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54 Cards in this Set
- Front
- Back
- 3rd side (hint)
What is the source of the Internal Arcuate Fibers? |
The Internal Arcuate Fibres arise from the Nuclei Cuneatus and Gracilis. |
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What do the Internal Arcuate Fibers form? |
They cross at the Sensory Decussation and form the contralateral ascending Medial Lemniscus. |
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What pathway is the Medial Lemniscus a part of? |
It is part of the somatosensory pathway, which carries proprioceptive, fine touch and vibration sensation up the Dorsal Column (DC). |
The DC consists of either the Fasciculus Cuneatus or Gracilis, depending on whether the upper or lower limbs are the source. |
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What is the function of the Lateral (Accessory) Cuneate Nucleus? |
It is the source of the Cuneo-Cerebellar Fibers, which convey proprioceptive information to the Cerebellum from the arm. |
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Where do the Corticospinal Tracts arise? |
They originate from the Frontal and Parietal lobes. |
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What do the Corticospinal Tracts form in the Medulla? |
The Pyramids. |
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How many of the axons of the Corticospinal Tracts cross at the Decussation of the Pyramids? |
Approximately 85% of the axons cross at the Decussation and descend the spinal cord through the Lateral Corticospinal Tracts. |
The remainder descend ipsilaterally through the Anterior Corticospinal Tracts. |
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What is the extent of the Hypoglossal Nerve Nucleus? |
It extends the length of the Medulla. |
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Where does the Hypoglossal Nucleus appear in cross section? |
It appears close to the midline, as is common for motor nuclei. |
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How many Vestibular Nuclei are there? |
Four: 1. Superior, 2. Inferior, 3. Lateral, and 4. Medial. |
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What is the posterior surface feature marking the location of the Hypoglossal Nucleus? |
In the Open Medulla, the Hypoglossal Trigone visibly shows the position. |
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What two nuclei sit on either side to the Dorsal Vagal Nucleus? |
Medially the Hypoglossal Nucleus. |
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What does the Dorsal Vagal Nucleus innervate? |
It provides parasympathetic preganglionic fibers that innervate the viscera of the thorax and the abdomen. |
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What is the vertical extent of the Vagal Dorsal Motor Nucleus? |
The extent of the Medulla, similar to the Hypoglossal Nucleus. |
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How can you locate the Nucleus Ambiguus in cross section? |
It's difficult to visualize, but two landmarks are that it's medial to the Spinal Tract of CN V, and dorsal to the Dorsal Accessory Olivary Nucleus, in the middle of the Medulla. |
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What sort of neurons are found in the Nucleus Ambiguus? |
It is the source for lower motor neurons of CN IX, X, and XI. |
It also provides parasympathetic preganglionic innervation to the heart. |
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What is the vertical extent of the Nucleus Ambiguus? |
It extends rostrally to just below the Pontomedullary Junction, and caudally to the level of the Foramen Magnum. |
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What does the Solitary Nucleus and Tract contain? |
Sensory fibers derived from |
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What is the vertical extent of the Solitary Tract and Nucleus? |
It extends rostrally to just above the level of CN X, and caudally to around the level of the Decussation of the Pyramids |
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What type of input does the Spinal Trigeminal Tract (and Nucleus) receive? |
It receives General Afferent fibers from, primarily, CN V, as well as CN IX and X. |
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What is the vertical extent of the Spinal Trigeminal Nucleus and Tract? |
It extends rostrally to the mid-pons, and caudally down into the cervical spine. |
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What is the role of the Vestibular Nuclei? |
They mediate information about balance and equilibrium, and coordinates head and eye movement in part by projecting axons via the Medial Longitudinal Fasciculus (MLF). |
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What is the source of axons for the Medial Longitudinal Fasciculous? |
The Vestibular Nuclei. |
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What type of signal is carried by the Medial Longitudinal Fasciculus? |
It carries mainly vestibular information that coordinates activities like the vestibulo-ocular reflex and gaze-holding. |
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What is the function of the Tectospinal Tract? |
It is involved in coordinating head and eye movements, similar to the MLF. |
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What is the source of axons for the Tectospinal Tract? |
It arrises from the contralateral Superior Colliculus. |
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What is the extent of the Tectospinal Tract? |
It descends from the contralateral Superior Colliculus all the way through the brainstem and to the cervical spinal cord. |
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What signals do the Vestibular Nuclei receive? |
They receive input from the vestibular apparatus |
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How many nuclei are included in each Inferior Olive? |
Three: |
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What sources give input to the Inferior Olives? |
They receive inputs from: |
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What fibres do the Olivary Nuclei give off? Where do they go? |
They give rise to Olivocerebellar Fibres, which cross the midline and enter the Cerebellum via the Inferior Cerebellar Peduncle. |
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What is the Reticular Formation? |
An area of intermingled grey and white matter occupying the central region of the brainstem throughout its extent. |
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What does the Reticular Formation do? |
It influences many things: |
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Where does the Lateral Lemniscus derive its fibres? |
A variety of sources: |
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What is the Lateral Lemniscus a portion of? |
It is a portion of the auditory pathway. |
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Where do the ascending fibres of the Lateral Lemniscus terminate? |
They terminate in the Inferior Colliculus. |
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What nucleus is indicated by the red arrow? |
The Facial Motor Nucleus. |
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What does the Facial Nucleus innervate? |
It provides motor innervation to the muscles of facial expression. |
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What surface feature do the does the Genu of the Facial Nerve form? |
It forms the Facial Colliculus seen in the floor of the Fourth Ventricle. |
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Where does the Facial Nerve exit the Brainstem? |
After encircling the Abducens Nucleus, they continue ventro-laterally toward their exit at the lateral margin of the ponto-medullary junction. |
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What nucleus is indicated by the red arrow? |
The Abducens Nucleus. |
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What does the Abducens Nucleus innervate? |
It provides motor innervation to the Lateral Rectus muscle of the eye. |
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Where do the fibres of CN VI exit the Brainstem? |
They exit medially on the ponto-medullary junction. |
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What nucleus is indicated by the green arrow? |
The Locus Ceruleus. |
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What system is the Locus Ceruleus a part of? |
It's a component of the Reticular Formation. |
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How many nuclear groups are associated with the Trigeminal Nerve? |
Four (3 sensory; 1 motor): |
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What does the Motor Nucleus of the Trigeminal Nerve innervate? |
It provides innervation to the muscles of mastication, through the Mandibular division of the Trigeminal Nerve. |
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What is the role of the Principal Sensory Trigeminal Nucleus? |
It mediates sensations of touch and pressure from various regions of the head. |
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What does the Mesencephalic Tract of CN V contain? |
It consists of of axons of the pseudounipolar neurons which make up the Mesencephalic Nucleus. |
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What type of sensation does the Mesencephalic Nucleus of CN V mediate? |
It mediates Proprioceptive information, particularly from the Temporomandibular Joint and the teeth. |
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Where do the Corticopontine Fibres originate? |
They originate from Frontal, Parietal, and to some extent Occipital regions of the Cerebral Cortex. |
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Where do the Corticopontine terminate? |
They terminate by synapsing on the Pontine Nuclei. |
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Which of the Cerebellar Peduncles carries mostly efferent fibres from the Cerebellum? |
The Superior Cerebellar Peduncle (it has very few afferent). |
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What happens to the fibres of the Superior Cerebellar Peduncle at the level of the rostral Pons and the caudal Mesencephalon? |
They undergo a decussation. |
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