Brain stem Flashcards
1
Q
BRAIN STEM COMPONENTS:
Midbrain:most rostal part
Pons
Medulla oblongata:most caudal part
A
2
Q
EMBRYOLOGICAL ORIGIN of the Midbrain
A
It arises from mesenphalon
3
Q
Embryological origin of the Pons & medulla:
A
arise from
rhombencephalon or hindbrain (together with cerebellum
4
Q
The midbrain is continuous
rostrally with _____
A
diencephalon of the forebrain
5
Q
The pons is continous rostrally with ____& caudally with ____
A
midbrain
medulla
6
Q
The brain stem lies on the ___ part of the occipital bone
A
Basilar part of the Ossipital bine
7
Q
The midbrain is continuous rostrally with
A
diencephalon of forebrain
8
Q
The pons is continous rostrally
with ___ & caudally with ____
A
midbrain
medulla
9
Q
The medulla is continuous
caudally with spinal cord at the margin of foramen magnum
A
10
Q
What’s the brainstem CONNECTION TO CEREBELLUM
A
Midbrain via superior cerebral peduncle
Pins via middle cerebral peduncle
Medulla via inferior cerebral peduncle
11
Q
The brainstem is the site of
origin & emergence of nuclei
of cranial
nerves
A
(from 3rd to 12th)
12
Q
Contains groups of nuclei & related fibers known as reticular formation
A
13
Q
reticular formation
responsible for:
control of level of
consciousness, perception of pain,
regulation of cardiovascular &
respiratory systems
A
14
Q
List all the cranial nerves
A
Oh, Oh, Oh, To, Try, And, Feel, Very, Good, Valet, Ah, Heaven
15
Q
Location and function of those nerves
A
16
Q
The ventral surface of the medulla
The median fissure
The lower part of this fissure is not easily visible because it is covered by the crossing of the pyramidal fibers____ fibres
A
pyramidal (corticospinal) fibers.
17
Q
These fibers are nerve pathways that originate from the cerebral cortex and cross over to the opposite side of the body, controlling voluntary muscle movements.
A
18
Q
Features of the ventral surface of the medulla
A
Pyramidal discussion
Olive
Ventral median fissure
19
Q
The olive is found on the lateral side of the pyramid and is separated from it by a groove called the _____.
A
ventrolateral sulcus
20
Q
The olive is also an elevation or bulge and is produced by the presence of the _____.
A
inferior olivary nucleus
21
Q
The olive is involved in ____
A
motor coordination and learning.
22
Q
Nerves emerging from the Medulla are?
A
Hypoglossal, glossopharyngeal, vagus, cranial part of assesory nerve
23
Q
The hypoglossal nerve emerges from ______
And it’s function is _____
A
Hypoglossal nerve (12th cranial nerve): This nerve emerges between the pyramid and the olive.
It controls the muscles of the tongue, allowing for movements such as swallowing and speech.
24
Q
Glossopharyngeal nerve (9th cranial nerve),
Vagus nerve (10th cranial nerve),
Cranial part of the Accessory nerve (11th cranial nerve):
These nerves emerges from
A
Emerges dorsolaterally (towards the back and side) to the olive, in a top-to-bottom arrangement.
25
Glossopharyngeal nerve (9th cranial nerve),
Vagus nerve (10th cranial nerve),
Cranial part of the Accessory nerve (11th cranial nerve):
What are the function of these nerves
controlling functions related to the throat, larynx, and various organs in the chest and abdomen, including swallowing, breathing, and heart rate.
26
Features of the ventral surface of the pons
Basilar sulcus
Transverse Pontine (Pontocerebellar) Fibers
27
What's the basilar sulcus, it's content & function of the content
The basilar sulcus is a groove running along the midline of the pons, dividing it into two halves. It is occupied by the basilar artery, which supplies blood to the brainstem and cerebellum.
28
Transverse Pontine (Pontocerebellar) Fibers
These are groups of neurons located in the pons. These fibers cross the midline and pass through the contralateral (opposite) middle cerebellar peduncle to enter the opposite hemisphere of the cerebellum.
29
Function of the Transverse Pontine (Pontocerebellar) Fibers
They are involved in connecting the pons with the cerebellum and play a role in motor coordination and balance.
