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266 Cards in this Set
- Front
- Back
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organ system:
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group of organs each w/ a specific structure & fxn;
coordinate & integrate w/ other systems to maintain homeostasis in individuals |
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Organ Systems ex:
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nervous sys, circulatory, respiratory, excretory, endocrine, reproductive
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circulatory ex:
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heart, bv's, lymph nodes, lymph vessels
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excretory ex:
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ureters, urinary baldder, urethra, kidneys
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Nervous System: general fxn
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short term/fast reacting coordination & integration of bodily fxns by using electrochemical communication; produce nerve impulses/AP's
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Nervous System:Properties
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1.irritability/excitability
2. conductivity |
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irritability
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ability to generate & produce AP's
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conductivity
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ability to move AP's from one area of the body to another area of the body
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Nervous System: Fxnl sequence of events
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1.reception of stimuli
2.conversion of stimuli 3.transmission of AP's 4.production of response |
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reception of stimuli:
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either from internal or external environment
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conversion of stimuli:
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stimuli converted into language of the nervous system: AP's
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transmission of AP's:
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from 1 region to another until reach final destination and ...
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produce response/action @:
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effector
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Nervous System: Divisions
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1.Central Nervous System
2.Peripheral Nervous System |
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Central Nervous System:
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brain & spinal cord
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Peripheral Nervous system:
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1.nerves & ganglia of Somatic NS
2.nerves & ganglia of Autonomic NS |
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Somatic NS:
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associated w/ skeletal muscle only
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Autonomic NS:
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associated w/ internal organs; made up of motor control units: 1.sympathetic NS & 2.parasympathetic NS
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Nervous System: Histological Elements
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1.Neurons 2.Neuroglial cells/Glial cells 3.WFCT/collagenousCT
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1.Neurons
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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
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2.Neuroglial/Glial cells
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supporting cells-support fxns of neurons; some divide by mitosis; if unregulated, produce brain tumors:glioma
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type of glial cell:
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Schwann cells
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Schwann Cells:
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aka neurolemmocytes; specific neuroglial cells found only in PNS; insulate axons & dendrites
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3.WFCT
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found largely in nerves
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Neuron: component parts
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1.Cell Body
2.Processor fibers |
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Neuron: Cell Body
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perikaryon; contains nucleus & most other cell organelles
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Neuron: Processor fibers
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1.axon: 1 per neuron; long in length comparitively to dendrites 2.dendrites: range 0, 1-200 per neuron; short in length
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Sensory Neuron
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contains only one axon & no dendrites
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Neuron: Morphological classification
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1.unipolar/pseudounipolar neuron
2.bipolar neuron 3.multipolar neuron |
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pseudounipolar neuron:
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contains cell body & 1 extension splitting quickly into 2 fibers continuous w/ one another->axon; associated w/ sensory fxns
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bipolar neuron:
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contains 1 dendrite & 1 axon @ opposite ends of the body; associated w/ vision, hearing, taste & smell; sensory interneurons (b/w other neurons)
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multipolar neuron:
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contains many dendrites & 1 axon; most common neuron found in body
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Neuron: Fxnl Classification
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1.motor/efferent neuron
2.sensory/afferent neuron 3.interneuron/association neuron |
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Motor/Efferent Neuron
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carry AP's from brain/spinal cord to muscle/gland; motor=telling muscle to carry out a response
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Sensory/Afferent Neuron
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carry AP's from periphery receptors to brain/spinal cord
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Interneurons/Association Neuron
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confined to brain/spinal cord; carry AP from neuron to another nerve cell/neuron OR from one neuron to a motor neuron
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Neuron: Structure (multipolar neurons)
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1.dendrites
2.cell body/perikaryon 3.axon |
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Dendrites:
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short extensions off cell body; carry AP to cell body after received from neuron
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Cell Body/Perikaryon:
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contains:
1.nucleus & nucleolus 2.mitochondria 3.golgi complexes 4.nissl substance 5.cytoskeleton |
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cell body: nucleus/nucleolus
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directs all life processes of cell
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cell body: mitochondria
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produce ATP
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cell body: golgi complexes
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make vesicles containing neurotransmitters
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cell body: nissl substance
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regions of RER & RNA that make proteins
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cell body: cytoskeleton
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maintains shape & is made of intermediate filaments & neurotubules
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axon:
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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
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axon that branches:
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collateral
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axon:AP route
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begins @ axon hillock -> down length of axon -> thru filaments -> ends at synaptic knobs
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axon fxn
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carry AP away from cell body
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dendrite fxn
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carry AP to cell body
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Neuron: Types Axons & Dendrites in PNS
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1.myelinated axon
2.unmyelinated axon |
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Myelinated Axon:
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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
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Unmyelinated Axon:
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1.several axons/fibers embedded in schwann cell cytoplasm 2. so, cant turn and turn to make myelin sheath
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Composition of Peripheral Nerves:
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1.epineurium
2.perineurium & fascicles 3.endoneurium |
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Epineurium:
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WFCT; found entirely around outside of nerve
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Perineurium & Fascicles:
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WFCT; comes from epineurium; creates groups of axons or dendrites; 1 group=fascicle
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Endoneurium:
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areolar CT; srround each individual axon or dendrite
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Fxnality of CT components:
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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 |
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@ surface, BV enters...
