Brain stem & cranial nerves Flashcards
What structures form the brainstem?
Medulla oblongata, pons and midbrain
Which foramen does the brainstem traverse out of the cranium?
Foramen magnum
What structure is the midbrain continuous with, rostrally?
Diencephalon
Which cranial nerves are contained within the brainstem?
Nerves 3-12, except XI
How is the cerebellum connected to the brain?
3 cerebellar peduncles
What is the term for roof to the brainstem?
Tectum
What is the term referring to the central grey matter region on either side of the cerebral aqueduct?
Tegmentum
Which midbrain anterior structure contains the descending and ascending tracts?
Cerebral peduncles
How are the cerebral peduncles separated?
Substantia nigra
Where are the superior and inferior colliculi located?
Posterior midbrain
Which two cranial nerve emerges from the midbrain?
Cranial nerve (III) = Oculomotor Cranial nerve (IV) = Trochlear
Which cranial nerve emerges from the anterior aspect of the midbrain?
Oculomotor nerve (III)
Which cranial nerve emerges from the posterior aspect of the midbrain?
Trochlear cranial nerve (IV)
Where is the pineal gland located?
Posterior midbrain
Where is the optic chiasm located in the midbrain?
Anterior aspect
Where is the mammillary body located along the brainstem?
Superoanterior aspect of the brain.
Where along the brainstem is the ventricular system more defined?
Defined within the pons, opening into the fourth ventricle, posteriorly.
Which structure does the pons open up into?
Fourth ventricle
What connects the cerebellum to the pons?
The middle cerebellar peduncles
Which cranial nerves emerge from the pontine nuclei?
5-8
Trigeminal, abducens, facial, vestibulocochlear
Where do the major descending tracts traverse through?
Cerebral peduncles
What are the two medullary sections?
Open (upper)
Closed (Lower)
Which ventricle is exposed in the open medulla?
Fourth ventricle
Which cranial nucleus is present in the open medulla?
Inferior olivary nucleus
Which cranial nerves emerge from the upper medulla?
glossopharyngeal (IX)
Vagus (X)
Hypoglossal (XII)
Which posterior tracts do the dorsal columns pass through?
Gracile and cuneate tracts
Where do second order neurones decussate to the contralateral side
Medullary pyramids
Where do second order neurones terminate?
Thalamus
Where are the medullary pyramids located within the medulla?
Anterior surface
Which tracts traverse through the anterior medullary pyramids?
Descending motor tracts
Corticobulbar, corticospinal
What structure characterises the lower closed medulla?
The central canal
Which blood vessels supply the cerebral hemispheres?
Derives fro the internal carotid system
Circle of Willis
Which blood supply arises posteriorly?
Emanates from the vertebral basilar arteries
Which two blood systems does the Circle of Willis connect?
Internal carotid
Vesterbro-basilar systems
Which two distinct branches bifurcate from the right and left internal carotid arteries?
Anterior and middle cerebral artery
How are the anterior cerebral arteries connected?
Anterior communicating artery
Where is the vertebrobasilar system located?
Located posteriorly, including the paired vertebral arteries than conform into the basilar artery
What is a cranial nucleus?
Collection of cell bodies (grey matter) in the brainstem.
Axons transmit information to and from the crania nerves from a synapse
Which nucleus contains cell bodies for oculomotor nerve?
Edinger-Westphal
What is the function of CN(III)?
Motor function to levator palpebral superiors, Superior rectus Medial rectus Inferior rectus Inferior oblique papillary reflex
What are the parasympathetic functions of the oculomotor nerve?
Motor to sphincter pupillae, ciliary muscles for accommodation
What are the motor functions of the trochlear nerve?
Motor to superior oblique.
Which 4 nuclei contain the cell bodies of the trigeminal nerve?
Mesencephalic
Chief
Spinal
Motor
What is the function of the trigeminal nerve?
Proprioception from muscles of mastication
Discriminative touch and vibration from head
Pain and temperature from the head
Motor to muscles of mastication
What is the function of the abducens nerve?
Motor to lateral rectus
What is the function of the facial nerve?
Motor to muscles of facial expression
Sensory from auditory meatus and skin posterior to ear
Parasympathetic motor to lacrimal, submandibular, sublingual glands, and mucous glands, glands of mouth and nose
Taste from anterior 2/3 tongue
What is the function of the vesitbulocochlear nerve?
Balance and hearing
What is the function of the glossopharyngeal nerve?
General sensation from posterior 1/3 tongue, tonsil, skin of external, internal surface of tympanic membrane, pharynx
Chemoreceptors and baroreceptors in the carotid body, visceral afferent information from tongue and pharynx (gag)
Taste from posterior 1/3 of tongue
Motor to stylopharyngeus
Parasympathetic to parotid gland
What is the function of the Vagus nerve?
Sensory from posterior meninges, external acoustic meatus, and skin posterior to the ear
Sensory from the larynx, trachea, oesophagus, thoracic, abdominal viscera, stretch receptors in aortic arch, chemoreceptors in aortic bodies adjacent arch
Sensory from taste buds in epiglottis
Motor to pharyngeal muscles and intrinsic muscles of the larynx
Parasympathetic to smooth muscles and glands of the pharynx, larynx, and thoracic and abdominal viscera.
Cardiac muscles
What is the function of the hypoglossal nerve?
Hyoglossus, genioglossus, styloglossus and all intrinsic muscles of the tongue.
