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The brain stem. Liu jiao Binzhou Medical University Department Of Anatomy. The brain. Telencephalon Diencephalon Cerebellum Brain stem. Names of cranial nerves. Ⅰ Olfactory nerve Ⅱ Optic nerve Ⅲ Oculomotor nerve Ⅳ Trochlear nerve Ⅴ Trigeminal nerve - PowerPoint PPT Presentation
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The brain stem
Liu jiao
Binzhou Medical University
Department Of Anatomy
The brain
Telencephalon Diencephalon Cerebellum Brain stem
Names of cranial nerves Ⅰ Olfactory nerve Ⅱ Optic nerve Ⅲ Oculomotor nerve Ⅳ Trochlear nerve Ⅴ Trigeminal nerve Ⅵ Abducent nerve Ⅶ Facial nerve Ⅷ Vestibulocochlear nerve Ⅸ Glossopharyngeal nerve Ⅹ Vagus nerve Ⅺ Accessory nerve Ⅻ Hypoglossal nerve
The brain stem
Consists of Midbrain Pons Medulla oblongata
Medulla oblongataVentral surface Pyramid: contain pyramidal tr
act (corticospinal tract) Decussation of pyramid: form
ed by crossing fibers of corticospinal tract
Olive: produced by underlying inferior olivary nucleus
Anterolateral sulcus: rootlets of hypoglossal nerve emerge from it
Retroolivary sulcus: rootlets of glossopharyngeal, vagus and accessory nerves emerge from it
Medulla oblongata
Dorsal surface Lower portion
Gracile tubercle: produced by und
erlying gracile nucleus Cuneate tubercle: marks the site
of cuneate nucleus Inferior cerebellar peduncle Obex
Upper portion: forms the lower half of rhomboid fossa
PonsVentral surface Basilar part Basilar sulcus Bulbopontine sulcus :
from medial to lateral, the abducent, facial and vestibulocochlear nerves appear
Middle cerebellar peduncle Trigeminal nerve Pontocerebellar trigone :
the junction of medulla, pons and cerebellum
Pons
Dorsal surface Superior cerebellar pedu
ncle Superior medullary velu
m Trochlear nerve
Midbrain
Ventral surface Crus cerebri Interpeduncular fossa o
culomotor nerves emerge from medial of crus cerebri
Posterior perforated substance
MidbrainDorsal surface Superior colliculus con
stitute centers for visual reflexes
Inferior colliculus associated with auditory pathway
Brachium of superior colliculi
Brachium of inferior colliculi
Fourth ventricle
Position Situated ventral to
cerebellum, and dorsal to pons and cranial half of medulla
Central canal →fourth ventricle →mesencephalic aqueduct→third ventricle
Boundaries Inferolateral: gracile an
d cuneate tubercles, inferior cerebellar peduncle
Superolateral: superior cerebellar peduncle
Lateral recess
Features Median sulcus Sulcus limitans Vestibular area overlies vestibular nuclei
Acoustic tubercle overlying dorsal cochlear nucleus
Medial eminence Striae medullares
Facial colliculus: overlies nucleus of abducent n. an
d genu of facial nerve
Hypoglossal triangle: verlyi
ng hypoglossal nucleus Vagal triangle: overlies dorsal nucleus of vagus n
erve
Funiculus separans Area postrema Locus ceruleus
Roof Anterior part: formed by s
uperior cerebellar peduncle and superior medullary velum
Posterior part: formed by inferior medullary velum and choroid plexus of fourth ventricle
Three apertures Median aperture of fourth
ventricle Two lateral apertures of fo
urth ventricle
Internal structures
Gray matter Cranial nerve nuclei Relay nuclei
General somatic motor nuclei
Nucleus of oculomotor n. Nucleus of trochlear n. Nucleus of abducent n. Nucleus of hypoglossal n.
Nucleus Site Cranial n. Function
Nucleus of
Oculomotor n.
Midbrain Ⅲ Supreior, inferior,and medial recti, inf. obliquus, levator palpebrae superioris
Nucleus oftrochlear n.
Midbrain Ⅳ Superior obliquus
Nucleus of abducent n.
Pons Ⅵ Lateral rectus
Nucleus of hypoglossal n.
Medulla Ⅻ Muscles of tongue
General somatic motor nuclei
Special visceral motor nuclei
Motor nucleus of trigeminal n.
