Anatomy Flashcards
nervous system def. describe its 2 parts
allows body to detect & react to stimuli/changes in in/external environ. CNS = brain + spinal cord, PNS = cranial + spinal n
why are there cervical vs lumbar enlargements in spinal cord?
d/t numerous packed motor & sensory neuron cell bodies from C4-T1 innervating UE vs from T11-S1 innervating LE
know the development of the nervous system (the cephalons and corresponding ventricles)
Lec 1, slide 10. Lec 7, slide 8
how does CNS form (embryo)?
starts as thickened plate of ectoderm (neural plate) –> ectoderm folds to enclose itself –> forms neural tube
neurons vs cell body vs dendrite vs axon vs Schwann cell vs axon hillock vs presynaptic terminal
fxnal units of nervous system for communication/signal transmission vs contains organelles vs receive signals and transports them to cell body, contain neurotransmitter receptor proteins vs transports signals from cell body vs envelops axon to make myelin sheath –> inc vel of signal conduction vs connects cell body to axon where AP starts vs converts chemical/electrical signal –> contacts adjacent postsynaptic neurons
multi vs bi vs pseudounipolar neurons
mult dendrites w/ an axon; most common, all motor neurons, all autonomic neurons vs 2 processes extending from cell body; olfactory, visual, auditory/vestbular vs central process extending from cell body for CNS and peripheral process extending from cell body for receptor organ
electrical signals vs chemical signals
convey info from 1 part of neuron to another vs carry info b/w neurons
what is a synapse? what happens at chemical vs electrical synapse?
region of communication b/w neuron and target. AP at axon terminal –> Voltage gated Ca2+ channels open –> Ca2+ enters presynaptic neuron –> Ca2+ signals presynaptic NT vesicles to move to membrane –> NT released into synapse via exocytosis and bind to postsynaptic receptors –> excitatory or inhibitory of postsynaptic neuron; unidirectional but can be bi vs communication b/w 2 neurons via bidirectional electrical coupling thru gap jxns by connexon channels; does not involve NT
neuroglia/glial cells. oligodendrocyte vs schwann cell vs astrocyte vs satellite cells of ganglia vs ependymal cell vs microglia. know which glial cells are for C/PNS
nonneuronal nonexcitable cells making up nervous tissue. myelin prod, electrical insulation of CNS; contain carbonic anhydrase for carbon buffer system, iron metab, pH imbal –> dec sz threshold vs myelin prod, electrical insulation of PNS vs structural and metabolic support for neurons, form blood/brain barrier, repair/scars, “feet” vs structural and metabolic support for neuronal cell bodies vs line brain ventricles and move CSF vs phagocytic and APC in CNS. schwann & satellite = PNS, others = CNS
endo vs peri vs epineurium
delicate connective tissue sheath round myelin sheath of axon vs tough connective tissue sheath surrounding fascicle vs outermost layer of connective tissue surrounding bundles of fascicles => peripheral n
grey vs white matter
collection of cell bodies (nucleus for CNS, ganglia for PNS) and neuropil (dendrites, capillaries, neuroglia) vs collection of tracts, un/myelinated axons
know C/PNS interface at cord. lat horn spans b/w what spinal lvls and what is it involve in? what’s the intermediate zone?
Lec 1, Slide 18; Lec 8-9, slide 14. T1-L2 and autonomics –> has multipolar pre-ganglionic sympathetic neurons. contains interneurons and special nuclei
dura vs arachnoid vs pia mater meningeal layer covering the CNS. which layers make up leptomeninges?
superficial; thick, fibrous, and strong, stuck to skull cap vs intermediate; overlies cerebral vessels in subarachnoid space, against dura vs deep; directly applied to surface of CNS –> goes into sulci. arachnoid + pia
what’s CSF and how is it made?
fluid made by choroid plexus cells in brain ventricles, or ultrafiltration of plasma thru capillary wall to ECF under basolat membrane of choroid epith; occurs / net transfer of NaCl that drives water isosmotically. circulates in subarachnoid space that’s continuous around brain and spinal cord via ependymal cells
neuro vs viscerocranium of cranium/skull
has dome like roof => calvaria/skullcap and cranial base => basicranium; 8 bones: ethmoid, sphenoid, frontal, occipital, parietal x2, temporal x2 vs facial skeleton
where do middle meningeal a/v flow?
