The following are derived from the neural crest EXCEPT?
Occipitals/ area around foramen magnum (derived from paraxial mesoderm) and laryngeals (derived from lateral plate mesoderm)
What are the differences between extradural, subdural, and subarachnoid hemorages (intracranial hemorages)?
1. Extradural (epidural) hematoma: blood collects between the calvaria and the periosteal layer of the dura; blood between dura mater and skull
2. Subdural hematoma: blood collects between the dura and the arachnoid
3. Subarachnoid hemorrhage: blood flows
Differentiate between the dural folds.
-Falx cerebelli- fold of cerebellum; main folds of the dura which divides up cranial cavity
-tentorium cerebelli- the tent over the cerebellum; separate cerebellum from cerebral hemispheres
-Diaphragma sella- surrounds diaphragm of sphenoid
-falx cerebri-
60% of blood flows through __________, while 40% of blood flows through __________.
veins; dural venous sinuses
How is the cavernous sinus connected to facial veins and to the pterygoid venous plexus?
There are facial deep veins going into facial deep to cavernus sinus
-Danger area of the face � here infections can travel to cavernus
-bacteria can travel from here (pimples) into cavernus sinus
What is the clinical importance of these connections (previous flash card)?
-conduits of infection meningitis, encephalitis, blood clots
Most of the venous blood from the cranial cavity drains into the __________ through the __________.
-internal jugular vein; jugular foramen
-more than 90% of blood empties into the internal jugular vein
What happens if the pterion is fractured?
rupture middle meningeal artery � hematoma in epidural space (pool of blood)
-likely to tear meningeal dura � bleed � blood will collect in epidural space (between 2 layers of dura; outer- periosteal; inner- meningeal (closer to brain))
Describe the Circle of Willis.
the bloody beltway" of the brain
-Supply of brain come from carotid artery and 2 vertebral arteries which unite to form basilar branches of basilar and internal carotid form circle of willis (bloody belt)
Where is the internal carotid artery located? What happens with an aneurism?
- located close to CN II
-aneurism squeeze CN II blurred vision, blindness
What does the labyrinthine artery supply? What happens if it is cut off?
-supplies the ear; if cut off � lose sense of hearing and balance
What is A.I.C.A ?
-anterior inferior cerebellar artery
-CN VII, VIII
-if have aneurism of labyrintine or anterior inferior cerebellar artery or both....squeeze CN 6, 7 (bell's palsy; paralysis of muscles of facial expression)
What happens if lose CN VIII?
lose hearing AND balance
What are some clinical implications of jugular foramen?
� glomus jugulare tumors
� schwannoma
� meningioma
� metastases.
What happens if compress CN XI?
-sternocleidomastoid m., trapezius m. affected torticollis and drooped shoulder
What happens if compress CN IX?
affects stylopharyngeus difficulty swallowing
The vestibular component of the vestibulocochlear nerve (CN VIII) controls _______________, while the cochlear component controls ________________.
balance, hearing
What cranial nerves control special senses?
-CN I, II, VIII
True or False: Most humans don't have sensory dorsal root
-true
Is there a cervical 1 dermatome?
-NO!...cervical 1 has MOTOR to 2 muscles
There are _____ pairs of spinal nerves and _____ cranial nerves.
-31; 12
Sensory transmission is from the _____ nervous system to the _____ nervous system.
-PNS to CNS
What happens if you have sensation on one side of your body (e.g. right hand)?
-will end up in left brain or contralateral in postcentral gyrus
-Peripheral fiber � brain usually on opposite side
If a blood vessel on right bursts, what side is affected?
-left
-almost always on opposite side
What is the definition of a nucleus or nuclei in relation to cranial nerves?
-A collection of cell bodies with similar purpose or function
-things lumped together
-e.g. Abducens nucleus drives eye muscles
Trigeminal nucleus- trigeminal area
-NOT like nucleus in a cell!
The cranial nerves enter or leave from ________ to ________.
-rostral to caudal
True or False: The trigeminal nerve is pseudounipolar.
-True
What is a ganglion?
- Collection of cell bodies in the PNS
Are autonomic ganglia sensory?
-YES!
Where does the optic nerve enter the skull? What artery passes through? Classification?
