PSY 260 - Chapter 2

examples of purines

ATP, adenosine, etc.

When the action potential reaches the presynaptic terminal, which ion must enter the presynaptic terminal to evoke release of the neurotransmitter?

Calcium

How does LSD influence behavior?

LSD binds to one type of serotonin receptor

What was Sherrington's evidence for inhibition in the nervous system?

Sherrington found that a reflex that stimulates a flexor muscle prevents contraction of the extensor muscles of the same limb. He therefore inferred that an interneuron that excited motor neurons connected to the flexor muscle also inhibited the input to the extensor muscle.

What evidence led Sherrington to conclude that transmission at a synapse is different from transmission along an axon?

Sherrington found that the velocity of conduction through a reflex arc was slower than the velocity of an action potential along an axon. Therefore, some delay must oxxur at the junction between one neuron and the next.

What was Loewi's evidence that neurotransmission depends on the release of chemicals?

When Loewi stimulated a nerve that increased or decreased a frog's heart rate, he could withdraw fluid from the area around the heart, transfer it to another frog's heart, and thereby increase or decrease its rate also.

What is a second messenger?

a chemical released inside a cell after stimulation at a metabotropic synapse

acetylcholine

a chemical similar to an amino acid, except that it includes an N(CH3)3 group instead of an NH2

G protein

a protein coupled to guanosine triphosphate (GTP)

second messenger

a secondary protein that communicates to many areas within the cell

Which neurotransmitter is broken into two pieces to inactivate it, after it excites the postsynaptic neuron?

acetylcholine

examples of modified amino acids

acetylcholine

amino acids

acids containing an amine group (NH2)

Where is aldosterone produced?

adrenal cortex

Where is cortisol produced?

adrenal cortex

Where are epinephrine and norepinephrine produced?

adrenal medulla

monoamine oxidase (MAO)

an enzyme that breaks down catecholamine transmitters into inactive chemicals

Which part of the pituitary - anterior or posterior - is glandular tissue and produces hormones that control the secretions by other endocrine organs?

anterior

Where are follicule-stimulating hormones produced?

anterior pituitary

Where are growth hormones produced?

anterior pituitary

Where are thyroid-stimulating hormones produced?

anterior pituitary

Where is ACTH produced?

anterior pituitary

Where is prolactin produced?

anterior pituitary

reflexes

automatic muscular responses to stimuli

Which drug acts by inhibiting release of neurotransmitters from the presynaptic neuron?

cannabinoinds

How do cannibinoids affect neurons?

cannibinoids released by the postsynaptic neuron attach to receptors on presynaptic neurons, where they inhibit further release of both glutamate and GABA

purines

category of chemicals including adenosine and its derivatives

neuropeptides

chains of amino acids

hormone

chemical secreted by cells in one part of the body and conveyed by the blood to influence other cells

monoamines

chemicals formed by a change in certain amino acids

neurotransmitters

chemicals that affect another neuron

reflex arc

circuit from sensory neuron to muscle response

Ritalin (methylphenidate) affects synapses the same way as which other drug?

cocaine

catecholamines

compounds containing a catechol group and an amine group

leptin

decreases appetite

examples of catecholamines

dopamine, norepinephrine, epinephrine

cortisol

elevated blood sugar and metabolism

examples of neuropeptides

endorphines, substance P, neuropeptide Y, etc.

What are the three catacholamine neurotransmitters?

epinephrine, norepinephrine, and dopamine

Where is leptin produced?

fat cells

function of estrogen and progesterone

female sexual characteristics and pregnancy

examples of amino acids

glutamate, GAPA, glycine, aspartate, etc.

The brain's most abundant excitatory neurotransmitter is ____, and its most abundant inhibitory transmitter is ____.

glutamate...GABA

excitatory postsynaptic potential (EPSP)

graded depolarization resulting from a flow of sodium ions into the neuron

In what way were Sherrington's conclusions important for psychology as well as neuroscience?

he demonstrated the importance of inhibition

glucagon

helps convert stored fats into blood glucose

insulin

helps glucose enter cells

growth hormone

increased body growth

ACTH

increased steroid hormone production by adrenal gland

prolactin

increases milk production

When a vigorous pinch excited a dog's flexor muscle, it decreased excitation of the extensor muscles of the same leg. Sherrington cited this observation as evidence for

inhibitory synapses

metabotropic effects

initiating a sequence of metabolic reactions that are slower and longer lasting that ionotropic effects

How can you cause a presynaptic terminal of an axon to release its transmitter without an action potential?

inject calcium into the presynaptic terminal

How do amphetamine and cocaine influence dopamine synapses?