30
Nerves emerging from the Pons are
Where they emerge from
Trigeminal nerve (5th cranial nerve):
Abducent nerve (6th cranial nerve):
Facial nerve (7th cranial nerve) and vestibulocochlear nerve (8th cranial nerve)
31
Nerves emerging from the Pons & Where they emerge from
5th -The trigeminal nerve emerges from the middle of the ventrolateral aspect of the pons
6th- emerges at the junction between the pons and the pyramid
7 & 8th- emerge at the cerebellopontine angle, which is the junction between the pons, medulla, and cerebellum.
32
The trigeminal roots and it's function
It has two roots: a small medial motor root and a large lateral sensory root.
The trigeminal nerve is responsible for sensations in the face and controlling the muscles involved in chewing
33
Function of the abducent nerves
It controls the movement of the lateral rectus muscle, which is responsible for outward eye movement.
34
The facial nerve has a motor root and a sensory root, while the vestibulocochlear nerve has two parts: the vestibular part and the cochlear part.
35
The facial nerve controls facial muscles and is involved in taste sensation, while the vestibulocochlear nerve is responsible for hearing and balance.
36
The midbrain contains important structures involved in motor control, sensory processing, and various other functions.
37
Features of the midbrain
Descending Fibers (Crus Cerebri or Basis Pedunculi)
Interpeduncular Fossa: The two crura cerebri,
38
The midbrain is primarily composed of a large column of nerve fibers known as the crus cerebri or basis pedunculi
These fibers are responsible for transmitting signals from the cerebral cortex (the outer layer of the brain) to the spinal cord and other parts of the body. They form a pathway for motor commands, enabling voluntary movement and muscle control.
39
Interpeduncular Fossa: The two crura cerebri, which are the descending fibers mentioned above, are separated by a depression or groove called the interpeduncular fossa.
40
What are the Nerve emerging from the Midbrain & emerges from____
And it's function
Occulomotor Nerve (3rd Cranial Nerve):
It emerges from the medial aspect (inner side) of the crus cerebri.
The oculomotor nerve is responsible for controlling the movement of certain eye muscles, including those that control eye position, pupil size, and focusing.
41
The dorsal surface of the medulla is divided into
• Caudal 2/3: Closed Medulla:
• Rostral 1/3: Open Medulla
42
Features of the dorsal surface of the medulla
CLOSED MEDULLA
Dorsal median sulcus
Fasciculus gralis
Fasciculus cuteanus
43
The fasciculus gracilis is located closer to ____, and an elevation called the ____ can be seen at the upper part of this bundle.
the midline
gracile tubercle
44
Gracile tubercle marks the site of the ____, which is does what function
gracile nucleus
the processing of sensory information related to touch, vibration, and conscious proprioception
45
fasciculus cuneatus is situated on the sides (lat.)of the fasciculus gracilis, and the cuneate tubercle is an elevation seen at its upper part. This tubercle indicates the location of the cuneate nucleus, which also plays a role in processing _____
sensory information from touch, vibration, and conscious proprioception, but primarily from the upper body.
46
Moving on to the open medulla, which forms the lower part of the floor of the fourth ventricle
47
On either side of the open medulla, there is an inverted V-shaped sulcus that divides this area into ____ parts when viewed from the mid. To lat.
3
48
The three parts are
And their function
Hypoglossal triangle, which overlies the hypoglossal nucleus. The hypoglossal nucleus is responsible for controlling the movements of the tongue.
Vagal triangle, which overlies the dorsal vagal nucleus. The dorsal vagal nucleus is involved in regulating functions of the autonomic nervous system, including the parasympathetic control of various organs in the body.
Vestibular area, which overlies the vestibular nuclei. The vestibular nuclei are associated with processing sensory information related to balance and spatial orientation.
49
___ Forms the upper part of floor of 4th ventricle
The dorsal surface of the pons
50
The dorsal surface of the Pons is seperated from the medulla by
Is separated from the medulla by an imaginary line passing between the caudal margins of
middle cerebellar peduncle
51
In the dorsal surface of the Pons
On either side, a sulcus divides the area into 2 parts (from medial to lateral):
Which are?
