Introduction to Cranial Nerves Flashcards
Compare and contrast a spinal nerve and a cranial nerve Be able to list the general functions of and the sites of “attachment” for the cranial nerves Understand the general layout of the cranial nerve nuclei in the brainstem and how it relates to the embryological development Be able to discuss (general) the role of the reticular formation and “pattern generators” in performing basic physiological functions Understand how cranial nerve information is processed in the CNS and how the nerves
Compare and contrast a spinal nerve and a cranial nerve
spinal nerves: 31 pairs (62 nerves)
- emerge from the spinal cord
- nerves carry motor and sensory information (visceral and somatic)
cranial nerves: 12 pairs (24 nerves)
- emerge from the forebrain or the brainstem
- carry motor, sensory (including special senses) or both
Be able to list the general functions of and the sites of “attachment” for the cranial nerves
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Understand the general layout of the cranial nerve nuclei in the brainstem and how it relates to the embryological development
Cranial nerve nuclei are located near the point where the nerve emerges
Knowing the location of the nerve along the brain/brainstem can help you guess where the corresponding nuclei should be located
Nuclei are arranged according to a plan established in the embryo
Understanding the general function of the nerve can help you locate the nuclei in a cross section
Reticular formation
diffuse “packing material,” critical for coordinating brainstem functions that support life including: arousal, respiration, swallowing, heart rate, BP, etc.
- not particularly devoted to any single modality, but performs more diffuse functions such as keeping you awake and breathing
Understand how cranial nerve information is processed in the CNS and how the nerves work individually and together to provide the CNS with information about the peripheral world
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Nerve cell locations
I: Telencephalon (Forebrain)
II: Diencephalon (Forebrain)
III, IV: Midbrain (Brainstem)
V, VI,VII,VIII: Pons (Brainstem)
IX,X,XI, XII: Medulla (Brainstem)
Pattern generators
An “autopilot” type of coordinated response
- Activated when a command comes down from motor cortex to a collection of brainstem neurons
- Neurons are wired together in a way such that pools of neurons are activated in the right order and timing to make something happen (e.g. chewing, swallowing, breathing, etc)
