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Exam 1
Cards for Exam 1 Review
416
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Graduate
10/01/2011

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Term
Gray matter
Definition
Outside and in center of brain and is cell bodies
Term
white matter
Definition
inside of brain an is axons
Term
Preembryonic time stage
Definition
0 to 2 weeks
Term
what happens during preembryonic stage?
Definition
once cell will mulitply to many cells and then forms the blastocyst which forms around what will become the body.
Term
what does the outside of the blastocyst become?
Definition
placenta
Term
What are the 3 stages in the preembryonic?
Definition
Fertilized egg, blastocyst, embryonic disk
Term
what are the two cell layers of the embryonic disk?
Definition
ectoderm (top layer) and endoderm (bottom layer)
Term
Time stage for embryonic stage?
Definition
weeks 2 to 8
Term
what happens in embryonic stage?
Definition
formation of organs
Term
ectoderm forms:
Definition
sensory organs, epidermis, NS
Term
mesoderm forms:
Definition
dermis, muscles, skeleton, excretory and circulatory sytems, CT
Term
endoderm forms:
Definition
gut, liver, pancreas, respiratory system
Term
what are the 3 developmental stages?
Definition
preembryonic, embryonic, fetal
Term
time stage for fetal?
Definition
week 8 to birth
Term
what ar 3 things that happen in the fetal stage?
Definition
development of the NS, myelination, and nerves become specific fibers and start to innervate structures
Term
when does the nerual tube formation happen?
Definition
days 18-26 (embryonic stage)
Term
What are the 6 steps involved in the neural tube formation process?
Definition
Thickening of ectoderm, edges of plate fold, neural tuve formed on day 21, cells separate from tube, neural tube and neural crest move inside the embryo, differentiation of tissue
Term
Where does the thickening of the ectoderm in the nerual tube formation occur? What is this called?
Definition
Happens at the embryo's back and is called the neural plate
Term
when the edges of the plate fold in neural tube formation, what does it form?
Definition
neural groove
Term
when the neural tube is formed, where does the formation start and what direction does it head?
Definition
starts in the middle and spreads toward head and tail
Term
when the cells separate from the tube in neural tube formation, what does it form?
Definition
neural crest
Term
Whate are the two types of tissue differention that happens in neural tube formation? What color is the tissue and what are they?
Definition
Mantle layer (inner)- cell bodies (gray matter)
Marginal layer (outer): white matter (axons)
Term
what are somites (nodules)?
Definition
nodules of cell clusters within mesoderm surrounding neural tube
Term
Whate are the 3 somites and what do they become?
Definition
Sclerotome: vertebrae and skull
myotome: skeletal muscle
dermatome: dermis
Term
what are the 4 structures that the neural crest becomes?
Definition
Sensory neurons, autonomic neuron, myelin-producing cells, parts of endocrine organs
Term
when does the brain begin to form?
Definition
day 26
Term
what are the 3 enlargments in brain formation?
Definition
hindbrain, midbrain, and forebrain
Term
what are the components of the hindbrain?
Definition
medulla, pons, cerebellum, fourth ventricle
Term
what are the components of the midbrain?
Definition
midbrain and cerebral aqueduct
Term
what are the components of the forebrain?
Definition
posterior forebrain (thalamus and hypothalamus and third ventricle); anterior forebrain (cerebrum, and lateral ventricles)
Term
where is the CSF stored?
Definition
ventricles
Term
between what time span in development can major developmental disorders occur in?
Definition
between day 14 and week 20
Term
What is anencephaly?
Definition
cerebral and cerebellar hemispheres are not formed, brainstem is present but malformed, skull does not form
Term
what causes anencephaly?
Definition
chromosomal abnormalities, maternal nutritional deficiencies, maternal hyperthermia
Term
in regards to the neural tube closure, what didn't happen which causes anencephaly?
Definition
didn't close at top correctly
Term
what is spina bifida?
Definition
inferior portion of neural tube doesn't close correctly, vertebrae do not close around neural tube, may hba normal function if neural tissue doesn't protrude
Term
what causes spina bifida?
Definition
maternal folic acid deficit
Term
what is chiari malformation?
Definition
herniation of cerebellar tonsil through the foramen magnum
Term
when do symptoms begin for chiari malformations?
Definition
adolescence or early adulthood
Term
what are symptoms of chiari malformations?
Definition
head and neck pain (occiptal headaches that usually are worse when cough, sneeze, or strain), nystagmus, double vision, cranial nerve dysfunction (#2-#7), poor coordination/walk irregularly/might choke on things more
Term
what can be done for chiari malformations?
Definition
surgery to remove part of back of skull to make more room for cerebellum
Term
what is cerebral palsy?
Definition
movement and postural disorder, permanent and non-progressive brain damage
Term
what causes cerebral palsy?
Definition
abnormal development in utero or after delivery; metabolic, immune, or coagulation disorders; infection; trauma; hypoxia (not enough O2)
Term
what are symptoms of cerebral palsy?
Definition
scissor gait (cross feet when walk); motor disorders; cognitive, somatosensory, visual, auditory, and speech deficits; may have normal and above normal intelligence; strabismus
Term
what is fetal alcohol syndrome?
Definition
cognitive, movement, and behavioral problems; growth deficiencies; mental retardation
Term
what are the facial anomalies associated with fetal alcohol syndrome?
Definition
small head, eyes set far apart, epicanthal folds, small palpebral fissure, short nose, thin upper lip
Term
what are the direct and indirect effects in fetal alcohol syndrome?
Definition
direct: crosses the placenta (and baby can become addicted)
indirect: vasoconstriction (don't get enough blood supply for fetus to develop properly)
Term
what is long-term potentiation in regards to learning and memory?
Definition
conversion of silent synapses to active synapses (stimulation of diff parts of brain creates more synapses)
Term
what is neuroplasticity?
Definition
lifelong ability of a nerve to compensate for injury and adjust its activity in response to the environment (brain grows and develops all through life)
Term
when is the most dramatic period of neuroplasticity?
Definition
first 2 years of life
Term
why is stimulation so important in the first 2 years of life in regards to neuroplasticity?
Definition
synapses form more and earlier; more dendritic branching; more synapses; higher gene expression
Term
what are 3 neuronal responses to injury?
Definition
wallerian degeneration, regeneration, and reorganization or the cerebral cortex
Term
what is wallerian degeneration?
