PNS Anatomy Flashcards

1
Q

PNS

A

-everything we sense consciously + unconsciously
-sensory division (afferent) + motor division (efferent)

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2
Q

sensory division (afferent)

A

somatic sensory and visceral sensory

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3
Q

motor division (efferent)

A

autonomic and somatic motor systems

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4
Q

autonomic motor system

A

parasympathetic (calming) and sympathetic (arousing)

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5
Q

somatic sensory

A

-afferent and how you experience world
-fingertips, pressure on soles of feet
-come out as portions of cranial nerves or spinal nerves and send out very myelinated axons out to effector organs
-do not go through the sympathetic chain

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6
Q

visceral sensory

A

-gut, liver, kidney
-not conscious of it all the time
-when things hit duandom, certain things are triggered with sensory input of small intestine

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7
Q

somatic motor system

A

-think and move hand
-send impulse and innervate muscles

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8
Q

autonomic motor system

A

-regulation of how we go through life
-includes sympathetic and parasympathetic divisions

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9
Q

parasympathetic system

A

-“rest and digest”
-brings everything down
-Acetylcholine is the primary neurotransmitter
Ex. meds utilize this like eye drops for glaucoma to constrict pupils
-long preganglionic fibers and short postganglionic fibers
-ganglia in or near effector organs
-pregangionlic fibers emerge from cranial or sacral regions of CNS
-preganglionic fiber exits spinal cord and travels long distance out to effector organ with ganglia where synapse occurs

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10
Q

sympathetic system

A

-“fight or flight”
-send resources to the right places at the right times
-involuntary but some pathways you can exert conscious control
-generally speaking unconscious and uncontrolled
-controls visceral organs, mostly involuntary
-2 neuron network but where synapse occurs matters
-short preganglionic fibers and long postganglionic fibers
-preganglionic fibers emerge from thoracic and lumbar regions
-also innervates adrenal medulla —> Epinephrine (adrenaline) is primary neurotransmitter
-upregulates body functions and ganglion is sympathetic chain that runs along spinal cord

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11
Q

ganglia in the parasympathetic system

A

-basilary ganglia- controls pupil
-pterygopalatine- provides sensation and regulates secretomotor functions for the mucous membranes of the nasal cavity, oropharynx, nasopharynx, and upper oral cavity
-submandibular- controls saliva secretion, which helps lubricate the oral cavity, aid in digestion, and make food easier to swallow
-otic- transmits parasympathetic and sympathetic fibers to the parotid gland

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12
Q

what nerves give parasympathetic innervations?

A

from brainstem:
-oculomotor
-facial
-glossopharyngeal
-vagus
from gut:
-pelvic

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13
Q

what does the vagus nerve do for parasympathetic contributions?

A

-helps with calming and regulatory pulses since we are constantly firing up the heart/slowing down, digestion, and adrenal gland
-single nerve has contributions on parasympathetic side to all of the viscera
-through evolution, the vagus nerve sits high and goes down low —> if you injure your spinal cord, you can still live since the vagus nerve is alive

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14
Q

sympathetic chain

A

-the sympathetic contributions start at T1 and goes down to L5
-innervation goes directly from chain to heart, stomach, liver, and other organs

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15
Q

how are nerves named?

A

-C1 is where the sympathetic trunk begins —> comes out between the skull and first vertebra
-7th cervical nerve is the spinous process
-C8 has a nerve above and below
-@ C7 you have switch from being named for the vertebra below to the vertebra above for thoracic and lumbar nerves

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16
Q

parasympathetic nerves vs sympathetic nerves

A

parasympathetic (rest and digest):
-constricts pupils
-stimulates saliva
-slow heartbeat
-constrict airways
-stimulate activity of stomach
-inhibit release of glucose; stimulate gallbladder
-stimulate activity of intestines
-contract bladder
-promote erection of genitals
sympathetic (fight or flight):
-dilate pupils
-inhibit salivation
-increase heartbeat
-relax airways
-inhibit activity of stomach
-stimulate release of glucose; inhibit gallbladder
-inhibit activity of intestines
-secrete epinephrine and norepinephrine
-relax bladder
-promote ejaculation and vaginal contraction

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17
Q

dorsal and ventral roots

A

-parasympathetic and sympathetic are only efferent
-motor is always associated with ventral root and dorsal root is always sensory

