neuropsychology Flashcards
Reflex
An automatic, stereotyped movement produced as the direct result of a stimulus
The Neuron:
number
10 billion to a trillion
(most popular estimate is 86 billion)
10,000 connections each
The Neuron:
parts
dendrites
cell body (or “soma”)
axon
terminal endings (or terminal buttons)
Nerve Impulse
= ACTION POTENTIAL
Potential quite literally means energy
Resting Potential
-70 mV
What does the stimulation of neurons let in?
Na+ ions
which makes the inside more positive: -70, -69, -68, -67
What happens when there are enough Na+ ions in for the potential to be reduced to -55 mV?
The doors (ion gates) to the cell membrane are flung open allowing for Na+ to rush in.
What is the maximum potential?
+40 mV
potential shoots up to +40 mV, so the inside is now positive relative to the outside (the ACTION POTENTIAL)
What and how is potential reduced back to -70 mV?
Ion pumps work to reduce potential back to -70 mV by pushing positive ions out (actually K+ because Na+ goes out slower; then ANOTHER pump takes Na+ back out and puts K+ back in)
What mV is considered a threshold?
-55 mV
below that voltage, there is no action potential – firing is “all-or-none”
True of False: More intense stimulation causes a more intense action potential.
FALSE
Just more frequent ones (up to 1000/sec!), and in more neurons
What part of the neuron does action potential travel down?
Axon
action potential travels down length of axon by depolarizing neighboring areas
What speed does action potential travel?
50 to 100 m/sec
NOT at speed of electrical current in wire
Synapse
Gap between two neurons (the presynaptic and the postsynaptic neurons)
terminal endings of presynaptic neuron relay impulse to dendrites of postsynaptic neuron
What do terminal buttons contain?
Little sacs (“vesicles”) of chemicals (“neurotransmitters”)
at action potential, vesicles burst and release neurotransmitters into synapse
What opens ion gates to allow Na+ inside in the first place?
Neurotransmitters
Receptor molecules on membrane of dendrite are like little locks to be opened
What is it called when neurotransmitters let Na+ inside?
excitatory (more likely to fire) because potential is getting smaller, toward -55
What is it called when a gate is opened that pushed positive K+ ions out?
Inhibitory (less likely to fire) because potential is getting larger (e.g., -70, -71, -72)
NERVOUS SYSTEM (“NS”)
central
peripheral
somatic
autonomic
sympathetic
parasympathetic
central
center
(brain, spinal cord)
peripheral
outside of center
(everything else aside from brain & spinal cord)
somatic
body
(muscles, senses)
autonomic
self rule
(vital functions: heart rate, breathing, digestion, reproduction)
sympathetic
excited states
- arousal: mobilizes for emergency (speeds heart and lungs, inhibits digestion and sexual function)
parasympathetic
vegetative, calm states
- calm: conserves energy (slows heart and lungs, etc.)
hindbrain
medulla
pons
cerebellum
cat transected above hindbrain: can move but not act
medulla
breathing, heartbeat, blood circulation
pons
arousal and attention
cerebellum
integration of muscles to perform fine movements, but no coordination / direction of these movements; balance