Definition
distal axon degenerates, myelin surrounding distal portion of nerve degenerates, macrophages phagocytize the myelin, call body and postsynaptic cell may also degenerate
Term
which nervous system has the most regeneration, PNS or CNS?
Definition
Some regeneration in PNS and none in CNS
Term
how does nerve regeneration happen?
Definition
Axon proximal to the cut first degenerates then starts the regeneration process. the Schwann cells form a column along the area where the axon was. the axon grows across the area which the nerve was cut and enter the schwann cell columns. the neuron reinnervates the structure, and a new myelin sheath is formed.
Term
what is collateral sprouting?
Definition
an undamaged neuron branches to make a synapse at a site where a damaged neuron used to synapse
Term
regenerative sprouting
Definition
occurs when the axon and its target have been damaged; injured axon send out side sprouts to a new target
Term
reorganization of cerebral cortex
Definition
cortical maps (maps of functional areas of the cerebral cortex) can be modified by sensory input, learning, or following injury to the brain
Term
what is a neuron
Definition
designed to receive information, process information, and generate output. transmits impulses from one area of the body to another.
Term
functions of dendrites
Definition
receive info from other neurons via NT and transmit it to cell body; produce local potentials, and if strong enough, action potential
Term
function of axon
Definition
transmit AP away from cell bodies; transmit proteins, NT, empty vesicles, and other substances between cell body and presynaptic terminals
Term
3 neuron types
Definition
bipolar, unipolar, multipolar
Term
bipolar neurons
Definition
single dendrite and single axon
Term
where are bipolar neurons found
Definition
some specialized sensory organs including retina
Term
unipolar neuron
Definition
single axon and no dendrites
Term
where are unipolar neurons found
Definition
general sensory organs
Term
multipolar neuron
Definition
several dendrites and a single axon
Term
where are multipolar neurons found
Definition
most neuron in CNS and muscle neurons are this
Term
what is depolarization
Definition
membrane potential becomes less negative than the resting potential (resting is -70 so it becomes more positive)
Term
what is hyperpolarization
Definition
membrane potential becomes more negative than resting
Term
what is the ratio of Na+ to K+ shuttled in and out of the cell?
Definition
3 Na+ go in for every 2 K+ that go out
Term
A resting membrane potential is caused when there is a balance between what 3 things?
Definition
permeability, concentration, and charge
Term
what ions or molecules are inside and what outside during resting MP?
Definition
Na+ and Cl- are outside and K+ and negativly charged proteins are inside
Term
concentration differences between inside and outside of cell are maintained due to what three things?
Definition
presence of negatveily charged proteins in cell, permeability of cell membrane, and sodium-potassium exchange pump
Term
what is a local potential?
Definition
depolarization or hyperpolarization which is confined to a small region of the cell. if it's strong enough, an action potential is produced.
Term
local potentials can be increased by what two things?
Definition
Temporal and spatial summation
Term
temporal summation
Definition
stimuli that occur multiple times within milliseconds are added together
Term
spatial summation
Definition
stimuli that occur in different locations are added together
Term
how strong does a local potential need to be to make an action potential?
Definition
-55 mV
Term
in regards to speed of action potentials, what diameter axons propagate them faster? Are myelinated or unmyelinated faster?
Definition
Large diameter axon propagate AP faster than smaller diameter ones. Myelinated goes faster than unmyelinated.
Term
what is the purpose of a refractory period?
Definition
keeps AP from reversing the direction of propagation
Term
what are the two types of refractory periods?
Definition
absolute and relative
Term
absolute refractory period
Definition
period of time in which the axon is not sensitive to another stimulus (during depolarization phase and most of the repolarization phase)
Term
relative refractory period
Definition
only a stronger than normal stimulus can cause another AP (during the last part of the repolarization phase)
Term
how do local anesthetics work in regards to action potentials?
Definition
Pain occurs due to an AP being sent from site of pain to CNS. These act at the site to block Na+ channels which prevent the propagation of AP along sensory neurons.
Term
what is hypocalcemia
Definition
High extracellular Ca2+ levels cause Na+ channels to close. When levels of calcium are low, it causes the cellular membrane to become more permeable to Na+.
Term
symptoms of hypocalcemia
Definition
muscles spasms/cramps (2 much Na+ coming in), nervousness, tetany (muscles locking up)
Term
causes of hypocalcemia
Definition
lack of calcium in diet, lack of vitamin D, decreased secretion of parathroid hormone
Term
what are neuroglia?
Definition
support system for the neurons
Term
what are the 3 neuroglia in the CNS
Definition
astrocytes, oligodendrocytes, microglial cells
Term
what is the one neuroglia in PNS
Definition
schwann cells
Term
Roles of astrocytes
Definition
star-shaped cells; provide physical support to neurons and blood vessels; role in cell signaling; aid in formation of the BBB by releasing chemicals that stimulate tight junctions between endothelial cells; regulates content of extracellular space; transport nutrients to neurons; guides nerves to where they need to be in CNS development; clean up cells and phagocytosis
Term
oligodendrocytes
Definition
protect and insulate neurons in CNS (gives us myelination); cytoplasmic extensions wrap around axons many time to produce the myelin sheath which allows for efficient conduction of AP; can supply myelin to several axons
Term
microglia
Definition
specialized macrophages in CNS; phagocytosis "immune system of CNS"
Term
schwann cells
Definition
protect and insulate neurons in PNS; wraps around an axon many times to produce the myelin sheath which allows for efficient conduction of AP; only myelinates one axon; phagocytic
Term
nodes of ranvier
Definition
in myelinated axons: interruptions in myelin sheath, contain high density of Na+ and K+ channels; allow AP to skip over and moves so fast
Term
saltatory conduction
Definition
AP jump from one node of ranvier to the next causing the AP to travel much faster than in an unmyelinate axon
Term
multiple sclerosis
Definition
autoimmune disease in which antibodies attack myelinated CNS nerves; all glial cells in CNS are affected; loss of saltatory conduction; axons can be sparred, partially damaged, or totally destroyed. if axons are totally destroyed irreversible neurological damage occurs
Term
symptoms of multiple sclerosis
Definition
weakness, lack of coordination, decreased vision, double vision, impaired sensation, bladder and bowel dysfunction, depression
Term
optic neuritis etiology
Definition
age of onset: 20-50 years with a mean age of about 30-35
more common in women
prevalence: 115 per 100,000
Term
optic neuritis symptoms
Definition
90% of patients have pain or discomfort around eye with eye movement; decreased vision (degree of loss varies widely, usually monocular); flashes of light may also occur
Term
optic neuritis signs
Definition
afferent pupillary defect; decreased visual acuity; acquired color loss; visual field deficit; decreased contrast sensitivity; optic neuritis (only 1/3 have this), the rest of retrobulbar optic neuritis
Term
treatment/prognosis for optic neuritis
Definition
90% spontaneously recover within 3-5 weeks; a 3 day course of IV corticosteroid followed by 15 days of oral prednisone and then interferon beta-1a lowers the risk of developing MS over 3 years to 35% instead of 50% risk in untreated patients
Term
Excitatory Postsynaptic potential
Definition
when a NT causes an increased permeability to Na+ ions causing a local potential, and if strong enough, an action potential
Term
inhibitory postsynaptic potential
Definition
when NT causes increase permeability to K+ and Cl-, hyperpolarization occurs
Term
neuromodulator
Definition
influences the likelihood an AP will occur in postsynaptic cell (released in axo-axonic synapse) and can influence the amount of NT released from the presynaptic terminal
Term
presynaptic inhibition
Definition
decreases NT release froom presynaptic membrane and less likely to get AP
Term
presynaptic facilitation
Definition
increases NT release from presynaptic membrane and more likely to get AP
Term
does the NT or receptor make the AP inhibitory/excitatory?