in epidural space
somatic vs autonomic nervous system
parts of C/PNS for sensory and motor innervation to body except viscera, sm muscle, glands vs motor fibers for sm muscle, cardiac conduction tissue, glandular/secretion cells; divides into para/sympathetic systems
para vs sympathetic nervous system
cranial/sacral (C3,7,9,10/S2-4); rest/digest –> pupil & bronchoconstriction, dec HR, salivation, intestinal vasodil vs thoracic/lumbar (T1-L3); f/light –> pupil & bronchodil, inc HR, inc glu, intestinal constriction
know the 7 types of neurons
Lec 2, slide 6
RMP for central vs peripheral neurons. AP for large vs small fibers
-70mV vs -90mV. -65mV vs -55mV
know graded vs action potential; spatial vs temporal summation; absolute vs relative refractory period
Lec 2, slides 11-20
what happens if there is greater vs lesser difference in RMP and threshold potential?
less excitable; hypokal = low [K+] in blood –> K+ efflux out of cells –> hyperpol –> greater stimulus required to reach threshold for AP vs more excitable; hyperkal = high [K+] in blood –> K+ influx into cells –> depol –> inactivates Na+ channels –> induces refractory period
how do myelin sheaths inc vel conduction? what occurs if you have demyelinating dz? know demyelination graphic
inc resistance and dec capacitance –> maintain current. dec resistance and inc capacitance –> lose current; internodes don’t have Na+ channels –> can’t make regenerative AP; K+ channels will be insulted from Na+ channels –> K+ channels oppose Na+ currents. Lec 2, slide 30 (dec conduction vel, freq-related block, total conduction block, ectopic-impulse gen, inc in mechanosensitivity)
neuronal cytoskel. microtubules vs intermediate/neurofilaments vs microfilaments/actin
dynamic part of cytoskel. provides tracks for axonal transport vs provides scaffold to resist pressure, connects nuclear membrane to cell membrane vs form synapses, interact w/ membrane-bound proteins
fast vs slow anterograde axonal transport. fast retrograde axonal transport
mito and vesicles move from cell body to presynaptic terminal along microtubules via motor protein kinesin driven by ATP vs cytoskel elements, soluble proteins, small neurotransmitters move but mechanism unclear. degraded vesicle and absorbed exogenous material (toxin, viruses) move from presynaptic terminal to cell body along microtubule via motor protein dynein driven by ATP
can neurons regen? can axons in CNS vs PNS regen? degen of synaptic terminal distal to lesion vs Wallerian degen vs myelin degen vs scavenging debris vs chromatolysis vs anterograde transneuronal degen vs retrograde transneuronal degen
no. not effectively vs can regrow and reconnect if environ allows it. transmission fails b/c dependent on axonal transport vs leion breaks axon into seg –> distal seg degen vs myelinated cell can survive and regen vs by microglia in CNS and macs + Schwann cells in PNS vs reversible rearrangement of cell body organelles vs degen of neuron receiving synaptic contact from injured cell vs degen of neuron that synapses on injured cell
know meninges and spaces of brain vs spinal cord
Lec 3, slide 7 vs Lec 4, slide 4
meningeal and periosteal layers of dura mater fuse except in?
dural reflections/infoldings and dural venous sinuses. KNOW EXAMPLES AND DRAINAGE/FXN
where can dural venous sinuses get deO2 blood and CSF?
cerebral veins to bridging veins in subarachnoid space –> drain to brain; emissary veins that connect to extracranial veins of scalp; diploe veins from flat bones; meningeal veins from meninges; arachnoid granulations from arachnoid mater in subarachnoid space
dura lining of ant/mid cranial fossa, falx cerebri, tentorium cerebelli vs dura lining of post cranial fossa SENSORY innervation. supratentorial dura vs dura of posterior cranial fossa = innervated by?
all 3 branches of trigeminal n vs meningeal branches of C2 & C3 spinal nerves. trigeminal n vs CN 10, 9, first 3 cervical nerves
Know what brain ventricles are. Steps of ventricular system
Lec 3, slide 22-23. choroid plexus –> lat ventricles –> interventricular foramen of Monro –> 3rd ventricle –> cerebral aqueduct of Sylvius –> 4th ventricle –> median aperture of Magendie, lateral aperture of Luschka –> subarachnoid space/cisterns/central canal of spinal cord –> arachnoid granulation
Choroid plexus
network of capillaries and ependymal cells in brain ventricles that produce CSF to protect CNS
subarachnoid space can be exaggerated to become cisterns. what are the types?
