Medulla oblongata (Bulbus) Flashcards
nucleii
Grey matter
Reticular nuclei location
Midbrain and medulla and pons
Linked with awareness
Medulla oblongata contains autonomic centers, their purpose is
regulate respiration, circulation and gastrointestinal motility
Medulla oblongata Extends from to
pyramidal decussation to the inferior pontine sulcus
Medulla oblongata gives rise to cranial nerves
CN IX to CN XII
The nuclei of ……..CNs extend caudally into the medulla
CN V and CN VIII
Medulla oblongata Connected to the cerebellum by
the inferior cerebellar peduncle
Medulla oblongata Connects the ….. superiorly with ……. inferiorly
Pons
Spinal cord
Medulla oblongata extends from ……. to ……..
inferior pontine sulcus (lower pontine margin)
transverse plane above C1
Pontine
Related to pons
Most inferior point of medulla
Internal structure similar to spinal cord, changes rostrally
Dimensions of medulla oblongata
3 cm in length, 2 cm at its widest, sagittally 1.3 cm thick
Caudally; dorsal ( back side) surface of medulla oblongata
occupies the
mid-line notch between cerebellar hemispheres
Rostral upper part of medulla forms
lower half of floor of 4th ventricle (rhomboid fossa)
Central canal in medulla oblongata
prolonged into its lower half, expanding above as 4th ventricle
Anterior median fissure Continuous below with
spinal anterior median fissure
Anterior median fissure ends above with tev
(lower pontine border=inferior pontine sulcus) in small, triangular foramen caecum
Anterior median fissure is interrupted by
obliquely crossing fascicles of pyramidal decussation
Posterior median sulcus is present only in
closed part
Posterior median sulcus is Continuous below with
spinal posterior median sulcus
Posterior median sulcus ends at
mid-level of medulla, where central canal expands into 4th ventricle
What lies between anterolateral sulcus
anterior median fissure
Obex:
Walls of 4th ventricle unite in the most inf part of rhomboid fossa
Pyramid
elongated ridge
Pyramid contains….. fibers
ipsilateral corticospinal
pyramidal decussation
When 70-90% of corticospinal fibers cross in and deep to anterior median fissure
Hypoglossal n. Emerges from, and it’s nerve number
Anterolateral sulcus
12
• Accessory, vagus, glossopharyngeal emerge through and their numbers
posterolateral sulcus
11, 10, 9
Olive definition and location
Oval prominence in the upper part Between anterolateral –posterolateral sulci
Caudal part of Posterior region : Upward continuation of
fasciculi gracilis and cuneatus
gracile and cuneate tubercles (nuclei gracilis and cuneatus) are found in
Posterior region
Posterior intermediate sulcus is in posterior region of medulla oblongata and it divides the
gracile and cuneate tubercles
At the Caudal end of 4th ventricle; there are elongated swellings caused by
gracile and cuneate tubercles (nuclei gracilis and cuneatus)
Rhomboid fossa features (locate)
Median sulcus
• Median eminence • Sulcus limitans
• Vestibular area
• Striae medullares of 4th ventricle
• Hypoglossal trigone (hypoglossal motor nucleus)
• Trigone of vagus (dorsal vagal nucleus)
Inferior cerebellar peduncle
2 peduncles diverge and incline toentercerebellar hemispheres
Inferior cerebellar peduncle purpose
Connects the cerebellum to the caudal medulla oblongata
3 points that Connects the cerebellum to the caudal medulla oblongata
Inferior cerebellar peduncle
Middle cerebral peduncle
Superior cerebral peduncle
Tracts of Inferior cerebellar peduncle
Posterior spinocerebellar tract Anterior spinocerebellar tract Cuneocerebellar tract Olivocerebellar tract Vestibulocerebellar tract
Cranial n. nuclei
- Spinal tract and spinal nucleus of trigeminal nerve
- Nucleus of solitary tract (7,9,10)
- Nucleus ambiguus (9,10,11)
- Nucleus of hypoglossal nerve
- Inferior salivatory nucleus
- Dorsal nucleus of vagus nerve
- Medial vestibular nucleus
- Inferior vestibular nucleus
Spinal tract and spinal nucleus of trigeminal nerve contains
first-order neuron GSA fibers that mediate pain, temperature, and light touch sensations from the face and neck
Spinal tract and spinal nucleus of trigeminal nerve ascends up to …. and descends up to……..
