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266 Cards in this Set

  • Front
  • Back
organ system:
group of organs each w/ a specific structure & fxn;
coordinate & integrate w/ other systems to maintain homeostasis in individuals
Organ Systems ex:
nervous sys, circulatory, respiratory, excretory, endocrine, reproductive
circulatory ex:
heart, bv's, lymph nodes, lymph vessels
excretory ex:
ureters, urinary baldder, urethra, kidneys
Nervous System: general fxn
short term/fast reacting coordination & integration of bodily fxns by using electrochemical communication; produce nerve impulses/AP's
Nervous System:Properties
2. conductivity
ability to generate & produce AP's
ability to move AP's from one area of the body to another area of the body
Nervous System: Fxnl sequence of events
1.reception of stimuli
2.conversion of stimuli
3.transmission of AP's
4.production of response
reception of stimuli:
either from internal or external environment
conversion of stimuli:
stimuli converted into language of the nervous system: AP's
transmission of AP's:
from 1 region to another until reach final destination and ...
produce response/action @:
Nervous System: Divisions
1.Central Nervous System
2.Peripheral Nervous System
Central Nervous System:
brain & spinal cord
Peripheral Nervous system:
1.nerves & ganglia of Somatic NS
2.nerves & ganglia of Autonomic NS
Somatic NS:
associated w/ skeletal muscle only
Autonomic NS:
associated w/ internal organs; made up of motor control units: 1.sympathetic NS & 2.parasympathetic NS
Nervous System: Histological Elements
1.Neurons 2.Neuroglial cells/Glial cells 3.WFCT/collagenousCT
neve cells; basic unit of cellular fxn in system; provide NS w/ general fxns; ~10billion neurons in human brain; ~1trillion neurons when add whole CNS
2.Neuroglial/Glial cells
supporting cells-support fxns of neurons; some divide by mitosis; if unregulated, produce brain tumors:glioma
type of glial cell:
Schwann cells
Schwann Cells:
aka neurolemmocytes; specific neuroglial cells found only in PNS; insulate axons & dendrites
found largely in nerves
Neuron: component parts
1.Cell Body
2.Processor fibers
Neuron: Cell Body
perikaryon; contains nucleus & most other cell organelles
Neuron: Processor fibers
1.axon: 1 per neuron; long in length comparitively to dendrites 2.dendrites: range 0, 1-200 per neuron; short in length
Sensory Neuron
contains only one axon & no dendrites
Neuron: Morphological classification
1.unipolar/pseudounipolar neuron
2.bipolar neuron
3.multipolar neuron
pseudounipolar neuron:
contains cell body & 1 extension splitting quickly into 2 fibers continuous w/ one another->axon; associated w/ sensory fxns
bipolar neuron:
contains 1 dendrite & 1 axon @ opposite ends of the body; associated w/ vision, hearing, taste & smell; sensory interneurons (b/w other neurons)
multipolar neuron:
contains many dendrites & 1 axon; most common neuron found in body
Neuron: Fxnl Classification
1.motor/efferent neuron
2.sensory/afferent neuron
3.interneuron/association neuron
Motor/Efferent Neuron
carry AP's from brain/spinal cord to muscle/gland; motor=telling muscle to carry out a response
Sensory/Afferent Neuron
carry AP's from periphery receptors to brain/spinal cord
Interneurons/Association Neuron
confined to brain/spinal cord; carry AP from neuron to another nerve cell/neuron OR from one neuron to a motor neuron
Neuron: Structure (multipolar neurons)
2.cell body/perikaryon
short extensions off cell body; carry AP to cell body after received from neuron
Cell Body/Perikaryon:
1.nucleus & nucleolus
3.golgi complexes
4.nissl substance
cell body: nucleus/nucleolus
directs all life processes of cell
cell body: mitochondria
produce ATP
cell body: golgi complexes
make vesicles containing neurotransmitters
cell body: nissl substance
regions of RER & RNA that make proteins
cell body: cytoskeleton
maintains shape & is made of intermediate filaments & neurotubules