Definition
receptor
Term
what is the 1 cholinergic NT
Definition
acetlycholine
Term
where is ACh found?
Definition
neuromuscular junction of skeletal muscle
Term
what kind of regulation is ACh involved in?
Definition
autonomic
Term
2 receptors for ACh
Definition
nicotinic (brief opening and ALWAYS excitation) or muscarinic (slow-acting and can be either excitatory or inhibitory depending on the tissue it's found in)
Term
what blocks the release of ACh causing paralysis?
Definition
botulinum toxin
Term
what is caused by the destruction of ACh receptors on skeletal muscle membranes?
Definition
myasthenia gravis
Term
what are 4 amino acid NT?
Definition
glutamate, aspartate, GABA, glycine
Term
what is the primary NT in CNS?
Definition
glutamate
Term
what do glutamate and aspartate do?
Definition
elicit neural plasticity in learning and development, contributes to cell death after injury to the CNS
Term
what is major inhibitory NT in CNS
Definition
GABA
Term
what does GABA do?
Definition
prevents excessive neural activity
Term
what 2 things activate GABA receptors?
Definition
benzodiazepines and barbituates
Term
What increases the presynaptic release of GABA reducing excessive muscle activity
Definition
baclofen
Term
what does glycine do?
Definition
inhibitory and prevents excessive neural activity
Term
what inhibits glycine receptors?
Definition
strychnine
Term
what are the 3 monoamine NT
Definition
norepinhephrine, serotonin, and dopamine
Term
what is norepinephrine's main role?
Definition
increasing attention to sensory information (fight or flight)
Term
where is norepinephrine found?
Definition
sympathetic ANS
Term
what are the 4 receptors for norepinephrine?
Definition
alpha1, alpha2, beta1, beta2
Term
is norepi excitatory, inhibitory, or both?
Definition
both
Term
what are two disorders that involved excessive levels of norepi?
Definition
panic disorder and post-traumatic stress disorder
Term
How do MAO inhibitors affect norep?
Definition
increase they affect of norepi by decreasing the activity of monoamine oxidase (typically breaks down norepi)
Term
what blocks reuptake of norepi?
Definition
cocaine
Term
what do amphetamines do to norepi?
Definition
increase release and block reuptake
Term
what is serotonin's role in the body?
Definition
arousal level, mood, and suppressing sensory information
Term
is serotonin excitatory or inhibitory?
Definition
inhibitory
Term
what do anti-depression drugs do to serotonin?
Definition
block its reuptake
Term
dopamine has an effect on what 3 things?
Definition
motor activity, congnition, and motivation
Term
is dopamine excitatory or inhibatory?
Definition
both
Term
what are the 3 peptide NT?
Definition
endorphins, enkephalins, and substance p
Term
endorphins/enkephalins are excitatory or inhibitory?
Definition
inhibitory
Term
substance p is excitatory or inhibitory?
Definition
excitatory
Term
what 3 NT are associated with pain perception?
Definition
endorphines, enkephalins, substance P
Term
how many pairs of nerves are in the PNS
Definition
43 pairs
Term
of the 43 pairs of nerves in the PNS, ho0w many are cranial and how many are spinal?
Definition
12 cranial and 31 spinal
Term
cell bodies are located where for the afferent division of the ANS?
Definition
dorsal root ganglia near spinal cord
Term
2 subdivisions of PNS
Definition
afferent and efferent
Term
2 subdivisions of efferent
Definition
somatic NS and ANS
Term
what is the somatic NS?
Definition
transmits AP from CNS to skeletal muscle
Term
where are the cell bodies located in SNS?
Definition
within CNS
Term
what does the ANS do?
Definition
transmits AP from CNS to smooth muscle, cardiac muscle, or glands
Term
what are the 3 subdivisions of ANS?
Definition
parasymp, symp, and enteric
Term
where do the preganglionic fibers of the Sympa NS originate?
Definition
central portion of the spinal cord
Term
The preganglionic fibers leave the spinal cord between what two vertebrae?
Definition
T1 and L2 vertebrae
Term
after the preganglionic fibers leave spinal cord in symp NS, where do they project to?
Definition
sympathetic chain ganglia
Term
what 2 nerves from the symp NS don't synapse in the symp chain ganglia?
Definition
splanchnic and adrenal medulla
Term
what does the splanchnic nerve innervate?
Definition
pancreas, abdomen, and gut
Term
what cells is the adrenal medulla derived from?
Definition
neural crest
Term
what does the adrenal medulla do?
Definition
secretes epineph and norepineph into bloodstream
Term
What % of cells in adrenal medulla secrete epinephrine? Norepinephrine?
Definition
80% epinephrine and 20% norepinephrine
Term
what do the branches from the superior cervical chain ganglia in the sympa nerve system supply?
Definition
blood vessels to skin/skeletal muscles of the face; sweat glands of face; salivary glands; dilator muscle of iris; mueller's muscle (around eyes and helps levator lift eyelid); blood vessels that supply the lacrimal gland
Term
if the sympa NS is stimulated for lacrimal gland and salivary gland, do the eyes/mouth get more wet or dry?
Definition
Get dry
Term
what is horner's syndrome?