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18
Q

sympathetic chain

A

-ventral root meets dorsal root (motor and sensory) —> form the spinal nerve
-dorsal ramus (branch) and ventral branch that comes out
-sympathetic chain runs along spinal cord communicating with ganglion
-1st short pre-ganglionic fiber comes from lateral horn and travels through the rootlets, through the ventral root into the spinal cord proper —> white ramus into ganglion

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19
Q

three paths that the post-ganglionic fiber will take

A
  1. leave ganglion through gray ramus communicans out to body through dorsal or ventral ramus to effector organ
  2. head up or down on sympathetic chain —> synapses and the post-ganglionic fiber goes through gray ramus into nerve and out into body
  3. through sympathetic trunk ganglion out to splanchnic nerve —> ganglion into gut
20
Q

dorsal root ganglion

A

always sensory whether talking visceral or somatic

21
Q

spinal nerves

A

-31 pairs of spinal nerves
-@ C8, you have a nerve above and below
-C1-C8 are the cervical nerves
-T1-T12 are the thoracic nerves
-L1-L5 are the lumbar nerves
-S1-S5 are the sacral nerves
-one coccygeal nerve

22
Q

intercostal nerves

A

-veins and arteries that run along intercostal will be in the same nerve, artery, and vein bundle (NAV)
-plural tap with needle need to make sure you do not go through the vessel or nerve

23
Q

blown disk in spinal cord

A

-intervertebral disk has anular ring with gel-like material in the middle that deteriorates with age —> this is why we shrink as we get older since the disks become less cushiony
-anular ring becomes disrupted and the gel slips out
-pulp pushes on either the dorsal or ventral root and causes issues with motor or sensory or both —> need to go in and trim away pulp to relieve pressure

24
Q

nerve plexuses

A

-plexus is like an aerial view of a train yard with trains coming together and being re-routed
-nerve roots are coming in and sending appropriate sensory/motor nerves where they need to go
-cervical, brachial, lumbar, and sacral

25
Q

brachial plexus

A

-in the anterior armpit, underneath the clavicle
-upper arms are controlled predominantly by C4 to T1
-you have nerve fibers coming out and there is jumbling to get them where they need to go
-nerve fibers first hit the trunk and these trunks are very medial and transition into divisions then cords
Ex. radial nerve comes from posterior cord and ulnar comes from medial cord
Ex. ulnar nerve goes behind the ulnar —> feel it in your funny bone, which leads to pain in the pinky and half of your ring finger and arm

26
Q

median nerve

A

comprised of muscular and digital branches

27
Q

carpal tunnel

A

-reinaculum is really tough tissue and from bad posture you get bend that causes irritation in the median nerve —> inflammation
-starts this cycle that pinches off nerve and closes compartments
-in the beginning, clinicians can give wrist brace to reduce inflammation along with anti-inflammatory meds
-found often late, however, so they have to do surgery by opening the area up and cutting the flexor reinaculum to release the impingement for blood to flow

28
Q

dermatomes

A

areas mapped on surface of body that can be attributed to motor or sensory nerve roots

29
Q

Max Brödel

A

-artist who came to JHU to be a medical illustrator
-got sepsis from live tissue in the lb
-he had numbness in his arm and he mapped where he was feeling the pain —> ulnar nerve (C8)
-scar tissue impinging on the ulnar nerve so they went in and freed up the tissue

30
Q

Rini’s Shingles

A

-he thought he had poison ivy and felt like flu on his shoulder
-he had a minor case of shingles and got anti-virals
-herpes zoster which stays latent in tissue for decades then can erupt —> often in your 50s or older
-follows dermatome since the virus is in nerve tissue and is usually limited to one dermatome or a few
-often develop a rash and usually in the shape of a dermatome

31
Q

Rini’s Dad - T4/T5 Dermatome

A

-Rini’s dad was having market pain in his spine
-they ruled out shingles and he had a hard time walking —> took a bone scan and x-rays which showed that there was some radio opaque on the radiography, which they thought was bone cancer
-he perfectly described the T4/T5 dermatome so they had a neural consult and turned out he had osteophytes stenosis- bone growth that rubs on the nerves in the spine

