Neurophysiology

Front 1

FUNCTION OF DENDRITES

Back 1

RECEIVE STIMULUS FROM OTHER NEURONS

Front 2

HAS A NUCLEUS AND ORGANELLES, CELL METABOLISM

Back 2

CELL BODY

Front 3

LITERAL MEANING OF HILLOCK

Back 3

LITTLE HILL

Front 4

FUNCTION OF THE AXON HILLOCK

Back 4

WHERE IMPULSES BEGIN

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WHICH WAY DO AXON IMPULSES TRAVEL

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AXON IMPULSES TRAVEL DOWN THE AXON

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ANOTHER NAME FOR AXON TERMINALS IS __________

Back 6

TERMINAL BUTTONS ( SEE PP 392 FOR PICTURE)

Front 7

WHAT IS THE FUNCTION OF AN AXON

Back 7

THE CONDUCTING COMPONENT OF THE NEURON, IT GENERATES NERVE IMPULSESAND TRANSMITS THEM AWAY FROM THE CELL BODY.

Front 8

STRUCTURE OF THE AXON SHEATH ( MYELIN SHEATH)

Back 8

CELLS WRAPPED AROUND THE AXON TO FORM A SHEATH.

Front 9

FUNCTION OF THE AXON SHEATH ( MYELIN SHEATH)

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PROTECTS AND ELECTRICALLY INSULATES FIBERS FROM ONE ANOTHER , AND INCREASES THE SPEED OF NERVE IMPULSES

Front 10

SECTIONS OF AXON NOT COVERED BY THE MYELIN SHEATH

Back 10

NODES

Front 11

DEFINE MEMBRANE POTENTIAL

Back 11

A SMALL ELECTRICAL CHARGE EXISTS ACROSS THE CELL MEMBRANE

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MEMBRANE POTENTIAL...EVERY CELL HAS A (+ OR - ) CHARGE ON THE OUTSIDE,,,AND A ( + OR - ) CHARGE INSIDE

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+ OUTSIDE,,, AND - INSIDE

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WHAT IS THE RESTING MEMBRANE POTENTIAL

Back 13

-70 mv

Front 14

WHAT ARE THE 3 WAYS THAT THE RESTING MEMBRANE POTENTIAL CAN CHANGE

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DEPOLARIZATION
REPOLARIZATION
HYPERPOLARIZATION

Front 15

GIVE THE EXAMPLE OF DEPOLARIZATION AND DEFINE

Back 15

MEMBRANE POTENTIAL BECOMES LESS NEGATIVE OR MORE POSITIVE -70 mv----- -55mv------ + 35 mv

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DEFINE REPOLARIZATION

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HAPPENS AFTER DEPOLARIZATION ,,,MEMBRANE GOES BACK TO - 70 mv

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DEFINE HYPERPOLARIZATION

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WHEN THE MEMBRANE BECOMES MORE NEGATIVE THAN -70 mv ....for example from -70 mv ------- - 90 mv

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WHAT ARE THE TWO WAYS TO OPEN GATED ION CHANNELS

Back 18

LIGAND GATED CHANNEL
VOLTAGE GATED ION CHANNEL

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ARE GATED ION CHANNELS ALWAYS OPEN

Back 19

NO

Front 20

GATED CHANNELS HAVE A MOLECULAR "GATE" ( USUALLY A PROTEIN MOLECULE) THAT CAN CHANGE SHAPE TO OPEN OR CLOSE THE CHANNEL IN RESPONSE TO VARIOUS SIGNALS

Back 20

NOTE FROM BOOK PP 398

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ANOTHER NAME FOR LIGAND IS _______

Back 21

CHEMICAL

Front 22

HOW DOES A LIGAND GATED CHANNEL OPEN

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A RECEPTOR IS ATTATCHED TO THE CHANNEL, WHEN A MOLECULE OR A LIGAND ( CHEMICAL) BINDS TO THE RECEPTOR THE CHANNEL OPENS

Front 23

WHEN A LIGAND GATED CHANNEL OPENS ,,,WHAT IS ALLOWED TO FLOW THROUGH

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IONS ARE ALLOWED TO FLOW THROUGH,,,,REMEMBER ,,,IT'S CALLED A GATED ION CHANNEL

Front 24

WHEN DO VOLTAGE GATED ION CHANNELS OPEN AND CLOSE

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THEY OPEN AND CLOSE IN RESPONSE TO CHANGES IN THE MEMBRANE POTENTIAL

