Anatomy Lecture #2 Flashcards
CNS Vs. PNS
CNS - Spinal cord + brain
PNS - Cranial Nerves + Spinal nerve + Ganglia + Nerves in the body
- Includes the extensions of nerves (axons + dendrites)
EXCEPTION - CNS includes 2 cranal nerves
Ganglia
Outposts of nerves
Where are cell bodies of nerves
IN CNS - Cerebelum + cerebrum
IN PNS - IN ganglia
Cranial nerves in CNS
- Optic nerve + retina
- Olfactory nerves (outcropping of CNS)
- Olfactory bulbs = right above nasal cavity
***Optic + Olfactory = listed as cranial nerves BUT are considered part fo CNS
Brain color in OR vs. Lab
Lab - blanched color + monotone
OR - Red/Pink + Has many blood vessels –> BECAUSE the brain is well profused
Movement in brain
There is movement in the brain (brain almost beats”) - because there is spinal fluid –> when the heart beats it chnages the pressure including in the body = brain “beats”
What is supported by the brain
Everything is supported by the brain - Circulatory + respitpry etc.
MEANS you need to keep the brain healthy
Recent definition of detah
Recentley doctors use the neurodefintion of death (Ie. braindeath)
Before - death had to do with end of breath and heartbeat
Issues with neurologic death
Survey paper shows that nuerologic death is subjective
- It becomes even more subjective as we inrease our ability to resesitate and maintain –> creates controvery over what is actually deceased
Weight of brain
3 lbs –> 2% of bdy weight
- Considered a small component of the body (only 2%) desipite its importance
Profusion of brain
Consumes 20% of blood circulation = well profused
Verterbrial artery + coroted artery = responsible for profusion
Grey Matter vs. White matter
Grey matter - Cell bodies (outter layer of teh cerebelum)
White matter = Connections (axons + dendrites)
- Contains the ‘highways’ that nuerons used to function (Called “Nueronal tracks)
Brain in newborn
Brain in new born = proportionally larger than the rest of the body
- It is more developed compared to other organs
- Not completley mylinated
Variability in brain (Rini story)
Brain is varaiable - story:
Rini was at the University of cincinatti –> spent 3 years doing nuersurgical llustrations –> his collegues would call about the braub ri ask what is normal and what is individualed –> Rini said hat it is like a finger print (similar but not the same)
- Rini explained - there are some things that will be the same (they will all have the same features) BUT the features will look different for each person
Ex. all people have lateral fissure BUT it will look different in different people (same feature but with varaition)
Lateral fissure (Sylvian fissure)
Seperates the temperal and frontal lobes
- Corresponds to the spehnoid wing –> definition between frontal and medial fossa
- Seen in every brain
Romandy fissure
Sperates the cheif motor and sensory regions of the brain - Conatins neurofunctional centers on either side
- Seen in every brain
Brain sturucture
Seperated into two parts
1. Cerebrum - contains the 2 hemispheres
2. Cerebelum (little brain)
- Smaller area at the bottom
Cerebelum
Function - Complex organzation of movement (Coordinates movment)
- NOT the basis of movement (not intiating movment)
Example - Not making fingers move but it allows you to play piano
Neoplasm in cereblum = patients are not paralyzed BUT the gait is disterbed + have unconrtoled moevments + lack of coordinations
Cross section of brain (ADD IMAGE)
See grey matter (Outter superficial layer)
See white matter - see tracks (Made of axons + dendrites)
- Tracks - Goes to the midrain + brainstem and are sent to the body or go from body to the midbrain and brainstem
Gyrai
Highpoints in the ridges (mounds of tissue turning on self)
WHY have them - result of the body packing as much surface area and function in the brain as possible
- making soace for the cell body in the brain
Sulci
Valleys
IF you put a probe into sulci you would hitt the bottom of the valley (hit brain matter)
Fissure
Major division between tissue
Fissure vs. Sulci
Sulci - if put probe in and go down valley you hit brain matter
Fissure - If put probe in and go through you would not touch the brain tissue
Example - lateral sulcas/lateral fissure
- Will be called a sulcas or a fissure depending on where you put the probe (IF put the pribe more posterior then you wil hit brain then it is the lateral sulcas ; if put more anterior then you could go through without hitting braun and it would be the lateral fissure)