begins just off cell body @ 1.axon hillock-begins broadly & narrows to form 2.axon-subdivides to many sub-branches, 3. axon terminals/terminal filaments-each ending in 4.synaptic knobs
axon that branches:
axon:AP route
begins @ axon hillock -> down length of axon -> thru filaments -> ends at synaptic knobs
axon fxn
carry AP away from cell body
dendrite fxn
carry AP to cell body
Neuron: Types Axons & Dendrites in PNS
1.myelinated axon
2.unmyelinated axon
Myelinated Axon:
1.indiv schwann cells line up & ea indiv produce myelin sheath wrapped around the axon 2.neurilemma: schwann cell cytoplasm + cell memb outside myelin sheath 3.axon hillock & terminals: no schwann cells cover either 4. nodes of ranvier: bare space b/w schwann cells; axon surface in space exposed to ECF
Unmyelinated Axon:
1.several axons/fibers embedded in schwann cell cytoplasm 2. so, cant turn and turn to make myelin sheath
Composition of Peripheral Nerves:
2.perineurium & fascicles
WFCT; found entirely around outside of nerve
Perineurium & Fascicles:
WFCT; comes from epineurium; creates groups of axons or dendrites; 1 group=fascicle
areolar CT; srround each individual axon or dendrite
Fxnality of CT components:
1.epineurium hold fascicles together to form a nerve
2.perineurium hold axon/dendrites together to form fascicle
3.endoneurium connects axons to axons/dendrites to dendrites
@ surface, BV enters...
epineurium -> perineurium ->endoneurium -> now has access to blood supply
Neuroglial Cells:
found only in PNS & CNS; 10-50x more than neurons in body
Neuroglial Cells: Types
1.Schwann Cells
5.Ependymal Cells
Neuroglial Cells: Schwann Cells
PNS only; fxn: produce myelin sheath on axons mostly & dendrites
Neuroglial Cells: Oligodendrocytes
CNS only; fxn: produce myelinated axons & dendrites; time phase: late fetus-2nd yr; Multiple Sclerosis
Neuroglial Cells: Oligodendrocytes- Mulitple Sclerosis
demyelinating disease; can affect vision; cause loss of mobility in lumbar area; lack use of motor fxns
Neuroglial Cells: Microgliocytes
CNS only; macrophage-like; destroy microorganisms & tissue debris; Stroke
Neuroglial Cells: Microgliocytes: Stroke
hemorrhagic stroke-bv's break in brain->bleeding into brain tissue; microgliocytes attracted here in high #s to rid of unwanted debris
Neuroglial Cells: Astrocytes
CNS only; fxns: attach neurons to BV's 2.contricute to BBB/blood-brain barrier-keeps ECF constant
1.estb by morphology of brain capillaries->tight jxn of endothial cells @ wall
2.impedes mvmt of water soluble sub b/c ECF & ICF
3.Lipid soluble sub have easy time crossing BBB from blood
4.astrocytes perivascular feet contact brain capillaries & help control K+ conc in ICF
water soluble sub blocked by BBB:
1.Na, K, glucose require special transport mech to get back in to the tissue
2.antibiotics: penicillin cant cross BBB from blood back to tissue; erythromyosin can
Neuroglial Cells: Ependymal Cells
1.line ventricles of brain & central canal of spinal cord
2.cover capillaries found in ventricles; together=choroid plexes
3.ciliated-cilia move & propel cerebrospinal fluid
4.cerebrospinal fluid-comes from blood plasma
plasma filtered thru choroid plexes & then called:
cerebrospinal fluid; ependymal cells help control the chemicals in this CSF
Nervous System: Membrane Potentials & Associated phemonena
1.Resting Potential
2.Action Potential
Resting Potential:
state of electrical potential difference across the neuron membrane; electrical diff b/w charges in/outside cell; axon not acting=resting state
Resting Potential: Basis
seperation of electrical charges; -70mV: -charge on inside & 70=how much charge; Na: high conc outside & low conc inside; K:high conc inside & low conc outside
Resting Potential: Factors
1.Sodium pump
2.Differential permeability of K & Na
3.Presence of non-diffusible anions
Sodium Pump:
active transport mech; requires ATP energy to operate; takes 3Na ions from inside->outside cell & 2K ions from outside->inside cell @ same time; estb Na/K conc differences
