Exam 2

Question 1

element or atom that has gained or lost an electron

Answer 1

ION

Question 2

any chemical that carries electrical charge when dissolved in water

Answer 2

ELECTROLYTE

Question 3

material where positively or negatively charged ions can move freely toward each other

Answer 3

CONDUCTOR

Question 4

material where oppositely charged ions can not move toward each other

Answer 4

INSULATOR

Question 5

form of potential energy created by difference between amounts of electrical charge

Answer 5

ELECTROCHEMICAL POTENTIAL

Question 6

membrane potential when membrane is resting and not actively conducting an electrical impulse

Answer 6

RESTING POTENTIAL

Question 7

change in the membrane potential whose magnitude is proportional to the strength of the stimulus

Answer 7

GRADED POTENTIAL

Question 8

rapidly moving wave of electrical charge that moves along the membrane of an active excitable cell

Answer 8

ACTION POTENTIAL

Question 9

channels whose molecular conformation responds to the changes in electrical potential across the membrane

Answer 9

VOLTAGE-GATED CHANNELS

Question 10

a stimulus strong enough to initiate an action potential by triggering opening of the activation gate

Answer 10

THRESHOLD STIMULUS

Question 11

a stimulus not strong enough to initiate an action potential by triggering opening of the activation gate

Answer 11

SUBTHRESHOLD STIMULUS

Question 12

rapid increase in concentration of Na+ in cell because of opening of the activation gate of the voltage-gated Na+ channel

Answer 12

DEPOLARIZATION

Question 13

process of regaining Vrest after depolarization

Answer 13

REPOLARIZATION

Question 14

undershooting of the Vrest due to excess K+ ions flowing out of the cell

Answer 14

HYPERPOLARIZATION

Question 15

brief space in time in which an excitable membrane is resistant to further stimulation

Answer 15

REFRACTORY PERIOD

Question 16

short period during and immediately after depolarization where a neuron or myofiber will not respond again to any stimulus, no matter how strong

Answer 16

ABSOLUTE REFRACTORY PERIOD

Question 17

period following absolute refractory period where neuron or myofiber will only respond to a strong stimulus

Answer 17

RELATIVE REFRACTORY PERIOD

Question 18

spread of an action potential along the membrane of an excitable cell

Answer 18

PROPAGATION

Question 19

used in unmyelinated axons and muscle cells

Answer 19

CONTINUOUS PROPAGATION

Question 20

used in myelinated axons

Answer 20

SALTATORY PROPAGATION

Question 21

a segmented wrapping around the axon formed by Schwann’s cells in the PNS and oligodendria in the CNS

Answer 21

MYELIN

Question 22

unmyelinated areas of a myelinated axon found between myelin sheaths

Answer 22

NODES OF RANVIER

Question 23

groups of neurons that influence each other’s activity by communicating at neuronal synapses

Answer 23

NEURONAL PATHWAYS

Question 24

site or junction where electrical signals are transmitted from one cell to another

Answer 24

SYNAPSE

Question 25

found between successive neurons in a neuronal pathway

Answer 25

NEURONAL SYNAPSES

Question 26

found between somatic alpha-motor neurons and myofibers of skeletal muscles

Answer 26

NEUROMUSCULAR JUNCTIONS

Question 27

found between autonomic motor neurons and autonomic effectors including smooth muscle and glandular cells

Answer 27

NEUROEFFECTOR JUNCTIONS

Question 28

neuron that carries impulse INTO the synapse

Answer 28

PRESYNAPTIC NEURON

Question 29

neuron that carries impulse AWAY FROM the synapse

Answer 29

POSTSYNAPTIC NEURON

Question 30

physical space separating two cells

Answer 30

SYNAPTIC CLEFT

Question 31

extracellular signal molecule released by neurons that diffuse across the synaptic cleft to stimulate or inhibit activity

Answer 31

NEUROTRANSMITTERS (NT)

Question 32

membrane proteins found on the postsynaptic neuron that bind a specific NT and generate a response in the postsynaptic cell

Answer 32

NEUROTRANSMITTER RECEPTORS

Question 33

depolarizing graded potential that brings postsynaptic neuron closer to the threshold for creating action potentials

Answer 33

EXCITATORY POSTSYNAPTIC POTENTIAL (EPSP)

Question 34

hyperpolarizing graded potential the moves a postsynaptic neuron further away from the threshold for creating action potentials

Answer 34

INHIBITORY POSTSYNAPTIC POTENTIAL (IPSP)

Question 35

process of integrating the input from multiple synapses

Answer 35

SUMMATION

Question 36

effect produced by the simultaneous release of neurotransmitters from more than one synaptic knobs on a single postsynaptic neuron

Answer 36

SPATIAL SUMMATION

Question 37

effect produced by stimulation of NT release from the same presynaptic knob in rapid succession on a postsynaptic neuron

Answer 37

TEMPORAL SUMMATION

Question 38

membrane potential of a postsynaptic neuron is held nearer to threshold then normal but not yet above

Answer 38

FACILITATION

Question 39

pathways in which a signal entering into a section of a neuronal pathway excites a greater number of signals leaving that section

Answer 39

DIVERGENT PATHWAYS

Question 40

pathways in which signals from multiple input fibers come together to excite a single output fiber

Answer 40

CONVERGENT PATHWAYS