Sulci + vessles
Sulci = major places for vessels to pass through
Blood vessles in the brain
There are no MAJOR blood vessles goring through the brain BUT around covering you have small vessles groing through and into the brain
- Many small vessles NOT one big vessel
Areas of the brain
Frontal - Word productions + problem solving + behavior control/emotion (Behvaior = lower part of frontal)
Cenral Fissure –> Between frontal + parietal
Occipital – Vision
temperal –> Memory + word understanding + Emotion
Sylvian fissure (Latra Sulcus) –> divides the frontal and temperal lobes
Motor strip
Function - Fine motor movement + Muscular/skelotal movement
Location - On the tempeoral lobe (anterior to cental sulcus)
- part of precentral gyrus (in front of the central sulcus) (As oppsoed to the post central hyrus is somatosensory)
Somatosensory strip
Function - feeling (Ex. feeling on fingertipes)
Location - In temperal (post central gyrus)
Image of somatorsensory and motor strips
Mapped pre and post central gyrus - see where on gyri get impsulues in or out + map amount of control areas have
- Motor strip = shows smaller icons - doesn’t have the same strength as somatosensory
Size = shows strength of control (biggers - more nerves conrtols)
- Ex. Large face for motor because have lots of fine movement in the face
Humunculous
3D version - shows how much control the motor or Somatosensory strip has
Takes the compoenetts of sometosensory and the motro strup and correlates them with function
- Shows sensitivity of strip + component of strip
Example - large hands –> Shows the snesitivity of the strip
Pre vs. Post sensory
Somotosensory = presnsory
Motorsnesory = postsensory
Midsagital section of the brain
Going down the sagital fissure
Towards the left = frontal lobe
Towards the right = Parietal lobe
THINGS to notice:
1. Pituitary gland
2. Pons
3. Ventriculus qurtas - ventra filled with spinal fluid
4. Medula oblongata
5. Midbrain
6. Brain stem (Midbrain + Medula + Pons)
7. Foraman magnum - where the brainstem exits from
Sagital fissure
Seperates the two hemispheres of the brain
Pons
Function -
1. Controls trigeminal nerve (nerve 5) –> important in face
- transmits sensory info to to the skin, sinues, and mucosual memranes
2. Abducens neve - controls lateral eye movmnt
3. Facial nerve
Connection between right and left cerebelum
NOT bilateral
Corpus colosum
NOT bilateral
Midbrain
Top of brainstem
Gives rise to 2 nerves:
1. Ocular motor nerves
2. Trocleir nerves (controls muscles in the eyes)
Brainstem
Consists of:
1. Pons
2. Medula oblongata
3. Midbrain
Everything in the brai stem goes to the spinal cord (eveyrthing going to spinal cord passes through the brainstem (through the midbrain and through the medula oblongata)
- Everything we sense and move passes though the brainstem
Neoplasm in brain stem = BIG issue (surgeons try to remove tumor without dusrupting tissue)
Tracks in Brainstem
In brainstem (including midbrain) - have tracks –>nerve tissue gathers in tracks (tracks go through medual and midbrains)
Medula oblongata
Function -
1. Controls vestibular cochlear nerve (controls balance and hearing)
2. Controls glycoferingal nerve (movement if tongue)
3. Vegus nerve (vegebond)
4. Accesory never - movement muscles in neck and upper back
5. Hypoglosal never (nevres of tongue)
- Harder to see (more fiber like)
Vegus nerve
Goes from CNS to heart and diaphram (works with digestive + respitory + circulatory)
Nerve = very high = if you have disrpution in the spine = nevre is so high that it won’t be disturbed = protects us to make sure our heart still beats even if we have an injury to the spine
Diencephalon
Location - Upper portion above brainstem
- Space between brainstem and brain
Function - conduit between the brainstem, body, brain
Includes: Thalumus + Pinial Gland + Hypothalumus
Contains:
1. Pituitary gland (hypophysis)
2. Penial gland
3. Aquduct
4. 3rd ventricle
5. Coorate
6. Vessels - make up most anterior profusion
Andre the giant
Had gigantism (neoplasm in the pituitary)
IF he had a medical procedure = anestsialogist couldn’t know how much anestsia to give –> They used his consumption of alchol as a gauge
- People say he had 156 beers i one sitting
- Possible his body metabolized alchol differentley
During filming of. amoviehe passout fromd rining and they couldn’t move him because he was too big
