Nervous System Flashcards
Neuron
Individual cell in the nervous system. Sends and receives messages with electrochemical signals.
Nervous system
Allows your body parts to communicate with each other, messenger system.
Central Nervous system
Brain and Spinal cord, encased in bone. Main control center.
Peripheral Nervous System
Nerves that go throughout the body. Connect the rest of the body to the CNS.
Autonomic nervous system
(involuntary) Communicates with internal automatic organs and glands. Sympathetic division (arousing) and Parasympathetic division (calming)
Somatic nervous system
Communicates with sense organs and voluntary muscle. Sensory system (sensory input) Motor nervous system (motor output)
Reflex Arc
Signal is sent from a sensory organ to the spinal cord, which processes the information, not sent to the brain.
Dendrite
Receive messages form other cells. Bushy, branch like structures.
Soma
Center of cell body, holds nutrients.
Cell body
The neurons life support center
Axon
passes messages from cell body to other neurons, muscles or glands.
Neural impulse
electrical signal traveling down the axon.
Myelin Sheath
Covers the axon of some neurons and helps speed neural impulses. Protects, insolates and provides nutrients to the neuron.
Terminal branches of axon
Form junctions with other cells. End of neuron.
Glial Cells
Grow around and provide physical support for neurons. Supply nutrients to neurons, clean up dead neurons, provide insulation. 90% of the brain is Glial cells.
Sensory neurons “afferent neurons”
neurons that carry incoming information from the sensory receptors to the brain and spinal cord.
motor neurons “efferent neurons”
neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.
interneurons
neurons within the brain and spinal cord that communicate internally and intervene between them.
S.A.M.E
sensory-afferent=motor-efferent
rating potential
the state of the inactive neuron when not firing a neural impulse
action potential “firing”
when sufficiently stimulated
threshhold
if stimulation is not strong enough neuron will not fire
refractory period
period of time during which a cell is incapable of repeating an action potential. occurs after action potential and usually last’s one millisecond.
reuptake
neurotransmitters are released back into the synapse and the originating neuron reabsorbs the excess neurotransmitters.
synapse “contact point”
meeting point between neurons, never touch
synaptic gap
gap between contact point, less than a millionth of an inch wide
receptor sites
receive signals
all or none principle
when a neuron fires it is at full strength or not at all, strength of action potential is constant.
neurons fire like DAT
Dendrites-axon-terminal
Neurotransmitters
chemicals in the brain that carry messages from one neuron to another
excitatory neurotransmitters
excite connecting neurons and causes them to fire
inhibitory neurotransmitters
inhibit the next neurons to fire
acetylcholine (ACh)
Motor, memory, attention. excitatory element present in both the PNS and CNS connected to motor movement.
acetylcholine surplus
associated with severe muscle spasms
acetylcholine deficit
too little in the hippocampus has been associated with dementia and Alzheimers.
seratonin
connected to mood regulation, emotion, hunger, wakefulness, and sexual desire.
Inhibitory
SSRI(selective serotonin reuptake inhibitor)
serotonin surplus
too much serotonin is associated with hallucinations
serotonin deficit
Associated with OCD depression and mood disorders
dopamine
inhibitory “Pleasure chemical.” Released into the pleasure centers of the brain. Associated with reward and motivation
dopamine surplus
too much dopamine has been associated with schizophrenia (too many dopamine receptors) and addiction.
dopamine deficit
Associated with depression and muscular rigidity or tremors in parkinsons
norepinephrine
excitatory “fight or flight” chemical. Associated with response with danger, increases alertness and arousal, mood elevation. Lowest during sleep and highest during times of stress
norepinephrine surplus
associated with anxiety disorders
norepinephrine deficit
associated with depression and mental dissorders
GABA
inhibitory “calming” transmitter. Slows things down, calming central nervous center, regulates sleep-wake cycles. Increases sleepiness and decreases anxiety, alertness, memory and muscle tension.
GABA surplus
Overly relaxed and sedated, often to the point that normal reactions are impaired. sleep/eating disorders
GABA deficit
associated with anxiety disorders, seizures, tremors, and insomnia
Glutamate
excitatory “memory” neuro transmitter. Major excitatory neurotransmitter, involved with most normal operations of the brain including thinking, long term memory, and learning.
glutamate surplus
overstimulates the brain producing migraines or epileptic seizures
glutamate deficit
too little deficit can result in difficulty concentrating or mental exhaustion
endorphins
inhibitory “euphoria” transmitter. Relieves pain and stress, “natural aspirin”.
endorphin surplus
too much leaves to not give adequate warning about pain. Artificial highs.
endorphin deficit
produces too much pain.
D.A.N.S E.G.G
Dopamine Acetylcholine Norepinephrine Serotonin Endorphins Glutamine GABA
Drugs and other Chemicals
Affect brain at the synaptic level, either amplifying or blocking a neurotransmitter’s activity.
Agonist
mimic effect or block neurotransmitter reuptake (exites)
Antagonist
blocks a neurotransmitter’s functioning (inhibits)
