Brainstem and Cerebellum Flashcards
What are the 3 broad functions of the brainstem?
- Conduit: Allows passage of long pathways between the brain, brainstem, thalamus, cerebellum and spinal cord
-
Integrative:
- Reticular formation: control of consciousness, cardiovascular and, respiratory functions, perception of pain.
- Influences motor patterns (e.g. balance, posture, muscle tone)
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Cranial nerves:
- Contains the nuclei of Cranial Nerves III to XII
- Head’s equivalent to spinal nerves plus sight, hearing, equilibrium and gustation
- Reflex centres

What is the reticular formation?
- A set of interconnected nuclei that are located throughout the brainstem. It is not anatomically well defined, because it includes neurons located in different parts of the brain.
- The neurons of the reticular formation make up a complex set of networks in the core of the brainstem that extend from the upper part of the midbrain to the lower part of the medulla oblongata.
What composes the brainstem?
- Midbrain
- Pons
- Medulla oblongata

What is the brainstem continuous with rostrally?
The midbrain is continuous with the diencephalon (D)

What is the brainstem continuous with caudally?
Medulla is continuous with the spinal cord (SC) at level of the foramen magnum

What is the brainstem continuous with ventrally?
The clivus of the occipital bone

What is the brainstem continuous with dorsally?
The cerebellum

Running through the brainstem are components of the ventricular system. What are these components?
- IVth Ventricle (IVth) - between the pons/medulla anteriorly and cerebellum posteriorly
- Cerebral aquaduct (Caq) - at the level of the midbrain

How many cranial nerves arise from the brainstem?
10 out of 12 cranial nerves - these are part of the PNS and have motor and sensory parts (somatic and autonomic)
Revision of development from neural tube


At any level of brainstem, what 3 areas can be identified?
- Tectum (blue)
- Tegmentum (purple)
- Basal area (red)

Where is the tectum found?
The most dorsal area (roof) –> posterior to the ventricular system

Where is the tegmentum found?
Anterior to ventricular system

Where is the basal area found?
Most ventral part of brainstem

At the level of the midbrain, describe the locatio of the tectum, tegmentum and basal area in relation to cerebral aqueduct
- Tectum – located posterior to the cerebral aqueduct
- Tegmentum - anterior to cerebral aqueduct
- Basal - most ventral

Which area of the brainstem has most significant tectum?
Midbrain
What is found in the tegmentum?
- The tegmentum is the location of several cranial nerve (CN) nuclei
- Some pathways that pass through the brainstem
What is the basal area important for?
Descending motor fibres - fibres start in cortex and bring motor info down through the brainstem either to spinal cord, brainstem or cerebellum
What does locked in syndrome typically occur from? Why does it result in this syndrome?
- Results from stroke at level of pons
- Descending motor pathways are affected (in basal area)
- Paralysis of everything except eye movements
Why are most eye movements still intact in locked in syndrome?
Nerves that are responsible for eye movement arise above the pons
In locked in syndrome, why are people still able to breathe and heart is still functioning?
The tegmentum where we find these centres isn’t affected
What is the junction between the pons and the medulla called?
Pontomedullary junction (PMJ)

There are several structures visible on the anterior surface of the medulla. What are these?
- the three fissures/sulci
- the pyramids
- the olives
- five cranial nerves.
What fissure is found in the midline of the medulla?
Anterior median fissure - continuous along the length of the spinal cord.





























