perimesencephalic cistern (around midbrain), prepontine cistern (in front of pons), cisterna magna (inf to cerebellum near foramen magnum), lumbar cistern (in lumbar region containing cauda equina, do LP here)
blood supply to brain
vertebral a: branch of subclavian a –> transverse foramen of upper 6 cervical vertebrae –> foramen magnum –> L/R vertebral aa together form basilar a –> vertebrobasilar/post circ of brain; gives of ant/post spinal aa, PICA
internal carotid a: branch of common carotid a –> carotid canal –> carotid/ant circ of brain
blood brain barrier vs blood CSF barrier
tight jxns at capillary endothel cells ctrl water-soluble ions and molec traffic in paracellular route b/w blood and brain tissue vs tight jxns at choroid plexus ependymal cells make 2-way barrier b/w CSF and brain tissue
blood supply to spinal cord
ant/post spinal aa, sulcal a, vasocorona aa, spinal branch; ant/post segmental medullary aa, great ant segmental medullary a/a of Adamkiewicz
describe great ant segmental medullary a/a of Adamkiewicz
unpaired, on left; T9-L2; reinforces ant spinal a for distal/inf spinal cord
vertebral foramen vs vertebral canal vs intervertebral foramen
formed by vert arch (pedicles + lamina) vs stacked vertebral foramens, where spinal cord runs through vs formed by inf vert notch of sup vertebra + sup vert notch of inf vertebra, where spinal nerve runs through
how to name cervical vs thoracic vs lumbar vs sacral spinal nerves
above associated vertebra vs below associated vertebra for rest, S5 and coccygeal spinal nerve run thru sacral hiatus
spinal cord segment
part of spinal cord containing 1 bil pair of spinal nerves
dorsal root/spinal ganglia contain what type of neurons? what does central vs peripheral process of this neuron do?
pseudounipolar. relay info to dorsal root to dorsal horn of spinal cord vs relay sensory info to post trunk/head/neck via dorsal rami and to anterolat trunk/limbs via ventral rami
ventral horn of spinal cord contain what type of motor neurons? what do their motor innervations do? how are motor neurons arranged in ventral horn? know where extensors/flexors/axial musculature would be in ventral horn
multipolar. innervate intrinsic back muscles via dorsal rami, innervate anterolat trunk/limbs via ventral rami. in vertical nuclear columns in ventral horn. Lec 8-9, slide 15
dorsal root/lets vs ventral root/lets vs spinal nerve, rami contain what kind of axons?
sensory axons only vs motor axons only vs mixed sensory and motor axons
characteristics of spinal nerves vs cranial nerves. fiber types for cranial nerves?
31 pairs, from dorsal/ventral roots –> give rise to dorsal and ventral rami –> contain sensory and motor axons vs 12 pairs, no dorsal/ventral roots –> no rami –> no transmitting same fiber type. sensory (skin/mucosa), motor (muscles), parasympathetic (autonomic glands/viscera)
cervical vs petrous vs cavernous vs cerebral part of ICA
b/w bifurcation of common carotid a and carotid canal vs in carotid canal w/ internal carotid plexus vs in cavernous sinus w/ CN III/IV/V1/V2/VI vs in circle of Willis
know the Circle of Willis/cerebral arterial circle
Lec 5, slides 7-10
Berry aneurysm vs intracerebral hemorrhage. is an aneurysm always a problem?
saccular aneurysm at bifurcation in Circle of Willis (at base of brain) –> subarachnoid hemorrhage, thunderclap HA –> tx w/ surgical clips or endovasc coiling vs rupture of vessel w/in brain parenchyma. not a prob unless it ruptures –> internal bleed, stroke, fatal
A1 vs A2 anterior cerebral a
ACA branches from ICA. precommunicating vs postcommunicating, cont posteriorly to longitudinal fissure; supplies frontal and parietal lobes w/ 2 branches: pericallosal a for corpus callosum & cingulate gyrus, callosomarginal a for frontal gyrus and paracentral lobule
what happens if A2 callosomarginal a = occluded/damaged?