Differential Permeability of K & Na:
leakage channels allowing mvmt; always open; Na enters & K exits through diffusion; K moves thru channel 100x faster than Na --> inside becoming more negative due to more K loss
Presence of non-diffusible anions:
proteins in cytoplasm with a negative charge; add to the internal negative charge
Action Potential:
1.Local Depolarization
3.Summation of Subliminal Stimuli
4.Sequence of events for AP
5.All or none
6.Refractory Periods
8.Conduction Velocity
Action Potential: Local Depolarization
not an AP; stimulus->segment of axon->emphasizes small amts Na enter segment & RP -70mV moves to -60mV ->K exits:repolarization & back to -70mV; local dep come & go w/o causing AP
Action Potential: Threshold
magic #= -55mV; give 1 strong stimulus & RP goes from -70mV to -55mV-> AP
to get to threshold,
summation of subliminal stimuli
Action Potential: Summation of Subliminal Stimuli
rapid # of subliminal stimuli in short period of time add together & form threshold -> leading to AP
Action Potential: Sequence of events for AP
1.axon must be @ RP
2.apply adequate stim to axon
3.stim increases Na permeability; Na enters axon; inside of axon becoming less - (raises memb pot to +30mV)
4.reversal of electrical charge->full dep->AP; -70 to +30mV = diff of 100mV *Na enters thru Na-voltage gated channels
5.repolarization: +30->-70mV cause by loss of K ions out of axon thru Kvoltage gated channels
6.Hyperpolarization due to more K lost than Na gained
Na voltage gated channels operate only...
during AP's
K voltage gated channels operate only...
during Repolarization
Action Potential: All or None law
value of 100mV difference, or no AP; aka must hit +30mV
Action Potential: Refractory Periods
1.Absolute Refractory Period
2.Relative Refractory Period
Absolute Refractory Period
threshold lasts to end of repolarization; no other AP can be stimulated
Relative Refractory Period
threshold during hyperpolarization; another AP can be stimulated, but stimulus must be stronger than 1st stim
Importance refractory periods
limit the # AP's passing over an axon; AP's can pass over axons 100-1000AP's/sec
Action Potential: Propagation
conduction of AP along axon;
1.unmyelinated axon-sequence
2.myelinated axon-sequence
Propagation: unmyelinated axon sequence
1.starts @ axon hillock; depolarized->repolarized
2.segment to seg stimulation; during dep phase stim axon seg next to it, dep->rep
3.self propagating continuous conduction; due to no myelin sheath
Propagation: myelinated axon sequence
1.starts @ axon hillock; dep->rep cycle; stim nodes of ranvier during dep
2.stim 1st node of ranvier after hillock, dep/rep, next node, etc
3.saltatory conduction: skipping over regions of memb covery by schwann cells; impt for pain stim in skin
Action Potential: Conduction Veloctiy
myelinated=10x faster (b/c myelin sheath removing parts of axon)
Action Potential: Tranmission of AP from neuron to neuron
2.chemical synapse assoc
3.excitation @ synapse
4.inhibition @ synapse
region b/w 2 neurons
presynaptic neuron -> neuron -> postsynaptic neuron
Synapse: Types
1.Electrical synapse
2.Chemical snyapse
Electrical synapse
few in #; contain gap junctions b/w neurons; AP travels quickly thru jxns
Chemical synpase
made of 1.synaptic knob, containing vesicles made of neurotransmitters that stim/inhib postsynaptic neuron, 2.synaptic cleft, & 3.postsynaptic membrane: containing NT receptors
Chemical synapse associations:
1.axodendritic: axon to dendrite
2.axosimatic: axon to cell body
3.axoaxonic: axon to axon
all usually inhibitory associations & few in #
Excitation @ synapse
presynaptic neuron stim AP in postsynaptic neuron:
1.AP moves down axon to synaptic knob in presynap neuron
2.Ca uptake into synp knob occurs; Ca stim NT vessicles in knob; vessicles fuse w/ knob memb
3.vessicles release NT by exocytosis
(3. vessicles release NT by exocytosis ...)
