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homeostasis
balance/equilibrium
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nervous system in order
- central nervous system/peripheral nervous system
- CNS - brain and spinal cord
- PNS - somatic nerves and autonomic nerves
- somatic nerves - sensory and motor
- autonomic nerves - sympathetic and parasympathetic
- sympathetic - motor and sensory
- parasympatheric - motor and sensory
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what are somatic nerves, are they voluntary or involuntary
sensory receptors, voluntary
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are autonomic nerves voluntary or involuntary
involuntary
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sympathetic and parasympathetic autonomic nerves are _____ to each other
antagonistic
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what do our sympathetic autonomic nerves do
control stress, fight flight freeze response
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what do our parasympathetic autonomic nerves do
rest and digest, calm
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what is the difference between motor and sensory
motor deals with muscles while sensory receives stimuli and transmit impulses
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what are the two cells of the nervous system
glial cells and neurons
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what are effectors
muscles and glands
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tell me about glial cells
outnumber neurons, support, nourish, defend neurons
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tell me about neurons, 3 types of neurons
- functional cell of nervous system
- motor neuron: stimulates effectors (PNS)
- interneurons: process information (CNS)
- sensory neurons: receive external or internal info (PNS)
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what is the order of impulses in a neuron
SIM
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what exactly do neurons do
- respond to stimuli and conduct electrochemical signals
- they release chemicals while glial cells provide framework
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what is a Schwann cell
type of glial cell that produces myelin sheath. it is insulation for neurons and SOME form neurilemma
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what does neurilemma do
promote regeneration
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what is the difference between axons that have myelin vs do not have it
- when neurons are myelinated they have white matter
- when neurons have no myelin they are grey and unmyelinated
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what does the axon do
conduct impulses away from the cell body
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nodes of ranvier
gaps between sections of myelin sheath along axon, nerve impulses jump and movement of nerve impulses speeds up
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what is the pathway of the reflex arc
stimulus to sensory receptor to sensory neuron to interneuron to motor neuron to effector
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what are the 2 states of nerve impulses
resting potential and action potential
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resting potential
resting nerve, -70mV, polarized (potential energy)
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action potential
excited nerve, +40mV, depolarized (reversal of energy)
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what is the movement of action potential
it is the wave of depolarization. The Na floods in as sections along the length of the axon rather than the whole length of the axon at one time. As one section of the axon becomes positive, it quickly becomes negative again (K out). This prevents action potential from going backwards.
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saltatory conduction
occurs in myelinated axons. Na and K gates are concentrated at the nodes of ranvier (not covered in myelin). The high concentration of Na ions rush into nodes of ranvier. The myelin conserves a pos. charge. AP is faster and appears to 'jump' from node to node.
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all or none response
neurons fire either maximally or not at all, the increasing stimulus will not increase the force of contraction of a muscle
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how does the brain interpret more intense stimuli?
more neurons are stimulated and reach the brain, different neurons have different thresholds
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what is a synapse
spaces between neurons (motor neuron and effector)
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