action potential

Question 1

how are neurons named?

Answer 1

shape
anatomical features
neurotransmitter
function

Question 2

what is the input zone of a neuron? (gets info)

Answer 2

dendrite

Question 3

where is the integration zone of a neuron?

Answer 3

cell body

Question 4

where is action potential initiated in a neuron?

Answer 4

axon hillock

Question 5

where does the signal leave the neuron?

Answer 5

axon terminal

Question 6

is an axon long or short?

Answer 6

long

Question 7

what is an action potential?

Answer 7

an electrical signal that travels from one end of a cell to the other rapidly

Question 8

what are the 4 major ions responsible for membrane potential?

Answer 8

K
Na
Cl
Ca2

Question 9

what do electrical signals in neurons depend on?

Answer 9

rapid changes in membrane potential

Question 10

what do ion channels do?

Answer 10

mediate the flow of ions that underlie the electrical signals in excitable cells

Question 11

what is the structure of ion channels?

Answer 11

a protein with a water filled pore for ions to go through

Question 12

what are the properties of ion channels?

Answer 12

acts as specific filters
conducting and non-conducting states (open and closed)
gating

Question 13

why do ion channels gate?

Answer 13

changes in membrane potential
ligand binding
mechanical forces

Question 14

describe step 1 of the action potential of K and Na voltage-gated channels;

Answer 14

initial depolarization. caused by trigger. Na channels open

Question 15

describe step 2 of the action potential of K and Na voltage-gated channels;

Answer 15

reaches threshold

Question 16

describe step 3 of the action potential of K and Na voltage-gated channels;

Answer 16

explosive depolarization. Na feed-back loop

Question 17

describe step 4 of the action potential of K and Na voltage-gated channels;

Answer 17

peak potential. Na begins to close and K opens.

Question 18

describe step 5 of the action potential of K and Na voltage-gated channels;

Answer 18

repolarization begins with Na closed and K open

Question 19

describe step 6 of the action potential of K and Na voltage-gated channels;

Answer 19

afterhyperpolarization. both cahnnels closed. cannot be restimulated at this stage

Question 20

describe step 7 of the action potential of K and Na voltage-gated channels;

Answer 20

resturn to rest ready to be restimulated

Question 21

action potentials are…

Answer 21

all or none

Question 22

what type of channel does action potential rely on?

Answer 22

voltage gated channels

Question 23

why don’t action potentials wane in size down the axon?

Answer 23

they are regenerative

Question 24

what prevents the backward propagation of action potential in the hillock?

Answer 24

the refractory period

Question 25

what are the roles of the refraactory period?

Answer 25

prevent backward propagation limit firing frequency

Question 26

what is the absolute refratory period?

Answer 26

no Na channels available so it is impossible to fire an action potential

Question 27

what is the relative refratory period?

Answer 27

more hyperpolarization makes it harder to fire an action potential but not impossible

Question 28

since action potentials are all-or-none, how are differences in the signal intensity conveyed?

Answer 28

firing frequency pattern of action potentials

Question 29

what is saltatory conduction?

Answer 29

what action potential jumps from one node of ranvier to the next

Question 30

what type of cells provide myelin?

Answer 30

glial

Question 31

what is myelin mostly made up of?

Answer 31

cell membrane

Question 32

electrical current propagates faster and farther along a myelinated axon; true or false

Answer 32

true

Question 33

does myelin conduct current?

Answer 33

no

Question 34

is myelin part of the axon?

Answer 34

no

Question 35

do thicker axons conduct faster or slower?

Answer 35

faster

Question 36

spped corresponds with function; true or false

Answer 36

true

Question 37

what is the associated function with A-alpha nerve fibers?

Answer 37

movement sensor, contraction of skeletal muscle

Question 38

what is the associated function with A-beta nerve fibers?

Answer 38

touch

Question 39

what is the associated function with A-gamma nerve fibers?

Answer 39

acute pain

Question 40

what is the role of nodes of ranvier?

Answer 40

propagation and regeneration

Question 40

what factors determine action potential velocity?

Answer 40

axon diameter, myelination and Na channel density

Question 40

what is the associated function with C nerve fibers?

Answer 40

chronic pain, temp and itch

Question 41

what type of cell in the CNS provide myelin?

Answer 41

oligiodendrocytes

Question 42

what type of cells in the PNS provide myelin?

Answer 42

schwann cells