NT now in synpatic cleft; by diffusion hits receptor sites in postsynp memb
4.stimulation of excitatory presynaptic potentials & summation
excitatory presynaptic potentials:
small amounts of NT combine w/ receptors->Na entry->local depolarizations: EPSP; RP -70mV->-60mV->AP
increased amts of NT combined w/ receptors-> several EPSP's created->add together & form AP; RP -70mV->-55mV->AP in postynaptic neuron
Examples of excitatory NT:
acetycholine, norepinephrine, dopamine, glutamic acid, aspartic acid, substance P: sends pain stimuli thru CNS, esp spinal cord
Inhibition @ synapse
presynaptic neuron causes hyperpolarization in postsynaptic neuron-becoming more negative (-70 to-80mV)
Inhibition steps:
1-3 same as exc.
1.Mvmt AP to synaptic knob
2.entry of Ca
3.vessicle release NT to synaptic cleft
4.sufficient NT combines w/ its receptors @ postsynap memb; NT in synp cleft->combines w/ receptors @ postsyn memb->K loss or Cl gain->RP more negative
5.increased K permeability & RP -70mV to -80mV
Increased K permeability=
-80mv= inhibitory postsynaptic potential IPSP; prevents postsynp neuron from being stimulated under normal conditions
Neurons can receive:
both kinds of input: IPSP & EPSP; relates to how many coming in and ease of stimulation: more EPSP than IPSP=stimulation; more IPSP than EPSP=inhibition
Examples of Inhibitory NT:
acetylcholine, norepinephrine, dopamine, gaba, enkephalins (inhibit pain stim)
1st three ex both EPSP/IPSP, how?
depends on postsynaptic neuron whether EPSP/IPSP
Nervous System: CNS covered w/
3 layers of connective tissue:
1.Dura Mater 2.Arachnoid 3.Pia Mater
Dura Mater
most outer layer;
2.spinal cord
3.Subdural Space
Dura Mater: Brain
exists in 2 layers:
1.cranial/periosteal dura mater
2.meningeal dura mater
Brain: Cranial Dura Mater
contacts cranial bones; serves as periosteum
Brain: Menineal Dura Mater
below cranial DM; most regions together, but some seperate & form spaces:1.blood sinuses & 2.partitions
Blood Sinuses
seperation of Cranial DM & Meningeal DM; create spaces & contain blood
made of 2 layers of Meningeal DM; wall of CT
1.Falx Cerebri: b/w L&R hemispheres
2.Falx Cerebelli: sep cerebrum & cerebellum
Dura Mater: Spinal Cord
exists only 1 layer:
Meningeal/Spinal Dura Mater
Meningeal/Spinal Dura Mater
continuous w/ Meningeal DM of brain
Dura Mater: Subdural Space
below MDM in both brain & spinal cord; contains fluid that keeps DM connected to arachnoid
subdural hematoma
blood clot in subdural space
middle layer; same in brain and spinal cord; 3 components:
1.arachnoid membrane
2.arachnoid trabeculae
3.subarachnoid space
Arachnoid: Arachnoid membrane
adjacent to subdural space
Arachnoid: Arachnoid trabeculae
partitions; extend from arachnoid membrane to pia mater
Arachnoid: Subarachniod space
below arachnoid membrane; contains CSF
Pia Mater
composed of areolar tissue; in direct contact w/ brain and spinal cord tissue; most inner layer
Clinical Aspect:
Meningitis: caused by bacteria & viruses; blood vessels inflammed->vasodilation
Bacterial Meningitis
heals on own
Viral Meningitis
antibiotics assist healing
Nervous System: CNS: Brain
2.Basal Ganglia
7.Reticular Activating Sys
8.Ventricular system
Brain: Cerebrum
largest part of brain; divided into hemispheres
Cerebrum: Fissures, Sulci & Lobes
1.Lonitudinal Fissure/Cerebral Fissure
2.Central Fissure/Fissure of Rolando
3.Lateral/Fissure of Sylvius
4.Parieto-Occipital Sulcus
Cerebral Fissure
(Longitudinal Fissure)
divides cerebrum into L&R cerebral hemispheres
