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77 Cards in this Set
- Front
- Back
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What structures are the neurons composed of? |
1) Dendrites 2) Axons 3) Soma 4) Terminal endings |
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What are dendrites? |
Primary site for receiving incoming chemical (signals) information from other neurons -- Extensions of plasma membrane (post synaptic membrane) |
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What are the post synaptic potentials in dendrites? |
1) IPSP - Inhibitory post synaptic potential 2) EPSP - Excitatory post synaptic potential |
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What is the role of dendritic spines? |
1) Modulation of signals 2) Long term potentiation |
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What leads to action potentials? |
When ions crosses the chemically gated channels on the neuron membrane a charge is formed. Summation of these charges leads to action potential ??? (not sure about this information) |
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What is postsynaptic potential? |
When chemicals are released, there are two things that can happen
1) IPSP 2) EPSP |
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Inhibitory post synaptic potential 1) Raise threshold - harder for the cell to fire 2) Lowers resting potentials - further away from depolarization 3) Opens chloride channels |
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Excitatory post synaptic potential 1) Lowers threshold - more sensitive, more likely to fire 2) Raises the resting potential - closer to depolarization 3) Opens sodium channels |
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Action Potentials are carried by ___________ through the ___________ and enhanced by _________ |
Axons Voltage gated channels Myelin |
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What is the action potential information coded into? |
Frequency of Aps
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What are Axons? |
Axons carry action potentials 1) Afferent towards the soma 2) Efferent away from the soma |
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Where are axons found? |
1) CNS and PNS |
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What are the types of Axons? |
1) Myelinated 2) Unmyelinated |
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T/F: Regeneration of the axons are possible in PNS and CNS |
FALSE PNS - regeneration is possibleCNS - no regeneration |
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What is cytoplasmic transport? |
Cytoplasmic transport along Microtubules of organelles, vesicles and molecules -- Energy consuming process -- Viruses can be transported (herpes, Rabies, HIV) |
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What are the two types of Axonal transport? |
1) Anterograde - away from soma guided by kinesin 2) Retrograde - to the soma by dynein |
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What is neural coding? |
The way in which the nervous system converts information to a meaningful pattern of AP Increased firing rate = increase stimulation --- Bladder urgency, muscular tone |
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What is myelin? |
Phospholipid layers surrounding axons
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What is the role of Myelin? |
1) Increases speed of transmission (Depolarizes) 2) Increased myelin = increased speed |
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What does white matter consists of? |
Myelinated axons |
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What does grey matter consists of? |
Soma |
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What is the pathophysiology in Multiple Sclerosis? |
Autoimmune demyelination -- Interrupting signals - potential to stop working altogether if it is area that needs myeline |
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What is the treatment for Multiple Sclerosis? |
Steroids to suppress immune system and decreases inflammation |
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What is diffuse axonal injury? |
1) White matter injury to axons 2) Acceleration injury (TBI) 3) Shear forces 4) No CNS regeneration of axons |
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What is exitotoxicity? |
Overstimulation of adjacent neurons after injury (stroke, TBI) 1) Cytoplasm leaks and over stimulated adjacent cells and they die (collateral damage to neurons) 2) Glutamate releases |
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What is the treatment for exitotoxicity? |
With Glutamate inhibitors |
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What is soma? |
Neuron cell bodies in the Grey matter Ganglia = Soma outside CNS Nuclei = Soma embedded in white matter |
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What are terminal endings?
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Distal end of efferent axons at presynaptic membranes
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What is the function of terminal endings? |
1) Releases neurotransmitters 2) Recycles neurotransmitters |
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What are motor neurons?