Medial eminence:
Vestibular area:
52
Medial eminence & vestibular area overlies
Medial eminence:overlies abducent
nucleus
Vestibular area: Overlies vestibular nuclei
53
The dorsal surface of the midbrain is characterized by ___ elevations, which are structures that are elevated or raised above the surrounding areas.
4
54
These four elevations:
& are involved in , their function
.
Two superior colliculi, which are involved in visual reflexes.
Two inferior colliculi, which are part of the auditory pathway.
The superior colliculi coordinate eye movements and attention based on visual stimuli.
The inferior colliculi process auditory information, helping with sound localization and auditory reflexes
55
What nerve emerges from the dorsal surface of the midbrain
The trochlear nerve (4th cranial nerve) emerges from the midbrain's dorsal surface, just below the inferior colliculus.
The trochlear nerve innervates the superior oblique muscle of the eye, contributing to eye movements and coordination.
56
Medulla@ olive
Principal olivary nucleus, dorsal asessory olivary nucleus is pst. to principal
&medual olivary nucleus is medial to principal
Together forms inferior olivary complex
57
Pyramid is located@ the ant. Surface of the medulla
In the pyramid@ the ant. Side is the Accurate nucleus
58
PST PART OF THE MEDULLA
@ the floor of the 4th ventricle anteriorly is the hypoglossal nucleus close to the mid line
Lat to the hypoglossal is the dorsal nucleus of vagus
Medial vestibular nucleus is the lat. To it
Then inferior vestibular nucleus & nucleus solitarus is also present in the pst medulla
59
PST PART OF THE MEDULLA
the inferior cerebellar peduncle is located@ what part
Pst lat part
60
PST PART OF THE MEDULLA
Inferior spinocerebelar tract is located@
Close to the surface & Lat. In between the inferior cerebellar peduncle & olive
61
Medial to the inferior spinocerebelar tract is
Spinal lamiscus
62
PST PART OF THE MEDULLA
The pst & ant. cochlear nucleus is located
Pst. To inferior cerebellar peduncle
Ant. To inferior cerebellar peduncle
63
Medial to the inferior cerebellar peduncle is the __&__
Spinal trigeminal tract & nucleus
Mid to first is nucleus ambiguous
64
@ midline is the from ant. To pst.
Mainly 3
(Pyramid,)
Medial meniscus, tectospinal tract & medial longitudinal fasciculus
65
In studying the internal features of the brain stem is studied @ the level of
Pst. Upwards
Level of pyramidal discussion
Level of sensory
Level of olive
66
@ the pyramidal discussion
The changes occurring in the grey mata @ pyramidal discussion is
The two elongation present that's absent in the spinal cord is
i.e the grey mata is becoming more defined
Nucleus gracilis & Cuneatus
& pst. Horn to spinal nucleus and tract of trigeminal
Dorsal & ventral spinal cerebellar( lat. Sides) spinotelamic tract(mid. To cerebellar)
Pst column is pst.
