12 - Peripheral and Autonomic Nervous Systems

how to remember whether the cranial nerves have sensory, motor, or both functions

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in the sympathetic division of the autonomic nervous system, where do the preganglionic neuron cell bodies originate?

T1-L2 of the spinal cord

what is a ganglion?

a group of cell bodies in the PNS

what is a nerve plexus?

a network of interweaving spinal nerves

in the parasympathetic division of the autonomic nervous system, what does the pre-ganglionic neuron axon look like?(think about myelination, length, and branches)

myelinated, long, few branches

how to remember what cranial nerves have motor functions of the eye muscles?

nerves 3,4, and 6 make the eyes do tricks!

describe a monosynaptic reflex. what are some examples?

no interneurons; only 1 CNS synapse in the anterior horn. The sensory and motor neurons are in the same organ. Ex: when a muscle is stretched unexpectedly it contracts to help keep posture - like patellar or knee-jerk reflex.

what does the brachial plexus innervate?

pectoral girdle and upper limbs

where are sensory neuron axons found?

posterior root

in the sympathetic division of the autonomic nervous system, what does the post-ganglionic neuron axon look like? (think about myelination, length, and branches)

not myelinated, long, few branches.

in the parasympathetic division of the autonomic nervous system, what does the post-ganglionic neuron axon look like?(think about myelination, length, and branches)

not myelinated, short, few branches

in the somatic nervous system, how many somatic sensory neurons are there, and how many somatic motor neurons are there?

1 somatic sensory neuron, 1 somatic motor neuron

in the autonomic nervous system, how many visceral sensory neurons are there, and how many autonomic motor neurons are there? where are divisions?

1 visceral sensory neuron, 2 autonomic motor neurons. There is a preganglionic autonomic motor neuron and a postganglionic autonomic motor neuron. (p.99)

what spinal nerves are in the cervical plexus?

C1 - C4

what spinal nerves are in the brachial plexus?

C5-T1 (splits into musculocutaneous, median, radial, and ulnar)

what spinal nerves are in the lumbar plexus?

L1-L4

what spinal nerves are in the sacral plexus?

L4-S4

how to remember the order of the cranial nerves and what their names are.

Oh, Oh, Oh, To Take A Family Vacation; Go Vegas After Hours. Olfactory Nerve I, Optical Nerve II, Oculomotor Nerve III, Trochlear Nerve IV, Trigeminal Nerve V, Abducens Nerve VI, Facial Nerve VII, Vestibulocochlear Nerve VIII, Glossopharyngeal Nerve IX, Vagus Nerve X, Accessory Nerve XI, Hypoglossal Nerve XII

what is a dermatome? why are they important clinically?

a specific segment of skin supplied by a single pair of spinal nerves - you can tell where a spinal cord injury is by tapping different areas. Know the general areas (p.95)

in the autonomic nervous sytem, where is the postganglionic axon?

after the autonomic ganglion, in the PNS, going to the effector organ (smooth, cardiac, glands)

what does the sciatic nerve innervate and what plexus is it part of?

all of lower limb except anterior/medial thigh. Sacral plexus

where are motor neuron cell bodies found?

anterior horn

what does the cervical plexus innervate?

anterior neck and parts of head and shoulders

where are motor neuron axons found?

anterior root

in the autonomic nervous system, where is the preganglionic axon?

before the autonomic ganglion, in the PNS

what are the functions of glossopharyngeal nerve IX?

both. S - tase of posterior 1/3 of tongue. M - swallowing and saliva

what are the functions of facial nerve VII?

both. S - taste of anterior 2/3 of tongue. M - facial muscles, saliva, tears

what are the functions of vagus nerve X?

both. S - visceral sensation (thoracic and abdominal cavities). M - swallowing, 70% of parasympathetic

what are the functions of trigeminal nerve V?

both. S = face, teeth, and tongue. M = mastication

where do the preganglionic neuron cell bodies originate in the parasympathetic division of the autonomic nervous system?