motor and sensory deficit in contralat lower limbs
where is mid cerebral a? M1 vs M2
insular cortex. branches from ICA vs splits into sup/inf division thru Sylvian fissure –> supply lat frontal, parietal, temporal lobes
what happens if M1 vs M2 sup vs inf division = occluded?
all M2 territories (contralat motor and sensory deficits, global aphasia) vs Broca’s aphasia, contralat head/neck/trunk/upper limb vs Wernicke’s aphasia
post cerebral a. what happens if occluded?
branch of basilar a –> supplies inf and medial temporal and occipital lobes, midbrain. visual field deficit or visual agnosia
watershed areas
anastomosed b/w cerebral aa providing collateral circ w/ artery occlusion; most susceptible to ischemic injury during global reduction of bloodflow like cardiac arrest; weakly supplies T4-T8
epidural hematoma vs subdural hematoma vs subarachnoid hemorrhage
lenticular/biconvex bleed in epidural space d/t trauma to pterion –> lacerate mid meningeal a; not crossing sutures vs venous crescent shaped bleed in subdural space d/t jerking of head –> rupture of bridging vein prior to draining into superior sagittal sinus; crosses sutures vs bleed in subarachnoid space d/t aneurysm of cerebral a (ex: berry aneurysm) –> thunderclap HA
what makes a NT?
substance made and stored vesicles in presynaptic neuron; substance receptors in postsynaptic neuron; mechanisms to remove substance must exist
calcium hypothesis
Ca2+ signaling connects to membrane excitability (lots of Ca2+ dependent structures like channels/receptors/proteins and mechanisms that ctrl intracellular Ca2+
low freq vs high freq stimulation on NT release
raises [Ca2+] close to membrane –> release NT from small vesicles vs higher [Ca2+] –> release NT from small and lg vesicles
what are 2 types of ionotropic/ligand-gated receptors
cation channels for Na+, some K+ and Cl-; opened by excitatory NTs (depol). anion channels for Cl-; opened by inhibitory NTs (hyperpol). both fast acting & short lived –> not for prolonged changes
metabotropic/2nd msgr/GPCR activations
activate cA/GMP in neuron –> activates long term changes in metab; activate 1+ intracellular enzymes –> activate specific fxns in cell; activate gene transcpxn –> new proteins made; slow and prolonged –> memory
3 ways to remove NT to prevent constant stim and reset postsynaptic AP
diffuse from cleft, enzyme degradation in cleft, recycle/reuptake in presynaptic neuron vesicles
small NT vs lg/peptide NTs
made in cytosol in cell body, slow axonal transport; fast acting –> acute response; degraded or reuptake vs made in Golgi in cell body, fast axonal transport; modify precursors to make peptides via endoproteases –> potent long term effects; diffuse or degraded
know class I acetylcholine vs class II catecholamine vs class II serotonin vs class III GABA
Lec 6, slides 22-25
what are 5 categories of neuropeptides/peptide NTs? what are the 1st 2?
brain-gut peptide = substance P: sensory NT in spinal cord; hippocampus, neocortex, GI tract, C-fiber nerves –> pain; inhibited by opioids –> no pain. opioids: endorphins, enkephalins, dynorphins, depressants/analgesics; throughout brain w/ GABA and serotonin; sexual attraction, addiction, aggression, schizo, autism. pituitary peptides, hypothalamic-releasing hormones, “others”
excitotoxicity = determined by? mechanism?
balance b/w gluE & GABA. gluE accumulation –> constant excitatory –> inc [Ca2+] –> free radicals accumulate –> autophagy, apop –> cell death –> anoxia, ischemia, neurodegen dz, sz
long term potentiation vs depression mechanism
gluE binds to AMPA receptor –> depol –> Mg2+ leaves –> gluE binds to NMDA receptor –> Ca2+ enters –> CaMKII & PKC signal cascade –> posttranslnal mods (early phase); PKA & CREB change gene expression to make new proteins (late phase) –> long term storage of info vs depol –> Ca2+ enters –> protein phosphatases –> lose AMPA receptors –> dec gluE
neuronal microenviron includes? BECF influences cell behavior, what are its components?
