The brain stem
description
Transcript of The brain stem
The brain stem
SHANDONG UNIVERSITY
Liu Zhiyu
The brain stem
Consists of Midbrain Pons Medulla oblongata
The brain stem
Position The brain stem occupies th
e posterior cranial fossa of the skull
Gross Appearance of the Brain Stem
Ventral Surface of the Brain Stem
Medulla oblongata Pyramid:
Composed of bundles of nerve fiber, pyra
midal tract Decussation of pyramid: Formed by crossing fibers of pyramidal tr
act Olive: Produced by underlying inferior olivary
nucleus Anterolateral sulcus : Emerge the roots of hypoglossal nerve Retroolivary sulcus : Emerge the roots of glossopharyngeal,
vagus and accessory nerves
Ventral Surface of the Brain Stem
Pons Basilar part Basilar sulcus Bulbopontine sulcus:
There emerge, from medial to lateral, the abducent, facial and vestibulocochlear nerves
Middle cerebellar peduncle Trigeminal nerve Emerges from the junction of basilar part a
nd middle cerebellar peduncles Pontocerebellar trigone: The junction of medulla, pons and cerebellu
m
Ventral Surface of the Brain Stem
Midbrain Crus cerebri Interpeduncular fossa
Oculomotor nerve emerges on the medial side crus cerebri
Posterior perforated substance
Dorsal Surface of the Brain Stem
Medulla oblongata Lower portion
Gracile tubercle: produced by underlying gracile nucleus
Cuneate tubercle: produced by underlying cuneate nucleus
Inferior cerebellar peduncle Obex
Upper portion: forms the lower half of rhomboid fossa
Dorsal Surface of the Brain Stem
Pons Superior cerebellar peduncle Superior medullary velum Trochlear nerve
Dorsal Surface of the Brain Stem
Midbrain Superior colliculus
Constitute centers for visual reflexes Inferior colliculus
Associated with auditory pathway Brachium of superior colliculus Brachium of inferior colliculus
Fourth ventricle
Position Situated ventral to cerebellum,
and dorsal to pons and cranial half of medulla
Central canal →fourth ventricle →mesencephalic aqueduct→third ventricle
Floor of the Fourth ventricle — Rhomboid Fossa
Boundaries Inferolateral: gracile and cune
ate tubercles, inferior cerebellar peduncle
Superolateral: superior cerebellar peduncle
Lateral recess
Floor of the Fourth ventricle — Rhomboid Fossa
Features Median sulcus Sulcus limitans Vestibular area Overlies vestibular nuclei Acoustic tubercle Overlying dorsal cochlear nucleus Medial eminence Striae medullares
Floor of the Fourth ventricle — Rhomboid Fossa
Facial colliculus Overlies nucleus of abducent n. and g
enu of facial nerve Hypoglossal triangle Overlies hypoglossal nucleus Vagal triangle Overlies dorsal nucleus of vagus ner
ve Funiculus separans Area postrema Locus ceruleus
Bluish-gray in color, it owes its color to a group of deeply pigmented nerve cells
Roof of the Fourth ventricle
Anterior part: Formed by superior cerebellar
peduncle and superior medullary velum
Posterior part: Formed by inferior medullary ve
lum and choroid plexus of fourth ventricle
Three apertures Median aperture of fourth ventri
cle Two lateral apertures of fourth v
entricle
Tela choroidea and choroid plexus
Internal structure of the brain Stem
Internal structure of the brain Stem
Central canal Gray matter
Cranial nerve nuclei Relay nuclei
White matter Reticular formation of brain stem
General somatic motor nucleiSpecial visceral motor nuclei
General visceral motor nuclei
Visceral sensory nuclei ( general and special )
General somatic sensory nucleiSpecial visceral motor nuclei
Cranial nerve nuclei
General somatic motor nuclei
Nucleus of oculomotor n. Nucleus of trochlear n. Nucleus of abducent n. Nucleus of hypoglossal n.
General somatic motor nuclei
Nucleus of oculomotor n. Nucleus of trochlear n. Nucleus of abducent n. N
ucleus 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
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, anterior belly of digastric, mylohyoid
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
Superior colliculus Nucleus of inferior colliculus Red nucleus Substantia nigra Pretectal area Superior olivery nucleus Pontine nucleus Nucleus ceruleus Gracile nucleus Cuneate nucleus Inferior olivary nucleus
Relay nuclei
Non-cranial nerve nuclei
Nucleus SiteSuperior colliculus Midbrain
Nucleus of inferior colliculus Midbrain
Red nucleus Midbrain
Substantia nigra Midbrain
Pretectal area Midbrain
Superior olivery nucleus Pons
Pontine nucleus pons
Nucleus ceruleus pons
Gracile nucleus Medulla (underneath gracile tubercle)
Cuneate nucleus Medulla (underneath cuneate tubercle)
Inferior olivary nucleus Medulla
White matter
Ascending tracts Medial lemniscus Spinothalamic tract ( Spi
nal lemniscus ) Trigeminothalamic tract ( Trige
minal lemniscus ) Lateral lemniscus
Ascending tracts
Spinal ganglion 1°neuron
Fasciculus gracilis
Fasciculus cuneatus
Gracile and cuneate nuclei2°neuron
Decussation of medial lemniscus
Medial lemniscus
VPL 3°neurons
Central thalamic radiation
T4
Medial lemniscus
Spinal ganglia1°neuron
Lamina , ~Ⅰ Ⅳ Ⅶ 2°neuron
Lateral spinothalamic tract
anterior spinothalamic tract
Spinal lemniscus
VPL 3°neurons
Central thalamic radiation
Ascending tracts
Spinothalamic tract
( Spinal lemniscus )
Trigeminal ganglion1°neuron
Pontine nucleus of V 2°neuron
Spinal nucleus of V 2°neuron
Trigeminal lemniscus
Spinal tract of trigeminal n.
VPM 3°neurons
Central thalamic radiation
Ascending tracts
Trigeminothalamic tract
( Trigeminal lemniscus )
Ascending tracts
Lateral lemniscus
Descending tracts
Pyromidal tract Corticospinal tract Corticonuclear tract
Rubrospinal tract Tectospinal tract Vestibulospinal tract Reticulospinal tract
Reticular Formation of Brain Stem
Ascending reticular activating system (ARAS)
Motor central and vital centres Reticulospinal tract Cardiovascular center 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 olivary nucu
leus 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 n
uclei
Midbrain
Rectum of midbrain Includes superior and inferior colliculi
Cerebral peduncle Tegmentum contain ascending tracts, mesencephal
ic aqueduct, 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
MidbrainRectum of midbrain Includes superior and inferior colliculi
Cerebral peduncle Tegmentum contain ascending tracts, mesencephalic a
queduct, central gray matter, red nucleus, 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