Fissure of Rolando
(Central Fissure)
exists in both hemispheres; seperates frontal lobe from parietal lobes in cerebrum
Fissure of Sylvius
seperates frontal & parietal lobes from temporal lobe
Parieto-Occipital Sulcus
shallow fissure; seperates parietal lobe from occipital lobe;
5th lobe; located @ base of fissure of Sylvius; very deep (not superficial like others)
Cerebrum: Neural Tissue Structure
1.Cerebral Cortex
2.White Matter
Cerebral Cortex
gray matter;
made of cell bodies of neurons;
includes unmyelinated axons & dendrites;
top most tissue of cerebrum;
ridges of gray matter seen superficially w/ dark lines b/w them: sulci; folding gyri increase surface area of gray matter
seperating gyri from one another;
White Matter
composed of myelinated axons/dendrites;
no cell bodies found;
made of specific tracts:
White Matter tracts w/ special actions:
adjacent gyri; in same lobe
connects gyri from different lobes, but in same hemisphere
few in #; interconnect 2 cerebral (L&R) hemispheres to each other; largest one=Corpus Callosum
Corpus Callosum
connection for L&R coordination
connects cerebral cortex to all other parts of CNS
Cerebrum: Physiological Divisions of Cerebral Cortex
1.Motor Cortex
2.Sensory Cortex
3.Association Cortex
Motor Cortex:
1.Primary Motor Cortex
2.Brocas Area
Primary Motor Cortex
located in frontal lobe;
anterior to Fiss Rolando;
originates all skeletal musc contractions
Broca's Area
located @ L frontal lobe of L hemisphere;
initiates skeletal musc contractions for speech
Sensory Cortex:
1.Primary Sensory Cortex/Primary Somesthetic Cortex
2.Olfactory Cortex
3.Auditory Cortex
4.Taste Cortex
5.Visual Cortex
Primary Sensory Cortex
located @ parietal lobe;
posterior to Fiss Rolando;
responsible for interpretation of sensations from skin (temp, pain, itch);
involved w/ sensations from skeletal musc
Olfactory Cortex
located @ frontal lobe;
where smells/odors interpreted
Auditory Cortex
located @ temporal lobe;
where sound interpreted
Taste Cortex
located @ parietal lobe;
chemical sensations from mouth/saliva detected here
Visual Cortex
located @ occipital lobe;
eyes help get info to this part of brain for interpretation
Association Cortex:
regions that associate past experiences w/ current input; memory fxn
1.Premotor Cortex
2.Prefrontal Cortex
3.Visual Association Cortex
4.Auditory Association Cortex
5.Wernicke's Area
Premotor Cortex
aka Motor Association Cortex;
located @ frontal lobe;
anterior to PMC;
coordinates groups of skeletal musc contractions
Prefrontal Cortex
located @ frontal lobe;
anterior to Premotor Cortex;
where reasoning occurs & judegement decisions made
Visual Association Cortex
located @ occipital lobe
Auditory Association Cortex
located @ temporal lobe;
allows you to hear something one time and recognize it
Werenicke's Area
located @ temporal lobe;
assoc. w/ speech;
allows for recognition of written/spoken word->language
Brain: Basal Ganglia
regions of gray matter;
unmyelinated axons/dend;
found embedded in white matter or cerebrum
Specific names of Ganglia:
Putamen, Caudate Nucleus, Globus Palidus
Basal Ganglia Fxn
modify nerve impulses coming out of PMC ... refining impulses->smooth, even contractions
Brain: Thalamus
located below Corpus Callosum & above Brainstem
Thalamus fxns
1.sensory relay station: all sensory impulses go to thal 1st & it sends to proper portion of cerebrum
2.gross pain receptor/heat receptor: thal interprets pain/heat stimuli
3.modification of sensory input: adjusts what is sent to Cerebral cortex
