Lecture 4 - Brainstem Flashcards
1
Q
Which cranial nerves have their nuclei in the midbrain?
A
CN III (Oculomotor)
CN IV (Trochlear)
CN V (trigeminal)
2
Q
Which cranial nerves have their nuclei in the pons?
A
CN V (trigeminal)
CN VI (abducens)
CN VII (facial)
CN VIII (vestibulocochlear)
3
Q
Which cranial nerves have their nuclei in the medulla oblongata?
A
CN IX (glossopharangeal)
CN X (vagus)
CN XII (hypoglossal)
CN V (trigeminal)
4
Q
What does the brainstem connect?
A
Cerebrum/Cerebelum to Spinal Cord
5
Q
What are the three compartments of the brainstem?
A
- midbrain
- pons
- medulla
6
Q
What is the division of the brainstem ONLY in the midbrain?
A
Tectum
7
Q
What is the division of the midbrain with the ascending tracts called?
A
Tegmentum
8
Q
What is the division of the midbrain with the descending tracts called?
A
Basilar
9
Q
What is a conduit?
A
ascending/descending pathways
10
Q
Where are 9/12 of the cranial nerves nuclei?
A
the brainstem!!
11
Q
What do the cranial nerves from the brainstem do? (generally)
A
head and body functions
12
Q
What are integrated functions of the brainstem?
A
consciousness, alert, arousal, vital centers, etc.
13
Q
What are the ascending tracts in the junction between the midbrain and diencephalon?
A
- spinal, trigeminal, medial leminisci
- parietal-temporal-occipital pontine fibers
- corticospinal fibres
- corticonuclear/corticobulbar fibers
- frontopontine fibers
14
Q
What does the cerebral peduncle contain?
A
descending tracts
15
Q
What is a peduncle?
A
column that supports the cerebrum
16
Q
What kind of functions do the corticonuclear and corticobulbar fibres do?
A
somatic motor
17
Q
What is the ventral posteiror nucleus?
A
fibers gather to form synapsis with their neurons in the thalamus nuclei here.
VPM - for the face and
VPL - for everything below the neck
18
Q
What is the riMLF in the junction between the midbrain and diencephalon?
A
an integrated function - the vertical gaze center
- controls eyes going up and down
- “rostral interstitial nucleus of medial longitudinal fasciculus”
19
Q
What are the two parts of the substantia nigra in the junction between the midbrain and diencephalon?
A
- pars compacta and pars reticularis
20
Q
What does the pars compacta part of the substantia nigra do?
A
UMN except eyes, controls somatic motor functions
21
Q
What does the pars reticularis part of the substantia nigra do?
A
EYES, Unique
22
Q
What is the UMN control system?
A
the red nucleus
23
Q
What is a colliculus?
A
“Small mountain”, two bumps
24
Q
How many colliculi are there?
A
4 - 2 superior and 2 inferior
25
Where are the colliculi?
posterior of the midbrain
26
We start to have ___ ___________ in the colliculus level of the rostral midbrain
CN attachments
27
What are the ascending tracts in the superior colliculus level?
- spinotectal tract
- spinal leminiscus / anterolateral system
- trigeminal lemniscus
- medial lemniscus
28
What is the spinotectal tract for?
sensory feedback for motor control
29
What is the spinal lemniscus / anterolateral system for?
perception, temperature, fine touch, vibration, pain, etc
30
What is the trigeminal lemniscus for?
perception, temperature, fine touch, vibration, pain, etc in the FACE
31
What is the medial leminiscus in?
dorsal column ascending up
32
What are the integrated functions in the rostral midbrain at the superior colliculus level?
- aqueduct and PAG
- red nucleus
- substantia nigra pars compacts
- substantia nigra pars reticularis
- ventral tegmnetal nucleus
33
What inetgrated function controls award and aversion, and is where addiction happens?
ventral tegmental nucleus
34
What is the PAG integrated function of the rostral midbrain?
Peri-Aqueductal Gray Matter
Peri - around
aqueductal - cerebral aqueduct
35
What are the nuclei of the oculomotor nerve? (CNIII)
- dinger-westphal nucleus and oculomotor nucleus
36
What is the difference between the nuclei of CNIII?