ECF, capillaries, glial cells, adjacent neurons. BBB protects BECF from fluctuating blood composition, CSF influences BECF composition via pia mater & gap jxns in ependymal cells, glial cells condition BECF
new 4th meningeal layer: subarachnoid lymphatic-like membrane (SLYM)
morphologically and immunophenotypically similar to mesothel lining of periphal organs & body cavities containing immune cells
nml pressure hydrocephalus vs cerebral edema
nml spinal tap but MRI shows enlarged 4 ventricles –> infxn or inflamm of meninges –> dmg arachnoid villi –> impaired CSF absorption –> dementia, incontinence, abnl gait –> do CSF shunt to venous blood or peritoneal cavity vs net accum of water in brain –> intracranial pressure > arterial pressure –> inc arterial pressure to partially compensate
if no pain receptors in brain parenchyma itself, what causes HA?
mechanical traction, irritation, inflamm of other innervated head structures (blood vessels, meninges, scalp, skull)
extracerebral hemorrhage
bleed b/w calvaria and brain –> hematoma puts pressure on soft brain –> rapid or slow incompressible mass –> intracranial pressure –> dmg brain tissue and other remote brain areas
cerebrovasc dz. emboli vs thrombus
interfere blood delivery –> ischemia (local anemia d/t mechanical obstruction) –> hypoxia (lower than nml O2). any plug blocking blood vessel vs plug from blood blocking blood vessel
stroke. ischemic vs hemorrhagic stroke
blood supply to brain = interrupted or reduced. d/t thrombus/embolus (ex: cholesterol deposits), most common vs d/t ruptured blood vessel, HTN = main risk factor
fibrous vs protoplasmic astrocytes. what is cytoskel of all astrocytes made of? Muller cells vs Bergmann cells. what do radial glial cells do?
long thin well defined process vs short frilly process. glial fibrillar acidic protein. retinal astrocytes vs cerebellar astrocytes. provide organized scaffold in forebrain from ventricle to pial surface
how does brain get glu?
first from blood; if blood glu absent –> astrocytes break down glycogen to glu and further to lactate for nearby neurons substrate buffering; astrocytic glycogens lasts 5min
conus medullaris vs cauda equina
terminal end of spinal cord at L1/2 (L3 in newborn b/c vertebrae and dura mater lengthen faster than neural tube) vs bundle of roots from lumbosacral enlargement & conus medullaris
denticulate lig vs filum terminale vs dural sac
extension of pia mater anchoring spinal cord to prevent excess lat mobility; separates ventral & dorsal roots vs extension of pia mater from conus med thru dural sac to coccyx to prevent distal spinal cord excess mobility vs continuous w/ cranial dura at S2
Rexed laminae of spinal cord
I-VI = dorsal horn, II = substantia gelatinosa; VII = nucleus of Clarke/intermediolateral nucleus, intermediate zone; VIII-IX = ventral horn; X = gray matter surrounding central canal
how does spinal cord drain? what’s the internal vertebral venous plexus?
via ant & post spinal vv. valveless network of veins and src of metastasis orignating in pelvis that spread to vertebral column and/or CNS; PROSTATE CA
know how to recognize spinal cord stains
Lec 8-9, slides 20-21
Medial motor systems ctrl movements bil –> unilat lesions make no obvi deficits. reticulospinal tract vs vestibulospinal tract vs tectospinal tract vs ant corticospinal tract
gross posture, gait, reaching vs medial = head/neck position, lateral = bal vs in sup colliculus, eye orientation, head turning to sound reflex; synapses w/ interneurons in cervical cord to project to neck motor nuclei vs bil axial and girdle muscles, don’t’ decussate
Lateral motor systems: lat corticospinal tract vs rubrospinal tract
“pyramidal tract” for distal musculature vs originates from magnocellular part of red nucleus; scratching, locomotion, learned/automated motor behaviors in other animals
s/s of injury to UMN vs LMN
hyperreflexia, hypertonia, spastic paralysis, Babinski sign, Hoffmann sign, clasp-knife response, clonus, disuse atrophy vs hyporeflexia, hypotonia, flaccid paralysis, fasciculations/twitching, muscle atrophy
know spasticity def & DTR grading
Lec 8-9, slides 32-33
