Exam 2 Flashcards
what ions are higher in concentration intracellularly?
potassium, negatively charged organic molecules
what ions are higher in concentration extracellularly?
sodium
what is the charge of a neuron?
none, they are electrically neutral
depolarization
potential difference is reduced. intracellular environment becomes more positive
repolarization
return to resting membrane potential. intracellular become more negative
hyperpolarization
intracellular more negative than resting membrane potential
what is resting membrane potential?
-55mV
what is another name for resting membrane potential?
threshold value
what causes an action potential?
the influx of sodium
what type of transport does depolarization and repolarization occur via?
diffusion
what occurs after action potential?
Na+/K+ pump (ATPase pump)
what is the most positive the amplitude during depolarization will get?
30-40mV
absolute refractory period
axon membrane is incapable of producing another action potential
relative refractory period
axon membrane can produce another action potential, but requires stronger stimulus
what channel opens during absolute refractory period?
Na+
what channel opens during relative refractory period?
K+
low frequency action potential will yield what kind of stimulus?
a weaker stimulus
high frequency action potential will yield what kind of stimulus?
a stronger stimulus
recruitment
when stronger stimuli activate more axons with a higher threshold
saltatory conduction
the process where electrical impulses jump between nodes of ranvier along a myelinated axon. fast rate of conduction
synapse
functional connection between a neuron and another neuron or effector cell
electrical synapse
broad effect. impulses can be regenerated w/o interruption in adjacent cells
electrical synapse gap junctions
adjacent cells electrically coupled through a channel
chemical synapse
specific effect. neurotransmitters are released within axon causing synaptic vesicles to fuse w/axon membrane + release NTs to cleft by exocytosis
excitatory postsynaptic potential (EPSP)
NT w/excitatory effects
example of an EPSP
glutamate, acetylcholine
inhibitory postsynaptic potential (IPSP)
NT w/inhibitory effects. inhibits reciprocal muscles from firing
example of IPSP
GABA
what electrical effect occurs during EPSP?
depolarization
what electrical effect occurs during IPSP?
hyperpolarization
lateral ventricles
paired c-shaped chambers in each hemisphere
what separates the anterior horns of the lateral ventricles?
the septum pellucidum
what is the roof of the anterior horn of lateral ventricles?
corpus callosum
what is the floor of the anterior horn of lateral ventricles?
superior thalamus + caudate nucleus (basal ganglia)
what is the floor of the inferior horn of the lateral ventricles?
hippocampus
what are the 3 horns in the lateral ventricles?
anterior (frontal), posterior (occipital), + inferior (temporal)
what is the atrium of the lateral ventricles?
triangular cavity where the body, posterior, and inferior horns communicate
what is another name for the atrium?
trigone
what allows communication and flow of CSF between the lateral ventricles and 3rd ventricle?
intraventricular foramen of monro
where is the 3rd ventricle located?
middle space between the thalamus + hypothalamus
superior border of the 3rd ventricle?
fornix
anterior border of the 3rd ventricle?
lamina terminalis + anterior commissure
floor of the 3rd ventricle?
infundibulum + optic chiasm
posterior wall of the 3rd ventricle?
pineal wall
lateral border of the 3rd ventricle?
medial nuclei of thalami
what are the 3rd ventricle recesses?
infundibular, supraoptic, pineal, suprapineal
what connects the 3rd to the 4th ventricle?
cerebral or mesencephalic aqueduct
what is another name for the cerebral aqueduct?
aqueduct of sylvius
what is the inferior portion of the 4th ventricle called?
obex
what does the obex connect?
the central canal of the spinal cord and the 4th ventricle
anterior border of the 4th ventricle?
rhomboid fossa
posterior border of the 4th ventricle?
cerebellar peduncles + superior/inferior medullary velum
lateral walls of the 4th ventricle?
cerebellar peduncles
how does the 4th ventricle communicate with the subarachnoid spaces?
medial foramen of magendie + lateral foramen of luschka
ependyma
thin, neuroepithelial lining of the ventricles and central canal of the spinal cord
choroid plexus
produces CSF + barrier between blood and CSF
function of CSF
provide cushion to protect the brain, drainage of cerebral metabolites, + regulate cerebral blood flow
CSF volume
150mL
CSF components
99.13% water + .87% organic/inorganic substances
flow of CSF
lateral ventricles > interventricular foramen > 3rd ventricle > cerebral aqueduct > 4th ventricle > subarachnoid space > cisterna magna > arachnoid villi > dural venous sinuses
where does CSF drain into?