brainstem (CN 3,7,9,10), and the sacral spinal cord

what are the 4 principal nerve plexuses?

cervical plexus, brachial plexus, lumbar plexus, sacral plexus

what is the defining feature of the autonomic nervous system?

chain of two motor neurons - preganglionic neuron and postganglionic neuron

in the parasympathetic division of the autonomic nervous system, where is the autonomic ganglion?

close to or within effector organ wall

in the sympathetic division of the autonomic nervous system, where is the autonomic ganglion?

close to the vertebral column

what innervates the anterior thigh muscles and what plexus is this a part of?

femoral nerve; lumbar plexus

in the autonomic nervous system, where is the preganglionic neuron cell body?

in the CNS (horns)

in the autonomic nervous system, where is the postganglionic (or just ganglionic) neuron cell body?

in the autonomic ganglion

besides dual innervation, what is another way that opposite effects on an organ can be achieved? example?

increasing or decreasing activity in the one division (sympathetic or parasympathetic) that innervates it. Ex: some blood vessels are not innervated by the parasympathetic nervous system, and so they are constricted (to increase blood pressure) when the sympathetic system is acting on them, and are dilated when the sympathetic system is NOT acting on them.

what is shingles? describe

initial infection of the chickenpox virus sometimes leaves the skin and invades the posterior root ganglia, where is remains latent until adulthood. Then if stress or something happens and it's activated, you get a rash of scaly, painful blisters on the dermatome(s) of the spinal nerve(s) infected

what does the lumbar plexus innervate?

lower limb

what does the sacral plexus innervate?

lower limb

what is the simplest of all reflexes?

monosynaptic reflexes

describe a polysynaptic reflex. what are some examples?

more than one CNS synapse involving interneurons within the reflex arc. it involves different organs. Ex: withdrawal reflex

what are the functions of oculomotor nerve III?

motor - ciliary muscle, pupil constriction, extrinsic eye muscles (except SOLR)

what are the functions of abducens nerve VI?

motor - lateral rectus (abducts eye)

what are the functions of accessory nerve XI?

motor - sternocleidomastoid, trapezius

what are the functions of trochlear nerve IV?

motor - superior oblique (it goes to the trochlea!)

what are the functions of hypoglossal nerve XII?

motor - tongue muscles

know where the cranial nerves are!! draw and label

p. 94

for dual innervation of the heart, what does the parasympathetic do and what does the sympathetic do?

parasympathetic - decreases heart rate sympathetic - increases heart rate

for dual innervation of the digestive system, what does the parasympathetic do and what does the sympathetic do?

parasympathetic - increases activities! churn! sympathetic - reduces activities

for dual innervation of the pupils, what does the parasympathetic do and what does the sympathetic do?

parasympathetic - pupil constriction sympathetic - pupil dilation

what innervates the diaphragm and what plexus is this part of?

phrenic nerve, part of cervical plexus

where are sensory neuron cell bodies found?

posterior/dorsal root ganglion

describe the steps of the reflex arc (draw and label)

receptor, sensory (afferent) neuron, interneurons, motor (efferent) neurons, effector. p. 98

what are the functions of vestibulocochlear nerve VIII?

sensory - hearing, balance

what are the functions of optic nerve II?

sensory - sight

what are the functions of olfactory nerve I?

sensory - smell

in the sympathetic division of the autonomic nervous system, what does the preganglionic neuron axon look like? (think about myelination, length, and branches) why?

short, branching, myelinated. Because it's fight or flight... need a widespread response, quickly, so you have branches

what are the divisions of the autonomic nervous system?

sympathetic (passion, fight or flight), parasympathetic (rest and digest)

be able to label the "M" of the brachial plexus

the gang sign - musculocutaneous, median, ulnar, radius (p.97)

what does the sciatic nerve split into and where? what plexus is the sciatic nerve part of?

tibial and common fibular nerve; sacral

what is dual innervation?

when organs are innervated by both sympathetic and parasympathetic divisions. This is true for most organs, and the two division often oppose each other.