Definition
any lesion that affects the sympa pathway to the eye
Term
signs of horner's syndrome
Definition
ipsilateral ptosis, miosis (constriction of pupils), anhidrosis (lack of sweating on same side)
Term
causes of preganglionic horner's syndrome
Definition
cerebral vascular accident (stroke), multiple sclerosis (degeneration of myelination on axons), pituitary tumor, pancoast's tumor (tumor of apex of lung), mediastinal mass (area between lungs), neck trauma, coronary bypass surgery, tyroidectomy
Term
causes of postganglionic horner's syndrome (not as serious)
Definition
head or neck trauma, migraine, vascular (diabetes, HTN), cluster headache, herpes zoster, internal carotid dissection (rip in wall and blood is turbulent going through)
Term
what is the first step in checking for horner's syndrome?
Definition
use 4 or 10% cocaine which blocks reuptake of norepinephrine. if not horner's, pupil will dilate. if it is horner's, pupil will not dilate.
Term
if no cocaine is available, what can you do instead to check for horner's?
Definition
use apraclonidine which is a glaucoma drug. it normally doesn't dilate the eye but it will cause dilation in patient with horner's. this is becaue when you get nerve damage, nerves become hypersensitive and things that normally wouldn't dilate the eye do dilate it.
Term
after you determine a patient has horner's, what do you do to determine where the damaged nerve is?
Definition
use 1% hydroxyamphetamine which stimulates release of norepi from postganlionic cell. no dilation will occur if damage is in postsynaptic nerve because norepi cannot be released from damaged nerve. if dilation occurs, it's preganglionic lesion.
Term
what 2 places do preganglionic fibers of the parasymp NS originate?
Definition
cranial nerve nuclei in brainstem and lateral parts of the sacral region of the spinal cord (S2-S4)
Term
what 4 nerves carry parasymp info?
Definition
3, 7, 9, 10
Term
parasymp fibers in oculomotor (CN 3) supply what two muscles?
Definition
ciliary muscles and sphincter muscle of iris (constrict pupil)
Term
what 3 things do the parasymp fibers in the facial nerve (CN 7) supply?
Definition
lacriaml gland, mucus glands in nasal cavity, and sublingual salivary glands
Term
when the parasymp stimulates lacrimal gland and salivary gland, do you get wet or dry sensations?
Definition
wet
Term
parasymp fivers in glossopharyngeal nerve (CN 9) supply what one thing?
Definition
parotid salivary gland
Term
parasymp fibers in vagus nerve (CN 10) supply what 4 things?
Definition
cardiac plexus, pulmonary plexus, esophageal plexus, and digestive organs
Term
what is a vasovagal response
Definition
person faints, or feels faint, due to the lack of blood to the brain
Term
what causes a vasovagal response?
Definition
powerful emotions stimulating the vagus nerve (like fear of drops being put in eye or something coming close to eye)
Term
before a patient has a vagovasal response, what might they report?
Definition
weakness, lightheadedness, nausea, blurred vision, impaired hearing, near syncope
Term
if someone is about to have a vasovagal response, what should you do with them?
Definition
lay them down for 20 min. DO NOT let them stand up
Term
all postganlionic neurons of parasymp system are what kind of receptor?
Definition
cholinergic
Term
almost all postganglionic neurons of sympa system or what kind of receptor?
Definition
adrenergic
Term
sympathetic effect on arteries
Definition
alpha constricts
beta dilates
Term
sympathetic effects on ciliary muscle
Definition
beta 2 possible slight relaxation
Term
sympathetic effect on pupil
Definition
alpha 1 dilation
Term
sympa effect on lacrimal gland
Definition
alpha: slight decreased tear production due to BV constriction
Term
sympa effect on salivary
Definition
alpha 1: BV constriction, slight viscouse saliva production
Term
sympa effect on salivary
Definition
alpha 1: BV constriction, slight viscouse saliva production
Term
sympa effect on salivary
Definition
alpha 1: BV constriction, slight viscouse saliva production
Term
sympa effects on heart
Definition
beta 1 and 2: increased contraction force
beta 1: increased heart rate
Term
sympa effect on lungs
Definition
beta 2: dilates bronchiole
Term
parasymp effect on arteries
Definition
none
Term
parasymp effect on ciliary muscle
Definition
muscarinic: contraction
Term
parasymp effect on pupil
Definition
muscarinic: constriction
Term
parasymp effect on lacrimal gland
Definition
muscarinic: increased tear production
Term
parasymp effect on salivary
Definition
muscarinic: BV dilation, thin saliva production
Term
parasymp effect on heart
Definition
muscarinic: decreased rate of contraction
Term
parasymp effect on lungs
Definition
muscarinic: constricts bronchiole
Term
beta blockers are used in treatment of what?
Definition
glaucoma
Term
phenylephrine stimulates what receptors?
Definition
alpha adrenergic
Term
what do you use when tou want to block cholinergic stimulation in the iris sphincter muscle and ciliary muscle
Definition
tropicamide
Term
what causes myasthenia gravis?
Definition
body produces antibodies to nicotinic receptors on skeletel muscle cells. normal amounts of ACh are released, but receptors are insufficient to cause an AP.
Term
what are the ages of onset of myasthenia in men and women?
Definition
women: 20-30 years
men: 60-70 years
Term
what are some muscle movements that are commonly affected in myasthenia?
Definition
eye movement and eylids are often affected first; facial expression; swallowing, chewing, and talking; proximal limb movement; respiration
Term
what are some opthalmic symptoms for myasthenia?
Definition
ptosis (progresses througout day and may involve one or both lids), double vision (gets worse throughout day)
Term
what are some opthalmic signs for myasethenia?
Definition
ptosis, ocular motility disorder and misalignment, saccades slow with fatigue, can open eyelids easily when patient tries to keep them closed indicating weak orbicularis muscle
Term
treatment for myasthenia
Definition
anticholinesterase medications: drugs that allow ACh to stay in the synaptic cleft longer; removal of thymus gland; immunisuppresive drugs
Term
what are the diff types of neuro-imaging
Definition
plain films (standard x-ray), CT/CAT (computer axial tomography), MRI (magnetic resonance imaging), angiography (look at blood vessels), CTA, MRA/V
Term
axial/horizontal cut
Definition
divides superior from inferior
Term
cranial cut
Definition
divides posterior from anterior
Term
coronal (frontal) cut
Definition
divides right from left
Term
what is the benefit of looking at several different cuts of imaging?
