Control L6 brainstem and intro to the cerebellum Flashcards
What are the general functions of the brainstem?
conduit and relay of signals
integration of pathways
Contains reflex centres and nuclei of cranial nerves
What are some behaviours/functions controlled by the brain stem?
Consciousness
Cardiovascular functions
Respiratory functions
Perception of pain
Influences motor patterns including balance, posture and muscle tone
What components of the ventricular system run through the brainstem?
Fourth ventricle and the cerebral aquaduct
What are the brain areas surrounding the brain stem?
Midbrain continuous with dienchephalon rostrally
Spinal cord caudally (continuous with the medulla at the level of the foramen magnum)
Clivus of the occipital bone ventrally
Cerebellum dorsally
What are the three sub divisions of the brainstem?
Midbrain
Pons
Medulla oblongata
What part of the brainstem do 10/12 of the cranial nerves come from?
Tectum
What cranial nerves emerge from the CNS not the brainstem?
Cranial nerves I and II
Which part of the nervous system are cranial nerve III - XII a part of?
Peripheral nervous system
What are the three areas of the brainstem?
Tectum
Tegmentum
Basal area
Where in the brainstem is the tectum found?
Posterior to the ventricular system
What areas of the brainstem are anterior to the ventricular system?
Tegmentum
Basal area
What travels down through the basal area?
Descending motor pathways
What travels/emerges from the tectum?
Cranial nerves III-XII
What area is in the pons?
The basal area
What is the pontomedullary junction?
Division between the medulla and the pons
Where is the anterior median fissue seen on the brainstem?
Ventral view on anterior surface of the medulla
What are the bulges that surround the anterior median fissue?
Pyramids of the medulla
What travels beneath the pyramids of the medulla?
Descending motor axons
What is the point where the anterior median fissue disappears called?
Decussation of the pyramids
What happens at the decussation of pyramids?
The nerve fibres cross over (as left brain supplies right body and vice versa)
What is found laterally to the pyramids of the medulla?
The olives of the medulla
What marks the division between the olives and pyramids of the medulla?
Anterolateral sulcus
What nerve fibres emerge at the anterolateral sulcus?
Cranial nerve XII
What nerves emerge laterally to the olives?
IX, X and some fibres of XI
What is the name of the area where cranial nerves IX, X and some fibres of XI emerge?
Posterolateral sulcus
What is the diamond shape seen in the dorsal view of the brain stem?
Floor of the 4th ventricle
What runs in the midline of the medulla seen from a dorsal view?
Posterior median fissure
What are the elevations either side of the posterior medulla fissure called?
Gracile fascicle
What are fasicicles?
Groups of axons
What sit laterally to the gracile fascicles?
The cuneate fascicles
What are the tubercles at the top of the gracile and cuneate fascicles called?
The gracile and cuneate tubercles respectively
What is contained in the gracile and cuneate tubercles?
Cell bodies
What is the rostral medulla also called?
Open medulla
Why is the rostral medulla called the open medulla?
It opens to the 4th ventricle
What is another name for the caudal medulla? Why?
Closed medulla - a membrane separates it from the 4th ventricle
What is the area where the fourth ventricle connects to the central canal of the spinal cord called?
Obex
What part of the medulla are the gracile and cuneate tubercles found?
Closed/caudal medulla
What part of the medulla are the olives found?
The open medulla
What part of the medulla are the pyramids found?
Both open and closed medulla
What is contained in the olives?
Nucleus
What connects the cerebellum to the brain stem?
Inferior cerebella penduncles?
What is the pontomesencephalic junction?
Where the medulla becomes the pons
What is the structure of the pons and its relation to the cerebellum?
Horizontal/transverse fibres that allow the hemispheres of the cerebellum to communicate
What is the groove in the middle of the horizontal fibres over the pons called?
The basilar groove
What nerve emerges from the middle of ventral pons?
Sensory and motor root of cranial nerve 5
What is the area called where the pons meets the cerebellum?
Cerebellopontine angle
What nerves emerge from the cerebellopontine angle?
Cranial nerves V, VI, VII and VIII
Where does cranial nerve VI emerge?
Pontomedullary junction
What are the three cerebella peduncles?
Superior, middle and inferior
What is the bump seen in the middle of the floor of the 4th ventricle called?
Facial colliculus
What sits in the basilar groove?
The basilar artery
What is the name for the descending motor fibres in the pons?
Corticospinal fibres
Why do the corticospinal fibres look less organised in the pons compared to the medulla?
They are interrupted by horizontal fibres so are less organised
Where does the cerebral aqueduct begin?
At the level of the rostral pons
What sits below the facial colliculus?
Nucleus of cranial nerve VI and fibres of cranial nerve VII which wrap around it
What separates the pons from the midbrain?
The pontomesencephalic junction
What connects the brain stem with the cerebrum?
Cerebral peduncles
What sits in between the cerebral peduncles?
The interpeduncluar fossa containing the mammillary bodies of the hypothalamus
Where does cranial nerve III emerge?
Interpeduncular fossa
Where does cranial nerve IV emerge?
Dorsal surface of the midbrain (wraps around to emerge anteriorly)
What are the four bumps seen in a dorsal view of the midbrain?
The paired superior colliculus and inferior colliculus
What connects the superior and inferior colliculus to the thalamus?
The brachium of the superior and inferior colliculus
What connects the cerebral peduncle to the tegmentum?
The substantia nigra
What area of the brainstem are the superior and inferior colliculus of the medulla?
The tectum
What is the reticular formation?
A complex, diffuse and multi synaptic network of neurones within the tegmentum of the brainstem
What makes up the reticular formation?
Reticular nuclei
Vital autonomic centre
Ascending reticular activating system (ARAS)
Pain modulation centre
Sleep wake cycle
Arousal centre
What is the role of the reticular nuclei?
Gives rise to the reticulospinal tract to send descending motor fibres for voluntary motion, breathing and consciousness
What is the role of the vital autonomic centres?
Vital respiratory and cardiovascular functions e.g. heart rate and breathing
What is the role of the ascending reticular activating system (ARAS)?
Travels to the cortex arose the brain into consciousness
How will patient’s with damage to the ARAS present?
In a coma as they cannot gain consciousness
What arteries supply the brainstem?
Superior cerebellar (SCA)
Basilar - including lateral pontine arteries
Anterior inferior cerebellar artery (AICA)
Posterior inferior cerebellar artery (PICA)
Vertebral arteries - lateral and paramedian branches