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Single axons |
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What is the role of motor neurons? |
Outgoing information from CNS - Efferent - Via Soma into CNS - Via Axon out to PNS |
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What are the sensory neurons and what is their role? |
Conveys information from the tissues & organs towards the CNS Originates in PNS Terminates in CNS |
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What types of branches are involved in unipolar or also known as pseudounipolar? |
Afferent and Efferent branches -- Soma in the dorsal root ganglion |
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What are interneurons? |
Single short axon, always in the CNS -- Also known as association neurons -- Contains 1000's of synapses |
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What is the role of interneurons? |
They act as modulators b/w the stimulus (Sensory) and the response (motor) |
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What are the synapses? |
Gap (cleft) b/w the terminal end of one neuron and the dendrite of another neuron |
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What is the significance/ role of synapse? |
Chemical connection b/w neurons -- Neurotransmitters are released and received at the synapses (1000 to 100,000 NT per neurons) |
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What is the role of the NTs at the synapses? |
Provide stimulation depending on the type of the NT and the receptors -- There are enzymes that can digest the NTs ---- Controls the stimulation effect -- There are types of drugs that can deactivate these enzymes resulting in prolonged stimulation |
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What are the different types of Neurotransmitters (NTs)? |
1) Dopamine 2) Norepinephrine 3) Acetylcholine 4) Seratonin 5) GABA 6) Substance P 7) Glutamate |
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What is the role of dopamine? |
Mood elevation and skeletal muscle control |
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What is the role of NE? |
Excites skeletal muscle, excites or inhibits smooth muscle depending on location |
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What is the role of AcH? |
Excites skeletal muscle, inhibits cardiac, excitatory or inhibitory on smooth muscle depending on the location |
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What is the role of serotonin? |
Sleepiness, alertness, thermoregulation and mood |
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What is the role of GABA? |
Amino acid -- MC inhibitory |
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What is the role of Substance P? |
Induce pain |
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What is the role of Glutamate? |
Amino Acid -- 75% EPSP |
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What is the Reflex arc? |
Nerve pathway involved in reflex action including a synapse b/w a stimulus (sensory) and response (motor) |
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What systems are involved in Reflex arc? |
Spinal cord & PNS only NO BRAIN REQUIRED |
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What modulates the response in reflex arc? |
Interneuron modulates the response |
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What is it called if only one motor and one sensory neuron are involved in reflex arc? |
Monosynaptic |
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What is myotactic (Stretch) reflex? |
The stretch reflex (myotatic reflex) is a muscle contraction in response to stretching within the muscle. It is a monosynaptic reflex which provides automatic regulation of skeletal muscle length. When a muscle lengthens, the muscle spindle is stretched and its nerve activity increases. |
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What are muscle spindles? |
Proprioceptors in the striated muscles -- detect the stretch in the muscle |
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What is the role of muscle spindles? |
Sensory neurons conduct AP to the spinal cord Positive feedback to the muscle stretched - agonist effects -- inhibition of the antagonist |
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Where are the muscle tone sensors located? |
They come from the cerebellum -- Cerebellar & Cerebral control |
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What are postural reflexes (i.e. Soleus)? |
Supports the control of balance |
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What is the role of gamma motor control? |
Allows for slower movements instead of jerking
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What are the functions of the muscle spindles? |
1) Positive feedback to muscle stretch 2) Muscle tone sensors 3) Postural reflexes 4) Gamma motor control |
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What are Golgi tendon organs (GTO)? |
Proprioceptors in muscle tendons eg. Strain receptors |
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What is the role of strain receptors? |
1) Prevent muscles from over use/over stretch --- Safety mechanism 2) Turns off the agonist and turns on the antagonist |
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What is rigidity? |
1) Increased muscle tone 2) Increase in passive resistance |
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What is Cogwheel Rigidity? |
On / off resistance eg. Parkinson's disease |
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What is Clasp Knife Rigidity? |
Sudden release eg. UMN lesion |
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What causes abnormal Posturing? |
CNS damage 1) Traumatic brain injury 2) Herniation 3) Chest pain |
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What is the scale used to diagnose abnormal posturing? |
Glasgow coma scale |
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What are the types of rigidity? |
1) Decorticate rigidity -- Flexor 2) Decerebrate rigidity -- Extensor |
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What is Decorticate rigidity? |
Upper flexor posture -- Damage above brainstem and CBL |
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What is Decerebrate rigidity? |
Upper extensor posture -- Damage below brainstem and CBL |
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What is the muscle function scale? |
1) Grade 5: Pt resists strong pressure 2) Grade 4: Pt resists moderate pressure 3) Grade 3: Pt resists gravity 4) Grade 2: Gravity neutral movement 5) Grade 1: Slight contraction, no movement 6) Grade 0: No contraction |
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What is glia? |
Support cells for neurons -- 10x the number of neurons in CNS -- Some provide myelination -- Easily replicated -- Glial scarring - leads to cancer |
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What are the types of Glia? |
1) Astrocytes: Support, ion regulation 2) Oligodendricytes: CNS myelination 3) Schwann cells: PNS myelination 4) Microglia: Immune function 5) Ependymal cells: Choroid plexes, CSF |
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What are the nerves? |
Bundles of peripheral axons - Contains both motor and sensory neurons |
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T/F: Nerves needs blood supply |
TRUE It is big enough that it will need blood supply |
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What are the three layers in the nerves? |
1) Endoneuroeum = surrounds each axon 2) Perineureum = surrounds each fascicles 3) Epineureum = surrounds a bunch of fascicles |
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What is conduction velocity? |
Measurement of the speed of the electric impulse through a nerve |
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What are the factors that play a role in conduction velocity? |
1) Increased axon diameter = increased speed of transmission 2) Increased myelination = increased speed of transmission **0.1 - 100 meters per second |
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Where is the conduction velocity FASTEST? |
1) Reflexes 2) Proprioceptors 3) Voluntary motor |
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Where is the conduction velocity SLOWEST? |
1) Itch 2) Slow pain 3) Autonomics |