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epineurium -> perineurium ->endoneurium -> now has access to blood supply
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Neuroglial Cells:
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found only in PNS & CNS; 10-50x more than neurons in body
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Neuroglial Cells: Types
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1.Schwann Cells
2.Oligodendrocytes 3.Microgliocytes 4.Astrocytes 5.Ependymal Cells |
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Neuroglial Cells: Schwann Cells
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PNS only; fxn: produce myelin sheath on axons mostly & dendrites
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Neuroglial Cells: Oligodendrocytes
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CNS only; fxn: produce myelinated axons & dendrites; time phase: late fetus-2nd yr; Multiple Sclerosis
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Neuroglial Cells: Oligodendrocytes- Mulitple Sclerosis
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demyelinating disease; can affect vision; cause loss of mobility in lumbar area; lack use of motor fxns
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Neuroglial Cells: Microgliocytes
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CNS only; macrophage-like; destroy microorganisms & tissue debris; Stroke
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Neuroglial Cells: Microgliocytes: Stroke
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hemorrhagic stroke-bv's break in brain->bleeding into brain tissue; microgliocytes attracted here in high #s to rid of unwanted debris
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Neuroglial Cells: Astrocytes
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CNS only; fxns: 1.support: attach neurons to BV's 2.contricute to BBB/blood-brain barrier-keeps ECF constant
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BBB
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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 |
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water soluble sub blocked by BBB:
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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 |
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Neuroglial Cells: Ependymal Cells
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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 |
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plasma filtered thru choroid plexes & then called:
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cerebrospinal fluid; ependymal cells help control the chemicals in this CSF
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Nervous System: Membrane Potentials & Associated phemonena
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1.Resting Potential
2.Action Potential |
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Resting Potential:
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state of electrical potential difference across the neuron membrane; electrical diff b/w charges in/outside cell; axon not acting=resting state
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Resting Potential: Basis
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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
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Resting Potential: Factors
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1.Sodium pump
2.Differential permeability of K & Na 3.Presence of non-diffusible anions |
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Sodium Pump:
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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
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Differential Permeability of K & Na:
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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
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Presence of non-diffusible anions:
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proteins in cytoplasm with a negative charge; add to the internal negative charge
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Action Potential:
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1.Local Depolarization
2.Threshold 3.Summation of Subliminal Stimuli 4.Sequence of events for AP 5.All or none 6.Refractory Periods 7.Propagation 8.Conduction Velocity |
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Action Potential: Local Depolarization
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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
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Action Potential: Threshold
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magic #= -55mV; give 1 strong stimulus & RP goes from -70mV to -55mV-> AP
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to get to threshold,
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summation of subliminal stimuli
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Action Potential: Summation of Subliminal Stimuli
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rapid # of subliminal stimuli in short period of time add together & form threshold -> leading to AP
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Action Potential: Sequence of events for AP
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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 |
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Na voltage gated channels operate only...