32
Q

CN1 olfactory nerve

A

-all sensory with no motor
-bulbs on plate leading to nasal cavity
-damage to the olfactory nerve (I) can cause an inability to smell (anosmia), a distortion in the sense of smell (parnosmia), or a distortion or lack of taste

33
Q

CN2 optic nerve

A

-all sensory
-damage to optic nerve can cause disruption in vision
Ex. aneurysm pushing on optic nerve/chiasm there would be issues with the nerve —> they have to consider disrupting the nerve and those consequences
-does no motor for the eye

34
Q

CN3 oculomotor nerve

A

-motor
-damage can cause diplopia (double vision), outward turning of the eye (lateral strabismus), droopy eyelid (ptosis)
-innervates the levator palpebrae muscle
-look at the anatomy of the eye —> you can see it controlling the medial rectus muscle and if it is not firing, it causes the eye to drift outwards

35
Q

CN4 trochlear nerve

A

-motor
-damage can also cause double vision (diplopia) and eye cannot move downward and inward properly
-innervates the superior oblique muscle

36
Q

CN5 trigeminal nerve

A

-sensory and motor
-beefy nerve coming out of brainstem
-important for innervation of face
-comprised of opthalmic, maxillary and mandibular divisions
-damage can cause trigeminal neuralgia or cluster headaches
-only the mandibular division has motor component, innervating the muscles of mastication including the masseter and temporal muscles

37
Q

trigeminal neuralgia

A

-pressure or disruption on trigeminal nerve, most people report the pain
-very unusual pain where it’s like someone hit you with a taser
-if it can’t be treated with meds, they will go in to the foramen (which allows passage of the trigeminal nerve) and take needle to find where the nerve is coming from and use heat to fry the nerve fibers
-left side of the brainstem, near the posterior inferior cerebral artery between pons —> aneurysm can press on the trigeminal nerve so they will go in and place a cotton plegit between the vessel and nerve

38
Q

sphenopalatine ganglioneuralgia (brain freeze)

A

-cold liquid —> pain sensation (trigeminal nerve) and it is the body protecting the internal temp
-vessels dilate and cause pain —> feeling in the roof of mouth, which is referred pain

39
Q

CN6 abducens nerve

A

-only motor
-movement of eye
-inward turning of eye
-damage to the abducens can cause double vision (diplopia) and inward turned eye (medial strabismus)
-innervates lateral rectus muscle
-nerve gets flacid —> eye moves

40
Q

CN7 facial nerve

A

-motor and sensory
-helps with chewing, talking, and facial expressions
-damage can cause uni or facial palsy (inability to move facial muscles) but would still be able to crease forehead and raise brow since the frontalis muscle is innervated by right and left muscles
-if you have a cyst or tumor in the coratid gland —> clinicians have to be careful around this nerve

41
Q

CN8 vestibulocochlear nerve

A

-sensory
-damage to the nerve in the vestibular portion can cause dizziness, loss of balance, and disorientation and in the cochlear portion it can cause partial or complete hearing loss

42
Q

Rini’s Dad’s Hearing Loss

A

-went to sleep and woke up with loss of hearing in his right ear —> he would accommodate by moving his head to the good ear
-David interfaced with an expert on acoustic neuromas, which are benign tumors that arise in the Schwann cells around the nerves and brainstem in extreme cases
-David said that he thought his dad had issue with vestibulocochlear nerve —> turned out he had a small tumor on the acoustic part of the nerve

43
Q

CN9 glossopharyngeal nerve

A

-motor and sensory
-damage can cause difficulty swallowing
-sensory and motor innervation to oropharynx and back of tongue

44
Q

CN10 vagus nerve

A

-great wanderer- comes off brainstem and travels down through neck to the whole body
-disruption can cause issues with digestion and voice issues
Ex. opera singer got operated on and had hoarse voice after —> thought that they cut nerve off the vagus nerve that innervates the larynx but it was clear the surgeons were not near the nerve in the surgery

45
Q

CN11 accessory nerve

A

-innervation of sternocleidomastoid, trapezius, and levator scapulae muscle
-damage can cause winged scapula, inability to shrug shoulders, and weakness in the SCM muscle

46
Q

CN12 hypoglossal nerve

A

-motor
-innervates muscles of tongue, control movements of speech, food manipulation, and swallowing
-damage causes muscles of tongue to atrophy and tongue to move to one side