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45 Cards in this Set
- Front
- Back
Structure of spinal cord Ends between:
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Ends between vertebrae L1 and L2
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Enlargements of the Spinal Cord
Caused by: |
Amount of gray matter in segment
Involvement with sensory and motor nerves of limbs |
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Cervical enlargement
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Nerves of shoulders and upper limbs
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The Distal End
Conus medullaris: Filum terminale: Cauda equina: |
-thin, conical spinal cord below lumbar enlargement
-thin thread of fibrous tissue at end of conus medullaris attaches to coccygeal ligament -nerve roots extending below conus medullaris |
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how many spinal cord segments
Cervical nerves are named for: All other nerves are named for: |
31 Spinal Cord Segments
are named for inferior vertebra are named for superior vertebra |
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Roots
Two branches of spinal nerves Ventral root contains: Dorsal root contains: Dorsal root ganglia contains: |
-contains axons of motor neurons
-contains axons of sensory neurons -contain cell bodies of sensory neurons |
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Dorsal and ventral roots join To form a:
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spinal nerve
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Mixed Nerves Carry both:
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Carry both afferent (sensory) and efferent (motor) fibers
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The Dura Mater (Tough and fibrous)
Cranially: -Fuses with -Is continuous with Caudally: -Tapers to -Joins |
-Fuses with periosteum of occipital bone
-Is continuous with cranial dura mater -Tapers to dense cord of collagen fibers -Joins filum terminale in coccygeal ligament |
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The Epidural Space
Between: site for: Contains: Subarachnoid space is between: |
-Between spinal dura mater and walls of vertebral canal
-Anesthetic injection site -Contains loose connective and adipose tissue -Between arachnoid mater and pia mater |
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Gray matter
Surrounds: Contains: Has projections: |
-Surrounds central canal of spinal cord
-unmyelinated axons -Has projections (gray horns) |
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White matter
-Contains: |
Contains myelinated and unmyelinated axons
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Connective tissue layers of spinal nerves:
Epineurium: -Dense network of : Perineurium: -Divides nerve into: Endoneurium: -Surrounds: |
Outer layer
-Dense network of collagen fibers Middle layer -Divides nerve into fascicles (axon bundles) Inner layer -Surrounds individual axons |
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Nerve plexuses- (definition,four major plexuses) EACH INCLUDES AND INNERVATES ?
The Cervical Plexus of the Ventral Rami : The Brachial Plexus of the Ventral Rami The Lumbar Plexus of the Ventral Rami The Sacral Plexus of the Ventral Rami |
Complex, interwoven networks of nerve fibers
The Cervical Plexus of the Ventral Rami -Includes ventral rami of spinal nerves C1–C5 -Innervates neck, thoracic cavity, diaphragmatic muscles The Brachial Plexus of the Ventral Rami • Includes ventral rami of spinal nerves C5–T1 • Innervates pectoral girdle and upper limbs The Lumbar Plexus of the Ventral Rami • Includes ventral rami of spinal nerves T12–L4 • innervate the pelvic girdle and lower limbs The Sacral Plexus of the Ventral Rami • Includes ventral rami of spinal nerves L4–S4 • innervate the pelvic girdle and lower limbs |
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Motor nerve
white ramus: carries what to what: |
carries visceral motor fibers to sympathetic ganglion of autonomic nervous system
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gray ramus:
-return from: -rejoin: |
unmyelinated nerves
-return from sympathetic ganglion -rejoin spinal nerve |
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Dorsal and ventral rami
dorsal ramus: contains ____ and ____ innervates : |
-contains somatic and visceral motor fibers
-innervates the back |
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ventral ramus:
• larger branch • innervates : |
ventral ramus:
• larger branch • innervates ventrolateral structures and limbs, |
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dorsal, ventral, and white rami also carry _____ information in addition to motor impulses