Definition
get a sense of how much tissue is involved in the problem
Term
what is something called that is bright on a scan?
Definition
bright signal
Term
why can't you use the word "enhancement"?
Definition
It means you looked at a scan before and after a contrast signal was used
Term
what are bright and dark spots referred to on CT scans?
Definition
hyperDENSE (bright) and hypoDENSE (dark)
Term
what are bright spots called on an MR scan?
Definition
hyperINTENSE (bright) and hypoINTENSE (dark)
Term
What are the benefits of plain film images?
Definition
fast and inexpensive
Term
what are plain films used for?
Definition
bone and metal/dense objects
Term
what color does air show as in a plain film?
Definition
black. air where you don't expect to see it may indicate a fracture
Term
what does air appear as in soft tissue in plain film?
Definition
air appears round
Term
what is contrast enhancement?
Definition
based on different attenuation of x-ray beam by various tissues (attenuation is the process of getting lighter)
Term
what does increased attenuation mean?
Definition
increase density, atomic number and electrons per gram. more attenuation= lighter image
Term
why should you do a plain film before an MRI in certain cases like a car accident?
Definition
determines if there are any metal pieces in the body. can't put person in MRI if they have metal in them because MRI is a big magnet...
Term
what are CAT/CT scans good for?
Definition
bone/calcium; blood (especially recent trauma and acute sub-dural, sub-arachnoid hemorrhage); meningiomas (tumors of covering of brain); fat; orbital muscles; mummies!!
Term
what is the scale rang on CT scans? what is darkest and what is lightest?
Definition
-1000 to +1000. -1000 is very black and +1000 is very light
Term
what is a scout?
Definition
generalized image of where you are located and let's you know where you're working at
Term
Bleeds show up light or dark in CT scans?
Definition
light
Term
What would the CT scan look like for someone with thyroid myopathy?
Definition
The tendons behind the eye look like a brontasaurus (fat body and thin tendon)
Term
why might someone with throid myopathy come into our office?
Definition
eye being pulled down and seeing double all the time
Term
what is hydrocephalus?
Definition
enlargement of the ventricles
Term
what is another term used for hydrocephalus?
Definition
water on the brain
Term
who should you avoid using CT scans on and why?
Definition
children and pregnant women because it uses a very high dose of radiation
Term
what are 3 good reasons to use CT?
Definition
available in ER (fast, no danger from meatallic objects); relatively low cost (compared to MRI); different window widths used
Term
what cut is not available in CT?
Definition
sagittal
Term
what kind of contrast is used in CT?
Definition
iodine based
Term
who should you avoid giving the iodine based contrast to?
Definition
ppl with allergies to iodine and shellfish and to people with abnormal kidney function (because it's metabolized in the kidney)
Term
what does it mean if contrast crosses the BBB in a CT?
Definition
there is a break in the BBB because things don't just go through
Term
what kind of scan can you use for an autopsy?
Definition
CT
Term
what color does air show up in a CT? Blood?
Definition
air= black and blood= white
Term
what are "windows" in CT scans?
Definition
manipulation of a volume of data based on ability to block xray beam... manipulates starting point
Term
why is MR premiere means for intracranial pathology evaluation?
Definition
1) radiation exposure with CT
2) increased soft-tissue contrast with MR
Term
what does a CT rely on to work?
Definition
different attenuation of x-ray beam
Term
what does MR rely on to work?
Definition
response of tissue to applied magnetic field
Term
What are MRIs used for?
Definition
Anatomy studies (soft tissue)
Term
What do MRIs use to work/how do they work?
Definition
usese magnetic field affecting H+ atom alignment. No radiation. Followed by radiofrequency pulse to realign atoms.
Term
What are sagittal sections of MRIs used to see?
Definition
pituitary gland, corpus callosum, cervico-medullary junction, pineal gland
Term
what does "weighting" mean in terms of an MRI?
Definition
look at relaxation rate
Term
what do T1 and T2 mean in MRIs?
Definition
Time to realign nuclei
Term
In T1 images, is high H2O content dark (hypointense) or light (hyperintense)?
Definition
High H2O content is DARK (hypointense)
Term
Are CSF and vitreous light or dark on a T1 image?
Definition
dark
Term
contrast can be used for T1 or T2?
Definition
T1
Term
what substance is used for contrast in T1?
Definition
Gadolinium
Term
why is gadolinium good to use in regards to allergies?
Definition
it's not iodine based so less potential for allergic rxn
Term
how is gadolinium administered?
Definition
IV
Term
how does gadolinium work?
Definition
alters magnetic field and crosses disrupted BBB
Term
does gadolinium brighten or darken things?
Definition
brightens things so can see them
Term
what do you use gadolinium for?
Definition
suspected mass, inflammation, infiltration
Term
what are T2 images good at detecting/ what are they used for?
Definition
pathology and edema
Term
can you use contrast in T2? why or why not?
Definition
No, becasue CSF and vitreous are already white
Term
what objects are bright in T2 images?
Definition
CSF and vitreous
Term
rapidly flowing blood is black in T1, T2, or both?
Definition
both
Term
What are some advantages of CTs?
Definition
1st day ischemic stroke (where blood and O2 don't get to a spot), 1st day cerebral or cerebellar hemmorhage, initial head injury, initial brain abcess, with ferrous metal, orbital bone fracture
Term
What are some advantges of MRIs?
Definition
Infarcts older than 1 day, cavernous sinus, brainstem/posterior fossa, demyelinating disease, chiasmal lesions, intracranial tumors
Term
what are some CT disadvantages
Definition
exposure to radiation, lower resolution, poorer visualization of most intracranial tissue (especially when surrounded by bone or other beam-hardening artifacts), artifacts (streak, motion)
Term
what are some disadvantages of MRI?
Definition
longer scan time, 50% higher cost, bone or calcium lesions not image well, metallic bodies (pacemakers, cochlear implants, stents), iron oxide in tattoos interfers, obesity, clautrophobia
Term
how do you study the orbit in imaging/ how do you order the tests?
Definition
1) must specify if orbital study is required
2) need many fine cuts- coronal
3) if MRI- must do fat suppression, T2 or STIR... gadolinium is usually needed
Term
why are angiographys good?
Definition
can visualize small aneurysms and A-V malformations
Term
MRAs allows for imaging of what?
Definition
arteries and veins
Term
MRA creates and intensity difference between what two things?