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during AP's
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K voltage gated channels operate only...
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during Repolarization
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Action Potential: All or None law
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value of 100mV difference, or no AP; aka must hit +30mV
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Action Potential: Refractory Periods
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1.Absolute Refractory Period
2.Relative Refractory Period 3.Importance |
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Absolute Refractory Period
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threshold lasts to end of repolarization; no other AP can be stimulated
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Relative Refractory Period
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threshold during hyperpolarization; another AP can be stimulated, but stimulus must be stronger than 1st stim
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Importance refractory periods
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limit the # AP's passing over an axon; AP's can pass over axons 100-1000AP's/sec
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Action Potential: Propagation
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conduction of AP along axon;
1.unmyelinated axon-sequence 2.myelinated axon-sequence |
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Propagation: unmyelinated axon sequence
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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 |
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Propagation: myelinated axon sequence
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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 |
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Action Potential: Conduction Veloctiy
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unmyelinated=slow
myelinated=10x faster (b/c myelin sheath removing parts of axon) |
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Action Potential: Tranmission of AP from neuron to neuron
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1.synapse
2.chemical synapse assoc 3.excitation @ synapse 4.inhibition @ synapse |
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Synapse
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region b/w 2 neurons
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structure:
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presynaptic neuron -> neuron -> postsynaptic neuron
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Synapse: Types
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1.Electrical synapse
2.Chemical snyapse |
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Electrical synapse
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few in #; contain gap junctions b/w neurons; AP travels quickly thru jxns
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Chemical synpase
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made of 1.synaptic knob, containing vesicles made of neurotransmitters that stim/inhib postsynaptic neuron, 2.synaptic cleft, & 3.postsynaptic membrane: containing NT receptors
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Chemical synapse associations:
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1.axodendritic: axon to dendrite
2.axosimatic: axon to cell body 3.axoaxonic: axon to axon all usually inhibitory associations & few in # |
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Excitation @ synapse
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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 |
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(3. vessicles release NT by exocytosis ...)
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NT now in synpatic cleft; by diffusion hits receptor sites in postsynp memb
4.stimulation of excitatory presynaptic potentials & summation |
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excitatory presynaptic potentials:
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small amounts of NT combine w/ receptors->Na entry->local depolarizations: EPSP; RP -70mV->-60mV->AP
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summation:
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increased amts of NT combined w/ receptors-> several EPSP's created->add together & form AP; RP -70mV->-55mV->AP in postynaptic neuron
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Examples of excitatory NT:
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acetycholine, norepinephrine, dopamine, glutamic acid, aspartic acid, substance P: sends pain stimuli thru CNS, esp spinal cord
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Inhibition @ synapse
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presynaptic neuron causes hyperpolarization in postsynaptic neuron-becoming more negative (-70 to-80mV)
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Inhibition steps:
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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 |
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Increased K permeability=
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-80mv= inhibitory postsynaptic potential IPSP; prevents postsynp neuron from being stimulated under normal conditions
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Neurons can receive:
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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
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Examples of Inhibitory NT:
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acetylcholine, norepinephrine, dopamine, gaba, enkephalins (inhibit pain stim)
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1st three ex both EPSP/IPSP, how?