-optic canal; ophthalmic artery; special sensory afferent
What is meant by LR6 (SO4)3?
-Lateral rectus muscle is innervated by CN VI moves eyes out
-Superior oblique muscle is innervated by CN IV moves eyes down and out
-all other muscles are innervated by CN III
-All of the rest of the eye for moving muscles or orbit is 3 including auton
Do CN III, IV, and VI control vision?
-NO....CN II
What are the branches of the V1?
-Nasociliary Nerve
-Frontal Nerve
-Lacrimal Nerve
If you poked yourself in the eye, what branch is this?
-nasociliary
Where are the cell bodies of the trigeminal nerve?
-trigeminal ganglion in middle cranial fossa synapse in pons of brainstem
Does the trigeminal nerve contain its own nucleus?
-NO...has no autonomics itself from brain to periphery
What is meant by nervus intermedius? What can you do?
-bundle of nerves as go out internal auditory meatus (CN VII, VIII)
-part of VII, carries autonomic fibers � special sense of VII
-Taste (special sense) � anterior 2/3
-submandibular ganglia go through here
What 2 ganglia in the autonomics does the facial nerve go to?
-submandibular ganglion (geniculate ganglion)
-pterygopalatine ganglion (When in the eye and orbit, pteroyopalatine ganglia is busy � very crowded � lacrimal gland is in the orbit and innervated by pteryopalatine ganglia)
What happens when you have a temporary ear infection like during cold or flu season and get impinged nerve at specific point?
-Bell's palsy
-paralysis of facial nerve and all muscles of facial expression are affected
-most complicated is the one going around the eye � the cornea dries out � corneal transplant
-usually Bell's palsy temp � treat with antibiotics
-Diagnosis must be
The marginal mandibular branch of the facial nerve goes all the way down to the muscles around ___________.
-orbicularis oculi
How many branches do V2 and V3 have?
-V2- about 20 branches
-V3- about 13 branches (5 sensory, 8 motor, 4 muscles of mastication)
If sensory, where are cell bodies located? If motor, where are cell bodies located?
-ganglia; pons
True or False: ALL sensory fibers are pseudounipolar.
True
What is the only ganglia on the mandible?
-submandibular ganglia synapse branches of lingual nerve go in here and go to tongue
Preganglionic cell bodies of CN VII are found where?
-superior salivatory (lacrimal) nucleus
Where is CN VII located?
-superior salivatory (lacrimal) nucleus
Where is CN VII located?
-pons
What is the autonomics to the eye? Is the lacrimal gland innervated by this same nerve?
-CN III
-NO!!....innervated by facial nerve CN VII
What is the difference between Bell's Palsy and a stroke?
-If have a stroke � won't go blind from corneal transplantation....so socket always works
-In bell's palsy, whole thing is paralyzed
What is meant by "9OP"?
-9th nerve goes to otic ganglia...synapse there...[comes from inferior salivatory nucleus located in pons (pregang in medulla] and drive the parotid gland make parotid secrete
-Three to the eye, 9 op the rest is 7
What is the MOST IMPORTANT NERVE with vagus to innervate the carotid sinus to control cardiovascular function?
-CN IX- glossopharyngeal nerve!!!
-Sensory fiber will go to carotid sinus which is pressure receptor
Also at corotid bifurcation carotid will divide into network.....carotid body is chemical receptor (o2 co2 affected) � if have too much CO2 will speed up
Describe the GAG reflex.
-when examining someone and they stick out their tongue to say "ah", go to pharynx and to back and touch (must leave the oral cavity); stick out your tongue is 12th cranial nerve, when say ah is 10th cranial nerve, and when touch the back of the pharynx i
True of False: CN IX is sensory to the pharynx.
-true
Where are cell bodies of CN IX located?
-superior and inferior glossopharyngeal ganglia
Sensory to the larynx is located where?
-below buccal fold
Where are the cell bodies of CN X located?
-superior and inferior vassal ganglia (aka jugular ganglia)
-located out in periphery near internal jugular vein
-all nuclei feeding into brain stem
-part it feeds into is medulla
What happens with swallowing?