subarachnoid space
where is the subarachnoid cistern located?
cisterns
compartments within the subarachnoid space where the pia mater + arachnoid membrane are not close
arachnoid villi function
return CSF to venous circulation through the dural venous sinus
dural venous sinuses
large valveless venous channels that drain venous blood from cranial cavity
where are dural venous sinuses located?
periosteal dura + meningeal dura
function of dural venous sinuses
maintain systemic circulation by collectively returning deoxygenated blood from the cranial vault
cerebral + cerebellar veins
cross subdural space to drain into the superior sagittal vein
emissary veins
venous structures that allow communication between intracranial + extracranial vessels
diploic veins
intraosseous venous vessels that drain blood between the inner + outer layer flat bones of the skull
meningeal veins
collect blood from the meninges + drain
arachnoid granulations
CSF returning to the venous circulation
superior sagittal sinus location
base of the falx cerebri + runs from the foramen cecum to occipital protuberance
what is the superior sagittal sinus function?
main location for CSF return after passing arachnoid granulations
inferior sagittal sinus location
free margin of the falx cerebri
inferior sagittal sinus function
collects blood from the falx + medial surfaces of brain hemispheres
where does the inferior sagittal sinus drain?
straight sinus
straight sinus location
within the posterior end of falx cerebri + middle of tentorium cerebelli
straight sinus function
drains the cerebellum, thalamus, + basal ganglia
confluence of sinuses
site of union for the superior sagittal sinus, straight sinus, occipital sinus, + transverse sinus
transverse sinus
paired. drains the blood from the veins of the cerebellum + inferior surface of brain
where does the transverse sinus receive blood from?
superior petrosal sinus
where does the sigmoid sinus drain into?
paired. drains into the internal jugular vein
where does the sigmoid sinus begin?
after the tentorium cerebelli ends
cavernous sinus function
drains the anterior/inferior surface of the brain
cavernous sinus location
either side of the sella turcica + body of the sphenoid bone
contents of cavernous sinus
oculomotor n (CN III), troclear n (CN IV), abducens n (CN VI), trigeminal ophthalmic branch, trigeminal maxillary branch, internal carotid artery
what can cause cavernous sinus syndrome?
mass effect from tumor, infection, or thrombus
pituitary adenoma
most common benign brain tumor in adults (10%)
superior petrosal sinus location
petrous part of the temporal bone in the base of tentorium cerebelloi
superior petrosal sinus function
drains the venous blood from the brainstem, temporal lobe of cerebrum, cerebellum, middle + inner ear
what is CN I?
olfactory
what is CN II?
optic
what is CN III?
oculomotor
what is CN IV?
trochlear
what is CN V?
trigeminal
what is CN VI?
abducens
what is CN VII?
facial
what is CN VIII?
vestibulocochlear
what is CN IX?
glossopharyngeal
what is CN X?
vagus
what is CN XI?
accessory
what is CN XII?
hypoglossal
CN I functional classification
sensory
CN II functional classification
sensory
CN III functional classification
motor
CN IV functional classification
motor
CN V functional classification
both sensory + motor
CN VI functional classification
motor
CN VII functional classification
both sensory + motor
CN VIII functional classification
sensory
CN IX functional classification
both sensory + motor
CN X functional classification
both sensory + motor
CN XI functional classification
motor
CN XII functional classification
motor
what nerves have parasympathetic functions?
CN III, VII, IX, X
what nerves are special somatic afferent?
CN II (optic) + CN VIII (vestibulocochlear)
what nerves are general somatic afferent?
CN V (trigeminal). small amount of fibers from CN VII (facial), CN IX (glossopharyngeal), and CN X (vagus)
what nerves are special visceral afferent?
CN VII (facial), CN IX (glossopharyngeal), CN I (olfactory)
what nerves are general visceral afferent?
CN IX (glossopharyngeal), CN X (vagus)
what nerves are general visceral efferent?
CN III (oculomotor), CN VII (facial), CN IX (glossopharyngeal), CN X (vagus)
what nerves are special visceral efferent?
