Chapter 5 Flashcards
acetylcholine (Ach)
First neurotransmitter discovered in the PNS and CNS; activates skeletal muscles in the SNS; may either excite or inhibit internal organs in the ANS.
epinephrine (EP, or adrenaline)
Chemical messenger that acts as a neurotransmitter in the CNS and as a hormone to mobilize the body for fight or flight during times of stress.
norepinephrine (NE, or noradrenaline)
Neurotransmitter that accelerates heart rate in mammals; found in the brain and in the sympathetic division of the ANS.
neurotransmitter
Chemical with an excitatory or inhibitory effect when released by a neuron onto a target.
Parkinson disease
Motor system disorder correlated with dopamine loss in the substantia nigra; characterized by tremors, muscular rigidity, and reduction in voluntary movement.
dopamine (DA)
Amine neurotransmitter involved in coordinating movement, attention, learning, and in reinforcing behaviors.
synaptic vesicle
Membranous compartment that encloses a quantum of neurotransmitter.
synaptic cleft
Gap separating the neuronal presynaptic membrane from the postsynaptic membrane.
chemical synapse
Junction at which messenger molecules are released when stimulated by an action potential.
presynaptic membrane
Axon terminal membrane on the transmitter, or output, side of a synapse.
postsynaptic membrane
Membrane on the transmitter, or input, side of a synapse.
storage granule
Membranous compartment that holds several vesicles containing a neurotransmitter.
gap junction (electrical synapse)
Area of contact between adjacent cells in which ion channels form a pore that allows ions to pass directly from one cell to the next.
transporter
Protein molecule that pumps substances across a membrane.
transmitter-activated receptor
Protein that has a binding site for a specific neurotransmitter and is embedded in the membrane of a cell.
autoreceptor
Self-receptor in a neuronal membrane; that is, it responds to the same transmitter released by the neuron.
quantum (pl. quanta)
Amount of neurotransmitter, equivalent to the content of a single synaptic vesicle, that produces a just-observable change in postsynaptic electric potential.
reuptake
Deactivation of a neurotransmitter when membrane transporter proteins bring the transmitter back into the presynaptic axon terminal for reuse.
small-molecule transmitter
Quick-acting neurotransmitter synthesized in the axon terminal from products derived from the diet.
histamine (H)
Neurotransmitter that controls arousal and waking; can cause the constriction of smooth muscles; when activated in allergic reactions, constricts airway and contributes to asthma.
rate-limiting factor
Any chemical in limited supply that restricts the pace at which another chemical can be synthesized.
serotonin (5-Ht)
Amine neurotransmitter; helps to regulate mood and aggression, appetite and arousal, perception of pain, and respiration.
glutamate (Glu)
Amino acid neurotransmitter; typically excites neurons.
gamma-aminobutyric acid (GABA)
Amino acid neurotransmitter; typically inhibits neurons.
neuropeptide
Short (fewer than 100), multifunctional amino acid chain; acts as a neurotransmitter and can act as a hormone; may contribute to learning.
endocannabinoid
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.
nitric oxide (NO)
Gaseous neurotransmitter; acts, for example, to dilate blood vessels, aid digestion, and activate cellular metabolism.
carbon monoxide (CO)
Gaseous neurotransmitter; activates cellular metabolism.
hydrogen sulfide (H2s)
Gaseous neurotransmitter; slows cellular metabolism.
ionotropic receptor
Embedded membrane protein; acts as (1) a binding site for a neurotransmitter and (2) a pore that regulates ion flow to directly and rapidly change membrane voltage.
metabotropic receptor
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.
G protein
Guanyl nucleotide–binding protein coupled to a metabotropic receptor; when activated, binds to other proteins.
subunit
Protein molecule that assembles with other protein molecules.
second messenger
Chemical that initiates a biochemical process when activated by a neurotransmitter (the first messenger).
cholinergic neuron
Neuron that uses acetylcholine as its main neurotransmitter; cholinergic applies to any neuron that uses ACh as its main transmitter.
activating system
Neural pathways that coordinate brain activity through a single neurotransmitter; its cell bodies lie in a brainstem nucleus; axons are distributed through a wide CNS region.
Alzheimer disease
Degenerative brain disorder related to aging; first appears as progressive memory loss and later develops into generalized dementia.
schizophrenia
Behavioral disorder characterized by delusions, hallucinations, disorganized speech, blunted emotion, agitation or immobility, and a host of associated symptoms.
noradrenergic neuron
From adrenaline, Latin for epinephrine; a neuron containing norepinephrine.
major depression
Mood disorder characterized by prolonged feelings of worthlessness and guilt, the disruption of normal eating habits, sleep disturbances, a general slowing of behavior, and frequent thoughts of suicide.
mania
Disordered mental state of extreme excitement.
obsessive-compulsive disorder (OcD)
Behavior characterized by compulsively repeated acts (such as hand washing) and repetitive, often unpleasant, thoughts (obsessions).
learning
Relatively permanent change in behavior that results from experience.
habituation
Learned behavior in which the response to a stimulus weakens with repeated presentations.
sensitization
Learned behavior in which the response to a stimulus strengthens with repeated presentations.
posttraumatic stress disorder (PtsD)
Syndrome characterized by physiological arousal associated with recurrent memories and dreams arising from a traumatic event that occurred months or years earlier.
