Brain And Behavior Chapter 3, 4, 5, 6

Front 1

axon hillock

Back 1

juncture of soma (cell body) and axon

Front 2

dendrite

Back 2

branching extension of a neuron's cell membrane; greatly increases the cell's surface area; collects information from other cells

Front 3

connectome

Back 3

comprehensive map of all structural connectivity (the physical wiring) in an organism's nervous system

Front 4

ependymal cell

Back 4

glial cell that makes and secretes CSF; found on the walls of the brain's ventricles

Front 5

astrocyte

Back 5

star-shaped glial cell that provides structural support to CNS neurons and transports substances between neurons and blood vessels

Front 6

blood-brain barrier

Back 6

tight junctions between the cells that compose blood vessels in the brain, providing a barrier to the entry of an array of substances, including toxins, into the brain

Front 7

microglia

Back 7

glial cells that originate in the blood, aid in cell repair, and scavenge debris in the nervous system

Front 8

myelin

Back 8

glial coating that surrounds axons in the central and peripheral nervous systems; prevents adjacent neurons from short-circuiting

Front 9

oligodendroglia

Back 9

glial cells in the CNS that myelinate axons

Front 10

Schwann cell

Back 10

glial cell in the PNS that myelinates sensory and motor axons

Front 11

resting potential

Back 11

electrical charge across the insulating cell membrane in the absence of stimulation; a store of potential energy produced by a greater negative charge on the intracellular side relative to the extracellular side

Front 12

graded potential

Back 12

small voltage fluctuation across the cell membrane

Front 13

action potential

Back 13

large, brief reversal in the polarity of an axon membrane

Front 14

threshold potential

Back 14

voltage on a neural membrane at which an action potential is triggered by the opening of sodium and potassium voltage-sensitive channels; about -50 mV relative to extracellular surround (also called threshold limit)

Front 15

absolutely refractory

Back 15

the state of an axon in the repolarizing period, during which a new action potential cannot be elicited (with some exceptions), because gate 2 of sodium channels, which are not voltage sensitive, are closed

Front 16

relatively refractory

Back 16

the state of an axon in the later phase of an action potential during which increased electrical current is required to produce another action potential; a phase during which potassium channels are still open

Front 17

node of Ranvier

Back 17

the part of an axon that is not covered by myelin

Front 18

saltatory conduction

Back 18

fast propagation of an action potential at successive nodes of Ranvier (saltatory means leaping)

Front 19

EPSP (excitatory postsynaptic potential)

Back 19

brief depolarization of a neuron membrane in response to stimulation, making the neuron more likely to produce an action potential

Front 20

IPSP (inhibitory postsynaptic potential)

Back 20

brief hyperpolarization of a neuron membrane in response to stimulation, making the neuron less likely to produce an action potential

Front 21

synaptic vesicle

Back 21

membranous compartment that encloses a quantum of neurotransmitter

Front 22

synaptic cleft

Back 22

gap separating the neuronal presynaptic membrane from the post synaptic membrane

Front 23

histamine (H)

Back 23

neurotransmitter that controls arousal and waking; can cause the constriction of smooth muscles; when activated in allergic reactions, constricts airway and contributes to asthma

Front 24

glutamate (Glu)

Back 24

amino acid neurotransmitter; typically excites neurons

Front 25

GABA (gamma-aminobutyric acid)

Back 25

amino acid neurotransmitter; typically inhibits neurons

Front 26

endocannabinoid

Back 26

class of lipid neurotransmitters, including anandamide and 2-AG, synthesized at the postsynaptic membrane to act on receptors at the presynaptic membrane; affects appetite, pain, sleep, mood, memory, anxiety, and the stress response

Front 27

ionotropic receptor

Back 27

embedded membrane protein; acts as a binding site for a neurotransmitter and a pore that regulates ion flow to directly and rapidly change membrane voltage

Front 28

metabotropic receptor

Back 28

embedded membrane protein with a binding site for a neurotransmitter linked to a G protein; can affect other receptors or act with second messengers to affect other cellular processes, including opening a pore

Front 29

G protein

Back 29

guanyl nucleotide-biding protein coupled to a metabotropic receptor; when activated, binds to other proteins

Front 30

autoreceptor

Back 30

self-receptor in a neuronal membrane; that is, it responds to the same transmitter released by the neuron

Front 31

agonist

Back 31

substance that enhances synapse function

Front 32

antagonist

Back 32

substance that blocks synapse function

Front 33

monoamine oxidase (MAO) inhibitor

Back 33

antidepressant drug that blocks the enzyme monoamine oxidase from degrading such neurotransmitters as DA, NE, and 5-HT

Front 34

tricyclic antidepressant

Back 34

first-generation antidepressant; its chemical structure, characterized by three rings, blocks 5-HT reuptake transporter proteins

Front 35

selective serotonin reuptake inhibitor (SSRI)

Back 35

tricyclic antidepressant drug that blocks 5-HT reuptake into the presynaptic terminal

Front 36

mood stabilizer

Back 36

drug for treating bipolar disorder; mutes the intensity of one pole of the disorder, thus making the other pole less likely to recur

Front 37

disinhibition theory

Back 37

explanation holding that alcohol has a selective depressant effect on the brain's frontal cortex, which controls judgment, while sparing subcortical structures responsible for more instinctual behaviors, such as desire

Front 38

wanting-and-liking theory

Back 38

explanation holding that when a drug is associated with certain cues, the cues themselves elicit desire for the drug (also called incentive sensitization theory)

Front 39

glucocorticoid

Back 39

one of a group of steroid hormones, such as cortisol, secreted in times of stress; important in protein and carbohydrate metabolism

Front 40

organizational hypothesis

Back 40

proposal that hormonal action during development alters tissue differentiation; for example, testosterone masculinizes the brain