Brainstem Flashcards
Bundles of axons mielinated in the brainstem along the same route but without connective tissue are called…
Funiculae, bundles, pathways or tracts.
Pathways or tracts in the brainstem…
Come from the same place, they arrive to the same place and they carry the same type of information.
THEY HAVE A SPECIFIC PLACE IN EVERYONE
To make relay means to…
Make synapse
Nuclei in the brainstem may be associated with…
CRANIAL NERVES
The brain –as the spinal cord‐ is also …. organized
metamerically
The ventral aspect of the rostrohindbrain is mainly covered by…
PONTINE REGION
Pons
Medulla, subarachnoid space
Which information is entering at the level of the brainstem?
Information from the head and neck.
The brain –as the spinal cord‐ is also …. organized Segments or neuromeres (metameric brain units) in the rhombencephalon are called …
Metamerically, rhombomeres
Pontine regions come from the…
Rhombenecephalon
On the basis of molecular regionalization there is a … hindbrain
Rostral and caudal
Prepontine, pontine and retropontine region come from the …
Rostral Hindbrain
Medulla oblongata comes from the …
Caudal hindbrain
Nuclei in the brainstem are located in the …
TEGMENTUM
Functional segregation within the neural tube
• Neurons located in the basal plate give rise to … neurons
• Neurons from the alar plate will be recipients of … information
- motor
- sensory
…: border between alar and basal plates, and later in development, between the dorsal (sensory) and ventral (motor) horns of the spinal cord
Sulcus limitans
The brainstem also has a functional segregation consisting of … plate derivatives
alar and basal
In the medulla and midbrain, sensory nuclei will be … and motor ones will be …, whereas in the pons, motor nuclei will be located …, and sensory ones …
- dorsal, ventral
- medially, laterally
Which type of orientation is this one?
Anatomical
Which type of orientation is this one?
Clinical
Medulla parts
Name the structure and what is marked
Medulla and inferior olives
Name these structures
Cerebellum and medulla
Name these structures
- TEGMENTUM
- Basilar pons
Bundles of fibers that connect pons to cerebellum:
CEREBELLAR PEDUNCLES
Midbrain parts
Which structure is this? Which parts are marked?
Midbrain
1. Rectum
2. Interpeduncular fossa
To which part corresponds each image? Name the structures
A. Medulla
B. Pons
C. Midbrain
The roof of the midbrain is formed by the…
Tectum (superior and inferior colliculli)
The ventral part of the midbrain is known as…
CRUS CEREBRI
The corticospinal tract descends through the … of the medulla
Pyramids
Medulla starts at the level of the … and extends rostrally until the…
Foramen magnum, inferior margin of the basilar pons
Pons starts from… and extends till…
Inferior margin, superior margin of the basilar pons
Midbrain starts from… and finishes at the…
Th superior margin, superior colliculli (of the tectum), towards the mamillary bodies
Along the ventral surface of the basilar portion of the pons, courses the….
Basilar artery
The pons is connected to the cerebellum by…
Cerebellar peduncles (formed by axons connecting the pons to the cerebellum).
Oculomotor ane Edinger-Westphal nuclei are located in the …
TEGMENTUM of the midbrain
Sensory structures in the midbrain are located in the…
Tectum
In the cerebral pedunculi of the midbrain we find…
Substantia nigra and crus cerebri (through which the corticospinal tract passes)
Corticospinal tract passes trough the… in the midbrain, and though the … in the medulla
Crus cerebri, pyramids
Most of the CN exit via the ventral aspect of the brain except from the…
TROCHLEAR NERVE (IV), which exits dorsally, but it then comes anterior turning around the brainstem to innervate the superior oblique. It courses through the cavernous sinus.
We see the …. CN originating under the inferior collicullus.
TROCHLEAR (IV)
Vibration, proprioception and fine touch are carried by the … pathway
Dorsal column-medial lemniscus
Which ascending pathway has fast-conducting, large diameter fibers?
Dorsal column-medial lemniscus pathway
Somatotopic organization posterior ascending pathway through spine
Leg medial, arm lateral
Topographic organisation medial lemniscus
Lower limbs lateral, upper limbs medial
1st synapse of the posterior ascending pathway occurs in…
Gracile (leg) and cuneate (arm) nucleus
2nd synapse of the posterior ascending pathway occurs in… thalamus
Ventral posterolateral nucleus of
3rd synapse of the posterior column pathways occurs in…
The sensory cortex
Name these parts an the spinal pathway in which they are found
Posterior ascending pathway. They decussate in the medulla of the brainstem.
