Chapter 2 Flashcards
Neurons communicate with each other using both ____ and ____.
action potential; neurotransmitters
Dr. Sherrington was able to demonstrate the concept of a synapse by studying ____.
reflexes
Repeated stimuli can have a cumulative effect and can produce a nerve impulse when a single stimuli is too weak as a result of ____.
temporal summation
Sherrington demonstrated that spinach cord interneurons could produce an excitatory message (called an _____) or an inhibitory message (called an ____) within the muscles.
EPSP; IPSP
Based on his work with frog hearts, Dr. Loewi concluded that nerves send messages by ____.
releasing chemicals
Neurotransmitters are stored in ____ at the end of axons until they are released into ____.
the vesicles; the synapse
Which of the following is a monoamine neurotransmitter?
dopamine
____ receptors function when a neurotransmitter attaches to the receptor and immediately opens ion channels
inotropic
Acetylcholine is broken down by acetylcholinesterase into ____
acetate and choline
Dr. West has diabetes. As such, she needs to take the hormone ____ since her ____ does not produce enough of its own.
insulin; pancreas
What is a synapse
the space between sending and receiving neurons
What is an example of a modified amino acid?
Acetylcholine
where is acetylcholine synthesized and abundantly found?
synthesized from choline and found in milk, eggs and peanuts
What does acetylcholinesterase do?
breaks acetylcholine into two parts; acetate and choline
what happens to acetylcholine molecules after they stimulate a postsynaptic receptor?
the enzyme acetylcholinesterase breaks it into smaller molecules; acetate and choline, when are then reabsorbed by the presynaptic terminals
Many chemicals are used as neurotransmitters most of which are what or derived from where?
Amino acids
How do amphetamine and cocaine influence synapses?
They block reuptake of released dopamine, serotonin, and norepinephrine
What is anandamide
a reverse transmitter
what hormones are synthesized in the anterior pituitary
TSH, Luteinizing hormone, FSH, ACTH, Prolactin, Growth hormone
what are autoreceptors
receptors that respond to released transmitter by inhibiting further synthesis and release
how do cannabinoids affect neurons?
attach to receptors on the presynaptic neurons, where they inhibit further release of both glutamate and GABA
In what way do cannabinoids differ from other drugs that affect the nervous system?
they act on the presynaptic neuron
what are catecholamines
contain a catechol group and an amine group
name the three catecholamine neurotransmitters
epinephrine, norepinephrine, and dopamine
what happens to serotonin and catecholamine molecules after they stimulate a postsynaptic receptor?
most serotonin and catecholamine molecules are reabsorbed by the presynaptic terminal. Some of their molecules are broken down into inactive chemicals, which they diffuse away.
what does cocaine do to the neurotransmitters
blocks reuptake of dopamine and several other transmitters
what happens when stimulant drugs increase the accumulation of dopamine in the synaptic cleft?
COMT breaks down the excess dopamine faster than the presynaptic cell can replace it
what does COMT stand for?
catechol-o-methyltransferase
What is EPSP?
excitatory postsynaptic potential and is a grade depolarization
what ion gates in the membrane open during an EPSP?
Sodium gates open
What is the relationship between EPSP and action potentials
EPSPs increase the frequency of action potentials
what is exocytosis
bursts of release of neurotransmitter from the presynaptic neuron
what is a gap junction?