Died young from heart failure (common in people with gigantism)
Corpus colosum
Bridges the right and left brain (allows right and left to communicate)
Contains tracks of white matter
Hemispheres of brain
Left - verbal tasks (Speech + writting)
Right - Spatial + movment
Brain works because have connection between them (connections - corpus colosum)
Cutting Corpus Colosum
Often need sto be cut in surgery to seperate conjoined twins (if you need to seperate brain) + Might need to be cut to treat epilepst
- Epilepsy - last treatment is to cut to corpus colosum and remove entire hemisphere
Ben Carson
Doctor who treated severe epilespy - removed half of brain (often in young kids with life thretaning seizures)
Kids regian fuction BUT some things the kids is not able to perceive/verbalize/interpret OR might have more issues in somatic
What happens when cut corcpus colosum
In people where it is not cut - people can accomidate (say what something is and apply it)
When cut corpus colosum = can see what people see with which eye (can divide the feild of vision and see what people see with which eye)
When divide feild of vision
1. Left eye goe sto right size of brain = can pick up a picture and match the picture with something (can put things tgether) BUT they can’t describe the picture or say the name for it
2. Right eye –> Goes to left brain = you can say what the picture is BUT you can’t associate it with other things (don’t know how it is used)
LEADS TO RIGHT VS. LEFT BRAINED THEORY
Right vs. left eye
Right eye = goes to left side of brain
Left eye = goes to right side of brain
Book about right vs. left brained
Author took people who couldn’t draw
Theory = people who can’t draw were left brained artists (processing desrptive from left side)
- Lft brain artists = see a picture of an ete and draw what they thing of an an (draw symbol of an eye)
- Rght brain = see an eye and see the folds + eyelid placement + fat pad + iris (more observant of details) –> look at the perspective of things NOT just drawing a symbol of thing
Book = took people who coudn’t draw ad had they draw things flipped = chnaged their perspective = breaks the smbolism = became more of a right brained observation
Skull - ADD image when uploaded
Function - protection of brain
Components:
1. Frontal - one single bone
2. Pareital - two paired bones
3. Temperal bones - two paired bones
4. Occipital - one bone
Back of neck muscles
Connect to nuchal line
- External occipital pertubance (bony bump on the back of the skull where the neck meets the head)
Skull base
Frontal fossa –> where the frontal sits
Soehnoid ridge - goes to claunoid process
- Tip of sphenoid ridge = temperal tip - sits in the sylvian fisure (important for dissections)
Crista galli (roosters bone) - bone between the hemispheres (divides the cryptoform plates)
- Olfactor bulbs sit in crystaform plates - fibers go to nasal cavity
Teproal tips –> temperal lobe goes right behind the eye
Middle fossa –> temporal lobe
Posterior fossa –> occipital is above and below is the cerebellum and foramen magnum with medulla oblongata above it
Falx cerebru (Fulcus serebri)
Interior boarders around corpus colosum
Tough tissue between right and left hempisphere of cerebrum
Top line in pink (see in image where arrow is) - vasuclatire along midsagital plane
Bone thickness in skull
Skull - have areas where the bone is thicker or the bone is thinner
- Often have thinner bone if the area is well protected by muscle (Example - temperal muscle protects bone of temporal area = thinner)
- Occipital + frontal = thicker bone
- Extensor side is thicker bone - protects the corpus colusum
Types of sinus
- Bone sinus
- Venous sinus
Soft tissue in brain
Soft tissue - forms puches
Have depressors at the bottm –> get movment of sinus
Example - venous sinus (vasculour sinus) –> sigmoid + ransverse sinus
- Have blood that is supplied to the brain –> blood then goes to foraman –> go to jugular –> goes to subclavian –> goes to superior vena cava
Openings in skull
Function - brings something in or send something out of skull base
Example:
1. Optic fissure - Let ocular motor nerve go to orbit
2. Left correnary came up to feed brain
3. Optic Foraman - Optic never goes to orbit
4. 4. Foramen Ovule - where corrated comes through neck
Foramaon
Allows oemthing to go to body or allows something to come into brain
Things in Skull base picture
- Frontal Fossa