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dorsal, ventral, and white rami also carry sensory information n addition to motor impulses
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Sensory neurons
-Deliver information to Motor neurons -Deliver commands to Interneurons: |
Sensory neurons
-Deliver information to CNS Motor neurons -Deliver commands to peripheral effectors Interneurons -Interpret, plan, and coordinate signals in and out |
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Neuronal Pools
Functional groups of: Each with limited input sources and output destinations May stimulate or depress parts of : |
Neuronal Pools
-Functional groups of interconnected neurons (with the help of interneurons) Each with limited input sources and output destinations May stimulate or depress parts of brain or spinal cord |
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Divergence:
Convergence: Serial processing: Parallel processing: Reverberation: |
-Divergence
Spreads stimulation to many neurons or neuronal pools in CNS -Convergence Brings input from many sources to single neuron -Serial processing Moves information in single line -Parallel processing Moves same information along several paths simultaneously -Reverberation Positive feedback mechanism Functions until inhibited |
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Reflexes- five steps in neural reflex:
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Step 1: Arrival of stimulus, activation of receptor
Physical or chemical changes Step 2: Activation of sensory neuron Graded depolarization Step 3: Information processing by postsynaptic cell Triggered by neurotransmitters Step 4: Activation of motor neuron Action potential Step 5: Response of peripheral effector • Triggered by neurotransmitters, Four classifications of reflexes and examples: |
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Four classifications of reflexes and examples:
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- Development
-Motor Response -Complexity of Neural Circuit -Site of Information Processing |
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Development
How reflex was developed innate: acquired: |
Innate reflexes:
• basic neural reflexes • formed before birth e.g sucking, grasping, withdrawal, blinking Acquired reflexes: • rapid, automatic • learned motor patterns e.g shielding a blow, covering ear from noise |
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Motor Response
Nature of resulting motor response • Somatic reflexes: • Visceral reflexes (autonomic reflexes): |
-Somatic reflexes:
• involuntary control of muscular system • superficial reflexes of skin, mucous membranes • stretch or deep tendon reflexes (e.g., patellar, or “knee-jerk”, reflex) -Visceral reflexes (autonomic reflexes): • voluntary control of systems other than muscular.g contraction of the muscles of the intestine during peristalsis(digestion) |
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Complexity of Neural Circuit
• Monosynaptic reflex • Polysynaptic reflex |
-Sensory neuron synapses directly onto motor neuron
stretch reflex, which provides automatic regulation of skeletal muscle length. -At least one interneuron between sensory neuron and motor neuron The tendon reflex monitors the external tension produced during a muscular contraction and prevents tearing or breaking of the tendons. Also withdrawal reflexes move affected parts of the body away from a stimulus.. |
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Site of Information Processing
• Spinal reflexes • Cranial reflexes |
Site of Information Processing
• Spinal reflexes • Occurs in spinal cord • Cranial reflexes • Occurs in brain,monosynaptic, polysynaptic, postural, tendon, withdrawal. |
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Reflex arcs.
Crossed Extensor Reflexes: |
Crossed Extensor Reflexes
-For example, flexor reflex causes leg to pull up Crossed extensor reflex straightens other leg To receive body weight Maintained by reverberating circuits |
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Characteristics of polysynaptic reflexes
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Involve pools of neurons
Are intersegmental in distribution Involve reciprocal inhibition Have reverberating circuits Which prolong reflexive motor response Several reflexes cooperate to produce coordinated, controlled response |
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Babinski:
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The plantar reflex (negative Babinski reflex), a curling of the toes, is seen in healthy adults.
