Lecture 3 - Brainstem Anatomy Flashcards
The three functions of the brainstem are:
- It is a _______ for the travel of information between brain and spinal cord
- ________ _______ originate from here
- ________ _______: complex motor patterns and cardiorespiratory control (involves reticular formation)
- conduit
- cranial nerves
- integrative functions
3 main subdivisions of brainstem (inferior to superior)
- all notecards will proceed from inferior to superior
- medulla
- pons
- midbrain
When thinking of the brainstem, it is best to separate each of the 3 main subdivisions into ____ and ____ halves.
- rostral
- caudal
Medulla Anatomy:
The portion of the medulla that is closed and forms a continuous central canal with the spinal cord is the _____ end. The portion of the medulla that is open and connects the central canal to the 4th ventricle anterior to the cerebellum is the ______ end.
- caudal
- rostral
Medulla Anatomy:
The apex of the 4th ventricle where it narrows into the central canal of the medulla is called the _____.
obex
Medulla Anatomy:
At the junction of the brainstem and spinal cord, the anterior median fissure is interrupted by an area containing the corticospinal tract called the _____ ______.
pyramidal decussation
3 nuclei of the medulla
- nucleus cuneatus
- nucleus gracillis
- olivary nucleus
Medulla Anatomy:
At the anterolateral or preolivary sulcus, the rootlets of the _______ nerve exit the medulla. At the postolivary sulcus, lateral to the olive, rootlets of the ______ and ______ nerves emerge. The regions these nerves emerge from small swellings called ________.
- hypoglossal (CN XII)
- glossopharyngeal (CN IX)
- vagus (CN X)
- trigones
Medulla Anatomy:
The embryonic dividing line between ______ (medial) and ______ (lateral) fibers is known as the ______ ______.
- motor
- sensory
- sulcus limitans
Medulla Anatomy:
The ______ ______ is where the facial nerve loops over the abducens nerve to exit the brainstem.
facial colliculus
One of the main functions of the pons is to act as a conduit between the ______ and _____ with its “cross fibers.”
- cerebrum
- cerebellum
- cerebropontocerebellar pathway
Pons Anatomy:
The large bulges on the posterior surface of the pons used for communication with the cerebellum are called the _______ _______ _______ (MCP).
middle cerebellar peduncles
Pons Anatomy:
Entering at the midpontine level through the middle cerebellar peduncle (MCP) is the ________ nerve. Near the midline of the pontomedullary junction, the _____ nerve exits the brainstem.
- trigeminal nerve (CN V)
- abducens nerve (CN VI)
Pons Anatomy:
Lateral to the abducens (CN VI) at the pontomedullary junction, the _____ nerve exits in 2 parts: a medial ______ and lateral ______ portion.
- facial nerve (CN VII)
- motor
- sensory
Pons Anatomy:
Lateral of both CN VI and CN VII at the pontomedullary junction, the ______ nerve exits the brainstem. It 2 divisions: the medial _______, and lateral ________.
- vestibulocochlear (CN VIII)
- vestibular
- cochlear
Pons Anatomy:
A cerebellar output junction that forms the roof of the 4th ventricle and enters the brainstem at the junction of the midbrain and pons is the ______ ______ _______.
superior cerebellar peduncle
Pons Anatomy:
Band of fibers that covers the superior cerebellar peduncle in the rostral pons that is part of the ascending auditory pathway is the _______ ________.
lateral lemniscus
Midbrain Anatomy:
The channel in the midbrain that connects the 3rd and 4th ventricles is the _____ ______. It is a remnant of the embryonic _________, and drains _____.
- cerebral aqueduct
- mesencephalon
- CSF
Midbrain Anatomy:
The gray matter mass in the roof of the ROSTRAL midbrain that has eye-related functions is the _____ ___. The gray matter mass in the roof of the CAUDAL midbrain that has auditory functions is the _____ _____.
- superior colliculus
- inferior colliculus
Midbrain Anatomy:
Large bundles of WHITE matter at the base of the midbrain that contain tightly packed fibers from the cerebral cortex on their way to the brainstem and spinal cord are ______ ______.
cerebral peduncles
Midbrain Anatomy:
In the rostral midbrain, the nerve that controls extrocular muscles and preganglionic parasympathetic neurons for ciliary muscles is the ________ nerve.
oculomotor nerve (CN III)
Midbrain Anatomy:
In the caudal midbrain, the nerve that exits below the inferior colliculus and controls the superior oblique muscles is the ______ nerve.
trochlear nerve (CN IV)
Midbrain Anatomy:
The inferior colliculus has a projection towards the thalamus for the auditory pathway called the _____ ______.
inferior brachium
3 areas of all parts of the brainstem:
- tissue anterior to ventricles is the ________
- tissue posterior to ventricles is the _______ (“roof”)
- “_______”
- tegmentum
- tectum
- “stuff added onto anterior surface”
3 main fiber tracts in brainstem:
- anterior: ____________ tract
- anterolateral: ___________ tract
- central/anterior/variable: ____________ __________
- corticospinal
- spinothalamic
- medial lemniscus
The CAUDAL medulla extends from the caudal edge of the _______ _______ to the _______.
- pyramidal decussation
- obex
The ROSTRAL medulla extends from the caudal portion of the ______ to the lateral recess of the _____ ______.