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depends on postsynaptic neuron whether EPSP/IPSP
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Nervous System: CNS covered w/
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Meninges
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Meninges:
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3 layers of connective tissue:
1.Dura Mater 2.Arachnoid 3.Pia Mater |
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Dura Mater
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most outer layer;
1.brain 2.spinal cord 3.Subdural Space |
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Dura Mater: Brain
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exists in 2 layers:
1.cranial/periosteal dura mater 2.meningeal dura mater |
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Brain: Cranial Dura Mater
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contacts cranial bones; serves as periosteum
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Brain: Menineal Dura Mater
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below cranial DM; most regions together, but some seperate & form spaces:1.blood sinuses & 2.partitions
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Blood Sinuses
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seperation of Cranial DM & Meningeal DM; create spaces & contain blood
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Partitions
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made of 2 layers of Meningeal DM; wall of CT
1.Falx Cerebri: b/w L&R hemispheres 2.Falx Cerebelli: sep cerebrum & cerebellum |
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Dura Mater: Spinal Cord
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exists only 1 layer:
Meningeal/Spinal Dura Mater |
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Meningeal/Spinal Dura Mater
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continuous w/ Meningeal DM of brain
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Dura Mater: Subdural Space
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below MDM in both brain & spinal cord; contains fluid that keeps DM connected to arachnoid
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subdural hematoma
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blood clot in subdural space
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Arachnoid
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middle layer; same in brain and spinal cord; 3 components:
1.arachnoid membrane 2.arachnoid trabeculae 3.subarachnoid space |
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Arachnoid: Arachnoid membrane
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adjacent to subdural space
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Arachnoid: Arachnoid trabeculae
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partitions; extend from arachnoid membrane to pia mater
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Arachnoid: Subarachniod space
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below arachnoid membrane; contains CSF
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Pia Mater
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composed of areolar tissue; in direct contact w/ brain and spinal cord tissue; most inner layer
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Clinical Aspect:
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Meningitis: caused by bacteria & viruses; blood vessels inflammed->vasodilation
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Bacterial Meningitis
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heals on own
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Viral Meningitis
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antibiotics assist healing
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Nervous System: CNS: Brain
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1.Cerebrum
2.Basal Ganglia 3.Thalamus 4.Hypothalamus 5.Cerebellum 6.Brainstem 7.Reticular Activating Sys 8.Ventricular system |
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Brain: Cerebrum
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largest part of brain; divided into hemispheres
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Cerebrum: Fissures, Sulci & Lobes
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1.Lonitudinal Fissure/Cerebral Fissure
2.Central Fissure/Fissure of Rolando 3.Lateral/Fissure of Sylvius 4.Parieto-Occipital Sulcus |
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Cerebral Fissure
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(Longitudinal Fissure)
divides cerebrum into L&R cerebral hemispheres |
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Fissure of Rolando
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(Central Fissure)
exists in both hemispheres; seperates frontal lobe from parietal lobes in cerebrum |
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Fissure of Sylvius
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seperates frontal & parietal lobes from temporal lobe
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Parieto-Occipital Sulcus
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shallow fissure; seperates parietal lobe from occipital lobe;
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Insula
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5th lobe; located @ base of fissure of Sylvius; very deep (not superficial like others)
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Cerebrum: Neural Tissue Structure
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1.Cerebral Cortex
2.White Matter |
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Cerebral Cortex
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gray matter;
made of cell bodies of neurons; includes unmyelinated axons & dendrites; top most tissue of cerebrum; gyri: |
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gyri
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ridges of gray matter seen superficially w/ dark lines b/w them: sulci; folding gyri increase surface area of gray matter
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sulci
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seperating gyri from one another;
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White Matter
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composed of myelinated axons/dendrites;
no cell bodies found; made of specific tracts: |
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White Matter tracts w/ special actions:
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1.Arcuate
2.Association 3.Commissural 4.Projection |
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Arcuate
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adjacent gyri; in same lobe
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Association
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connects gyri from different lobes, but in same hemisphere
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Commissural
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few in #; interconnect 2 cerebral (L&R) hemispheres to each other; largest one=Corpus Callosum
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Corpus Callosum
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connection for L&R coordination
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Projection
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connects cerebral cortex to all other parts of CNS
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Cerebrum: Physiological Divisions of Cerebral Cortex
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1.Motor Cortex
2.Sensory Cortex 3.Association Cortex |
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Motor Cortex:
