Between Midterms Flashcards
CNS contains
Brain, spinal cord, optic nerve. retina,
PNS contains
Cranial nerves, spinal nerves, autonomic NS ( sympathetic, parasympathetic, enteric), somatic etc.
Cellular components of the brain
Neuron
Glial cell
Neuron
basic unit of the nervous system, each composed of a cell body, dendrite, and axon.
also called a “nerve cell”. human brain contains approximately 67-86 billion
Glial cell
nonneuronal brain cells that provide structural, nutritional, and other types of support to the brain. (glia/neuroglia) , 4 different types, approx. 40-50 billion
Parts of a neuron
Dendrites, soma, axon, axon terminals
Dendrites
tapered extensions of cell body
collect info from other neurons
soma (cell body)
dendrite(s) and typically one axon
synthesize macromolecules, integrate electrical signals
Axon
single, cylindrical; may be many cm(s) long; may be myelinated or unmyelinated
conduct info to other neurons
axon terminals ( synaptic endings/ terminals/boutons
vesicle filled apposition to port of another neuron
transmit information to other neurons
axon terminal
synaptic vesicle
neurotransmitter
synapse
synaptic cleft
synaptic vesicle
spherical sac containing neurotransmitters
neurotransmitter
the chemical released from the (presynaptic) axon terminal that serves as the basis for communication between neurons
synapse
space between two connecting neurons through which messages are transmitted chemically
synaptic cleft
a gap into which neurotransmitters are released from the axon terminal
Neural impulse
resting potential threshold depolarization action potential refractory period r
resting potential
electrical charge difference (-60 mV) across the neuronal membrane when the neuron is not being stimulated or inhibited
threshold
membrane potential necessary to trigger an action potential
depolarization
the reduction of a membrane’s resting potential so that it becomes less negative
action potential
electrical impulse that travels down the axon triggering the release of neurotransmitters
refractory period
the time during which another action potential is impossible, limits the maximal firing rate of the neuron
receiving signals
postsynaptic potential (PSP)
inhibitory PSP
excitatory PSP
reuptake
postsynaptic potential (PSP)
a voltage change at a receptor site on a postsynaptic cell membrane
inhibitory PSP
a negative voltage shift that decreases the likelihood that the postsynaptic neuron will fire action potentials
excitatory PSP
a positive voltage shift that increases the likelihood that the postsynaptic neuron will fire action potentials
large molecule neurotransmitters (neuropeptides)
pituitary peptides,
hypothalamic peptides,
brain-gut peptides, opioid peptides, miscellaneous peptides, endorphins
small- molecule neurotransmitters
amino acids, monoamines, acetylcholine, unconventional neurotransmitters
amino acids
glutamate, aspartate, glycine, GABA
monoamines
chatecholamines (dopamine, epinephrine, norepinephrine), indolamines (serotonin)
acetylcholine
acetylcholine
unconventional neurotransmitters
soluble gases (nitric oxide, carbon monoxide), endocannabinoids (anandamide)
acetylcholine (ACh)
released by motor neurons controlling skeletal muscles, contributes to the regulation of attention, arousal and memory, nicotine stimulates ACh receptors, memory enhancers increase ACh, insecticides block the breakdown of ACh creating excess amounts, botox causes paralysis by blocking ACh release, Alzheimer’s disease is associated with low levels of ACh
Agonist
a chemical that mimics the action of a neurotransmitter when it binds with the neurotransmitters receptor site
antagonist
a chemical that blocks the action of a neurotransmitters receptor site
dopamine (DA)
monoamine, contributes to control of voluntary movement, cocaine and amphetamines elevate activity at DA synapses, dopamine circuits in medial forebrain bundle characterized as “reward pathway”, degeneration of DA neurons is believed to be responsible for symptoms of Parkinson’s disease
Serotonin (5-HT)
monoamine, involved in regulation of sleep and wakefulness , eating and aggression, prozac and similar antidepressant drugs affect serotonin circuits
norepinephrine (NE)
monoamine, brain arousal and other functions like mood, hunger, sleep and sexual behaviour. Drugs such as amphetamines, methamphetamines increase NE levels. also known as noradrenaline, functions as both a hormone and a neurotransmitter
GABA
amino acid, gamma-aminobutyric acid, the brain’s main inhibitory transmitter, contributes to regulation of anxiety and sleep/arousal, valium and similar antianxiety drugs work at GABA synapses
Glutamate
main excitatory neurotransmitter in the nervous system, participates in relay of sensory information and learning
Anandamide
unconventional neurotransmitter, binds to the same receptors as THC, comes from the Sanskrit word “Ananda” meaning “joy, bliss, delight”, occurs in both the CNS and PNS, likely plays a role in eating, memory, motivation and sleep. Pain, fear, healing?
endorphins
neuropeptide, naturally occurring (endogenous) analgesic, inhibit communication of pain signals to the spinal cord, insensitivity to pain (oversupply), hypersensitivity to pain (undersupply)