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WHAT IS THE THRESHOLD VOLTAGE OF VOLTAGE GATED ION CHANNELS

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THRESHOLD VOLTAGE IS -55 mv

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WHEN DISCUSSING VOLTAGE GATED ION CHANNELS,,ONCE THE GATE IS OPENED AT THRESHOLD -55 mv,,, THE GATE STAYS OPEN FOR A SHORT PERIOD,,,THEN THEY INACTIVATE,,ONCE INACTIVE,,THE GATE WILL NOT OPEN AGAIN,,,EVEN AT THRESHOLD OF -55 mv,,,AFTER THE INACTIVE STATE,,THE GATE GOES BACK TO A CLOSED STATE

Back 26

NOTE

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WHAT ARE THE ONLY TYPES OF CELLS THAT CAN HAVE ACTION POTENTIALS

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ONLY CELLS WITH EXCITABLE MEMBRANES ( NEURONS) AND MUSCLE CELLS CAN GENERATE ACTION POTENTIALS

Front 28

WHEN DISCUSSING ACTION POTENTIAL,,,,NA+ ENTERING THE CELL CAUSES THE CELL TO ( POLARIZE OR DEPOLARIZE)

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DEPOLARIZES BECAUSE NA+ IS ENTERING THE CELL

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A.P. ....IF THE MEMBRANE POTENTIAL REACHES THRESHOLD (-55mv) THEN VOLTAGE GATED NA+ CHANNELS DO WHAT

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THEY OPEN

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A.P. WHEN THE AXON DEPOLARIZES,,,WHAT IS THE VOLTAGE

Back 30

+35 mv

Front 31

NA + GOES IN
K + GOES OUT

Back 31

NOTE

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A.P. ,,,, WHEN K+ DIFFUSES OUT ,,,WHAT THEN HAPPENS TO THE AXON

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THE AXON REPOLARIZES SO,,,WE HAVE NA+ CHANNELS CLOSING AND K+ CHANNELS OPEN

Front 33

WHAT IS THE FUNCTION OF THE NA+?/K+ PUMP WHEN DISCUSSING THE A.P.

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NA+ IS FORCED OUT, K+ IS FORCED IN ,,,MEMBRANE POTENTIAL GOES BACK TO RESTING ( -70 mv)

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WHAT ARE THE TWO WAYS THAT AN ACTION POTENTIAL CAN BE MOVED OR CONDUCTED

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CONTINUOUS CONDUCTION
SALUTORY CONDUCTION

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DEFINE CONTINUOUS CONDUCTION

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THIS IS THE SPEED OF THE A.P. THIS IS IN UNMYELINATED AXONS AP IS FROM THE HILLOCK TO THE TERMINALS,,,SLOWER THAN SALUTORY CONDUCTION

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SALUTORY CONDUCTION

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OCCURS ON MYELINATED AXONS ,,,ACTION POTENTIALS OCCUR AT THE NODES,,,1000X FASTER THAN CONTINUOUS CONDUCTION

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ALL OR NONE LAW

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ONCE THE MEMBRANE REACHES THRESHOLD, THERE WILL BE AN AP....NO STOPPING IT,,,ALL AP ARE THE SAME SIZE

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WHY DONT AP RUN BACKWARDS

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BECAUSE VOLTAGE GATED NA+ CHANNELS W/IN 2mm UPSTREAM OF THE LAST AP ARE INACTIVE

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DEFINE REFRACTORY PERIOD

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EITHIER IMPOSSIBLE OR DIFFICULT FOR AN AXON TO HAVE AN AP

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DEFINE ABSOLUTE REFRACTORY PERIOD

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WHEN VOLTAGE GATED NA+ CHANNELS ARE INACTIVE

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DEFINE RELATIVE REFRACTORY PERIOD

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WHEN IT IS DIFFICULT BUT NOT IMPOSSIBLE FOR THE AXON TO HAVE AN AP

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WHAT KIND OF REFRACTORY PERIOD OCCURS WHEN THE CELL IS HYPERPOLARIZES

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RELATIVE REFRACTORY PERIOD

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DEFINE SYNAPSE

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TO CLASP OR JOIN

Front 44

DEFINE SYNAPSE

Back 44

A JUNCTION THAT MEDIATES INFORMATION TRANSFER FROM ONE NEURON TO THE NEXT