at an electrical synapse where the membrane of one neuron comes into direct contact with the membrane of another neuron
what is the result of a G protein
an increased concentration of a second messenger
what is a G protein
a protein that is coupled to a guanosine triphosphate, an energy-storing molecule
Which neurotransmitters are gases
NO (nitric oxide), maybe others
what do hallucinogenic drugs resemble
serotonin
what is a hormone
a chemical secreted by cells in one part of the body and covered by the blood to influence the other cells
what is an IPSP
a temporary hyper polarization of a membrane
what is the relationship between IPSP and action potentials
IPSPs decrease the frequency of action potentials
in the membrane of a neuron, what happens during an IPSP
the potassium or chloride gates open
what is an inotropic effect
synaptic effects that depend on the rapid opening of some kind of gate in the membrane
what do inotropic effects depend on
glutamate or GABA
are inotropic effects fast or slow
they are fast and brief
what are ligand-gated channels
channels that open when a neurotransmitter attaches
what does MAO mean
monoamine oxidase
what happens when you block MAO
you increase the brains supply of serotonin, dopamine, and norepinephrine
What does MAO do in the brain
it covers catecholamine transmitters into inactive chemicals
what is a metabotropic effect
a sequence of metabolic reactions that produce slow and long lasting effects at the synapse
what is methylphenidate
stimulant drug prescribed for ADHD that increases the stimulation of dopamine synapses by blocking the reuptake of dopamine by the presynaptic neuron
what are monoamines
chemicals formed by a change in certain amino acids
what are some examples of monoamines
indoleamines: serotonin
catecholamines: dopamine, norepinephrine, epinephrine
what is a neuromodulator
chains of amino acids
what are neuropeptides
chains of amino acids
what are some examples of neuropeptides
endorphins, substance P, neuropeptide Y, many others
what is required for neuropeptide release
repeated stimulation
what diffuses widely, slowly affecting many neurons in their region of the brain
neuropeptides
what is important for hunger, thirst, and other long term changes in behavior and experience
neuropeptides
what are neurotransmitters
chemicals released by neurons that affect other neurons
what is nicotine
a stimulant drug that stimulates certain acetylcholine receptors
what does nicotine increase
dopamine release
what is nitric oxide
a gas released by many small local neurons
what does nitric oxide do
dilates the nearby blood vessels, thereby increasing blood flow to that brain area
what is oxytocin
a hormone released by posterior pituitary; important for sexual and parental behaviors
what does oxytocin do
uterine contractions, milk release, sexual pleasure
what are peptide hormones
hormones composed of short chains of amino acids
what do peptide hormones do
they attach to membrane receptors, where they activate a second messenger within the cell
What two hormones does the posterior pituitary release
vasopression and oxytocin
What is composed of neural tissue as opposed to glandular tissue
posterior pituitary
what is the posterior pituitary
portion of the pituitary gland, which releases hormones synthesized by the hypothalamus
what is a presynaptic neuron
neuron that delivers transmission to another neuron
what are protein hormones
hormones composed of long chains of amino acids
what two types of hormones are there
protein and peptide
what are the neurotransmitters that are purines
ATP, adenosine, maybe others
what are purines
a category of chemicals including adenosine and several of its derivatives
what is a reflex arc
a circuit form sensory neuron to muscle response
what are three properties of reflexes
- slower than conduction
- several weak stimuli produce stronger reflex than just one
- one set of muscles gets excited another set relaxes
what are reflexes
automatic muscular responses to stimuli
what is a releasing hormone
a hormone released by the hypothalamus that flows through the blood to the anterior pituitary
what do releasing hormones do
they stimulate or inhibit the release of other hormones
what is reuptake
reabsorption of a neurotransmitter by the presynaptic terminal
where does reuptake take place
through special membranes called transporters
What is a second messenger
a chemical that, when activated by a neurotransmitter, initiates
which type of synapse relies on second messengers
metabotropic synapse
what is spatial summation
combination of effects of activity from two or more synapses onto a single neuron
Although one pinch did not cause a dog to flex its leg, several simultaneous pinches at nearby locations did. Sherrington cited this observation as evidence for what
spatial summation
what is the difference between temporal and spatial summation
temporal summation is the combined effect of quickly repeated stimulation at a single synapse. Spatial summation is the combined effect of several nearby stimulation’s at several synapses onto one neuron
what is spontaneous firing rate
a periodic production of action potentials even without synaptic input
what is a synapse
a specialized gap as a point of communication between two neurons
what is temporal summation
a cumulative effect of repeated stimuli within a brief time
Although one pinch did not cause a dog to flex its leg, a rapid sequence of pinches did. Sherrington cited this observation as evidence for what?
temporal summation
what are transmitter-gated channels
ion channel that opens temporarily when a neurotransmitter binds to it
what is a transporter
special membrane protein where reuptake occurs in the neurotransmitter binds to it
