Anatomy Lecture #3 Flashcards
PNS
Extension of CNS
Includes everything except the brain + spinal cord (Ex. Cranial Nerves)
Function - Conduit for sensory going to and from the brain (responsible for everything we sense)
- Ties CNS to bodu
Division of PNS
Sensory Division
Things going from the brain to the body (AFFERENT)
Inlcudes:
1. Somatic input - Get impulses from body surfaces
2. Visceral sensory - Get input al of the time but we might not be aware of it (Ex. when food hits the diadnum in the small intestine –> Pancerues secretesthings and walls of disteive system constict – This occurs because we have sensory input in small intestine but we don’t feel that input)
Motor Division
Efferent - Things go out form brain to cause a response
Divides into:
1. Autonmoic motor system
2. Somatic motor system
Autonomic motor system
Includes involentary things
- We can exert some consicous control BUT generally it is unconciuous and uncontrolled
- Allows us to react before we think
Plays an improtant rile in regulation of body
Somatic motor system
CNS –> goes out to PNS –> goes to muscle
- Example - nerve goes to muscle
- Uses cranial and spinal nerves
Example - Think about moving our hand and move hand to grab something
Autonomic (Overall)
Impulses coming from Vicera (Vicera = smooth mucles in inetstines + upils + heart muscle etc.)
Divides into sympathetic and Parasympatheic
Parasympathetic vs. Sympathetic nervous system
Parasympathetic (calming - like PARACHUTE) - deregulates everything (brings everything to resting state)
Sympathetic (Fight or flight; arousing) - kicks in when scared (body is focused on what is needed to survive)
- Ex. you wait after you eat to swim because the bidy put blood in the digestuve to digest food but for swimming you would want profusion to the muscles (want resoures in the right place at the right time)
- To remeber - people sympathize with someone being eaten by an animal
***Both are counter to each other
Autonomic Nervous System definition
Controls viceral organs
Mostly involentray and subconcious level but can be infleuned by volentray control via somatic motor system (mostly unconcious but have some control)
Sympathetic + Parasympathtic affect on body
Sympathetic + Parasympathetic - innervates the blood vessles + smooth muscles + Organs + Viscera
BOTH work in opposition to one another (quick sympathetic repsonse vs. regulatory dampening parasympathetic)
Synapses of Sympathetic + Parasympathtic
Fibers synapse after existing the spinal cord - uses a two neuron network
Two nueron network (2 nerve fibers come together) - lightly mylinated presynaptic nueron to a non-mylinated post syenmaptic neuron
- Post synmaptic nueron goes to effector organ
Difference between the two = where the synapse occurs
Parasypathetic
Overall - Downregulates a number of bodily functions
Considered the rest or digest/feed and breed
Achytlcholine = primary nuerotransmitter
Comes from the brain stem - long fibers
Parasypathetic Synapse
Synapse - Long preganlionic fibers (first nerve fiber is long) + short post ganlionic fibers
- Ganglia is within or near effector organs
- Pre-ganglionic fibers = emerge from cranial and sacral regions of the CNS
Overall - First nerve fiber is longer –> first nerve fober exits the CNS (exist the spinal cord) —> first nerve fiber travels a long distance to the effector organ –> nerve fiber goes to the ganglia (ganglia will be near effector organ)
Example - Cillary ganglia control the pupil or Optic ganglia control the salivary or Sublacromol ganglia
Ganglia
Where the synape between two nerve fibers occur
Thickening of the nerve (conglomeration of synapses)
In parasympthatic - occurs close to effector organ
Acytlycholine medication
Have medications that use achytlcholine
Example - eye drops –> Acytlcoline is the nuerotransmitter for parasympathtic = relaxes and dilates pupils = use eyedrops with acytlcoline to treat glaucoma because the ayclcholeine will relax the celiary muscles in the eye and reelive pressure
Sympathetic
Upregulates a number of bodily functions
Inervates the adrenal medulla –> releases adrenalin (einephrine) into the blood stream
- Epinephrine = main nuerotramitter of sympathetic
Sympathetic synapse
Short preganglionic fibers + long post ganglionic fobers
- ganglia = in sympathetic trunks/chain on either side of the spinal cord (looks like string of perals)
- Preganglionic fibers emerge from thoracic and lumbar regions of spine
- Post ganglian fiber goes to body