1 exception of sensory relays w/ thalamus:
olfactory sensations go directly to cerebral cortex w.o thalamus help
involved w/ reticular formation->sends info to thalamus->info to cerebral cortex
RF active=awake, conscious
RF inactive=coma, unconscious
Brain: Hypothalamus
region of gray matter below thalamus; contains many regions involved w/ physiological fxns
Hypothalamus Fxns
1.body temp control, "Human Thermostat": maintain constant body temp
2.water balance:hypoth makes hormone ADH antidiruetic horm-H2O reabsorption in kidneys
3.produces "releasing hormones":control secretion of antipituitary hormones
Hypothalamus Fxns (cont)
4.Satiety Center: monitors blood looking for glucose, AA's, & FA's;
low levels=hunger feeling
high levels=full feeling
5.rage/fear: hypoth as affect on CV responses; inc HR & BP orgasms sensation related to hypoth
Brain: Cerebellum
2nd largest portion of brain;
located posteriorly/inferiorly to cerebrum
Cerebellum: External Structure
made up of ridges:Folia
& grooves: Sulci
3 major regions:
1.Lhemisphere 2.Rhemisphere 3.Vermis connecting the 2
Cerebellum: Internal Structure
gray matter (makes up folia) & white matter (makes up nerve tracts)
white matter=arbor vitae: connects cerebellum to other parts of CNS
Cerebellum: Fxns
coordination of muscular actions b/w brain & skeletal muscles;
reads sensory input from musc's & motor output from brain ... fine tunes the final output
Final Output:
1.coordinates synergistic & antagonistic voluntary musc contractions for manual dexterity
2.maintenance of balance & posture
maintenance of balance & posture:
reads sensory inputs from eye, ear balance receptors in brain, & proprioceptors in musc's + motor outputs --> fine tunes fnal output
Brain: Brainstem
below thalamus & in front of cerebellum;
2 subcomponents: Midbrain, Pons, Medulla Oblongata
2 portions:
1.Cerebral Peduncles
3.Corpora Quadrigemina
Cerebral Peduncles
nerve tracts; intermediates:
1.take sensory fibers from pons->thalamus; receive nerve fibers from cerebellum
2.take motor fibers from cerebrum->pons
Corpora Quadrigemina
4 structures:
1/2.Superior Colliculi: visual reflexes; protect eyes from bright light
3/4.Inferior Colliculi: auditory reflexes; protect ears from loud, sudden noises
Midbrain: Substantia Nigra
(one of basal ganglia, but not located in cerebrum)
1.dark pigmented region(melanin)
2.produces NT dopamine
3.gradual degeneration of tissue causes Parkinsons Disease
4.Resulting in localized muscular tremors (limbs/head) & muscular rigidity (facial musc)
initial treatment:
L-DOPA; cant treat w/ dopamine b/c cant get into remaining cels; L-DOPA enters S.Nigra cells->synthesize L-DOPA to form->dopamine
made of nerve tracts; "Bridge"
1.nerve tracts
2.ancillary breathing centers
nerve tracts
mostly white matter;
receives sensory fibers from medulla ob & sends fibers up to thalamus & cerebrum;
motor fibers come to it from cerebrum & sends down to med ob
ancillary breathing centers
pneumotaxic center &
apneustic center
Medulla Oblongata
Nerve tracts: mostly white matter; receives sensory fibers from spinal cord->pons;
motor fibers from pons->spinal cord
Med Ob: Physiological Nerve Centers
1.Cardiac Center-affects HR
2.Vasomotor Center-affects BP
3.Respiratory Center-affects breathing mvmts
4.Coughing, Swallowing, Vomitting Centers
Brain: Reticular Activating System
(aka Reticular Formation)
very diffuse Gray Matter
RF fxn
maintain alertness & arousal by sending sensory impulses up to cerebrum