67
The pyramidal discussion is made up of what fibres
Corticospinal & cortico nuclear @ the level of pyramidal discussion
Cortico pontine fibres (passes @ d Pons to the cerebellar) s included before i.e above the discussion
Lateral corticospinal tract is the cortico tract involved in discussion
68
The part of the grey matter (ant. Part) that's cut off @ the pyramidal discussion is
Final nucleus of Assesory nerve & supra spinal nucleus of 1st cervical nerve
69
Sensory decussation is when what is formed
Medial lemniscus
70
@ sensory decussation
The nucleus Cunateuus & gracilis that's formed @ the lower part of the medulla, seperates from the main grey matter as a two set of nucleus
71
@ sensory decussation
The second order neuron croses to the opposite side to form
Medial lemniscus
72
@ sensory decussation
The pst. Column is replaced by
Medial lemniscus
73
The fibres going to form the medial lemniscus is called
Internal arcuate fibes
74
Pst to the nucleus cuneatus is
Assesory cuneate nucleus
75
Ant. to nucleus cuneatus is
Spinal nucleus & tract of trigeminal nerves
76
The assesory cuneate nucleus function
It sends fibres to the cerebellum known as pst. External arcuate fibres
77
Want. External arcuate fibres corticospinal
78
Reticular fibres is seen through out the brain stem
79
@ sensory decussation
Medial longitudinal fasciculus is located@ the midline and it's function
It connects important nuclei like 3,4,6,8& 11
It coordinates the movement only the head & neck in response to stimulus of CN8
80
@ sensory decussation
The nucleus located at the hear shaped grey matter is
Hypoglossal,dorsal nucleus of vagus & nucleus of tractus solitarus
81
@ the olive or 4th ventricle
No central canal
82
@ the olive or 4th ventricle
Inferior Vestibular nucleus appears
83
Nucleus of tractus solitarus I'd formed by
7,9 & 10
84
@ the olive or 4th ventricle
The nucleus ambiguous is formed by
9,10,11
85
Medial (anterior) medullary syndrome: might cause
Hemiplegia (contralateral)
This refers to paralysis or weakness affecting one side of the body, which is opposite to the side of the brain damage
Loss of sense of vibration and position:
Paralysis of tongue muscles (ipsilateral): The muscles of the tongue on the same side as the affected artery are paralyzed
86
Lateral medullary syndrome: might cause
Paralysis of muscles of the soft palate, pharynx, and larynx
Loss of temperature and pain sensation (ipsilateral): The ability to feel temperature and pain on the same side as the affected artery is lost.
Loss of temperature and pain sensation (contralateral): The ability to feel temperature and pain on the opposite side of the affected artery is also lost.
Loss of equilibrium: The sense of balance and coordination is affected.
87
Lateral medullary syndrome, also known as Wallenberg syndrome is caused by damage to
posterior inferior cerebellar artery (PICA)
88
damage to what causes medial medullary syndrome
damage to the medial branches of the anterior spinal artery
89
Pons hemorrhage can lead to
Paralysis of face and limb on the opposite side of the damage
Coma
Hyperpyrexia: This term indicates extremely high body temperature
90
Damage@ the cerebelopontine angle may cause
Facial paralysis and loss of sensation on the same side of the damage
Ataxia: Ataxia refers to a lack of coordination and unsteady movements
Deafness and vertigo: This condition involves hearing loss and a sense of dizziness or spinning.
Loss of corneal reflex: The corneal reflex is the blinking response when the cornea is touched
91
Millar Gubler's syndrome causes
Facial paralysis (ipsilateral):
Hemiplegia (contralateral): weakness affecting one side of the body, which is on the opposite side of the brainstem damage
Loss of abduction: This means the inability to move the affected eye outward, away from the nose.
92
Text
93
The changes in the arrangement of the grey & white matter is mainly due to
Presence of 4th ventricle
94
@ pyramidal discussion
Between the ventral grey horn & spinal nucleus of trigeminal nerves is _____
Reticular formation
95
@ pyramidal discussion
The spinal nucleus is of trigeminal nerves is related superficial to
Spinal tract of trigeminal nerves
96
Pyramidal discussion
Is backwards and medial
97
@ pyramidal discussion
Defending tracts seen are
Rubrospinal
Vestibulospinal
Olivispinal
Tectospinal
(Trigeminal nerves)
98
@ pyramidal discussion
Ascending tract seen
Fasciculus gracilis
Fasciculus cuneatus
Spinothalamic
Spinocerebellar
Spinotectal
Spini-olivary
99
@ sensory discussion
What structure remain in the same position as the level of pyramidal discussion
Nucleus gracilis, cuneatus spinal nucleus of trigeminal nerves, & pyramid
100
@ sensory discussion
The cuneatus & gracilis are shorter and no longer continuous with grey matter
101
@ sensory discussion
Arcuate fibres appear crossing the mid line
102
@ sensory discussion
____ fibres constitute the lemniscus decussation (sensory)
Crossing the midline forming medial lemniscus
Arcuate fibes
103
@ sensory discussion
The ascending tracts are
Gracilis & cuneate fasciculus
Spinothalamic
Spinocerebellar
Spinotectal
Spino-olivary tract
104
@ sensory discussion
Defending tracts present are?