-The banbiski sign(positive feedback) occurs in the absence of descending inhibition. It is normal in infants, but pathological in adults. |
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Brain alteration of spinal reflexes:
Integration and Control of Spinal Reflexes -Reflex behaviors are automatic but -Automatic reflexes can be activated by brain as needed by using few nerve impulses to control Walking, running, jumping |
Brain alteration of spinal reflexes: Integration and Control of Spinal Reflexes
-Reflex behaviors are automatic but processing centers in brain can facilitate or inhibit reflex motor patterns based in spinal cord -Automatic reflexes can be activated by brain as needed by using few nerve impulses to control complex motor functions like Walking, running, jumping. |
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Voluntary Movements and Reflex Motor Patterns
Higher centers of brain incorporate: |
-Voluntary Movements and Reflex Motor Patterns
Higher centers of brain incorporate lower, reflexive motor patterns |
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Reinforcement of Spinal Reflexes:
Higher centers reinforce spinal reflexes by: Creating ____ at reflex motor neurons and facilitating _____ neurons |
Reinforcement of Spinal Reflexes:
Higher centers reinforce spinal reflexes by stimulating excitatory neurons in brain stem or spinal cord, creating EPSPs at reflex motor neurons and facilitating postsynaptic neurons |
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Inhibition of Spinal Reflexes:
Higher centers inhibit spinal reflexes by Stimulating ______ neurons Creating _____ at reflex motor neurons and ______ postsynaptic neurons |
Inhibition of Spinal Reflexes:
Higher centers inhibit spinal reflexes by Stimulating inhibitory neurons Creating IPSPs at reflex motor neurons Suppressing postsynaptic neurons |
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Neurotransmitters:
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Norepinephrine (NE)
• Dopamine • Serotonin • Gamma aminobutyric acid (GABA) |
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Classes of opioids:
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(relieve pain by reducing the intensity of pain signals to the brain)
Enkephalins Endomorphins Dynorphins |
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The larger the diameter,
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The larger the diameter, the lower the resistance(the faster it'll go down the axon)
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Excitatory postsynaptic potential (EPSP):
Inhibitory postsynaptic potential (IPSP): Presynaptic inhibition: Presynaptic facilitation: |
-Graded depolarization of postsynaptic membrane
-Graded hyperpolarization of postsynaptic membrane -Action of an axoaxonic synapse at a synaptic knob that decreases the neurotransmitter released by presynaptic membrane -Action of an axoaxonic synapse at a synaptic knob that increases the neurotransmitter released by presynaptic membrane. |
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Two methods of propagating action potentials
Continuous propagation: Saltatory propagation: |
Continuous propagation: unmyelinated axons(slower process because it's unmyelinated so it can affect one axon at a time)
Saltatory propagation: myelinated axons.(faster and uses less energy),Moves action potentials generated in axon hillock Along entire length of axon A series of repeated actions, not passive flow |
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Ion Movements and Electrical Signals.
Five main membrane processes in neural activities resting potential: graded potential: action potential: synaptic activity: information processing: |
resting potential: The transmembrane potential of resting cell, graded potential: Temporary, localized change in resting potential.Caused by stimulus, action potential: Is an electrical impulse.Produced by graded potential. moves along axon, synaptic activity: Releases neurotransmitters at presynaptic membrane. Produces graded potentials in postsynaptic membrane, information processing: Response (integration of stimuli) of postsynaptic cell.
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Four types of neuroglia in CNS-
ependymal cells: astrocytes: oligodendrocytes: microglia: |
Four types of neuroglia in CNS-
ependymal cells: Line central canal of spinal cord and ventricles of brain, astrocytes: Maintain blood–brain barrier (isolates CNS), oligodendrocytes: Wrap around axons to form myelin sheaths in CNS, microglia: immune defense in CNS. |
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Types of sensory receptors- interoceptors:
exteroceptors: proprioceptors: |
Types of sensory receptors-
interoceptors: Monitor internal systems (digestive, respiratory, cardiovascular, urinary, reproductive) -Internal senses (taste, deep pressure ,pain.) exteroceptors: External senses (touch, temperature, pressure)-Distance senses (sight, smell, hearing), proprioceptors: Monitor position and movement (skeletal muscles and joints). |
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Functional classifications of neurons-
sensory: motor: interneurons: |
Functional classifications of neurons-
sensory: Afferent neurons of PNS, motor: Efferent neurons of PNS, interneurons: Association neurons serves as link btwn sensory & motor neurons. |
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Structural classifications of neurons-
anaxonic: Found in bipolar: Found in unipolar: Found in multipolar: Common in the ____,Include all ___ |
Structural classifications of neurons-
anaxonic: Found in brain and sense organs, bipolar: Found in special sensory organs (sight, smell, hearing), unipolar: Found in sensory neurons of PNS, multipolar: Common in the CNS,Include all skeletal muscle motor neurons. |