1.stimulates consciousness/increases activity
2.decreased activity brings on sleep: mild=unconscious & severe=coma
Brain: Ventricular System
hollow spaces in cerebrum;
connecting openings/ducts associated here;
filled w/ CSF
Ventricular System: Structure
4ventricles in 4 superficial cerebral lobes;
1.1st&2nd ventricles/Lateral ventricles
2.Foramen of Monro/intraventricular foramen (2)
3.3rd Ventricle
4.aqueduct of sylvius/cerebral aqueduct
5.4th ventricle
lateral ventricles
1/2nd vent; found under corpus callosum
foramen of monro
1 for each lateral ventricle; opening that connect lateral vetnricles to 3rd vetnricle
3rd ventricle
near thalamus; goes into a single opening
aqueduct of sylvius
connects 3rd & 4th ventricles
4th ventricle
space b/w cerebellum & medulla oblongata
Ventricular System: Formation & Circulation of CSF
1.Choroid Plexes
2.Formation of CSF
3.Flow of CSF thru Ventricles
4.Exit of CSF from Vent Sys
5.Flow of CSF in Subarachnoid Space of Spinal Cord
6." of Brain
Choroid Plexes:
in all 4 ventricles; made up of blood capillaries; covered by ependymal cells
Formation of CSF:
blood filtered thru choroid plexes->ependymal cells->fluid appears in ventricle & called CSF; filtered blood plasma/chemically altered blood plasma; *CSF forming in all 4 vent @ same time
Flow of CSF through Ventricles:
from lateral vent 1&2->thru foramen monro->3rd vent (more CSF added)->cerebral aqueduct sylvius->4th vent (more CSF added)
Exit of CSF from Ventricular System:
CSF in 4th vent->central canal of spinal cord:absorbs incoming fluid w/ nervous tissue->openings into subarachnoid space for CSF to flow to brain/spinal cord:
1.Median Aperture of Magendie
2.Lateral Apertures of Luschka (2)
Flow of CSF in subarachnoid space of Spinal Cord
@ base of brain, some fluid flows down posterior side of sp cord->to anterior side of sp cord->upward toward base of brain again
Flow of CSF in subarachnoid space of Brain
CSF flows upward over cerebellum, over cerebrum, toward lonitudinal fissure of cerebrum ... target=top of brain
CSF in subarachnoid space near longitudinal fissure..
passes thru arachniod villi->allowin fluid to enter blood sinuses->send fluid to internal jugluar vein
Properties of CSF:
1.volume 90-150mL adults
2.clear, watery fluid
3.chem comp > Na&Cl & < Protein, glucose, K than blood plasma
4.derived from & returned to blood plasma
Fxns of CSF:
1.mechanical protection to CNS-"shock absorber"
2.medium of exchange-exchange of nutrients & waste products b/w nerve tissue
Clinical Note of CSF:
diagnosis of diseases: brain tumors, hydrocephalis, bleeding in CNS, meningitis (infxn), Multiple Sclerosis; analysis thru Lumbar puncture @ 3/4th L vert
Nervous System: CNS: Spinal Cord
found in vertebral/spinal canal; starts @ foramen magnum->ends @ L1-L2
Covered by:
Spinal Cord: Meninges
1.Spinal/Meningeal Dura Mater
3.Pia Mater
Spinal Cord: Terminal Structures
1.conus medullaris
2.cauda equina
3.filum terminale
conus medullaris:
end piece @ L1/L2 region; cone shaped
cauda equina:
last 9 pairs of spinal nerves; extend down into vertebral canal; some enter sacral canal
filum terminale:
cord of pia mater CT; purpose to attach conus->coccyx ... stablizing bottom portion of spinal cord
Spinal Cord: Cross Sectional Structure
oval shaped; divided in almost 2
1.dorsal/posterior median sulcus (shallow)
2.ventral/anterior median fissure (deeper)
Spinal Cord: Gray Matter
in center; made up of cell bodies & unmyelinated fibers
a)arranged in H shape w.