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1.Primary Motor Cortex
2.Brocas Area |
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Primary Motor Cortex
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located in frontal lobe;
anterior to Fiss Rolando; originates all skeletal musc contractions |
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Broca's Area
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located @ L frontal lobe of L hemisphere;
initiates skeletal musc contractions for speech |
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Sensory Cortex:
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1.Primary Sensory Cortex/Primary Somesthetic Cortex
2.Olfactory Cortex 3.Auditory Cortex 4.Taste Cortex 5.Visual Cortex |
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Primary Sensory Cortex
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located @ parietal lobe;
posterior to Fiss Rolando; responsible for interpretation of sensations from skin (temp, pain, itch); involved w/ sensations from skeletal musc |
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Olfactory Cortex
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located @ frontal lobe;
where smells/odors interpreted |
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Auditory Cortex
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located @ temporal lobe;
where sound interpreted |
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Taste Cortex
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located @ parietal lobe;
chemical sensations from mouth/saliva detected here |
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Visual Cortex
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located @ occipital lobe;
eyes help get info to this part of brain for interpretation |
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Association Cortex:
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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 |
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Premotor Cortex
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aka Motor Association Cortex;
located @ frontal lobe; anterior to PMC; coordinates groups of skeletal musc contractions |
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Prefrontal Cortex
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located @ frontal lobe;
anterior to Premotor Cortex; where reasoning occurs & judegement decisions made |
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Visual Association Cortex
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located @ occipital lobe
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Auditory Association Cortex
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located @ temporal lobe;
allows you to hear something one time and recognize it |
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Werenicke's Area
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located @ temporal lobe;
assoc. w/ speech; allows for recognition of written/spoken word->language |
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Brain: Basal Ganglia
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regions of gray matter;
unmyelinated axons/dend; found embedded in white matter or cerebrum |
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Specific names of Ganglia:
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Putamen, Caudate Nucleus, Globus Palidus
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Basal Ganglia Fxn
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modify nerve impulses coming out of PMC ... refining impulses->smooth, even contractions
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Brain: Thalamus
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located below Corpus Callosum & above Brainstem
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Thalamus fxns
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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 4.consciousness |
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1 exception of sensory relays w/ thalamus:
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olfactory sensations go directly to cerebral cortex w.o thalamus help
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consciousness:
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involved w/ reticular formation->sends info to thalamus->info to cerebral cortex
RF active=awake, conscious RF inactive=coma, unconscious |
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Brain: Hypothalamus
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region of gray matter below thalamus; contains many regions involved w/ physiological fxns
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Hypothalamus Fxns
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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 |
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Hypothalamus Fxns (cont)
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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 6.sex: orgasms sensation related to hypoth |
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Brain: Cerebellum
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2nd largest portion of brain;
located posteriorly/inferiorly to cerebrum |
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Cerebellum: External Structure
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made up of ridges:Folia
& grooves: Sulci 3 major regions: 1.Lhemisphere 2.Rhemisphere 3.Vermis connecting the 2 |
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Cerebellum: Internal Structure
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gray matter (makes up folia) & white matter (makes up nerve tracts)
white matter=arbor vitae: connects cerebellum to other parts of CNS |
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Cerebellum: Fxns
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coordination of muscular actions b/w brain & skeletal muscles;
reads sensory input from musc's & motor output from brain ... fine tunes the final output |
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Final Output:
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1.coordinates synergistic & antagonistic voluntary musc contractions for manual dexterity
2.maintenance of balance & posture |
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maintenance of balance & posture:
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reads sensory inputs from eye, ear balance receptors in brain, & proprioceptors in musc's + motor outputs --> fine tunes fnal output
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Brain: Brainstem
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below thalamus & in front of cerebellum;
2 subcomponents: Midbrain, Pons, Medulla Oblongata |
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Midbrain:
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2 portions:
1.Cerebral Peduncles 3.Corpora Quadrigemina |
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Cerebral Peduncles
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nerve tracts; intermediates:
1.take sensory fibers from pons->thalamus; receive nerve fibers from cerebellum 2.take motor fibers from cerebrum->pons |
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Corpora Quadrigemina
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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 |
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Midbrain: Substantia Nigra
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(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) |
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initial treatment:
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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
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Pons