CN V (trigeminal), CN VII (facial), CN IX (glossopharyngeal), CN X (vagus), CN XI (accessory)
what nerves are general somatic efferent?
CN III (oculomotor), CN IV (trochlear), CN VI (abducens)
CN III parasympathetic functions
pupil constriction. smooth muscle of inner eye
CN VII parasympathetic function
salivatory and lacrimal glands
CN IX parasympathetic function
parotid gland (salivation)
CN X parasympathetic function
muscles of heart, lung, and bowel that are involved in movement + secretion
special somatic afferent function
sensory info about vision, balance, + hearing
general somatic afferent function
sensory info from receptors in skin, muscle, + joints of head
special visceral afferent function
sensory info about taste and smell
general visceral afferent function
sensory info from viscera in the core (heart, vessels, lungs)
general visceral efferent function
preganglionic autonomic fibers to the core + periphery
special visceral efferent function
motor info to muscles of the jaw, face, larynx, pharynx from branchial arches
general somatic efferent function
motor info to skeletal muscles of the eye and tongue
CN I function
smell
CN II function
vision
CN III function
eye movements, pupillary constriction, upper eyelid
CN IV function
eye movement (intorsion - down + in)
olfactory receptors
bi-polar neurons
sustentacular cells
supporting cells of olfactory epithelium
what cranial nerve does NOT have to relay information to the thalamus?
CN I - olfactory
what is 80% of our reality based on?
vision
special somatic sensory pathway
retina > optic nerve > optic chiasm > optic tract > lateral geniculate nucleus > loop of meyer > calcarine sulcus
what is it called when there is a leison to the optic nerve?
bitemporal hemianopsia
associated field of defect with bitemporal hemianopsia
lateral field of vision, bilateral
LR6 SO4
3
meaning
lateral rectus m, CN 6. superior oblique m, CN 4. All other eye muscles, CN 3
what is the edinger-westphal nucleus?
nucleus of parasympathetic function for oculomotor n
pupillary constriction is mediated through which cranial n?
oculomotor n
what is the smallest cranial n in diameter?
trochlear n
what cranial nerve arises from posterior brainstem?
trochlear n
CN V function
somatic sense from, mouth, cornea. muscles of mastication
CN VI function
lateral eye movement
CN VII function
muscles of facial expression. taste to anterior 2/3 tongue
CN VIII function
hearing + sense of balance
trigeminal n branches
opthalmic, maxillary, and mandibular
what are the muscles of mastication innervated by the trigeminal n?
masseter, temporalis, medial and lateral pterygoid muscles
what extraocular muscles are innervated by abducens n?
lateral rectus
facial n motor function
muscles of facial expression
facial n parasympathetic function
salivary and lacrimal glands
facial n visceral function
taste for anterior 2/3 tongue
stapedius function
transmit vibration to sound in the ear
stroke vs bells palsy
vestibularcochlear n functions
balance/equilibrium and hearing
cochlear branch of CN VIII pathway
lateral lemniscus > inferior colliculus > medial genticulate nuclei > primary auditory cortex
CN IX function
sensory - posterior 1/3 of tongue and pharynx. taste - posterior 1/3. chemoreceptors + baroreceptors
CN X function
autonomic function of gut. cardiac inhibition. sensation from larynx + pharynx. muscles of vocal cords. swallowing
CN XI function
trapezius and sternocleidomastoid
CN XII function
movement of tongue
CN IX parasympathetic function
stimulation of parotid gland
CN IX taste function
posterior 1/3 of tongue, bitter taste
CN IX somatic sensory function
general sensation to posterior 1/3 tongue, pharynx, external ear, tympanic membrane
CN IX parasympathetic modality
general visceral efferent (GVE)
CN IX taste modality
special visceral afferent (SVA)
CN IX somatic sensory modality
general somatic afferent (GSA)
what cranial nerve is considered to be 75% parasympathetic functions?
CN X - vagus
CN X parasympathetic function
saliva production
what nucleus is associated with the parasympathetic function of vagus n?
dorsal motor nucleus
CN X somatic sensory somatic function
posterior meninges, skin on back of ear, external acoustic meatus, pharynx, larynx
what does CN XI innervate?
trapezius and sternocleidomastoid
CN XII function
tongue movements. speech and swallowing
CN XII modality for tongue movement function
GSE