pons superiorly
1st and 2nd segments of spinal column
trigeminal nerve number
5
Spinal tract of trigeminal nerve is located
and the nucleus is located
posterolateraly in medulla oblongata
medial to the tract
Tracts are … while nuclii is
White matter
Grey matter
solitary tract numbers
7,9,10
Nucleus of solitary tract
What type of fibers and what it conveys 7,9,10:
Aff fibers
Conveys gustatory information from lingual, palatal mucosa
SVA
Nucleus of solitary tract
What type of fibers and what it conveys: 9,10
aff fibres
Conveys sensory information from
larynx, pharynx, trachea, esophagus, thorax and abdominal viscera (GVA)
In the Nucleus of solitary tract The inferior endes of the two solitary nuclei fuse with each other and forms
commissural nucleus
Nucleus ambiguus Represents
special visceral efferent (SVE) cell column whose axons innervate pharyngeal arch muscles of the larynx and pharynx
The SVE fibers in Nucleus ambiguus contribute to
parts of CN 9 and CN 10
Inferior salivatory nucleus type of fibers and function and number
Efferent fibers
• Innervates parotid gland after a synapse at otic ganglion
9
Dorsal nucleus of vagus nerve number
10
Superior vestibular nuc. Lateral vestibular nuc location
Inferior vestibular nuc. Medial vestibular nuc.
Location
Pons
Bulbus
Superior vestibular nuc. Lateral vestibular nuc
Inferior vestibular nuc. Medial vestibular nuc. Are the parts of
Vestibular nucleii
Olive [inferior olivary nucleus] Associated with
voluntary movement
The cells of the inferior olivary nucleus send fibers medially across the midline to enter ….. through
the cerebellum through the inferior cerebellar peduncle
What type of fibers and where do they reach this nucleus from
Afferent fibers reach the nucleus from the spinal cord and from the cerebellum and cerebral cortex
Reticular nuclei parts
- Lateral reticular nuclei
- Ventral reticular nuclei
- Gigantocellular nucleus
- Parvocellular nucleus
- Paramedian reticular nuclei
- Raphe nuclei
Parts of raphe nuclie
– Obscurus – Pallidus
– Magnus
Reticular Formation (definition)
A mixture of nerve fibers and nuclei placed deeply posterior to olivary nucleus
RF is found in …. but also..
olivary nucleus
pons and midbrain
RF is a diffuse system related with
the awakenes of human body. be aware of external stimuli
Medial lemniscus are fibera thar form
flattened tract on each side of the midline posterior to the pyramid
Medial lemniscus emerge from the decussation of
and convey sensory information to
the lemnisci
the thalamus
(MLF)
Medial longitudinal fasciculus
MLF is situated beneath
the floor of the fourth ventricle on either side of the midline
MLF is the main pathway that connects
the vestibular and cochlear nuclei with the nuclei controlling the extraocular muscles
extraocular muscles
(oculomotor, trochlear, and abducens nuclei)
Arteries of medulla oblongata
Vertebral artery
Anterior spinal artery
PICA (Posterior inferior cerebellar artery)
The lateral part of medulla oblongata is supplied by
PICA (Posterior inferior cerebellar artery)
Pica is a branch of
vertebral artery
The medial part of medulla oblongata is supplied by
vertebralartery
Pons length, and it connects what
2.5 cm long
medulla of oblongata methencephalon to the midbrain