Study Guide Cranial Nerves Half Midterm #2 Flashcards
Control of the autonomic nervous system is from the ____
Hypothalamus as well as certain brainstem nuclei.
Efferent preganglionic axons are always myelinated and enter the PNS via the ____ root of the spinal nerve
Anterior/ventral
Ventral root carries motor/efferent somatic and autonomic information
Efferent/motor Arising from the neuron cell body is the post-ganglionic axon, which is always ____
Un-myelinated. This axon now travels to the effector.
All preganglionic sympathetic nerve fibers leave the spinal cord ___ from __ to __.
Anteriorly/ventrally from T1 to L2 (thoracolumbar). This means sympathetic nerves found anywhere in the body emerge from spinal nerves in this region.
Sympathetic nerve fibers destined from the head exit from T1.
Upon sympathetic nerve fibers entering the sympathetic chain, there are 3 possible destinations for the axon.
- Synapse with post ganglionic neuron immediately. The postganglionic axon then exits via the grey ramus to the spinal nerve, then to its destination.
- Ascend or descend in the sympathetic chain and synapse with a post ganglionic axon then exit via the grey ramus to the spinal nerve, then its destination.
- Pass through the sympathetic chain without synapsing, exiting via the splanchnic nerves. These preganglionic axons synapse within the prevertebral sympathetic ganglia of the abdomen (celiac, renal, superior and inferior mesenteric ganglia)
These divisions from the splanchnic nerves receive sympathetics from which divisions of the spinal cord?
- Greater
- Lesser
- Least
- Lumbar
- T5-T9
- T10 and T11
- T12
- L1 and L2
The parasympathetic cranial nerve nuclei are (4):
- Edinger-Westphal of the midbrain supplies the oculomotor nerve, CN III.
- Superior salvitory of the pons supply the facial nerve, CN VII.
- The Inferior salvitory of the medulla supplies the glossopharyngeal nerve, CN IX.
- The dorsal nucleus of vagus of the medulla supplies the vagus nerve, CN X
Parasympathetic ganglia associated with the head and neck
- Edinger Westphal - CN III - Ciliary ganglion
2, 3. Superior salvitory - CN VII- pterygopalatine and submandibular ganglion
- Inferior salvitory- CN IX - otic ganglion
Parasympathetic. Edinger-Westphal nuclei pathway
Edinger-Westphal
CN III
Goes to ciliary ganglion, which is behind globe
Innervates spinster and ciliary muscles of globe
Parasympathetic. Superior salvitory nuclei pathway
Superior Salvitory nuclei pathway.
CN VII
- Goes to pterygopalatine ganglion, which is inferior and posterior to orbit.
Innervates lacrimal and nasal glands. - Goes to submandibular, which is near the salivary gland.
Parasympathetic. Inferior salvitory nuclei pathway
Inferior salvitory
CN IX, glossopharyngeal
Goes to Otic ganglion, which is inferior to foramen vale
Innervates the parotid salivary gland
2 Plexi of the enteric nervous system
- Inner sub mucous plexus (Meissner’s) controls glandular secretions
- Outer myenteric plexus (Auerbach’s) controls smooth muscles of the digestive tract will
Parastalsis depends upon these plexuses, but can occur even in the absence of innervation from the CNS. The system controls itself, but the autonomic input helps modulate activity.
The somatic nervous system has one peripheral synapse at the neuromuscular junction. The axon is a ____
Nicotinic cholinergic axon (ACH)
Receptor for NE/Epi
Receptor for ACH
Adrenergic
Cholinergic- nicotinic or muscarinic
ALL preganglionic autonomic axons are ___
Nicotinic cholinergic axons
Parasympathetic pre and post ganglionic axon synapses
Pre: Nicotinic cholinergic (ACH)
Post: Muscarinic cholinergic (ACH)
-Ending on smooth muscle, cardiac muscle, or glandular tissue.
Sympathetic pre and post ganglionic axon synapses
Pre: Nicotinic cholinergic (ACH)
Post: For the most part, adrenergic (NE)
Brachial/pharyngeal arches (look at SVE fibers)
Arch 1- V3 Arch 2- VII Arch 3- IX Arch 4- X Arch 6- X, and XI(s)
Cranial nerve origins within the brain
Proencephalon
- Telencephalon (CN I)
- Diencephalon (CN 2)
Mesencephalon (CN 3, 4)
Telencephalon
- Mesencephalon (CN 5, 6, 7,
- Myelencephalon (CN 8-12)
Sensory nerves typically exit the brainstem __
Motor nerves typically exit the brainstem___
Laterally
Medially
CN I enters the anterior cranial fossa via the
Olfactory foramina found in the cribriform plate of the ethmoid.
CN II exits the orbit via the ___ into the ____ above the __
Exits via the optic canal into the middle cranial fossa above the cavernous sinus
CN III palsy looks like
Down and out. Since the only two muscles that CN III doesn’t innervate are the LR (out) and SO (down).
Pupil may be blown, mydriasis.
Aneurysms of the internal carotid artery in cavernous sinus associated. Epsilateral.