- obex
- 4th ventricle
Caudal Medulla summary (4 parts):
- central canal
- gracillis and cuneate tracts
- internal arcuate fibers form medial lemniscus
- pyramidal decussation
Rostral Medulla summary (5 parts):
- 4th ventricle
- inferior olivary nucleus
- CN XII (hypoglossal)
- internal arcuate fibers form IO (inferior olivary nucleus) to ICP (inferior cerebellar peduncle)
- pyramids
The CAUDAL pons extends from the rostral wall of the lateral recess of the ______ _______ to the rostral edge of the ______ ______ _______ (attachment to cerebellum).
- 4th ventricle
- middle cerebellar peduncle
The ROSTRAL pons extends from the top of the _____ ______ _______ to the _______ ________.
- middle cerebellar peduncle
- cerebral aqueduct
Summary: the rostral pons contains the ______ ______ _______, while the caudal pons contains the ______ _____ ______ and ______ ______ _______.
- superior cerebellar peduncle
- middle cerebellar peduncle
- inferior cerebellar peduncle
The CAUDAL midbrain contains the _______ _______. The ROSTRAL midbrain contains the ______ _______.
- inferior colliculi
- superior colliculi
caudal midbrain summary (3 things):
- inferior colliculi
- CN IV (trochlear)
- decussation of SCP (superior cerebellar peduncle)
rostral midbrain summary (4 things):
- superior colliculi
- CN III (oculomotor)
- red nucleus (???)
- substantia nigra
The blood supplying the brainstem is part of the ______-______ system. Anterior and medial portions of the brainstem are also supplied by ______ branches.
- vertebral-basilar
- perforating
Exterior arteries wrapping around and supplying the lateral brainstem and cerebellum are _______ arteries.
circumferential
- includes SCA, AICA, PICA
Medial and lateral portions of the brainstem are often _______ affected in strokes (one side suffers more).
preferentially
Look at the picture on slide #42 for regional blood supply.
Just do it.
List the 12 cranial nerves in order.
- CN I = olfactory
- CN II = optic
- CN III = oculomotor
- CN IV = trochlear
- CN V = trigeminal
- CN VI = abducens
- CN VII = facial
- CN VIII = vestibulocochlear
- CN IX = glossopharyngeal
- CN X = vagus
- CN XI = accessory
- CN XII = hypoglossal
Which cranial nerve is somatic afferent for skin, muscles and joints of the head?
trigeminal (CN V)
Which cranial nerve is visceral afferent for the cranial, thoracic, and abdominal viscera?
vagus (CN X)
Which 2 cranial nerves are visceral afferent for taste buds?
- facial (CN VII)
- glossopharyngeal (CN IX)
Which cranial nerve is special afferent for the inner ear?
- vestibulocochlear (CN VIII)
Which 3 cranial nerves are somatic efferent for the extraocular muscles?
- oculomotor (CN III)
- trochlear (CN IV)
- abducens (CN VI)
Which cranial nerve is somatic efferent for the tongue muscles?
facial (CN VII)
Which cranial nerve is visceral efferent for the parasympathetic ganglia for cranial, thoracic, and abdominal viscera?
vagus (CN X)
Which cranial nerve is brachial efferent for the jaw muscles?
trigeminal (CN V)
Which cranial nerve is brachial efferent for the facial muscles?
facial (CN VII)
Which cranial nerve is brachial efferent for the laryngeal and pharyngeal muscles?
vagus (CN X)
Which 2 cranial nerves are brachial efferent for the middle ear muscles?
- trigeminal (CN V)
- facial (CN VII)
Which cranial nerve is brachial efferent for the SCM and trapezius muscles?
accessory (CN XI)
An axon that receives input for pain, temperature, or mechanical signals is _______ ______. It enters the spinal cord via the ______ root.
- somatic sensory
- dorsal
An axon that receives input from the GI tract or blood vessels is ______ _______. It enters the spinal cord via the ______ root.
- visceral sensory
- dorsal
A preganglionic autonomic axon is ______ ______. Enters the spinal cord via the _____ root.
- visceral motor
- ventral
An axon that innervates skeletal muscle is _____ _____. Enters the spinal cord via the _____ root.
- somatic motor
- ventral
Vision, smell, hearing, and equilibrium signals are received by _____ ______ neurons.
special sensory
Nerves supplying muscles derived embryologically from the pharyngeal arches are called ______ ______ neurons.
branchial motor
From most lateral to most medial in the brainstem, list the arrangement of the 6 neuron types:
- special sensory
- SA
- VA
- VE
- branchial efferent
- SE
- S = somatic; V = visceral; A = afferent/sensory; E = efferent/motor
Which 4 cranial nerves are exclusively somatic efferent (motor)?
- oculomotor (CN III)
- trochlear (CN IV)
- abducens (CN VI)
- hypoglossal (CN XII)
Which 3 cranial nerves are exclusively special sensory?
- olfactory (CN I)
- optic (CN II)
- vestibulocochlear (CN VIII)
Which 5 cranial nerves have mixed fibers, and are also “branchiomeric?”
- trigeminal (CN V)
- facial (CN VII)
- glossopharyngeal (CN IX)
- vagus (CN X)
- accessory (CN XI)