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made of nerve tracts; "Bridge"
1.nerve tracts 2.ancillary breathing centers |
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nerve tracts
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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 |
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ancillary breathing centers
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pneumotaxic center &
apneustic center |
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Medulla Oblongata
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Nerve tracts: mostly white matter; receives sensory fibers from spinal cord->pons;
motor fibers from pons->spinal cord |
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Med Ob: Physiological Nerve Centers
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1.Cardiac Center-affects HR
2.Vasomotor Center-affects BP 3.Respiratory Center-affects breathing mvmts 4.Coughing, Swallowing, Vomitting Centers |
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Brain: Reticular Activating System
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(aka Reticular Formation)
very diffuse Gray Matter |
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RF fxn
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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 |
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Brain: Ventricular System
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hollow spaces in cerebrum;
connecting openings/ducts associated here; filled w/ CSF |
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Ventricular System: Structure
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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 |
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lateral ventricles
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1/2nd vent; found under corpus callosum
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foramen of monro
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1 for each lateral ventricle; opening that connect lateral vetnricles to 3rd vetnricle
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3rd ventricle
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near thalamus; goes into a single opening
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aqueduct of sylvius
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connects 3rd & 4th ventricles
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4th ventricle
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space b/w cerebellum & medulla oblongata
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Ventricular System: Formation & Circulation of CSF
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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 |
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Choroid Plexes:
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in all 4 ventricles; made up of blood capillaries; covered by ependymal cells
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Formation of CSF:
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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
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Flow of CSF through Ventricles:
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from lateral vent 1&2->thru foramen monro->3rd vent (more CSF added)->cerebral aqueduct sylvius->4th vent (more CSF added)
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Exit of CSF from Ventricular System:
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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) |
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Flow of CSF in subarachnoid space of Spinal Cord
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@ base of brain, some fluid flows down posterior side of sp cord->to anterior side of sp cord->upward toward base of brain again
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Flow of CSF in subarachnoid space of Brain
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CSF flows upward over cerebellum, over cerebrum, toward lonitudinal fissure of cerebrum ... target=top of brain
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CSF in subarachnoid space near longitudinal fissure..
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passes thru arachniod villi->allowin fluid to enter blood sinuses->send fluid to internal jugluar vein
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Properties of CSF:
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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 |
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Fxns of CSF:
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1.mechanical protection to CNS-"shock absorber"
2.medium of exchange-exchange of nutrients & waste products b/w nerve tissue |
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Clinical Note of CSF:
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diagnosis of diseases: brain tumors, hydrocephalis, bleeding in CNS, meningitis (infxn), Multiple Sclerosis; analysis thru Lumbar puncture @ 3/4th L vert
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Nervous System: CNS: Spinal Cord
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found in vertebral/spinal canal; starts @ foramen magnum->ends @ L1-L2
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Covered by:
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Meninges
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Spinal Cord: Meninges
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1.Spinal/Meningeal Dura Mater
2.Arachnoid 3.Pia Mater |
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Spinal Cord: Terminal Structures
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1.conus medullaris
2.cauda equina 3.filum terminale |
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conus medullaris:
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end piece @ L1/L2 region; cone shaped
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cauda equina:
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last 9 pairs of spinal nerves; extend down into vertebral canal; some enter sacral canal
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filum terminale:
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cord of pia mater CT; purpose to attach conus->coccyx ... stablizing bottom portion of spinal cord
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Spinal Cord: Cross Sectional Structure
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oval shaped; divided in almost 2
1.dorsal/posterior median sulcus (shallow) 2.ventral/anterior median fissure (deeper) |
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Spinal Cord: Gray Matter
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in center; made up of cell bodies & unmyelinated fibers
a)arranged in H shape w. posterior horn, lateral horn, anterior horn; gray commissure |
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lateral horn:
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not present in all segments of spinal cord; only Thoracic & lumbar regions; associated w/ sympathetic NS
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gray commissure:
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@ center; connects 2 sides of H; encloses central canal
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Spinal Cord: White Matter
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found outside/around; made of nerve tracts->myelinated fibers; specifically organized
1.Funiculi 2.Fasciculi |
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Funiculi
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3 pairs of tracts: posterior, lateral, anterior (on both sides); subdivisions w/in:
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Fasiculi(Fasicles)