- Temperal Fossa
- Sultusa - Where pititary sits
- Petris ridge - Cochlear nerve goes to ear then goes to ridge then to the internal auditory meatus
- Cochlea sits in petris ridge
- External and internal Auditory meatus
In image - left blue dent = left cerebelum ; right blue dent = right cerebelum ; top of blue circle = medula above the foraman
Covering of the brain
All together - Considers the Meningies
Includes:
1. Dura
2. Arachnois
3. Piamoter
Dura
Most extreior covering of the brain
Location - inside the skull
As get older = becomes adherabt to the inside of the bone (more motile when young)
Splits and creates a vascular sinus (Ex. creates the superior sagital signus - spent blood from brain is collected to go to heart)
Sagital sinus
Created by the Dura
Functions as a vein
Things are able to flow into it but its made by Dura NOT by vascular wall
Blood goes from sagital sinus –> transvers sinus –> sigmoid sunius -> jugular veins
Arachnoids
2nd layer around brain
Has a spider web appearance (Contains fine filaments)
Jumps Sulci (covers the sulci)
Thinner than Dura
Subarachnoid space = part of arachnoid
Vasculature = passes in arachnoid layer
Piamotor
Very thin
Can’t dissect from brain
Goes to sulci
Superior Sagital Sinus
Blood goes into it (created by the Dura)
Fulcus created by the dura
Dura = goes between hemispheres = creates the fulcus cerebri
Epideral Hematoma
Invloves memngial arteries (arteures supply the menigies ; travel in the memngies ; supply the memngies NOT te brain) and somethimes veins
- Often in the temperal region
- Occurs if have trauma to head –> trauma disrupts vessels = blood goes to outside of dura (Because disrputing the vessles that go to the dura)
Issue = outide of the dura (bleed between brain and dura)
Solution - drill burr holes = release pressure
Ex. Brandom murry (got hit but got treated in time); Atkins (slid on ice and died); Natasha neilson (Skiing) ; garry colman (Died)
Onset of epideral hematoma
Typicall have a lucid period followed by inconciousness
- Have a latencey period - people feel fine right after BUT they keep bleeding into the space = pressure builds
- Often too late to treat once person feels ill
Scanes - Have a Biconvex lens appearnce
- Can see hematoma in radiography
- Football shape (apex at end)
- Pulls the Dura away from the skull –> blood spills into the space
- In image = can see the dura attaches to bone –> bood pushes dura in + add pressure on brain
Secondary issue with Epideral hematoma
Can herneate the brain stem –> medula can be push towards the foraman magmum
Vasculature in Epideral hematoma
vasculature = feed outside of brain (feed the meninges)
- Epideral = bleed outside of the dura –> puts pressure on brain
In skulls = you can see depressitions wgere you have vessels between the skull and the dura
- Middle mengies = most common to cause epideral hematoma
Subderal hematoma
Involves bridging veins
Issue = under dura
Bridging veins
veins that drain brain and put things in sagital sinus
- Go from achachnoid space through dura to the sagital sinus
Part of arties and veins in arachnoid space
Onset of Subderal Hematoma
Typically has gradual onset of headache and confusions
- can go fro some time (depending on how many veins were disrupted)
- Often don’t lose conciouness
- Might have sleepinness
What increases chnace of subderal hematoma
Often occurs in elderly following trauma (because elderly brains shrink and are dehydtrated)
IF brain is smaller + less fluid around the brain = have more traction in the brain –> if have injury the veins can rupture –> can bleed under dura = get subderal hemaoma
if have injury to head when brain is more able to move –> brain moves fowards and hit skull –> movement f brain = bursts bridging veins
Example - head banging = disrupts bridging veins = get subderal
Subderal hematoma on Scans
Crecent shaped appearance
Dura = still packed against bone BUT the brain is being pushed in
Subachnoid hematoma
Usually from a rupture intercranial anuerysm
- Burst vessles that supply the brain (Vessels that supply the brain travel in the sub aarchnoid space)
Often associated with a Thinderclap headache
Rapid onset from seconds to minutes
Issue = vessles inside subachnoid space ruptures under archnoids)
Could be due to trauma or pericing injury (ex. gun shut)
Example - Rini Studnet had anuerysm rupture
Subachnoid hematoma on scane
Blood diffusion within subachnoid space
