Lec. 3 (neurons) Flashcards
basic fundamental unit of the nervous system
neuron
the study of the cells and organs of the body and the physical and chemical changes involved in behavior + mental processes; branch of psychology concerned with the links between BIOLOGY and BEHAVIORS
(behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists)
biological psychology
nervous system components (“organs”) =
brain + spinal cord
brain is composed of ________ of neurons “connected” to each other
billions
of CONNECTIONS between neurons =
trillions
T/F: there are more neuron connections in your brain than there are stars in the universe
true
types of neurons (3):
1) sensory neuron
2) inter-neuron
3) motor neuron
type of neuron: sends information from the outside world TO the nervous system; exist outside the spinal cord
sensory neuron
type of neuron: exist strictly in the brain and spinal cord; process information
inter-neurons
type of neuron: send information from the nervous system to the rest of the body
motor neurons
PARTS of a neuron (3):
- dendrites
- axon
- terminal branch
part of a neuron: ‘tree;” bushy TOP part
dendrites
part of a neuron: trunk
axon
part of a neuron: “roots”
terminal branch
neuron component: receives messages from other cells
dendrites
neuron component: the cell’s life-support center
cell body
neuron component: passes messages away from the cell body to other neurons, muscles, or glands
axon
neuron component: covers the axon of some neurons and helps SPEED neural impulses
myelin sheath
neuron component: form junctions with other cells
terminal branches
neuron component: action potential; electrical signal traveling down the axon
neural impulse
white fatty substance; insulator; excellerates neural impulses
myelin sheath
disease in which the body attacks myelin sheath in the brain; makes it hard to control smooth motor movements (jerky); signals are less effective
MS (multiple sclerosis)
T/F: you don’t have much myelin sheath when you are born; neurons are myelinated as you age
true
when are you fully myelinated?
17-18
which lobe of the brain is myelinated LAST?
frontal lob (judgement + decision making)
dendrites are _________
filamentous
how do neurons communicate with each other?
action potentials (neural impulses)
at rest, the charge difference between inside/outside of a neuron 0s ________
-70 mV (1/200 the charge of an AA battery – weak but a gradient)
dendrites are constantly receiving input; when threshold exceeds a certain value, neural impulse fires and travels down the axon =
action potential
action potential steps
1) depolarization
2) sodium channels opens
– sodium (positive) rushes into cell making that section positive
3) pumps immediately start removing sodium to restore NEGATIVE charge
4) but the depolarization has moved down the axon…
the function of action potentials all has to do with a ________ _______ membrane
selectively permeable
action potentials are with ______ or _______
ALL or NONE (on/off)
T/F: an action potential can be weak and slow
false (can either be on/off like a gun)
how do neurons code intensity (2):
- the RATE of on-off pulses (speed)
- the # of neurons transmitting
do neurons physically touch each other?
no!
the space beetween neurons
synapse or synaptic gap
action potentials are propagated by chemicals called __________ to communicate through synapses
neurotransmitters
natural pain killers
endorphins
NTs or neurotransmitters lock into ________
dendrites (of receiving neuron)
what can/must happen when NTs are flooded into a synaptic gap (2) ?
1) NTs are cleared out
2) re-uptake (reabsorbing NTs)
when NTs are re-absorbed and broken down; chemicals float back up after being received from the receiving neuron (recycled)
re-uptake
what drug blocks the re-uptake of serotonin allowing it to linger in the synapse longer?
SSRIs (serotonin reuptake inhibitors)
steps of Neuron Signal Transmission
1) an action potential shoots down the axon
2) NTs are released into the synapse, changing the membrane potential of the dendrite
3) if the depolarization is strong enough, it spreads down the dendrite and across the cell body
4) if the threshold is reached, the cell fires, shooting an action potential down the axon
NT: muscle actions, learning, and memory
acetylcholine
NT: movement, learning, attention, and emotion
dopamine
NT: mood regulation + sleep
serotonin
NT: memory; excitatory neurotransmitter
glutamate
NT: inhibitory neurotransmitter (calms activity in brain); tells it to STOP sending messages
GABA
NT: altertness + arousal; “adrenalin”; smoking releases this
norepinephrine
__________ is an EXCITATORY neurotransmitter and _________ is an INHIBITORY neurotransmitter
glutamate; GABA
Parkinson’s is due to one’s inability to use/produce which NT?
dopamine
each NT binds to specific __________
receptors
NTs binding to receptors is like a _____________________ mechanism; very specific; dendrite receptors only accept certain NTs
lock & key
key =
lock =
NT
receptor
chemicals that MIMIC natural NTs; foreign chemicals that’s shape is close enough to fit into the receptor and ACTIVATE it
agonists
what are AGONISTS for endorphins?
morphine + heroine
chemicals that BLOCK the function of a NT; takes up receptors (gum in lock); not similar enough to activate it
antagonist
what is an ANTAGONIST for acetylcholine?
curare (paralyzes you***)
what is an ANTAGONIST for heroine (or morphine)?
narcane (so you don’t overdose; blocks receptors from taking in drugs)