Definition
flowing and stationary tissue
Term
what do MRAs focus on?
Definition
high-signal flowing blood (shows up on this whereas it shows up black on MRI and CT)
Term
MRA cannot detect aneurysms smaller than what size?
Definition
3 mm
Term
in CTA, what is injected into the patient?
Definition
IV contrast
Term
what are CTAs?
Definition
high-speed spiral CT scanning and computer-assisted generation of images of large to medium-sized arteries. shows relation of bone to vessels
Term
how are CTAs done?
Definition
patient is moved at a constant rate through the scanning field during a single breath-hold
Term
why are CTAs good?
Definition
exams are quick, less radiation and contrast are used, and patients with aneurysm clips or implanted stimulators can be scanned
Term
what are some disadvantages of CTA?
Definition
sensitivity of CTA in aneurysm detection may be limited by surgical slips or clot from recent SAH, aneurysms of PICA (posterior inferior cavernous artery) and cavernous sinus are more difficult to image, cannot resolve small vessels, patients may have adverse reactions to iodinated contrast
Term
what are the 4 ventricles
Definition
2 lateral, third, fourth
Term
which 2 ventricles are connected to form which ventricle?
Definition
2 lateral are connected in the middle to form the 3rd ventricle
Term
where is the CSF produced?
Definition
choroid plexus (inner layer)
Term
what does the brain float in? why is this important?
Definition
in the CSF so it's not banging on hard objects
Term
what are the 3 horns of the lateral ventricle?
Definition
frontal, occipital, temporal
Term
how is CSF produced?
Definition
network of capillaries embedded in connective tissue (3 layers of cells: capillary wall, CT, epithelium). formed from blood by filtration, active transport, facilitated transport and is very similar to plasma
Term
What does the CSF do?
Definition
1.clear and colorless
2.regulates extracellular environment
3.supplies water, amino acids, glucose, ions to extracellular fluid
4.protects CNS (shock absorber)
5.removes metabolites from brain (probable)
Term
How does the CSF circulate?
Definition
it is made in the choroid plexus (floor of lateral ventricles and roof of 3rd and 4th ventricles). flows from lateral ventricles into third ventricle via the interventricular foramina and from third ventricle into the fourth via the cerebral aqueduct. the CSF exits the fourth ventricle through the lateral (luschka) and medial (magendie) foramina, entering the subarachnoid space.
Term
describe the 3rd ventricle
Definition
a pair of c-shaped "horns"
horns are: anterior/frontal, occipital/posterior, inferior/temporal
extend into each hemispheric lobe
Term
where are the lateral ventricles located
Definition
below is thalmus (superior to thalmus)
above is corpus callosum (inferior to corpos callosum)
outside wall is caudate nucleus (part of limbic system)
the 2 sides connct through third ventricle
Term
how are the lateral ventricles associated with the visual pathway?
Definition
The LGN sits near inferior horn and the optic radiations (fibers going back to occipital lobe) follow the LAT ventricle back to posterior horn
Term
where is the third ventricle located
Definition
in midline of diencephalon
walls are thalamus and hypothalamus
Term
what midbrain canal connects the 3rd and 4th ventricles?
Definition
cerebral aqueduct
Term
why are the 3rd ventricles bigger in older people?
Definition
brain matter starts to shrink and ventricles expand to fill space
Term
what happens when you have an obstruction in a narrow canal like the cerebral aqueduct?
Definition
fluid can't drain and pressure builds up
Term
describe location of fourth ventricle
Definition
*space between pons and medulla anteriorly
* cerebellum posteriorly
* inferiorly continuous with central canal of spinal cord
Term
the 4th ventricle drains into subarchnoid space via:
Definition
two lateral foramina (luschka) and midline opening (magendie)
Term
what is a Danny Walker cyst? who is susceptible to them?
Definition
blocks the 4th ventricle
kids are susceptible to them
Term
what are cisterns?
Definition
big pooling area for CSF
Term
cisterns are a continuation of what?
Definition
subarachnoid space?
Term
the largest cistern is located where?
Definition
lumbar cistern located betwen L2 and S2
Term
where is CSF drawn using a spinal tap?
Definition
lumbar cistern between L2 and S2
Term
adults produce how much CSF daily? what does that equate to per min?
Definition
1 pint per day and is about .5 mL per minute
Term
how many mL are in the subarachnoid space and how many in lumbar sac?
Definition
90 mL in subarachnoid space and 30 mL in lumbar sac
Term
how long does it take for complete CSF circulation?
Definition
24 hours
Term
why would the ventricles swell?
Definition
back up of fluid
Term
symptoms of hydrocephalus in children
Definition
vomiting, failure to thrive (don't develop at normal rate), delay of developmental milestones, irritability, sunset sign (looks like a sunset)
Term
what causes hydrocephalus
Definition
1) excessive production of CSF (or tumors in the chorodial plexus which are rare)
2) blockage of CSF circulation (this is big one!)
3) poor secretion of CSF into venous sinuses (scarring from meningitis or hemmorhage)
4) structural (born with cysts or misformed canals)
5) bleeding
6) infection
7) neoplasm (growth like tumor)
8) vascular
9) trauma
Term
how do you help hydrocephalus
Definition
shunt
Term
what do shunts do?
Definition
fluid drains into one of these and gets reabsorbed
Term
what encloses the optic nerve and what surrounds it?
Definition
the meninges enclose the optic nerve and the CSF surrounds it
Term
___ fuses with ____ at the optic nerve
Definition
dura fuses with sclera
Term
what space surrounds the nerve
Definition
subarachnoid space
Term
what happens if there is increased intracranial pressure?
Definition
1) pressure on Central Retinal Vein (CRV) will cause the loss of spontaneous venous pulsation (will see this in the optic nerve)
2) pressure on axons within optic nerve will stop axoplasmic flow thus contributing to edema
Term
what are spontaneous venous pulsations
Definition
imbalance between pressure inside and outside vein wall
Term
spontaneous venous pulsation is seen in what % of normal eyes
Definition
75% of normal eyes
Term
spontaneous venous pulsation is lost when the intracranial pressure is over what?
Definition
200 mm Hg
Term
why, when you look at the optic nerve, do you see th spontaneous venous pulsation/why is it needed?
Definition
need pressure in eye to get vein out into brain
Term
what is papilledema
Definition
elevated intracranial pressure compresses CRV which causes edema and elevation of optic nerve head
Term
how can you tell if someone has papilledema by looking in the bakc of the eye
Definition
optic nerve outline is kind of fuzzy and it looks raise a bit and blood vessels look like corkscrews
Term
what causes an increase in brain pressure?