posterior horn, lateral horn, anterior horn; gray commissure
lateral horn:
not present in all segments of spinal cord; only Thoracic & lumbar regions; associated w/ sympathetic NS
gray commissure:
@ center; connects 2 sides of H; encloses central canal
Spinal Cord: White Matter
found outside/around; made of nerve tracts->myelinated fibers; specifically organized
3 pairs of tracts: posterior, lateral, anterior (on both sides); subdivisions w/in:
inside Funiculi; specific nerve tracts:
1.ascending fascicles: move sensory impulses up spinal cord to brain
2.descending fascicles:move motor impulses down from brain to spinal cord
Spinal Cord: Fxns
1. 2-way conducting pathway for nerve impulses (brain & sp cord)
2.reflex center-associated w/ spinal nerves
Nervous System: PNS
Cranial Nerves
Spinal Nerves
Cranial Nerves
all originate from ventral side of brain: cerebrum or brainstem
3 groups: sensory, motor, mixed
Cranial Nerve I
Olfactory Nerve/Tract:
assoc w/ sense of smell
Cranial Nerve II
Optic Nerve:
assoc w/ vision
forms optic chiasma & optic tracts lead away
Optic Chiasma
decussation: crossing over of nerve fibers allowing for stereoscopic/3D vision
Optic Tracts
sends APs to specific portions of occipital lobe of brain
Cranial Nerve III
Oculomotor Nerve:
stim extrinsic & intrinsic musc of eye
Cranial Nerve IV
Trochlear Nerve:
stim ext musc of eye to contract
Cranial Nerve V
Trigeminal Nerve:
Sensory-picks up sensations from face/teeth/gums
Motor-innervates musc of mastication
Cranial Nerve VI
Abducens Nerve:
stim ext musc of eye
Cranial Nerve VII
Facial Nerve:
Sensory-innervates taste buds @ ant 2/3 tongue
Motor-stim musc of facial expression, swallowing, stim salivary glands to secrete
Cranial Nerve VIII
Vestibulocochlear/Auditory/Acoustic Nerve:
Vestibule Branch-innervates semicircular ducts, vitricle, saccule: all involved w/ sense of balance
Cochlear Branch-organ of corti: assoc w/ hearing process
Cranial Nerve IX
Glossopharyngeal Nerve:
Sensory-monitors BP, O2 content in arterial blood, innervates taste buds on post 1/3 tongue
Motor-stim musc of swallowing, speech/vocal cords, salivary glands
Cranial Nerve X
Vagus Nerve:
Sensory-monitors BP, O2content in blood, detects sensations from resp/dig tracts
Motor-slows HR, stim secretion of gastric glands in stomach, secretion of pancreas, stim mvmt/peristalsis in dig tract
Cranial Nerve XI
Spinal Nerve:
stim musc of head-neck-shoulder area
Cranial Nerve XII
Hypoglassal Nerve:
stim musc of tongue-speech & swallowing
Spinal Nerves:
-31 pairs
-arise just under foramen magnum->conus medullaris
-all found in vertebral/sacral canal EXCEPT:
Spinal Nerve 1, b/c
exits spinal cord above C1
Spinal Nerve: Structure
Dorsal/Posterior Root
Ventral/Anterior Root
Dorsal Root
-contains enlargement:Dorsal Root Ganglion
-transmits sensory axons from spinal nerve->spinal cord
Dorsal Root Ganglion
contains cell bodies of pseudounipolar neurons
Ventral Root
-fuses w/ Dorsal root & together form spinal nerve
-contains only motor axons, so sends motor axons from spinal cord->spinal nerve
Spinal Nerve: Fxns
participate in spinal/Somatic and Visceral/Autonomic Reflexes
1.Reflex Arc
2.Elements of Somatic Reflex
3.Types of Somatic Reflex
Reflex Arc:
fxnal unit of NS/physiological unit of NS
-pathway APs take to produce reflex
involuntary purposeful rxn to some stimulus
Elements of Spinal/Somatic Reflex Arc:
2.Somatic Afferent/Sensory Neuron
4.Somatic Efferent/Motor Neuron
reacts to stimulus; produces APs; sends AP to sensory/afferent neuron
Somatic Afferent Neuron
Sensory; sends APs from spinal nerve into spinal cord
not always present; take AP from sensory neuron to another interneuron OR to somatic efferent neuron
Somatic Efferent Neuron
Motor; take AP from within spinal cord to spinal nerve, who then sends AP to effector
Skeletal Muscle; carries out action/response
Types of Spinal Somatic Reflexes
1.Stretch/Myotactic Reflex
2.Tendon Reflex
Stretch/Myotactic Reflex
-involves only 2 neurons (sensory & motor, not inter)
-stim=stretch on musc, stimulates musc spindle (receptor)->starts AP->sent to sensory neuron->enters arc thru spinal cord->sends AP directly to motor neuron->comes out of spinal cord to spinal nerve->to muscle
Motor Neuron...
stimulates the stretched muscle to contract (antag)-->preventing musc from being over stretched/damaged
Tendon Reflex: Receptor
=golgi tendon organ found in tendons of musc; detect tension on tendon
golgi tendon organ ...
sends APs->sensory neuron->sends AP to interneuron on spinal cord->interneuron=inhibitory interneuron->inhibits motor neuron hat is stim musc contrxn that is putting tension on musc->tension reduced
this prevents:
tendon from being detached from musc