Motor

61
Q

Where does the corticospinal tract decussate?

A

At the pyramids

62
Q

What do the dorsal aspects of the brainstem contain?

A

Cranial nuclei and reticular formation

63
Q

What do the ventral (basis) aspects of the brainstem contain?

A

Structures associated with the descending motor tracts (corticospinal tracts).

Midbrain: cerebral peduncles, substantia nigra, red nuclei

Pons: CB nuclei, middle cerebellar peduncle

Medulla: inferior olivary nuclei