Pyramids
Rubrospinal
Vestibulospinal
Olivospinal
Mrdial longitudinal fasciculus
105
@ level of 4th ventricle/ olive
106
@ level of 4th ventricle/ olive what structures are in the same position as @ sensory discussion
Pyramid, medial lemniscus, spinal nucleus of trigeminal nerves & reticular formation
107
@ level of 4th ventricle/ olive
Lat. To the spinal nucleus of trigeminal nerves ___ is seen
& it's function
Inferior cerebellar peduncle
Connects the medulla to the cerebellum
108
@ level of 4th ventricle/ olive
What cranial nucleus can be seen in relation to the forth ventricle
From mid. To lat.
Hypoglossal
Dorsal vagal nucleus
Vestibular nucleus
109
@ level of 4th ventricle/ olive
___&___ is seen in relation to inferior cerebellar peduncle
Dorsal & ventral cochlear nucleus
Other grey matter nucleus are
Medial &dorsal accessory olivary nucleus
Lat. Reticular nucleus
Arcuate nucleus
110
@ level of 4th ventricle/ olive
The defending tracts present are
Pyramid
Tectospinal
Vestibulospinal
Rubrospinal
Spinal tracts of trigeminal nerves
111
@ level of 4th ventricle/ olive
The ascending tracts present are
Medial lemniscus
Spinothalamic
Spinocerebellar
Spinotectal
112
The pons
The pons is a part of the brainstem divided into ventral (basilar) and dorsal (tegmentum) parts.
The ventral part contains
transverse and vertical fibers and houses the pontine nuclei
113
@ the pons
Pontine nuclei act as a relay station between
act as a relay station between the cerebral cortex and the contralateral cerebellar hemisphere.
114
Depending longitudinal fibres @ the ventral/ Basilar part of pons
Corticospinal
Cortico nuclear
Cortico pontine
115
Corticopontine fibers transmit information from the
from the frontal, temporal, parietal, and occipital lobes to the pontine nuclei.
116
The pontine nuclei receive fibers from various other sources, including the tectum, mammillary body, lateral geniculate body, etc.
117
Descending longitudinal fibers include corticospinal fibers and corticonuclear fibers, which primarily connect with the motor nuclei of cranial nerves.
118
Transverse fibers from the pontine nuclei cross to the opposite side, forming the
forming the middle cerebellar peduncle (pontocerebellar fibers).
119
The trapezoid body separates the basilar and tegmental parts of the pons and contains fibers from the ventral cochlear nuclei, contributing to the auditory pathway.
i.e ventral from dorsal
120
Features @ the Lower Part of the Pons
The medial lemniscus is located next to the midline and occupies a transversely elongated oval area
Lateral to the medial lemniscus are the trigeminal and spinal lemnisci (lateral spinothalamic tract).
The ventral spinothalamic tract, spinal lemnisci (lateral spinothalamic tract)., the trigeminaltrigeminal lemnisci, spinothalamic & spinotectal tract are arranged lat. To mid
121
Ventral to the lemnisci, there are transversely running fibers forming the trapezoid body.
122
Upper Part of the Pons:
The ventral spinocerebellar tract is seen within
within the superior cerebellar peduncle.
123
Upper Part of the Pons:
Descending tracts passing through the dorsal part of the pons include the
include the tectospinal tract and the rubrospinal tract
124
@ the lower part of the pons @ facial colliculi
the presence of two cranial nerve nuclei are present which are?
the abducent nucleus (medial) and the vestibular nuclei (lateral).
125
@ the lower part of the pons @ facial colliculi
Deeper within the section, two additional nuclei are observed namely
spinal nucleus of the trigeminal nerve (along with its tract) and the facial nucleus.
126
the lower part of the pons @ facial colliculi
The dorsal and ventral cochlear nuclei are positioned dorsal and ventral, respectively, to the inferior cerebellar peduncle.
127
the lower part of the pons @ facial colliculi
The fibers from the facial nucleus take an unusual course which is
running dorsally and medially to reach the lower pole of the abducent nucleus, then ascending on the medial side of that nucleus, closely associated with the medial longitudinal fasciculus.
128
The facial nerve fibers turn forwards and laterally, passing above the upper pole of the abducent nucleus, and descend between the facial nucleus (medially) and the spinal nucleus of the trigeminal nerve (laterally)
129
facial colliculus on the floor of the fourth ventricle is formed by?