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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 |
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Spinal Cord: Fxns
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1. 2-way conducting pathway for nerve impulses (brain & sp cord)
2.reflex center-associated w/ spinal nerves |
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Nervous System: PNS
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Cranial Nerves
Spinal Nerves |
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Cranial Nerves
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12pairs;
all originate from ventral side of brain: cerebrum or brainstem 3 groups: sensory, motor, mixed |
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Cranial Nerve I
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Olfactory Nerve/Tract:
sensory assoc w/ sense of smell |
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Cranial Nerve II
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Optic Nerve:
sensory assoc w/ vision forms optic chiasma & optic tracts lead away |
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Optic Chiasma
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decussation: crossing over of nerve fibers allowing for stereoscopic/3D vision
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Optic Tracts
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sends APs to specific portions of occipital lobe of brain
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Cranial Nerve III
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Oculomotor Nerve:
Motor stim extrinsic & intrinsic musc of eye |
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Cranial Nerve IV
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Trochlear Nerve:
Motor stim ext musc of eye to contract |
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Cranial Nerve V
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Trigeminal Nerve:
mixed; Sensory-picks up sensations from face/teeth/gums Motor-innervates musc of mastication |
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Cranial Nerve VI
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Abducens Nerve:
Motor stim ext musc of eye |
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Cranial Nerve VII
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Facial Nerve:
mixed; Sensory-innervates taste buds @ ant 2/3 tongue Motor-stim musc of facial expression, swallowing, stim salivary glands to secrete |
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Cranial Nerve VIII
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Vestibulocochlear/Auditory/Acoustic Nerve:
Sensory Vestibule Branch-innervates semicircular ducts, vitricle, saccule: all involved w/ sense of balance Cochlear Branch-organ of corti: assoc w/ hearing process |
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Cranial Nerve IX
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Glossopharyngeal Nerve:
Mixed: 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 |
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Cranial Nerve X
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Vagus Nerve:
Mixed: longest:medulla->abdomen 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 |
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Cranial Nerve XI
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Spinal Nerve:
Motor stim musc of head-neck-shoulder area |
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Cranial Nerve XII
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Hypoglassal Nerve:
Motor stim musc of tongue-speech & swallowing |
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Spinal Nerves:
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-31 pairs
-arise just under foramen magnum->conus medullaris -all found in vertebral/sacral canal EXCEPT: |
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Spinal Nerve 1, b/c
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exits spinal cord above C1
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Spinal Nerve: Structure
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Dorsal/Posterior Root
Ventral/Anterior Root |
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Dorsal Root
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-contains enlargement:Dorsal Root Ganglion
-transmits sensory axons from spinal nerve->spinal cord |
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Dorsal Root Ganglion
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contains cell bodies of pseudounipolar neurons
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Ventral Root
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-fuses w/ Dorsal root & together form spinal nerve
-contains only motor axons, so sends motor axons from spinal cord->spinal nerve |
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Spinal Nerve: Fxns
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participate in spinal/Somatic and Visceral/Autonomic Reflexes
1.Reflex Arc 2.Elements of Somatic Reflex 3.Types of Somatic Reflex |
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Reflex Arc:
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fxnal unit of NS/physiological unit of NS
-pathway APs take to produce reflex |
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Reflex:
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involuntary purposeful rxn to some stimulus
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Elements of Spinal/Somatic Reflex Arc:
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1.Receptor
2.Somatic Afferent/Sensory Neuron 3.Interneuron 4.Somatic Efferent/Motor Neuron 5.Effector |
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Receptor:
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reacts to stimulus; produces APs; sends AP to sensory/afferent neuron
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Somatic Afferent Neuron
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Sensory; sends APs from spinal nerve into spinal cord
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Interneuron
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not always present; take AP from sensory neuron to another interneuron OR to somatic efferent neuron
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Somatic Efferent Neuron
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Motor; take AP from within spinal cord to spinal nerve, who then sends AP to effector
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Effector:
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Skeletal Muscle; carries out action/response
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Types of Spinal Somatic Reflexes
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1.Stretch/Myotactic Reflex
2.Tendon Reflex |
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Stretch/Myotactic Reflex
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-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 |
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Motor Neuron...
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stimulates the stretched muscle to contract (antag)-->preventing musc from being over stretched/damaged
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Tendon Reflex: Receptor
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=golgi tendon organ found in tendons of musc; detect tension on tendon
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golgi tendon organ ...
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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
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this prevents:
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tendon from being detached from musc
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