* dinger-westphal nucleus - parasympathetic for visceral motor control
* oculomotor nucleus - somatic motor control
37
What are the colliculus tracts for reflexive neck motions?
Decussation of the tectospinal tracts
38
What is decussation?
CROSSOVER
39
What level is the decussation of the tectospinal tracts at?
superior colliculus level
40
The ______ _______ is the crossover part of the optic nerve
optic chiasm
41
What do reflexive neck motions at the decussaion of the tectospinal tracts do?
from the tectum (midbrain) in the spinal cord, help fix eyes on a target, so when turning our heads we can lock in on a target to view it
42
A patient who suffers from a left MCA stroke can speak fluently but meaningless, What type of aphasia is this?
Fluent aphasia aka conduction aphasia
43
Where is the lesion located in a patient with fluent aphasia?
Wernicke's area in the temporal lobe and possibly the arcuate fasciculus
44
What are the three areas for language in the brain?
ALL LEFT BRAIN
1 - broca's area / Brodmann's 44 and 45 in the frontal lobe
2 - Arcuate fasciculus
3 - Werneike's area / Brodmann's 22 in the temporal lobe
45
What happens in the caudal midbrain at the inferior colliculus level that differs from the superior colliculus level?
the sensory tracts in the tegmental midbrain feather slightly, gather tighter when they ascend in the superior colliciulus level
46
What CN crosses over at the inferior colliculus level?
CN IV (trochlear) crosses over and attaches on the posterior midbrain
47
What happens in the caudal midbrain that can help us determine what level a transverse section is at?
NO red nucleus anymore
48
What are the nuclei of the trochlear nerve that can be seen in the caudal midbrain at the inferior colliculus level?
- decussatio of trochlear nerves
- mesencephalic nucleus of CN V (nuclei in tegmental midbrain)
- trochlear nuclus
49
What is an exception of CNV in the caudal midbrain?
it goes out, crosses over and attaches on the POSTERIOR midbrain
50
Where does the superior cerebellar peduncle cross over?
the caudal midbrain
51
What peduncle is the largest?
middle is biggest
52
What is the inferior peduncle from?
medulla oblongata and spinal cord, is smaller than others
53
What happens in the brainstem with parkinson's disease?
the substantial nigra is degenerating, along with the ventral tegmental area
54
What can also be impacted with PKD due to the structures involved?
addiction!!!!
55
What forms the middle cerebellar peduncle?
the corticopontine, corticospinal, and corticobulbar tracts synapse, crossover and form the middle cerebellar peduncle from the contralateral side of the pontine nuclei
56
When do the corticopontine and corticospinal fibers dissappear?
After the pons
57
What is the main nucleus of CNV?
the pontine sensory nucleus of CNV
58
What does the pontine sensory nucleus of CNV do?
fine touch and proprioception
59
What is the motor nucleus of CNV in the midpons for?
proprioception
60
Where is the trigeminal nerve?
on the mid pons but LATERAL ***
61
What are the nuclei of CNV in the middle pons?
- Mesencephalic nucleus of CNV
- pontine sensory nucleus of CNV
- motor nucleus of CNV
- sensory root of CNV
- trigeminal nerve of CNV
62
What is the pontine raphe nucleus part of? What does it do?
- in the mid pons and part of the reticular formation
- for arousal status
63
What fibers form the middle cerebellar peduncle?
transverse fibers of pons
64
What is the nuclei pontis?
aka the pontine nucleus, descends to mid pons, synapses, crosses over, then forms the middle cerebellar peduncle
65
What is the locus coeruleus?
locus coeruleus, a small nucleus located in the pons, is the main source of noradrenaline in the forebrain. Together with other nuclei located in the anterodorsal part of the brain stem, it belongs to what used to be described as the ‘ascending reticular activating system’, an area critical for arousal and wakefulness.
66
What is the descending sympathetic tract in the caudal pons?
center of visceral motor center is the hypothalamus, this has fibers from it
67
Where does the spinal trigeminal tract go to?
C2 level, nucleus exits
68
What do the corticopontine fibers do in the caudal pons?
control different levels of the LMN
69
What are the nuclei of CN 6 in the caudal pons?
the nerve and abducens nucleus
70
What are the nuclei of CN7?
just 1 nuclei! CNVII
71
What are the nuclei of CN 8?