The abducent nucleus and the looping fibers of the facial nerve around it form the surface elevation known as the facial colliculus
130
The vestibular nuclei are located in the vestibular area, situated in the lateral part of the floor of the fourth ventricle, visible in the lower part of the pons and upper part of the medulla.
131
Other notable structures in the lower part of the pons include the superior olivary complex, consisting of several nuclei, and the nuclei of the trapezoid body, scattered cells within this body.
132
Upper part of the pons @ the level of trigeminal nerves
dorsal part is bordered laterally by
by the superior cerebellar peduncles
133
Upper part of the pons @ the level of trigeminal nerves
Medial to each peduncle, there are two important nuclei related to the trigeminal nerve:
the main sensory nucleus and the motor nucleus
134
The main sensory nucleus is situated closer to the peduncles, while the motor nucleus is located further inward.
135
Upper part of the pons @ the level of trigeminal nerves
The The superior olivary nucleus,, The lateral lemniscus, trapezoid body are present
136
Tegmental/ Dorsal Part of Pons
The dorsal part (tegmentum) of the pons is an upward continuation of the
upward continuation of the posterior part of the medulla, behind the pyramids.
It continues superiorly and is connected to the tegmentum of the midbrain.
137
Tegmental/ Dorsal Part of Pons
Posteriorly, it is bounded by the
Posteriorly, it is bounded by the fourth ventricle.
138
The dorsal part of the pons
Laterally, it is associated with the inferior cerebellar peduncles, particularly in the lower part
& @ it's upper part to the superior cerebellar peduncle.
139
The spinal nucleus & tracts of the trigeminal nerves lies medial to those peduncle
140
The midbrain
Can be divided into
Cerebral peduncle & tactum
141
The cerebral peduncle can then be divided into
Tegmentum, substantia nigga, crus cerebri
142
The part of the midbrain lying dorsal to the the transverse line drawn @ aqueduct is
It consists of ___ at the two sides
Tectum
Superior & inferior colliculi @ both sides
143
_____ is a mass of vertically running fibers descending from the cerebral cortex.
The crus cerebri
144
The crus cerebri consists of
It consists of corticopontine, corticospinal, and corticonuclear fibers.
145
The substantia nigra is located
behind and medial to the crus cerebri.
146
The substantia nigra contains
pars compacta and pars reticularis, with different types of neurons.
147
____ is produced by the substantia nigra is transmitted to the striatum.
Dopamine
148
Reduced dopamine levels in the striatum are associated with Parkinsonism.
149
The substantia nigra is functionally connected to the
to the corpus striatum
150
The midbrain contains the cerebral aqueduct surrounded by central gray matter
151
The tegmentum lies between the
substantia nigra and tectum
152
The tegmentum contains
the red nucleus and the reticular formation.
153
The tegmentum and tectum have different internal structures at various levels.
154
the midbrain at the level of the inferior colliculus
155
Lesions in the inferior colliculus can result in
in defects in tone appreciation, sound localization, and reflex movements in response to sound.
156
The inferior colliculus plays a role in sound localization and differentiating sounds received by both ears.
157
midbrain at the level of the inferior colliculus
The trochlear nucleus is located in the
The mesencephalic nucleus of the trigeminal nerve is found in the
the ventral part of the central gray matter.
in the lateral part of the central gray matter.
158
compact bundle of fibers in the tegmentum includes the
includes the medial lemniscus, trigeminal lemniscus, and spinal lemniscus.
159
spinal lemniscus & medial lemniscus carries fibres from
The medial lemniscus carries fibers of the ventral spinothalamic tract, while the spinal lemniscus contains fibers of the lateral spinothalamic tract and spinotectal tract.
160
The lateral lemniscus runs ventrolateral to the inferior colliculus.
161
The rubrospinal tracts occupy the ventral part of the tegmentum.
162
The inferior colliculus is located
It's function
located in the tectum,
is a large mass of gray matter involved in auditory processing.
163
Inferior colliculus receives fibers from____ and relays it to _____
from the lateral lemniscus and relays auditory impulses to the medial geniculate body and auditory cortex.
164
Efferent fibers from the inferior colliculus project to the
to the contralateral inferior colliculus and the superior colliculus.