Overall - first neuron is short (barley exits the spinal cord –> goes to ganglia (ganglia is near the spinal cord) –> goes to second nueron (long) –> 2nd neruon goes to effector organ/tissue
Exception in Sympathetic
Exception = pevic splanchnics to abdomen
Ex. Hind gut - exception to the long/short preganglian
Sympathetic = blue string in middle –> see that the ganglian are ina smpathetic chain
- Chain goes from T1 to L5
- At bottom = have the Pelic splanchnic - exception BUT everything else goes from sypathetic chain to body
Parasympathetic - red lines –> contributions of parasympathetic come from the brainstem
- Parasympathetoc comes from those nerves
- Ex. vegus nerve sends parasympathetic regulatory impulses to the heart (nerve affects parasympathetic to all vicera - can see it has many red lines branching off cegus nerve)
Vegus nerve
Exits from very highand goes to the body (possible that this was an evolutionary adaptation)
Most things come out closer to the effector tssues BUT the vegus comes from brainstem and goes to effector –> protects people in cas eof injury to the spinal cord the nerve can still be active because it is higher up
- Example - liver and diaphram can still work
Left side = head
Bottom = back wall of body
Big line in middle - sympathetic chain ; above chain = spinal column (bodies of vertebra)
verticle lines under synaptic chain = spinal nerves (inervate the trunk ; located between the ribs)
Where does the sympathetic trunk start
Sympathetic trunk starts at C1
Naming nerves
Start at cranial nerves - cranial nerves between the skull and the vertbarate
Then go to C2 = above the second vertabra
Spinal nerves that comes in cervical region = names for vertabrate below it until C8
- C8 arises below vertabra promians
- C7 = last cervical vertabra
- After C8 - nerve root = based on vertabra above it (thoracic - named for the vertabrarea above them)
- At C8 = Have a nerve above and below it = called C8 even through there are only 7 cervical vertabrae
What do the parasympathetic and Sympathetic affect
Example:
1. Up/down regulation of airways (logical based on what the systems affect)
- Para = constricts air
- Sympathetic = relaxs air (allows for running)
2. Para (homeostasis) = slows heart beat + dialate pupils + constict airways + activity in stomach + parastalsis + inhibit release glucose + contract bladder
3. Dilate pupils + inhibit salviation (not digestion) + relax airway to get as much air as possible
Some affects = not as logical (Ex. Parasympathetic promotes stimulation of gentials but sympathetic allows for climax)
NOTE - para = longer fibers to go to effector ; sympathetic where the fibers come out at the level that they are needed (more direct route)
VAN complex
Intercostal nerves - run under lower edge of rib –> when clinicals do plural puncture or injectins need to hug top of lower rib –> if go to high they g through nerve and do nerve dmaage or can hit artery in VAN complex
VAN (vein + artery + nerve) - run together in the groove on the lower edge of the rib
Spinal nerves contributions to para vs. Sympathetic
C1-8 ; T 1-12; L 1-5 = symoathetic contributions
S1 - 5 = parasympathetic
What do Parasympathetic and sympathetic combine to
Parasympathetic + Sympathetic – form effernet response = motor = associated with ventral root
Mechanism of Sympathetic chain
Start at the lateral horn –> Ventral root exits from the lateral horn (root comes from the antorior sulcus of spinal cord) –> goes through the rootlet –> ventral root joins the dorsal rot –> joining forms the spinal nerve –> spinal nerve splits into the dorsal branch and the ventral branch
Ventral splits of spinal nerve comminucates iwth the sympathetic chain through the grey ramus communicans and the white ramus communicans –> synpase with the post ganglia fiber –> nerve leaves the ganaglia through the grey ramus communicans –> goes to the body to go to effector
Alternative mechanism for sympathetic chain
Fiber comes from the lateral horn to the ventral root to the spinal nerve to the white ramus communicans BUT instead of synapsing wirh the ganglion on the ame level it will go up or down on the chain to ge closeer to the effector and then will synapse at ganglion –> then will go to grey communicans –> go to body
Third mechanism of synaptic chain
IF ganglion is near effector - occurs with the splonik nerve
- Ganglion is not in the chain INSTEAD it is by the effector organ
Have ventral root –> goes to form spinla nerve –> goes to the white ramus communicans –> goes around the gangion of the synaptic chain–> goes to splanic nerve –> ganglion in the gut
