Brainstem Flashcards
What are the functions of the brainstem?
It has conduit, cranial nerve and integrative functions.
(1) CONDUIT- acts like a “pipe” to transfer info from the brain to the spinal cord and back.
(2) CRANIAL NERVE- the brainstem takes care of the sensory and motor functions for the head. The spinal cord does this function for the body
(3) INTEGRATIVE FUNCTIONS- reticular formation controls maintenance of consciousness
Unique features of the medulla.
- It has Pyramids, olives and is underneath about half of the 4th ventricle.
- Affiliated with the inferior cerebellar peduncles
Unique features of the pons.
- Has the basal pons which hangs down
- Affiliated with the middle cerebellar peduncles
- Found underneath part of the 4th ventricle
Unique features of the midbrain
- Affiliated with the superior cerebellar peduncles
- Affiliated with the cerebral peduncles
- Has the superior and inferior colliculi (2 superior, 2 inferior)
- Has cerebral aqueduct aka aqueduct of sylvius
How man cerebellar peduncles? How many cerebral?
3 cerebellar
1 cerebral
Where does the brainstem live?
It lives in the POSTERIOR FOSSA, which is composed of:
FLOOR- The occiput and some temporal bone
ROOF- tentorium cerebelli (sheet of dura)
What does fossa does CN III exit?
The interpeduncular fossa
Part of medulla which is not under the 3rd ventricle.
Closed medulla. Also known as caudal.
What does the cerebral aqueduct connect?
3rd ventricle to 4th ventricle
Superior colliculi general function? Inferior?
SUPERIOR- Vision
INFERIOR- Hearing
Superior cerebellar peduncle is associated with the…
Midbrain
Middle cerebellar peduncle is associated with the…
Pons
Inferior cerebellar peduncle is associated with the…
Medulla
Which cerebellar peduncle is the largest one?
Middle
Cerebellar peduncles are also known as…
Feet of the cerebellum. These are white fibers going to the cerebellum.
Which peduncle(s) are all afferent to the cerebellum?
Middle and Inferior
Which peduncle(s) are efferent from the cerebellum?
Superior– except for the ventral spinal cerebellar tract, which enters the cerebellum
“Slo-Aim”
SLO:
The SUPERIOR colliculi, talk to the LATERAL geniculate, which is dealing with OPTIC functions.
AIM:
The AUDITORY system uses the INFERIOR colliculi which communicate with the MEDIAL geniculate
Cerebral peduncles
Attach to the midbrain and connect the cerebrum with the brainstem and thus the spinal cord.
What is something most peduncles, both cerebral and cerebellar, have in common?
They consist of fibers which are mostly white matter (myelinated)
What does the olive of the medulla do?
Connects the dentate nucleus of the cerebellum.
What makes up the pyramids of the medulla?
They consists of pyramidal tract fibers of the CST. They decussate as the medulla becomes the spinal cord.
The 4th ventricle sits…
above the medulla and below the cerebellum
4th ventricle openings
Inferiorly (2)- The obex opens into the central canal
Superiorly (2)- The aqueduct of sylvius opens into it
What is the big nerve coming out of the Pons?
CN V
Cisterna magnum
Reflection of arachnoid where CSF can gather and then flow all over the CNS
What is significant about CN IV
It is the only CN to cross and come from the dorsum of the brainstem
Where does CN VI come from in relation to the brainstem?
The ponto-medullary juncture
Arbor vitae are associated with the…
Cerebellum
The 4th ventricle is what shape from above?
Diamond shaped
What is lateral to the 3rd ventricle?
The thalamus (one on either side)
What is the other name for the 4 colliculi?
Tectum
Mossy Fibers
Fibers which come from the pons and cross and go through the middle cerebellar peduncles
Most important bump on the floor of the 4th ventricle,
Facial colliculus
Where is the pineal?
It projects out near the back of the 3rd ventricle
Lateral geniculate nucleus
A relay center in the thalamus for the visual pathway. Receives a major sensory input from the retina.
Back of thalamus is also known as…
Pulvinar
Mammillary bodies
2 bumps on the ventral side of the brainstem which function in memory
CST
Corticospinal Tract
STT
Spinothalamic tract
ML
Medial lemniscus
ION
Inferior Olivary Nucleus
MCP
Middle Cerebellar Peduncle
SCP
Superior Cerebellar Peduncle
SCP X’s
Superior Cerebellar Peduncles Decussate
RN
Red Nucleus
SN
Substantia Nigra
IAF
Internal Arcuate Fibers- crossing fibers of the dorsal column pathway.
Nucleus gracilis handles what?
Lower extremities
Nucleus cuneatus handles what?
Upper extremities
Spinal Tract and Nucleus of CN V does what?
Relays pain and temperature from the head
The Spinal Nucleus of CN V is equivalent to what nucleus in the spinal cord?
Nucleus proprius
The spinal trigeminal tract descends from…
The pons (where CN V enters and exits) and runs down into the cervical cord to synapse on the spinal trigeminal nucleus. It relays pain and temperature from the head.
MLF
Medial Longitudinal Fasciculus
Pathway that runs down and connect the cranial nerves controlling eye movement and the vestibular system, allowing you to move your head in response to loud noises, flashes of light etc.
Deep Cerebellar Nuclei
Nuclei which sit deep in the cerebellum.
Fat Guys Eat Donuts
(1) Fastigial
(2) Globose
(3) Emboliform
(4) Dentate
Pontine Gray Nuclei
Diffuse Nuclei in the Pons
PAG
Peri Aqueductal Gray
Modulation of pain and Autonomic Functions
What does the medial lemniscus enter and how?
Enters the thalamus, upside down.
Where does the corticle spinal tract run? Where did it originate from?
- Runs in the center of cerebral peduncle.
- Originates from pyramidal cells of area 4 of the motor cortex.
Degeneration of _____ ______ plays a role in Parkinson’s disease
Substantia nigra (domaine producing cells)
Red nucleus deals with what kind of movements?
Gross.
If you see the red nucleus, you’re in…
Midbrain
Reticular Core
Involved in multiple functions:
- Control of movement
- Modulation of transmission of pain information
- Contains autonomic reflex circuitry
- The control of arousal and consciousness
Blue Dot
Locus Ceruleus. Contains noradrenalin (norepinephrine) and projects all over the brain.
Works to adjust the background level of sensitivity, deals with arousal/sleep, emotions etc.
Substantia nigra contains…
Dopamine
VTA
Ventral Tegmental Area
Contains Dopamine
Raphe cells contain…
Serotonin
What cells contain Acetylcholine
Neurons of the Rostral Brainstem and Basal Forebrain
What are the key nuclei in the basal forebrain that contain Ach?
Basal nucleus of Meynert and the Septal Nuclei
A lack of Acetylcholine is oft associated with…
Alzheimer’s disease
SE Raphe’s Substantial Dopey Blue NE’s
Mneumonic for…
Raphe- Serotonin
Substantia Nigra- Dopamine
Locus Ceruleus (blue dots)- Noradrenalin
Most important circle of willis vessel in regards to the medulla
PICA- which is a branch of the vertebral
3 Important Cerebellar Arteries
- Superior Cerebellar Artery (SCA)- comes off basilar
- Anterior Inferior Cerebellar Artery (AICA)- comes off basilar
- Posterior Inferior Cerebellar Artery (PICA)
Wallenberg Syndrome
Occurs following an occlusion of the posterior inferior cerebellar artery (PICA)
Characterized by sensory deficits affecting the torso and extremities on the OPPOSITE side of the infarction, and sensory deficits affecting the face and cranial nerves on the SAME SIDE as the infarct.