Definition
tumor or mass, generalized brain swelling, obstruction of CSF flow or absorption, increase in CSF production
Term
what is the flow of CSF after leaving the brainstem?
Definition
CSF continues into subarachnoid space, through arachnoid villi, through dura, and to the sagittal sinus
Term
how much CSF is usually in the central spinal canal
Definition
normally a negligible amount
Term
what are 3 clinical implications of blocked CSF
Definition
hydrocephalus (particularly lateral ventricles), increased intracranial pressure (ICP), loss of spontaneous venous pulsation
Term
how do you check the ICP
Definition
CSF tap pressure
Term
what is something you should also consider if a patient's ICP is high?
Definition
Pseudotumor cerebri aka Benign idiopathic (specific to you) intracranial hypertension. this is likey a meningeal absorption defect and it is slow, no dilation of ventricles.
Term
what are other symtpoms of hydrocephalus (maybe more for adults)
Definition
headache, difficult with vertical gaze (and brining their eyes together), paranaud's syndrome (sylvian aqueduct syndrome), problems with: gait, balance, incontinent (retain urine)
Term
how is a lumbar puncture/spinal tap done
Definition
patient is in lateral recumbent position (laying down on side with knees to chest) and a syringe is place into lumbar cistern (connected to a meter). the CSF exits resulting in movement on the pressure meter. The CSF flows into manometer until level steady
Term
what are the normal values for an adult. what about if they are overweight?
Definition
less than 200 if they are normal and about 250 for overweight
Term
what are the normal CSF pressures for infant, child, and older child?
Definition
infant: 40-50
child: 40-100
older child: 150
Term
what are the meninges?
Definition
series of membranes that cover brain. brain is supended within skull by three membrane CT covering
Term
what is the function of the meninges
Definition
stabilize, anchor, and cushion the brain
Term
what is within the meningeal layers
Definition
CSF
Term
what are the 3 layers of meninges
Definition
dura mater (closest to bone)
arachnoid (middle)
pia mater (right next to brain)
Term
what does dura mater mean
Definition
tough mother
Term
what is the dura mater made out of
Definition
dense connective tissue
Term
the outer periosteal layer of the dura mater is attached to what
Definition
skull
Term
the meningeal arteries are located where
Definition
out periosteal layer of dura mater
Term
the inner meningeal layer is attached to what
Definition
arachnoid
Term
the two layers of dura are fused except where they split to form what?
Definition
venous sinuses
Term
what are venous sinuses
Definition
where the CSF drains
Term
can the dura feel pain
Definition
yes, it is pain sensitive because of CN V (trigeminal) and CN X (vagus)
Term
the middle fossa is innervated by what cranial nerve
Definition
middle fossa: middle of brain
cranial nerve V (trigeminal)
Term
the posterior fossa is innervated by what nerve
Definition
CN X (vagus)
postior: brain stem and occipital
Term
what does the dura get its blood supply from
Definition
meningeal arteries
Term
what is located between 2 layers of dura, between bone and dura, and between dura and arachnoid?
Definition
no space. only potential spaces if something is forced in to separate these tissues
Term
the only true space between the meninges is where
Definition
between arachnoid and pia
Term
what are 2 potential spaces in cranial meninges
Definition
epidural (extradural) space: between cranium and periosteals layer of dura
subdural space: between dura and arachnoid
Term
what could cause potential spaces in meninges
Definition
blood leaking in
Term
what causes an epidural hematoma (when blood leaks in)
Definition
traumatic head injury, often fracture to temporal bone, rupture of middle meningeal artery
Term
where is an epidural hematoma located? how fast does it occur?
Definition
located between bone and dura
slowly develops because it's hard to separate these two
Term
what causes a subdura hematoma
Definition
shearing forces sever VEINS connecting to dural sinuses. could happen from violent shakes like in shaken baby syndrome
Term
where is a subdura hematoma located
Definition
between dura and arachnoid
Term
what are the two types of subural hematomas
Definition
chronic: develops slowly (weeks)
acute: faster leak and often other intracerebral injuries are evident too
Term
what is the falx cerebri and where is it located
Definition
* folds on inner layer of dura
* lies in longitudinal fissure
* extends from crista gall to tentorium cerebelli
* partially separates the 2 cerebral hemispheres (superior sagittal sinus outer border and inferior sagittal sinus at free border)
Term
what is the tentorium cerebelli and where is it located
Definition
* separates the middle cranial fossa from the posterior cranial fossa
* infratentorial compartment contains cerebellum and brainstem
* transverse sinus along outer border
* straigh sinus where falx meets tentorium
Term
tent-like appearing images in the tentorium indicate what
Definition
bleeds
Term
what does arachnoid mater stand for
Definition
spider mother
Term
what is the arachnoid mater made of
Definition
thin connective tissue
Term
the cells of the arachnoid mater are joined together by what kind of junctions? what is this for?
Definition
tight junctions. to control passage of substances
Term
how is the arachnoid connected to the pia
Definition
arachnoid trabeculae
Term
aracnoid granulations protrude into what and what do they do?
Definition
protrude into superior sagittal sinus and reabsorb CSF
Term
where is the subarachnoid space located
Definition
between arachnoid and pia
Term
at does the subarachnoid space contain
Definition
CSF
Term
what passes through the subarachnoid space
Definition
cerebral arteries and veins (for cerebrum)
Term
pools of CSF in the subarachnoid space are called....
Definition
subarachnoid cisterns
Term
what two things can cause a subarachnoid hematoma
Definition
hemorrhagiv stroke (blood vessle breaks and blood pumped out... most severe but less common) and aneurysm bleed "aschemic stroke" (blood doesn't get to where it needs to go)
Term
it a patient has a subarachnoid hematoma, what might they complain about/say
Definition
"worst headache of my life"
Term
how do you determine if it's a subarachnoid hematoma
Definition
* CT shows blood in subarachnoid space
* spinal tap shows blood in CSF
Term
what does pia mater mean
Definition
tender mother
Term
what is the pia mater
Definition
delicate CT layer
tightly adherent to brain and spinal cord surfaces
follows gyri and sulci
separates brain from CSF (which runs in subarachnoid space)
Term
what is the arterial system called that supplies the brain
Definition
circle of willis
Term
the anterior system of the brain is supplied by what general structures?