Comparison of the Autonimic and Somatic motor systems
Nerves in Somatic nervous system
Nerves come out as part of cranial or spinal nerves –> THEN send this heavily mylinated axon to an effector
- Nerves go through the brainstem to the spinal nerves then to the body
- Goes thrugh spinal cord or directley to organ through cranial nerves
Somatic nevres = sends axon directly to muscle (same pathway as Autonmic but not the same path)
Somatic pathway
Somatic sensory - nerve goes from the lateral horn to the DORSAl root –> goes to the dorsal root ganglian to the organ (ex. to the skin)
Somatic motor neuron - goes from laternal horn to the ventral root to the muscle
Additional represenation of Autonomic pathway
Lateral horn –> dorsal root ganglion –> goes througjh the grey ramus commincans –> then goes to body
Posterior view of spinal nerves
At C8 = have. anerve abve and below it = called C8 even through there are only 7 cervical vertabrae
- At C8 = switches to be named for the one above it (before this named for the vertabrate below it)
Have 5 Lumbar nerves
Thoracic nerves = named for the vertabrate above them
Bigger neveres - bottom is the rootlet going to ventral and dorsal root –> coelece to the spinal nerve –> go to the underside of rib above (co=me out beloew the vertebral bodies)
Smaller thing –> intercostal nerve
VAN - nerve + artery + vein –> all combine together
Open spinal column - see canal
Top down look a spinal nerves
Notice:
white matter surrounds the grey matter
have lateral horn in grey matter
Spinal nerve splites into two branches
Rootlet (many small roots coming out of the lateral horn) –> rootlets come together in ventra root
Spinal nerves (cornal cut)
Middle yellow - see the ganglia –> go to the spinal nerve –> sinal nerve branches –> ventral branch (ventral ramus) beccomes the intercostal nevre and runs along the rib
Dorsal branch = goes to the deep mucles of the back
Brachial Plexus
Function - Inervates the upper limbs (controlled and sensed by C4-T1)
Nerves go from spinal nerves into truncks –> then go to divisions —> then go to lateral/posteror/medial cords –> then break these up into nerves proper
Example -
1. Medial nerve –> runs under reticulum
- medial and lateral cord make up the medial nerve
2. Radial nerves - come from the posterior cord
3. Ulnar nerve - comes from the median (hurts when hit funny bone)
Nerves of the upper limb
Note:
1. Musculotenous nerve - Goes to muscles and skin
2. Ulna nerve - behind the Articulatio cubiti (elbow) –> goes to the pinky and forth finger
3. Median Nerve - inervates the hand
Brachial Plexus Nevres
Dermatomes
Areas of surface of body that can be attributed to motor or sensory nerve inervates
Example -
1. C5 inervates area
2. C8 - Ulna nerves gets contribution from 8th cervical spinal nerve (dermatome show where the ulna gets contribution)
Max Bradle story
Started medical illutsration program - Was recruited to do medical illustration at Hopkins (needed him to draw discievries because people couldn’t take photographs of them)
He got sepsis –> resulted in illness + he had numbness in arm and theyd didn’t know why –> he mapped where he felt the numbness and drew the area –> area decsribed the ulnar nerve - they thought there was scarr tissue impinging on the ulnar nerve –> they operated and freed the scarr tissue and he was healed
- Shows anatomy gives the where and why
- Sketched anatomy to describe where the systemeric effects were happening
Cranial nerves (Image)
Some nerves = motor/ some are sensory/ some are both
Muscles controled by ocular motor
- levator palpebrae suprios muscle
- Suprior rectus msucle
- Medial rectus muscle
- Iferior rectus muscle
- Infrior oblique muscle
Painting by van goh
people say that it is someone with trigeminal nueralgia
Rini Dad hearing story
Dad woke up from nap and couldn’t hear in irght ear –> in 1960s he went to physicial and they didn’t ko why defa in right ear –> was deaf for a while = he would have to trun is head = in church he would trun is head = Rini’s classmate asked why they go to church if dad look out window the whole time but the dad was just turning to be able to hear
20 years later Rini was working with nuerosurgeon who was exper in vetsibuluarcochlear nerve/schwanomas –> Rini called gis dad and thought he had issue with vestibular cochelar nerve –> foubd that teh dada had coutsin neuroma –> They left it there because not growing
- Schwanomas = often bengign but cause issues because press on Brainstem
Image = large accoustic nueroma