-1st phase of swallowing: food in oral cavity...tongue will go forward...start second phase of swallowing
-NOT a typical gag reflex!!!
-When have a normal meal, to swallow when the fluid leaves oral cavity, it touches the pharynx � same sensory innervatio
What 4 cranial nerves with sensory ganglia are in the periphery?
-V, VII, IX, X
5-trigeminal ganglia
7- geniculate ganglia
9- superior and inferior glossopharyngeal ganglia
10- superior and inferior vagal ganglia
The maxillary division of trigeminal nerve will come through ______ and come forward into _______.
-inferior orbital fissure; infraorbital canal
What is significant about the lamina papayracea?
- of ethmoid bone separates orbit from ethmoidal air cells
-important b/c paper thin infections from blunt trauma (exceedingly fragile)
: What is the thinnest skin on the body?
-skin over eyelid
Is the subcutaneous tissue elastic?
-NO!
- has no elastic tissue and very liitle connective tissue, so if get blunt trauma � swells (fluid accumulates) � get swollen eye easily (lack of elastic tissue)
-even mild damage can cause significant swelling
What holds the eyelid firmly against the eyeball so that doesn't droop?
-tarsal plate (dense connective tissue)
Describe the orbital septum
-weak membranous sheet that extends from tarsi to orbital rims, where it is continous with periosteum
-keeps orbital fat in separate compartment
-keeps sockets separate from infections
What is significant about having lipids outside of the eyeball? What produces these lipids?
-important cover outside layer of tears
-help hold tears against eyeball
-tarsal glands
-glands can get stocked up b/c lipids are waxy get plugged chalazion (painless) expansion of the tarsal glands
: What is sty?
-infection of ciliary glands
-found at base of eyelashes often gets infected sty
Any infection of eyelids can go through __________ to brain.
-ophthalmic vein
What is happening when you anesthetize a patient's maxillary nerve and the patient says their eye is paralyzed?
-branch of cutaneous nerves coming from infraorbital...just numbness in lower eyelid
What happens when you blink?
-orbicularis oculi compresses lacrimal sac and squeeze tears into nasal cavity
Why does your nose run when you cry?
-b/c nasolacrimal duct will empty into inferior meatus of nasal cavity
How does the cornea get nutrients and oxygen?
-Cornea has NO arteries...so has to get nutrients from somewhere.....so from lacrimal fluid
Do sympathetic fibers from the lacrimal gland synapse at the pterygopalantine ganglion?
-NO!!!....synapse in the superior cervical ganglion
-sympathetic fibers control blood vessels vasomotor
Where do parasympathetic preganglionic fibers from the lacrimal gland synapse?
-pterygopalantine ganglion
-Greater petrosal nerve...branch of the facial nerve...come through superior surface of temporal bone
Combine with deep petrosal nerve and go through pterygo canal and this time SYNAPSE at pterygopalatine ganglion....jump into b
What can happen with damage to the greater petrosal nerve?
-If damage to greater petrosal nerve...instead of nerves regenerating..take wrong road and go back up to lacrimal gland � crocodile tears (when someone is looking at juicy steak...salivate and get tears in eyes)
What are functions of ocular movements?
-fixation- move eye so that image falls on part of retina that is best at focusing; real detailed perception � not only move eyes to something but also accommodate to head movement � happens automatically
-move so that image falls on area of maximum acuit
Why do we want oblique muscles that will actually rotate the eye?
- b/c if tilt head, your eyeballs will twist to accommodate so that visual world is still right side up
What muscle opens the eye?
-levator palpebrae muscle
What happens if lose sympathetic innervations to eyelid?
-will droop
-partial droop Horner's syndrome
Describe the fascial sheath
-Bulbar sheath surrounds eyeball and blends with muscular fascia
-Check ligaments attach to medial and lateral orbital borders
-Suspensory ligament supports eyeball from below
What is meant by distance accommodation?
- Everytime that you try to figure out how far something is...distance
- If move something closer, both eyes adduct
-If something far, both eyes abduct
What is diplopia
-acquired double vision
-If grew up where eyes aligned and then something happens where get infection of orbit causing misalignment of eye � diplopia (double vision)
-Brain cannot handle 2 different vision when viewing 2 dif things