Cochlear nucleus, vestibular nuclei, and CN8
72
What cranial nerves are on the lateral pontomedullary junction?
CN VII and VIII
73
What CN is on the medial pontomedullary junction?
CN VI
74
What is the PPRF? Where is it?
Caudal pons
- Paramedial Pontine Reticular Formation
- horizontal gaze center, for vision side to side! Frontal eye field (FEF) controlls the eye cross over
75
Which midbrain nucleus is one compartment of the basal nuclei?
Substantia nigra
76
What pathology will a patient present with if the substantia nigra degenerates and loses function?
PKD
77
What are the CN nuclei in the rostral medulla oblongata?
- CN 12
- Hypoglossal nucleus
- nucleus ambiguus
- CN 10
- spinal trigeminal nucleus
- vestibular nuclei
- solitary nucleus
- dorsal motor nucleus of vagus
78
What are the asvending and decending tracts in the rostral medulla oblongata?
- inferior ceredbellar peduncle
- spinal trigeminal tract
- sponothalamic tract
- trigeminal leminiscus
- medial leminisucs
- corticospinal tract in pyramid
79
What tract is no longer present at the rostral medulla oblongata?
Corticopontine tracts
80
What are the integrated functions in the rostral medulla oblongata?
- inferior olivary nucleus for learning new skills and training
- raphe nuclei which is part of the reticular formation
81
What will happen if the inferior olivary nucleus is injured?
the person cannot learn new skills
82
What CN and nuclei are in the caudal medulla oblongata? (LOTS)
- Retroambiguus nucleus
- vagus nerve
- dorsal nucleus of vagus
- hypoglossal nerve
- solitary tract and nucleus
- inferior salivatory nucleus
- spinal tract and nuclus of trigeminal nerve
- glossopharyngeal nerve
- nucleus ambiguus
- hypoglosssal nucleus
83
What are the ascending and descending tracts in the caudal medulla oblongata?
- spinal lemniscus/anterolateral system
- medial leminiscus
- pyramid
84
What are the integrated functions present in the caudal medulla oblongata?
- olivary nucleus
- accessory olivary nuclei
- magnus raphe nuclus
- pontine reticulospinal tract
- paramedial reticular formation (horizontal gaze center)
85
What is unique about the inferior cerebellar peduncle in the caudal medualla oblongata?
- only contralateral olivary projecting fibers to cerebellus crossing over
86
What is the anterolateral spinothalamic tract for in the caudal medualla?
Sensory decussation in the spinal cord
87
What is the dorsal column in the medial lemniscus in the caudal medulla for?
decussation in the caudal medulla
- DONT CROSSOVER, ascend through the caudal or medial medualla, synapse, then crossover to form the medial lemniscus in the lateral tegmental midbrain which goes to the ventral posterior nucleus of the thalamus
88
What is the corticobulbar/corticonuclear tract for in the caudal medulla?
for cranial nerve motor functions
- control somatic motor nuclei of cranial nerves
- crossover CNV, CNVII, CNXII
89
What percentage of the corticospinal tract is cross over (decussation)?
70-90%
90
What percentage of the corticospinal tract does not crossover?
10-30%
91
What happens to the ipsilateral lateral corticospinal tract?
stays on the same side of the column, if stroke here theres more function left over because no crossover
92
What happens to the anteiror corticospinal tract?
DOESNT DESCEND, stays anterior and does not crossover
93
What is the reticular formation made up of?
3 columns
94
What is the ascending reticular activating system for in the reticular formation?
arousal and staying alert
95
What is the descending spinal tract for?
motor control (visceral and somatic)!!
96
What happens if there is a stroke in the vital centers such as the pons or medulla oblongata?
likely death
97
Which cranial nerves have their nuclei in the pons?
- CNV (trigeminal)
- CNVI (abducens)
- CNVII (facial)
- CNVIII (vestibulocochlear)
98
Which ascending sensory and descending motor tracts decussate in the medulla?
- inferior cerebellar peduncel from contralateral olive
- medial lemniscus
- 70-90% corticospinal tract