interfere with reuptake of released dopamine

How do ionotropic and metabotropic synapses differ in speed and duration of effects?

ionotropic synapses act more quickly and more briefly than metabotropic synapses

In contrast to the posterior pituitary, the anterior pituitary...

is glandular tissue that produces hormones that control other endocrine organs

What does a transporter protein do at a synapse?

it pumps used neurotransmitter molecules back into the presynaptic neuron

How does a metabotropic synapse differ from an ionotropic synapse?

its effects are slower to start and last longer

Where is renin produced?

kidneys

function of testosterone

male sexual characteristics and pubic hair

What does a highly active brain area do to increase its blood supply?

many stimulated neurons release nitric oxide, which dilates the blood vessels in the area and thereby increased blood flow to the area

gap junction

membrane of one neuron comes into direct contact with the membrane of another at an electrical synapse

Why is methylphenidate generally less disruptive to behavior than cocaine is despite the drug's similar mechanisms?

methylphenidate effects develop and decline in the brain much more slowly than cocaine

In what way is a neuropeptide intermediate between neurotransmitters and hormones?

most neurotransmitters are released in small amounts close to their receptors. neuropeptides are released into a brain area in larger amounts or not at all. when released, they diffuse more widely. hormones are released into the blood for diffuse delivery throughout the body.

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 are broken down into inactive chemicals, which then diffuse away.

presynaptic neuron

neuron that delivers transmission

postsynaptic neuron

neuron that receives transmission

How are neuropeptides special compared to other transmitters?

neuropeptides are released only after prolonged stimulation and are released in large amounts by all parts of the neuron, not just the axon terminal. neuropeptides diffuse widely, prolonging long-lasting effects on many neurons.

In what way is a neuropeptide intermediate between neurotransmitters and hormones?

neuropeptides diffuse more widely than other neurotransmitters but less than a hormone

Which drug exerts its behavioral effects by binding to the same receptor as a neurotransmitter?

nicotine

How does nicotine influence behavior?

nicotine binds to one type of acetylcholine receptor

gases

nitric oxide and others

examples of gases

nitric oxide, etc.

Can an inhibitory message flow along an axon?

no. only action potentials propagate along an axon. IPSPs decay over time and distance.

How do opiates influence behavior?

opiates bind to endorphin receptors

Where are estrogen and progesterone produced?

ovaries

Where is insulin and glucagon produced?

pancreas

spontaneous firing rate

periodic production of action potentials even without synaptic input

Where is melatonin produced?

pineal

Which part of the pituitary - anterior or posterior - is neural tissue, similar to the hypothalamus?

posterior

Where is oxytocin produced?

posterior pituitary

Where is vasopressin produced?

posterior pituitary

Which type of synapse relies on second messengers?

postsynaptic cell

During an IPSP, the ____ gates open.

potassium or chloride

What ion gates open during an IPSP?

potassium or chloride gates open

function of hypothalamus hormones

promote/inhibit release of hormones from pituiary

follicule-stimulating hormone

promotes ovum maturation in females, sperm production in males

vasopressin

raises blood pressure, decreases urine volume

autoreceptors

receptors that respond to the released transmitter by inhibiting further synthesis and release, thereby providing negative feedback

aldosterone

reduces release of salt in the urine

renin

regulates blood pressure, contributes to hypovolemic thirst

temporal summation

repeated stimuli within a brief time have a cumulative effect

examples of indoleamines (monoamine)

serotonin

tryptophan is a precursor to which neurotransmitter?

serotonin

functions of epinephrine, norepinephrine

similar to actions of sympathetic nervous system

melatonin

sleepiness, also role in puberty

During an EPSP, the ____ gates in the membrane open.

sodium

What ion gates in the membrane open during an EPSP?

sodium gates open

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 ____.

spatial summation

synapse

specialized gap between neurons

thyroid-stimulating hormone

stimulates thyroid gland

spatial summation

summation over space; synaptic inputs from separate locations combine their effects on a nueorn

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 ____.

temporal summation

inhibitory postsynaptic potential (IPSP)

temporary hyperpolarization of a membrane; occurs when synaptic input selectively opens the gates for potassium ions to leave the cell

Where is testosterone produced?

testis

What happens to acetylcholine molecules after they stimulate a postsynaptic receptor?

the enzyme acetylcholinesterase breaks acetylcholine molecules into acetate and choline, which are then reabsorbed by the presynaptic terminal

oxytocin

uterine contractions, milk release, sexual pleasure

ionotropic effects

when a neurotransmitter binds, it twists the ionotropic receptor enough to open its central channel