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The Nervous System - flashcards
Karten in diesem Stapel (56)
- 1Afferent DivisionCarries Sensory Information from the Peripheral Nervous System sensory receptors to the Central Nervous System. "INCOMING DIVISION"
- 2Efferent DivisionCarries Motor Commands from the Central Nervous System to the Peripheral Nervous System, muscles and gland. "OUTGOING DIVISION"
- 3Somatic Nervous SystemThe Somatic Nervous System controls:
Skeletal muscle contractions (a voluntary response to stimuli)
AND
Reflexes (an involuntary response to stimuli) - 4Autonomic Nervous SystemThe Autonomic Nervous System regulates:
Smooth muscle tissue, cardiac muscle and glandular secretions (subconscious response)
Sympathetic and Parasympathetic divisions - 5Sensory NeuronsAFFERENT Neurons of the PNS
Deliver information FROM Sensory Receptors TO the CNS - 6Somatic Sensory NeuronsMonitor the external conditions
- 7Visceral Sensory NeuronsMonitor the internal conditions
- 8Sensory ReceptorsProprioceptors (position in space and movement)
Exteroceptors (external/outside)
Interoceptors (internal/inside) - 9Motor NeuronsEFFERENT Neurons of the PNS
Deliver information FROM the CNS to the peripheral EFFECTORS - 10Somatic Motor NeuronsInnervate Skeletal Muscle
- 11Visceral Motor NeuronsInnervate "other" effectors (e.g. smooth muscle)
- 12Anaxonic NeuronAnaxonic Neurons have more than two processes and they are all dendrites. They have NO axon.
- 13Bipolar NeuronBipolar Neurons have two processes separated by the cell body. They have only one dendrite, with dendritic branches at the distal tip.
They occur in special sense organs and relay information about sight, smell, or hearing. - 14Unipolar Neuron (pseudounipolar neuron)Unipolar Neurons have a single elongated process with the cell body off to the side.
Most sensory neurones of the Peripheral Nervous System are Unipolar Neurons.
Axons can extend a metre or more (e.g.. toes to spine), ending at synapses in the Central Nervous System. - 15Multipolar NeuronsMultipolar Neurons have more than two processes; there is a single son and multiple dendrites, They are the most common neuron in the Central Nervous System.
All the motor neurons that control skeletal muscle are multipolar. Their axons can be very long (e.g. spine to toes) - 16Ependymal Cell (Central Nervous System)Ependymal Cells line ventricles of the brain and the central canal of the spinal cord.
They assist in producing, circulating and monitoring Cerebrospinal Fluid (CSF) - 17Astrocyte (Central Nervous System)Astrocytes maintain the blood-brain barrier, provide structural support, regulate ion, nutrient and dissolved gas concentrations. They absorb and recycle neurotransmitters.
They may form scar tissue after injury. - 18Ogliodendrocytes (Central Nervous System)Ogliodendrocytes myelinate the Central Nervous System axons, provide structural framework,
- 19Microglia (Central Nervous System)Microglia remove cell debris, waste, and pathogens by phagocytosis.
- 20Satellite Cells (Peripheral Nervous System)Satellite cells surround neuron cell bodies in ganglia, regulate O2 and CO2, nutrient and neurotransmitter levels around the neurones in the ganglia.
- 21Schwann Cells (Peripheral Nervous System)Schwann Cells surround all axons in the Peripheral Nervous System, are responsible for the myelination of peripheral axons and participate in repair processes after injury.
- 22Graded Potentialtransient, occurs in dendrites and soma. Size and Duration determined by input size and duration. Does NOT usually move into axon. Synapse closer to trigger zone may result in an action potential.
- 23Action potentialdoes not decay with distance like graded potential - conducted down axon unchanged
all or none potential - 24Synapsewhere two neurons meet - usually axon/dendrite
- 25Leak ChannelsAlways open
- 26Voltage Gated ChannelsOpen/Close when membrane crosses a voltage value
- 27Refractory Perioddifficult/impossible to trigger another potential in this part of the membrane
- 28EPSPexcitatory post synaptic potential
- 29IPSPinhibitory post synaptic potential
- 30temporal summationthe addition of stimuli occurring in rapid succession at a single synapse that is active repeatedly.
- 31spatial summationoccurs when simultaneous stimuli applied at different locations (synapses) have a cumulative effect on the membrane potential
- 32CNSbrain and spinal cord
- 33spinal cordpassage of sensory information to the brain, passage of motor information from brain to defectors, integrates information and controls spinal reflexes
- 34posterior - sensory PSanterior - motor
AM - 35central canal of spinal cord (ependymal canal)CSF space, runs longitudinally, continuous with ventricular system of brain
- 36dorsal root gangliadorsal = sensory
DRG = cell bodies of sensory neurons - 37dorsal rootdorsal = sensory
dorsal root = axons of sensory neurons - 38ventral rootsventral = motor
ventral roots = axons of motor neurons - 39gray matterforms butterfly shape around central canal. dominated by cell bodies of neurons, neuroglia, unmyelinated axons. Nuclei = masses of gray matter = functional group.
integrates info and initiates commands. - 40white matter - tracts carry info into and out of CNSsuperficial to grab matter, large number of myelinated and unmyelinated axons.
ascending tracts carry sensory info
descending tracts carry motor info
LOGICAL - 41spinal nervessurrounded by 3 layers
epineurium - outer, collagen.
perineurium - forms fascicles (bundles of axons)
endoneurium - surrounds individual axons - 42dermatonemonitored by spinal nerves - specific region,
- 43spinal reflexesrapid, automatic responses triggered by specific stimuli
controlled by spinal cord alone.
interconnected sensor, motor, and interneurons.
producer simple and complex reflexes. - 44reflex arcstimulus sensed by receptor
sensory neuron transmits signal from PNS to CNS
integration centre decodes
Motor neuron sends direction back, effector responds - 45stretch reflex monosynapticstimulus - > receptor (muscle spindle) - > effector stretch and contract
allows load to be added to muscle. - 46golgi tendon reflexskeletal muscle contraction causes agonist to lengthen and relax -
inverse of stretch reflex, protects from excessively heavy loads. - 47withdrawal reflex ipsilateral (same side) polysynapticmoves affected part of body away - reciprocal inhibition
crossed extensor similar, but crosses body. - 48polysynaptic reflexespools of interneurons
intersegmental distribution extend across spinal segments
reciprocal inhibition
reverberating circuits prolonged motor response
coordinated and controlled - 49receptorstouch - tactile / mechano
pressure - mechano
temperature - thermo
pain - nociceptor
body position - proprioceptor
somatosensory cortex interprets - 50tonic recptorsalways active - slow to adapt
- 51phasic receptorsonly active sometimes
quick to adapt - 52somatosensory pathwaysfirst order neuron - delivers info to CNS
2nd order neuron
3rd order neuron
spinothalamic
posterior column
spinocerebellar - 53spinothalamic pathway touch, paincrosses at spinal cord
arrives at primary sensory cortex - 54posterior column pathway touch, vibrations, proprioceptioncrosses at medulla oblongata
arrives at sensory cortex - 55spinocerebellar pathway proprioceptioncrosses at spinal cord
ends at cerebellum - 56somatic nervous system - corticospinal pathwayhigher and lower nerouns
medial - gross
lateral - fine