Brainstem
What are the 3 portions of the brainstem?
Medulla oblongata, Pons, Midbrain
What is the purpose of the Medulla Oblongata?
To act as a relay center for both sensory and motor pathways (afferent and efferent)
What primary purpose does the pons serve in the NS?
To act as a bridge between the cerebrum and the cerebellum
What are the key Fxs of the midbrain in the NS?
To coordinate motor control, eye movements, auditory, and visual reflexes
What does cerebellum mean?
"little brain"
What is the general Fx of the brainstem?
To integrate and coordinate both CNS and PNS information, and regulate vital body Fxs (breathing, blood pressure, eye movement, heart rate, sleep, etc.)
As the spinal cord passes through the foramen magnum, what does its name change to (hint: it's a brainstem structure!)
Medulla Oblongata
What are some things that make up the anterior surface of the pons?
-Large bulging mass of white matter (myelinated axons)
-Forms the middle cerebellar peduncle (brachium pontis)
-Inferior and superior cerebellar peduncle
What are the 3 main regions of the midbrain?
-Tectum (roof)
-Tegmentum (central core)
-Basis pedunculi (crus cerebri)
What is the Fx of the cerebellum?
To contribute to the maintenance of equilibrium and coordination of skilled motor activity via modifying the cortical motor function (aka motor coordination)
From most dorsal to most ventral, what is the order of the 3 main portions of the brainstem? (Bonus points if you can tell me where the cerebellum and thalamus are in relation to the brainstem)
Midbrain, Pons, Medulla Oblongata
Name at least 2 cranial nerves that have connections in the medulla oblongata
CN IX (glossopharyngeal)
CN X (vagus)
CN XI (accessory)
CN XII (hypoglossal)
What is at least 1 Fx of the pons?
-House cranial nerve nuclei, ascending/ descending tracts, autonomic centers
-Roles in respiration, facial sensory/ motor control, hearing, and equilibrium
Does the ventral surface or the dorsal surface of the midbrain contain the corpora quadrigemina?
Dorsal surface
T/F: The cerebellum is responsible for balance and posture
True
What are at least 2 examples of brainstem reflexes?
Immediate and involuntary responses: cardiovascular reflexes, gag reflex, swallowing reflex, pupillary reflex, vestibulo-ocular reflex, and respiratory reflex
What are the 3 key pathways in the medulla/ spinal cord?
Corticospinal, dorsal column-medial lemniscus, and spinothalamic tracts
What are the 3 things that the dorsal surface of the pons consists of?
-Facial colliculus
-Median sulcus
-Striae medullares
What is the Fx of the lateral lemniscus?
Pons-->midbrain, processing of temporal aspects of sound (both onset and duration)
How is the cerebellum connected to the brainstem?
through 3 fiber bundles called "cerebellar peduncles" (superior, middle, inferior)
Which embryonic origin(s) does the anatomy of the brainstem arise from?
Mesencephalon-->midbrain
Rhombencephalon--> Metencephalon-->Cerebellum, Pons
Rhombencephalon--> Myelencephalon-->Medulla Oblongata
What is "pyramidal decussation"?
When the right and left pyramidal tracts cross over each other (ex. output from the right side of the brain goes to the left side of the body)
What is a neurological disease that can occur due to TBIs/damage to the myelin sheath/ curare poisoning?
Lock-in-Syndrome (LIS), from damage to the ventral pons
T/F: The reticular formation network is only located in the midbrain
False
What can manifest (pathology) as a result of damage to the cerebellum?
Ability to perform skilled and sequential movements; ex., tremors, movement paucity, ataxia, dysarthria, balance