Overview of Brainstem Organisation Flashcards Preview

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Flashcards in Overview of Brainstem Organisation Deck (68):
1

What is the brainstem a gateway between?

Spinal cord and higher cortical areas

2

Why do anencephalic babies survive?

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

3

What are the functions of the brainstem?

Reflexive and unconscious behaviour
Modulation of arousal and conscious states

4

What are the parts of the brainstem?

Midbrain
Pons
Medulla oblongata

5

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

Midbrain

6

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

Medulla

7

In which cranial fossa is the brainstem?

Posterior

8

What is the rostral to caudal boundary of the brainstem?

Mammillary bodies rostrally to pyramidal decussation caudally

9

Describe the dorsal aspect of the midbrain

Two pairs of bumps = superior and inferior colliculi

10

What are the superior colliculi important for?

Eye movement control

11

What are the inferior colliculi important for?

Hearing

12

Describe the dorsal aspect of the pons

Linked with cerebellum via cerebellar peduncles
Limited by 4th ventricle

13

What are the cerebellar peduncles?

White matter tracts
Where cerebellum joins rest of brain

14

Describe the dorsal aspect of the medulla

Caudally, dorsal columns and nuclei:
- Gracile and cuneate fasciculus

15

What happens at the gracile and cuneate fasciculi?

Synapse of spinothalamic tract, carrying somatosensory info

16

Describe the ventral aspect of the midbrain

Cerebral peduncles between interpeduncular fossa

17

What are the cerebral peduncles?

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

18

Describe the ventral aspect of the pons

Attached to cerebellum dorsolaterally by cerebellar peduncles
- Superior
- Middle
- Inferior

19

Describe the ventral aspect of the medulla

Rostrally, two bulges = inferior olivary nuclei
Pyramids descending to pyramidal decussation

20

What are the inferior olivary nuclei important for?

Hearing

21

What is the tectum?

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

22

What is the tegmentum?

Most of action of brainstem
Continuous with spinal cord

23

Where are the cranial nerve nuclei?

Dorsal tegmentum

24

What is in the basus of the brainstem?

Nuclei and long fibre tracts containing motor control to body

25

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

Ventrally

26

Where is the reticular formation?

Tegmentum

27

What do cranial nerves supply?

Somatic and visceral motor and sensory information to head

28

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

Neck
Chest
Most abdominal organs

29

From which surface do most cranial nerves exit the brainstem?

Ventral

30

Which cranial nerve doesn't exit the brainstem ventrally?

CN IV

31

Which cranial nerves are exclusively motor?

III
IV
VI
XI
XII

32

Which cranial nerves are exclusively sensory?

I
II
VIII

33

Which cranial nerves are mixed?

V
VII
IX
X

34

What is the rule of 4s?

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

35

What determines the location of motor and sensory columns?

Development

36

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

Ventricular system

37

Which nuclei develop from the alar plate?

Sensory

38

Which nuclei develop from the basal plate?

Motor

39

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

Alar plate becomes dorsal horns
Basal plate becomes ventral horns

40

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

Pushes them laterally

41

How are nuclei positioned in the brainstem?

In columns

42

How are cranial nerve nuclei grouped?

Based on similar functions

43

Where are motor nuclei located?

Closer to midline

44

Where are sensory nuclei located?

Laterally

45

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

3
- General somatic motor
- Branchial motor
- General visceral

46

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

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

47

Which columns are closer to the midline?

Motor

48

Which columns are located laterally?

Sensory

49

What is the reticular formation continuous with?

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

50

What are the rostral functions of the reticular formation?

Higher cortical function
- Maintain alert conscious state

51

Where is the rostral reticular formation?

Midbrain and upper pons

52

What are the caudal functions of the reticular formation?

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

53

Where is the caudal reticular formation?

Pons and medulla

54

How does the reticular formation modulate forebrain activity rostrally?

Via
- Ascending reticular activating system
- Long projection systems

55

What are long projection systems defined by?

Neurotransmitter

56

What are some long projection systems?

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

57

What does a lesion in the midbrain mean?

Coma

58

What does the ventrolateral medullary reticular formation do?

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

59

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

Chewing

60

What is the region surrounding facial nucleus important for?

Crying
Smiling

61

Which major pathways traverse the brainstem?

Dorsal column-medial lemniscus system
Anterolateral system
Corticospinal system

62

What are the ascending pathways in the brainstem?

Dorsal column-medial lemniscus system
Anterolateral system

63

What are the descending pathways in the brainstem?

Corticospinal system

64

Describe the dorsal column-medial lemniscus system

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

65

Describe the anterolateral system

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

66

Describe the corticospinal tract

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

67

What do the dorsal aspects of the brainstem contain?

Cranial nerve nuclei
Reticular formation

68

What do the ventral aspects of the brainstem contain?

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

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