Nucleus of facial n. Nucleus ambiguus Accessory nucleus
Special visceral motor nuclei
Nucleus Site Cranial n. Function
Motor nucleus of trigeminal n.
Pons Ⅴ Masticatory muscles
Nucleus of facial n.
Pons Ⅶ Facial m., platysma, posterior belly of digastric, stylohyoid, stapedius
Nucleus ambiguus Medulla Ⅸ, .Ⅹ Ⅺ Skeletal m. of pharynx, larynx and upper part of esophagus
Accessory nucleus Medulla-cervical cord
Ⅺ Sternocleidomastoid, trapezius
General visceral motor nuclei
Accessory oculomotor nucleus
Superior salivatory nucleus
Inferior salivertory nucleus
Dorsal nucleus of vagus n.
General visceral motor nuclei
Nucleus Site Cranial n.
Function
Accessory oculomotor nucleus
Midbrain Ⅲ Sphincter pupillae and ciliary m.
Superior salivatory nucleus
Pons Ⅶ Submandibular, sublingual and lacrimal glands
Inferior salivertory nucleus
Medulla Ⅸ Parotid gland
Dorsal nucleus of vagus n.
medulla Ⅹ Many cervical, thoracic and abdominal viscera
Visceral sensory nuclei ( general and special ) Nucleus of solitary tract
Visceral sensory nuclei ( general and special )
Nucleus Site Cranial n. Function
Nucleus of solitary tract
Medulla Ⅶ, ,Ⅸ Ⅹ Taste and visceral sensation
General somatic sensory nuclei
Mesencephalic nucleus of trigeminal n.
Pontine nucleus of trigeminal n.
Spinal nucleus of trigeminal n.
General somatic sensory nuclei
Nucleus Site Cranial n. Function
Mesencephalic nucleus of trigeminal n.
Midbrain Ⅴ Proprioception of head
Pontine nucleus of trigeminal n.
Pons Ⅴ Tactile sensation of head
Spinal nucleus of trigeminal n.
Medulla Ⅴ Pain and temperature sense of head
Special somatic sensory nuclei
Cochlear nuclei
Vestibular nuclei
Special somatic sensory nuclei
Nucleus Site Cranial n. Function
Cochlear nuclei
Pons and medulla
Ⅷ Sense of hearing
Vestibular nuclei
Pons and medulla
Ⅷ Sense of equilibrium
Gracile nucleus Cuneate nucleus Inferior olivary nucleus Superior olivery nucleus Pontine nucleus Nucleus of inferior colliculus Gray matter layers of superi
or colliculus Red nucleus Substantia nigra Pretectal area
Relay nuclei
Non-cranial nerve nuclei Nucleus Site
Gracile nucleus Medulla (underneath gracile tubercle)
Cuneate nucleus Medulla (underneath cuneate tubercle)
Superior olivery nucleus Pons
Pontine nucleus pons
Nucleus of inferior colliculus Midbrain
Gray matter layers of superior colliculus
Midbrain
Red nucleus Midbrain
Substantia nigra Midbrain
Pretectal area Midbrain
White matter
Ascending tracts Medial lemniscus Spinal lemniscus Trigeminal lemniscus Lateral lemniscus
Medial lemniscus
Spinal lemniscus
Trigeminal lemniscus
Descending tracts
Corticospinal tract Rubrospinal tract Tectospinal tract Vestibulospinal tract Reticulospinal tract
Lateral lemniscus
Reticular formation of brain stem Ascending reticular a
ctivating system (ARAS)
Motor central and vital centres Reticulospinal tract Cardiovascular center an
d respiratory center Serotonergic rapheal
nuclei
The characters of internal structure of
brain stem
Medulla oblongataLower part (closed part) Two decussations–
Decussations of medial lemniscus Decussations of pyramid
Medulla oblongata
Upper part (open part) Appearance of inferior oliv
ary nuculeus and inferior cerebellar peduncle
Enlargement of central canal to form the fourth ventricle floor
Pons Tegmentum of pons directed upward continuation of me
dulla oblongata Basilar part contain both longitudinal and transv
erse fibers intermixed with pontine nuclei
Midbrain Rectum of midbrain: includ
es superior and inferior colliculi Cerebral peduncle
Tegmentum :
contain ascending tracts, central gray matter, recticular formation and so on Substentia nigra Crus cerebri :
Pyramidal tract middle three-fifths of the crus: Frontopontine tract medial one-fifth: pariatotempopontine tract lateral one-fifth