Annurysm
Little bleb - tender weakend portion of vessels can form little bleb –> can rupture (like garden hose example)
Example - optic chiams = common anurism
Treatment - anurism clips IF no collaretral circulation (Circular of willis) - go through catheter (in groin)–> catherter goes to artyer in artery –> goes to anurysm –> tiny platnium coils are placed into the anurysm to filll it and seal it off from the main artery
What protects the brain
Skull + Mengies + Fluid
Spinal fluid
Function - protects the brain (cushions the brain)
- Surrounds the brain
- Decreased friction = brain ca move in skull
Lateral ventricle
Space in brain - filled with CSF
When is fluid made
Fluid is always produced - Corre plexus (look like small string of grapes) in vessles produce CSF
- Coroid plexus = fund in 3rd ventricle, 4th ventricle , and Latera ventricle
- Found in subcranial space
CSF flows through subderal space –> Dura outpuches In sagital sinus –> Blood in sinus flowing by and CSF flows by the sinus –> as the blood flows over the CSF is picked up by the blood through osmosis
- Arachnoid granuals absorb CSF
- Blood sucks fluid through thin memebrane
herneating medula
If hernate the medual then brain goes outside of ckull –> blcoks the flow of fluid = disrputs fluid around the spinal cord
Neoplasm in Midbrain
Neoplasm in midbrain = closes aqaduct = CSF is blocked = builds pressure
- Causes alnocheiry syndorme in adults
- Causes hydrosepholy
- Causes enlarged brains in young kids because flexible bones
Flow of fluid in brain
IMAGE - black arrows show flow of fluid in brain
Fluid = goe sto ventricles then to spave around spinal cord
Corbid plexus
Where spinal fluid is produced (Can see in image)
Vasculator of the brain
Posterior - Blood supply = right and left vertebral arteries (results of vessels in spinal column_ –> come together and form baslar artery –> baslar artery leads to the posterior cerebrum
- baslar artery sits in front of the pons
- Posteriro cerebral artery - goes towards posterior part of cerebrum
Anterior - Anteiori corrated truns on either side at the optic chiasm –> branches into the anyior, middle, and posterior cerebral
- Posterior cerebral = connects anterior segment with posterior segment
Posterior supirior cerebelum - goes to back of cerebelum ; Posteerior superior cerebrum goes to back of cerebrum –> ocular motor nerve comes between the two
Circle of Willis
Includes :
1. Anterior cerebral
2. Middle cerebral
3. Posterior cerebral - connectes anterior segemnt with posterior segment
4. Anterior comminucating artery - between right and left anteerior cerebral
5. Vertabral arteries combining to the baslar artery –> beccomes posterior cerbral
Function: Connects collateral circulation
***Check info in video
Story - rini college didn’t have coladeral circulation in surgery = died- can see vertabral artery
Formation of sinuses
Brain tissue leaves voids as the brain developes –> Creates ventricles and sinuses
Example:
1. 4th ventricle - filled with CSF
2. 3rd ventrcile (between the right and left thalumus) - filled with CSF
3. Aquaduct (Connects 3rd and 4th venctrile) - Passage way for CSF
Subarchnoid space
Where blood vessels that supply brain travel
Arnold chiary Syndrom
Medula + cerebelum = being pushed out through foramaon magnum
- Often due to tumor on brainstem or hydrosepholy
Thalumus
Receives input from periphery via brainstem
- Center of aqusition of knowldge
Penial gland
Secretes melatonin (internal clock)
Hyothalumus
related to relfexes + smell + temper + emotion + agression + pain + Pleasure
Optic chiasm
Where optic tracks come together
Sulturasm
Depression that pituitary sits in
Ladan and lelah Conjoind twins
Vasclature was main issue - Mostly issue was sagital sinus (collectes blood in cerebleum)
-vasculature was the main issue and it came down to the sagittal sinus —> sole structure collecting all of the blood supplying the cerebellum
-each sister had their own sagittal sinus but posteriorly they were fused
-took saphenous vein from leg and reconstructed the posterior sagittal sinus
-the base of the skull had cisterns like sinuses but with thin walls and one of the sisters died during the surgery
Tabia and Lea conjoined twins
Vasclature was main issue
-jugular in one of the sisters but not the other and the main part was shared
-took from one confluence and the other
-jugulars for lea were intact