165
Midbrain at the Level of Superior Colliculi:
166
Two large oval masses of grey matter called ____ are observed.
red nuclei
167
_______nucleus is located in relation to the ventral part of the central grey matter.
The occulomotor nucleus
168
The ______ nucleus, closely related to the superior colliculi, is involved in the pupillary light reflex pathway.
pretectal nucleus
169
Ascending fiber bundles like
are positioned dorsally due to the presence of the red nucleus.
medial lemniscus
trigeminal lemniscus
and spinal lemniscus
170
Edinger Westphal nucleus part of the oculomotor complex supplies the sphincter pupillae and ciliaris muscle.
171
The _____ lemniscus is not seen at this level, but the inferior brachium, conveying auditory fibers to the medial geniculate body, is visible.
lateral lemniscus
172
The tegmentum near the midline shows two groups of decussating fibers:
the dorsal tegmental decussation (originating in the superior colliculus) and the ventral tegmental decussation (originating in the red nucleus).
173
The red nucleus is located in the _____dorsomedial to the substantia nigra and plays a role in the extrapyramidal motor system
anterior part of the tegmentum
174
Afferent fibers to the red nucleus come from the
cerebral cortex, cerebellum, globus pallidus, subthalamic nucleus, hypothalamus, substantia nigra, and tectum.
175
Efferent fibers from the red nucleus cross in the ventral tegmental decussation and project to the spinal cord,cranial nerve motor nuclei, inferior olivary nucleus, reticular formation, substantia nigra, cerebral cortex, and thalamus.
176
The superior colliculus is involved in visual reflexes and receives afferent fibers from the retina, spinal cord, visual cortex, and inferior colliculus.
177
Efferent fibers from the superior colliculus project to the
tectospinal tract, tectobulbar tract, cranial nerve nuclei, retina, cerebellum, and reticular nuclei.
178
________ are considered a center for reflex movements of the head and eyes in response to visual stimuli, as well as complex interactions between visual inputs and body activities.
The superior colliculi
179
Other fiber bundles in the brainstem include the medial longitudinal fasciculus, central tegmental tract, dorsal longitudinal fasciculus, and parts of the medial forebrain bundle and mammillary peduncle.
180
Vestibular Nucleus:
Receives sensory information from the vestibular nerve.
Detects balance and spatial orientation.
Gets signals from the inner ear about head movement, position, and gravity.
Sends output signals to various parts of the central nervous system.
181
Outputs include
Vestibulocerebellar pathway
Medial Longitudinal Fasciculus (MLF) (for coordinating eye movements).
Vestibulospinal pathway (to the spinal cord for posture and balance).
Lateral vestibular nucleus (part of the lateral lemniscus pathway).
182
Cochlear Nuclei:
Receives sensory information from the cochlear nerve.
Involved in hearing.
Gets signals from the inner ear about sound.
Sends output signals to various parts of the central nervous system.
183
Outputs include
Superior Olivary Nucleus (involved in sound localization).
Corpus Trapezoides (part of the auditory pathway).
Nucleus of the Lateral Lemniscus (part of the lateral lemniscus pathway).
184
CST (corticospinal tract) carries motor signals from the brain to the spinal cord.
Facial nucleus receives signals from CST to control facial muscle movements.
185
Reticular formation is a network of nerve cells in the brainstem.
Reticular formation regulates consciousness and arousal.
Damage to the reticular formation can cause a coma.
186
Temperature Regulatory Fiber from Hypothalamus:
Hypothalamus regulates body functions, including body temperature.
Temperature regulatory fibers transmit signals from the hypothalamus.
Helps maintain stable body temperature.
187
Flocculus is involved in motor coordination.
Ataxia is a lack of muscle coordination affecting various movements
Damage to the flocculus can cause ataxia.
188
Dysfunction of the _____can cause vertigo.
Vertigo is a sensation of spinning dizziness.
vestibular branch of vestibuloocular
189
_____ triggers the corneal reflex
Nucleus of V nerve
Nucleus of V nerve (trigeminal nerve) transmits sensory signals from the face.
190
Damage to the ____ nerve causes loss of abduction.
abducens
The eye
