Brain Stem and Cranial Nerves Flashcards
What is the function of the brain stem?
Highway for afferent and efferent information between the spinal cord and brain
What are the three structures of the brain stem?
Medulla, pons, and midbrain
What are the four ascending tracts through the brainstem?
Spinothalamic, dorsal column, spinocerebellar, and trigeminal lemniscus
What are two main descending motor tracts?
Corticospinal - not modified
Corticobulbar - synapse with cranial nerves
What cranial nerve is located in the thalamus?
Optic nerve (II)
What cranial nerve is located in the midbrain?
Oculomotor nerve (III)
What cranial nerves are located in the pons?
Trigeminal nerve (V), abducens nerve (VI), and facial nerve (VII)
What cranial nerves are located in the medulla?
Trigeminal nerve (V), facial nerve (VII), vestibulococchlear nerve (VIII), glossopharyngeal nerve (IX), vagus nerve (X), and hypoglossal nerve (XII)
What cranial nerve is located in the spinal cord?
Spinal accessory nerve (XI)
What structure is the medulla continuous with?
Spinal cord
Where does cranial nerve V synapse?
Inferior medulla
What percentage of corticospinal tract axons cross at the medulla pyramids?
85%
What is the function of the upper medulla?
Sends information from the medulla to the cerebellum
What is the function of the medulla?
CV control, breathing, head movement, and swallowing
Where is the pons located?
Between the midbrain and the medulla
What descending tracts does the pons carry?
Corticospinal and corticobulbar tracts
What is the posterior section of the pons called?
Tegmentum
Where is the origin point of the cranial nerves?
Lower pons
What does the midbrain connect?
Pons and the diencephalon
What are the three regions of the midbrain?
Basis pedunculi (ventral), tectum (middle), tegmentum (dorsal)
What are the four main pathways of the brainstem and what type are they?
Corticospinal tract (descending), dorsal columns/medial lemniscus (ascending), spinothalamic tract (ascending), and spinocerebellar tract (ascending)
What sections of the brainstem are only three of the four tracts visible?
Pons and midbrain - corticospinal tract, dorsal column/medial lemniscus, and spinothalamic tract
What are the five brainstem nuclei and what are their functions?
- Ventral tegmental area - produces dopamine
- Pedunculopontine nucleus - influences movement
- Raphe nuclei - (along midline) - mood, sleep, feeding/satiety, and pain
- Locus ceruleus - produces norepinephrine - arousal, stress, anxiety, depression, and PTSD
- Medial reticular area
What is the function of the brain stem reticular formation?
Regulates input and output to all parts of the CNS - control of movement, pain pathways, autonomic reflex circuitry, arousal, and consciousness