Complete the scheme and name the pathway
Posterior ascending pathway
Gross touch and thermoalgesic sensation is detected by the …. Spinal pathway
Anterior ascending
Poorly myelinated or unmyelinated fibers and slow conduction are characteristic of… spinal pathway
Anterolateral ascending
Spinal synapse takes place in… spinal pathway
Anterolateral ascending
Somatotopic organisation in anterior and lateral spinothalamic tracts
Lower limbs lateral, upper limbs medial
Cortex Somatotopic organization
Lower limbs medial cortex, upper limbs lateral cortex
Main tract in anterolateral system
Spinothalamic tract
Decussation of the anterolateral system occurs in…
The anterior white comissure
Fibers that go from the thalamus to the cortex are called….
Thalamocortical fibers (posterior ascending pathway)
The corticospinal tract passes through the … of the midbrain
Crus cerebri (cerebral peduncles)
Cortico spinal pathway passes through the … of the pons
Pontine nuclei (basilar pons)
Corticospinal tract passes through the … of the medulla
Pyramids
Decussation of the corticospinal tract occurs in…
The medulla-spinal cord juncture (decussation of pyramids)
The second synapse of the corticospinal pathway occurs in…
Anterior horn spinal cord
Esquema ascending pathways
Esquema descending pathway
Recap of the brainstem
The anterolateral system ascends … to the inferior olive
Lateral and superior
The corticonuclear tract goes to…
CN nuclei in the brainstem
The corticopontine fibers go to…
Cerebellum
Trigeminothalamic pathways convey…
Somatosensory info from the face
Info gathered about propioception, fine touch and vibration from the face makes its first synapse in the…
PRINCIPAL SENSORY NUCLEUS
The info about oral cavity travels … through the trigeminothalamic fibers after making a first synapse in the…
Dorsomedial, principal sensory nucleus
Info conveyed about pain, gross touch and temperature makes its first synapse in the…
Spinal nucleus of the trigeminal
The second synapse of the trigeminothalamic fibers is done in the…
Ventral posteromedial nucleus of the thalamus
Complete this scheme about the trigeminothalamic tracts
Make a scheme of the trigeminothalamic pathway
Fibers of the trigeminothalamic pathway (specifically info about propioception, fine touch and vibration), are inverted in the…
Principal sensory nucleus
Para el cierre rápido de la mandíbula, se lleva a cabo el jaw-jerk reflex (monosynaptic reflex), donde solo encontramos una neurona aferente y una eferente. Su sinapsis se hace en…
MESENCEPHALIC NUCLEUS OF CN V
Complete this image about the trigeminal ascending pathways
MESENCEPHALIC nucleus and tract scheme
CORTICONUCLEAR TRACT is responsible for the … innervation to the motor nucleus of the V and superior half of the facial nucleus
BILATERAL
The CORTICONUCLEAR TRACT is responsible for the …. innervation of the inferior half of the facial nucleus, nucleus ambiguus and hypoglossal nucleus.
Contralateral
The corticonuclear tract is responsible for the… innervation of the cervical spinal cord for XI.
Ipsilateral
Innervation of the facial nucleus
bilateral to the upper half of the face, only contralateral to the lower half
Why does the first man have a parcial paralysis and the second one a central paralysis?
In A there has been a lesion in the corticonuclear fibers that go to the facial nucleus, in B the lesion is in the root of the facial nerve.
La X grande indica la localización de la lesión.
(The FACIAL NUCLEUS has bilateral superior innervation and contralateral inferior innervation)
A is a central lesion (between upper neuron and nucleus)
It still receives Ipsilateral innervation from the other nucleus.
B is a peripheral lesion, BELL’S PALSY, lesion is after the nucleus.
If there is a lesion in the corticonuclear right fibers to the nucleus ambiguus and the hypoglossal nucleus, there would be a deviation of the tongue to the…
LEFT
(contralateral innervation)
Brainstem reticular (scattered) formation can be…
Parvocellular (smaller) and magnocellular (larger)
Lateral reticular formation function
generation of simples motor patterns and brainstem reflexes (chewing)
Medial (central) reticular formation function
Postural control: reticulospinal tracts
Median reticular formation function
Pain control (antinociception) - Raphe nuclei
(SEROTONERGIC)
Ascending reticular activating system (ARAS) function
conscious state, sleep‐ wake cycle (Daergic, cholinergic, etc.)
DOPAMINERGIC (nuclei that control behavioural states)
Paramedian reticular formation functional
Control of eye movements (gaze centers)
What can be seen in this image?
Axonal arborization of a neuron from the rat reticular formation
Autonomic fibers arise… to the sulcus limitans
The closest
In the brainstem, somatic motor nuclei are located close to the…
Midline
In the brainstem, visceral motor nuclei are located…
Close to the sulcus (medially)
In the brainstem, visceral sensory nuclei are located close to the…
Sulcus, laterally
In the brainstem, somatic sensory nuclei are located…
Most kateral
Special sensory nuclei (vestibular and cochlear nuclei) are located … in the brainstem
Dorsal and lateral
The corticonuclear tract travels trough the … of the thalamus and in the crus cerebri (midbrain) travels … to the corticospinal tract
Internal capsule, medially
Peripheral and central lesion of hypoglossal nerve
