Transcript action potential

DMA
Please write down both questions (don’t forget to leave space for your answers).
1. The space between neurons is called the
______________
2. Explain how messages travel to and from the brain
through the nervous system.
Please turn in this week’s DMAs
Today’s Agenda
 DMA / turn in
 Chapter 2 FRQs
 Neurons
 Transmission/communication
 Parts
Homework
•Prologue AND Chapter 1 notes – due Monday, Sept. 19th
•Prologue & Chapter 1 take home test – due Monday, Sept. 19th
Chapter 2 FRQs
Don’t forget
•Prologue & Chapter 1 notes – due Monday
•Prologue & Chapter 1 test – due Monday
Neural Communication
 Biological Psychology
 branch of psychology concerned with the links between
biology and behavior
 some biological psychologists call themselves behavioral
neuroscientists, neuropsychologists, behavior geneticists,
physiological psychologists, or biopsychologists
 Neuron
 a nerve cell
 the basic building block of the nervous system
Neural Communication
 Dendrite
 the bushy, branching extensions of a neuron that receive messages
and conduct impulses toward the cell body
 Axon
 the extension of a neuron, ending in branching terminal fibers,
through which messages are sent to other neurons or to muscles or
glands
 Myelin [MY-uh-lin] Sheath
 a layer of fatty cells segmentally encasing the fibers of many neurons
 enables vastly greater transmission speed of neutral impulses
Neural Communication
Neural Communication
 Action Potential
 a neural impulse; a brief electrical charge that travels
down an axon
 generated by the movement of positively charged atoms in
and out of channels in the axon’s membrane
 Threshold
 the level of stimulation required to trigger a neural
impulse
Neural Communication
Cell body end
of axon
Direction of neural impulse: toward axon terminals
Neural Communication/Transmission
 depolarization – change in the cell’s membrane potential
 all-or-none principle - the cell either fires completely or not
at all; it doesn’t fire a little or a lot
 direction of impulse - the cells only fire one way, the impulse
can’t come the other direction.
 refractory period - after a cell fires, it won’t fire again for a
certain period of time.
 resting potential- the cell is “waiting” to fire
 The overall negative charge inside the neuron waiting for
depolarization
Neural Transmission
With a neighbor/partner…
 Discuss how neural transmission is like flushing a toilet.
 Include these elements in your discussion:
 Depolarization
 All-or-none principle
 Direction of impulse
 Refractory period
 Threshold
 Resting potential
 Action potential
Toilet & Neural Transmission
 depolarization - represented by the toilet flushing
 all-or-none principle - the toilet either flushes completely or not at all; it





doesn’t flush a little or a lot
direction of impulse - the toilet only flushes one way, the impulse can’t
come the other direction (you hope!)
refractory period - after you flush the toilet, it won’t flush again for a
certain period of time, even if you push the handle repeatedly
threshold - you can push the handle a little bit, but it won’t flush until you
push the handle past a certain critical point - this corresponds to the level of
excitatory neurotransmitters that a neuron must absorb before it will fire
resting potential- if you are using a toilet with a tank, the water in the tank
can represent resting potential. The toilet is “waiting” to fire, and the water in
the tank represents the overall negative charge inside the neuron waiting for
depolarization
action potential - the action potential is represented by opening the flap in
the tank and the water
Neural Communication
 Synapse
 junction between the axon tip of the sending neuron and the
dendrite or cell body of the receiving neuron
 tiny gap at this junction is called the synaptic gap or cleft
 Neurotransmitters
 chemical messengers that traverse the synaptic gaps between
neurons
 when released by the sending neuron, neuro-transmitters travel
across the synapse and bind to receptor sites on the receiving
neuron, thereby influencing whether it will generate a neural
impulse
Neural Communication
Serotonin Pathways
Dopamine Pathways
Human Neuron Party
 Volunteer #1 – needs a name that begins with “D”, stand




with a jazz hand.
Volunteer #2 – needs a name that begins with “S”, likes to
hold hands with #1
Volunteer #3 - needs a name that begins with an “A”, hold
hands with #2 & stretch your arms out straight.
Volunteer #4 - needs a name that begins with the initials
“T.B.”, hold hands with #3, hold squirt bottle.
Volunteer #5 - has the same name as volunteer #1, stand
very close to #4 but don’t touch him/her.
Human Neuron Party
 Volunteer #1 – Dendrite
 Volunteer #2 – Soma
 Volunteer #3 - Axon
 Volunteer #4 – Terminal Buttons
 Volunteer #5 - Dendrite