Definition
paired interal carotids
Term
the posterior system of the brain is mostly supplied by what
Definition
paired vertebrals
Term
what is the venous system? it draws blood from where to where?
Definition
system of sinuses
draws blood from head to jugular
Term
about what % of ppl have a complete circle of willis
Definition
40%
Term
the circle of willis connects what two things
Definition
anterior and posterior circulation
Term
what are the 5 main arteries of the CoW
Definition
Anterior cerebral arteries, Middle cerebral arteries, Posterior cerebral arteries, Anterior communicating arteries, Posterior communicating arteries
Term
what 3 big structures are located in the head of CoW
Definition
pituitary gland, optic chiasm, cavernous sinus
Term
what artery goes to eyeball
Definition
internal carotid artery
Term
what is the flow from heart to internal carotid artery?
Definition
aortic arch to common carotid to internal/external carotid
Term
what are the 4 segments of the internal carotid artery
Definition
cervical, petrous, cavernous, supraclinoid/intracranial
Term
describe cervical segement of the internal carotid
Definition
vertical straight, then goes into bone of head and bend into brain and goes into cavernous sinus.
vertical portion
in the neck
Term
describe petrous portion of ICA
Definition
sharp horizontal bend
enters temporal bone
Term
describe cavernous segment of ICA
Definition
S-shaped
Term
describe supraclinoid/intracranial segment of ICA
Definition
bends posteriorly
Term
What is the acronym used for the branches of the ICA
Definition
OPAAM
Term
what are the 5 branches off the ICA
Definition
Opthalmic, posterior communicating, anterior chorodial, anterior cerebral, middle cerebral
Term
describe the opthalmic branch of the internal carotid
Definition
tiny, skinny and goes to the eyeball and supplies almost everything in eye
Term
describe the anterior chorodial
Definition
small and goes backwards to supply chorodial plexus and around thalamus area
Term
what are the 4 vascular areas
Definition
anterior cerebral artery, middle cerebral artery, posterior cerebral artery, deep cerebral blood supply
Term
what two things make up the deep cerebral blood supply
Definition
lenticulostriate arteries and anterior chorodial artery
Term
describe the anterior cerebral artery
Definition
sweeps back over corpus callosum; supplies most of anterior medial surface; medial portion of parietal lobe
Term
describe the middle cerebral artery
Definition
travels with the sylvian fissure; supplies most of the lateral convexity of the brain (but not much of medial)
Term
describe the posterior cerebral artery
Definition
curves back around the brainstem; can cause problem with vision; supplies inferior and medial temporal lobe and occipital cortex (little portion of lateral)
Term
describe the lenticulostriate arteries
Definition
from middle cerebral artery; supplies basal ganglia and internal capsule
Term
describe the anterior chorodial artery
Definition
from ICA; supplies hippocampus, basal ganglia, thalamus (LGN), and posterior internal capsule (takes all fibers from brain and compresses down to brainstem)
Term
what is a transient ischemic attack
Definition
mini stroke; symptoms last about 10 min; temporary brain ischemia (not enoug blood to brain); positive (flashes of light, tingling) or negative (darkness, numbness) signs; will have double vision; will have full blown stroke if this happens and not caught; can take place in any blood vessel in brain
Term
what is a stroke
Definition
"cardiovascular accident"; inadequate blood supply causes infarction (death) of tissue... permanent disability
Term
what are the 2 types of strokes
Definition
hemorrhagic: intracerebral or subarachnoid(this is worse type of stroke)
Ishemic: something cutting blood supply off to part of brain
Term
what causes a stroke
Definition
embolic or thrombotic infarct
Term
embolic infarct
Definition
piece of material (clot) comes from differ part of bloodstream and lodges in vessel of brain
Term
thrombotic infarct
Definition
blood clot formed in that area
Term
middle cerebral artery stroke symptoms
Definition
aphasia (left hemisphere... can't talk); hemi-neglect (right hemisphere... can see both sides in vision but ignore one side); hemianopia (1/2 vision gone); sensory loss in face and arm; weakness of face and arm; contralateral deficits
Term
anterior cerebral artery stroke symptoms
Definition
leg weakness; behavior abnormalities (cuz frontal lobe controls behavior); contralateral deficits
Term
posterior cerebral artery stroke symptoms
Definition
usually only have vision loss; hemianopia; contralateral deficits
Term
watershed infarcts
Definition
loss of blood where vascular areas overlap; region between cerebral artery territories; most susceptible to ischemia; proximal arm and leg weakness; aphasia
Term
carotid stenosis
Definition
usually severe loss fo vision in 1 eye; atherosclerotic disease; thrombi can cause embolus distally; result in TIA or infarcts; amaurosis fugax (loss of blood causing loss of vision over about 10 min time... then will go away)
Term
aneurysm
Definition
dilation of arterial wall; as it grows it compresses structures much as a tumor would; can rupture subarachnoid hemorrhage (sudden and worse HA of life; sudden death)
Term
arteriovenous malformation
Definition
congential connection between artery and vein (not supposed to); "steals" blood from adjacent brain tissue; may rupture and bleed
Term
superficial structures of the brain drain to waht two things
Definition
superior sagittal sinus and cavernous sinus
Term
where is the superior sagittal sinus located
Definition
along top of brain
Term
what things go through cavernous sinus
Definition
internal carotid and cranial nerves of eye except number 2
Term
deep structures in the brain drain to what
Definition
great vein of galen
Term
what is a confluence of sinuses
Definition
where sinuses come together
Term
everything eventually drains to what...
Definition
internal jugular veins
Term
everything eventually drains to what...
Definition
internal jugular veins
Term
sagittal sinus thrombosis
Definition
associated with hypercoagulable state; obstruction of venous drainage raised ICP; hemorrhages; decreased perfusion and infarcts; seizures; HAs and papilledema
Term
BBB
Definition
tight junctions between capillary endothelium prevents large molecules from exiting the capillary; tight junctions in arachnoid cell layer have same function; excludes many pathogens from the CNS
Term
necessity of constant blood flow
Definition
brain cannot store glucose or oxygen efficitenly; oxygen consumption increases from brainstem to cerebral hemispheres (cerebral cortex is more vlubnerable than brainstem)
Term
2 ways autoregulation can occur
Definition
1) CNS can regulate own blood supply (blood pressure; metabolites)
2) dilation of arteries with (low blood pressure, oxygen, or pH; high CO2 or lactic acid)
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