Xiaoming Zhang

Zhejiang University

telencephalon

diencephalon cereb

ellum

mid-brain

pons pons myelencephalmyelencephal

onon

Brain Stem

The brain stem

Ⅰ. General features:

1. 3 parts: midbrain, pons and medulla

oblongata (from superior to inferior)

2. Position: spinal cord---Diencephalon--cerebellum

Ⅱ. External features:

1. Ventral surface of the brain stem

2. Dorsal surface of the brain stem

ventral surface

dorsal surface

Ⅲ. Internal structures:

A. General features:

Nuclei

cranial nerves Somatic motor nucleus:

oculomotor nucleus,

trochlear nucleus,

abducentis nucleus,

hypoglossal nucleus

Visceral motor nucleus:

motor nucleus of trigeminal n.,

facial nucleus,

ambiguus,

spinal accessory nucleus,

accessory oculomotor nucleus,

superior salivatory nucleus,

inferior salivatory nucleus,

dorsal nucleus of vagus n.

visceral afferent nucleus: nucleus of solitary tract

somatic afferent nucleus:Mesencephalic nucleus, pontine nucleus and spinal nucleus of trigeminal n. cochlear nuclei, vestibular nuclei

The non-cranial nerve nuclei

gracile nucleus,

cuneate nucleus

superior colliculus,

inferior colliculus

red nucleus,

substantia nigra

(dopamine)

white matter of brain stemThe long ascending and descending tractslong ascending tracts:1). Medial lemniscus(fine touch and proprioceptive sense)

2). Spinothalamic

Lemniscus

(superficial sensation)

3). Trigeminal lemniscus

(superficial sensation of

opposite side head and

facial )

4) lateral lemniscus

(Sense of hearing)

Descending tractsDescending tracts pyramidal system

①①corticospinal tract

lateral

anterior②②corticonuclear tract

formatio reticularis

keep waking state

nuclei of median raphe（（ 5-HT5-HT ）。）。

Thank You