Neuroscience I

Question 1

a highly specialized cell found in nervous systems of animals that communicates with other cells by electrical or chemical signals

Answer 1

neurons

Question 2

a structure found in the peripheral nervous system that is composed of multiple myelinated axons bound by connective tissue; carries information to or from the central nervous system

Answer 2

nerves

Question 3

the brain and spinal cord

Answer 3

central nervous system (CNS)

Question 4

all nerves and ganglia outside the brain and spinal cord

Answer 4

peripheral nervous system (PNS)

Question 5

a part of a neuron that contains the cell nucleus and other organelles

Answer 5

cell body

Question 6

a treelike extension of the plasma membrane of a neuron that receives electrical signals from other neurons

Answer 6

dendrites

Question 7

an extension of the plasma membrane of a neuron that is involved in sending signals to neighboring cells

Answer 7

axon

Question 8

the part of an axon closest to the cell body; typically where an action potential begins

Answer 8

axon hillock

Question 9

the end of an axon, which conveys electrical or chemical messages to other cells

Answer 9

axon terminals

Question 10

cells that surround the neurons; a major class of cells in nervous system that perform various functions

Answer 10

glia

Question 11

exposed area along the axons of myelinated neurons that contain many voltage-gated Na+ channels and are the sites of regeneration of action potentials

Answer 11

nodes of Ranvier

Question 12

the glial cells that form myelin on axons that travel outside the brain and spinal cord

Answer 12

Schwann cells

Question 13

glial cells that produce the myelin sheath around neurons in the central nervous system

Answer 13

oligodendrocytes

Question 14

in the nervous system, an insulating layer made up of specialized glial cells wrapped around certain axons

Answer 14

myelin sheath

Question 15

a neuron that detects or senses information from the outside world, such as light, sound, touch, and heat; also detect internal body conditions such as blood pressure and blood temperature

Answer 15

sensory neurons

Question 16

a neuron that sends signals away from the central nervous system and elicits some type of response from a gland, muscle, or other structure

Answer 16

motor neurons

Question 17

a type of neuron that forms interconnections between other neurons

Answer 17

interneuron

Question 18

a simple circuit that allows an organism to respond rapidly to inputs from sensory neurons and consists of only a few neurons

Answer 18

reflex arc

Question 19

the difference between the electric charges along the inside and outside surfaces of a cell membrane

Answer 19

membrane potential

Question 20

the differences in charges across the plasma membrane in an unstimulated neuron

Answer 20

resting membrane potential

Question 21

a dual gradient across a membrane having both electrical and chemical components; determines what directions the ions will move

Answer 21

electrochemical gradient

Question 22

the membrane potential at which the flow of an ion across a membrane is at equilibrium, with no net movement in either direction

Answer 22

equilibrium potential

Question 23

the change in the membrane potential that occurs when a cell membrane becomes less polarized, less negative inside the cell relative to the extracellular fluid

Answer 23

depolarization

Question 24

the change in the membrane potential that occurs when the cell membrane becomes more polarized than it is at rest

Answer 24

hyperpolarization

Question 25

ion channels that will open and close in response to changes in voltage across a cell membrane

Answer 25

voltage-gated ion channels

Question 26

a type of cell surface receptor that binds a ligand and functions as an ion channels; ligand binding either opens or closes a channel

Answer 26

ligand-gated ion channels

Question 27

the membrane potential, typically around -55 to -50 mV, that is sufficient to trigger an action potential in an electrically excitable cell such as a neuron

Answer 27

threshold potential

Question 28

a string of amino acids that juts out from a channel protein into the cytosol and can swing into the channel pore to block the movements of ions through the channel

Answer 28

inactivation gate

Question 29

the period during an action potential when the inactivation gate of the voltage-gated Na+ channel is closed; during this time, it is impossible to generate another action potential

Answer 29

absolute refractory period

Question 30

the period near the end of an action potential when voltage-gated K+ channels are still open; during this time a new action potential can be generated if a stimulus is sufficiently strong to raise the membrane potential to the threshold

Answer 30

relative refractory period

Question 31

a junction where an axon terminal meets another neuron, a muscle cell, or a gland cell and through which an electrical or chemical signal passes

Answer 31

synapse

Question 32

the extracellular space between a neuron and a receiving cell

Answer 32

synaptic cleft

Question 33

the neuron that sends an electrical or chemical signal to another cell

Answer 33

presynaptic cell

Question 34

the cell that receives the electrical or chemical signal

Answer 34

postsynaptic cell

Question 35

a synapse in which a chemical called a neurotransmitter is released from an axon terminal and acts as a signal from the presynaptic to the postsynaptic cells

Answer 35

chemical synapse

Question 36

the response to an excitatory neurotransmitter that depolarizes the postsynaptic membrane; the depolarization brings the membrane potential closer to the threshold potential that would trigger an action potential

Answer 36

excitatory postsynaptic potential (EPSP)

Question 37

the response to an inhibitory neurotransmitter that hyperpolarizes the postsynaptic membrane; this hyperpolarization reduces the likelihood of an action potential occurring

Answer 37

inhibitory postsynaptic potential (IPSP)

Question 38

the process that occurs when multiple excitatory postsynaptic potentials are generated at one time at synapses along different regions of the dendrites and/or cell body and their depolarizations and hyperpolarizations sum together to initiate action potential

Answer 38

spatial summation

Question 39

the process that occurs when two or more postsynaptic potentials arrive at the same location on a dendrite or cell body in quick succession and their depolarizations and hyperpolarizations sum together to initiate an action potential

Answer 39

temporal summation

Question 40

the contact point between an axon terminal of a motor neuron and a skeletal or cardiac muscle fiber

Answer 40

neuromuscular juction

Question 41

one of two types of postsynaptic membrane receptors; consists of a ligand-gated ion channel that opens in response to the binding of a neurotransmitter

Answer 41

iontropic receptor

Question 42

a G-protien coupled receptor that initiates a signaling pathway in response to a neurotransmitter

Answer 42

metabotropic receptor