Brain and Behavior Chapter 2

. Which terms refers to a chemical that binds to another chemical?

ligand

Electrical Synapses

A few special-purpose synapses operate electrically

Synapse

A gap between neurons where a specialized type of communication occurs

excitatory postsynaptic potential (EPSP)

A graded depolarization

Dale's Principle

A neuron can release only one neurotransmitter

Inhibitory postsynaptic potential (IPSP):

A temporary hyperpolarization of a postsynaptic cell

3rd major event at a synapse

Action potentials travel down the axon

4th major event at a synapse

At the axon or presynaptic terminal, the action potentials cause calcium to enter the cell which leads to the release of the neurotransmitters from the terminal into the synaptic cleft

neurotransmitters

Chemicals released by one neuron at the synapse and affect another neuron

Graded potentials

Either depolarization (excitatory) or hyperpolarization (inhibitory) of the postsynaptic neuron.

8th major event at a synapse

In some cells empty vesicles are returned to the cell body

7th major event at a synapse

In some cells much of the released neurotransmitters are taken back into the presynaptic neuron for recycling.

neuromodulators

Metabotropic effects utilize a number of different neurotransmitters and are often called

1st major event at a synapse

Neurons synthesize chemicals called neurotransmitters.

2nd major event at a synapse

Neurons transport these chemicals to the axon terminal

5th major event at a synapse

Neurotransmitters, once released into the synaptic cleft, attach to receptors and alter activity of the postsynaptic neuron.

Temporal summation

Repeated stimulation of one presynaptic neuron

Spatial summation

Several synaptic inputs originating from separate locations exerting a cumulative effect on a postsynaptic neuron

Spontaneous firing rate

The ability to produce action potentials without synaptic input (EPSPs and IPSPs ).

6th major event at a synapse

The neurotransmitters will separate from their receptors and (in some cases) are converted into inactive chemicals.

hormone

a chemical secreted by a gland or other cells that is transported to other organs by the blood where it alters activity.

reflexes

an automatic response to stimuli

Endocrine glands

are responsible for the production of hormones

pituitary gland

attached to the hypothalamus and consists of two distinct glands that each release a different set of hormone

antagonist

blocking the effects of a neurotransmitter

Inactivation

broken down by enzymes

When an action potential reaches the end of an axon, the depolarization causes what ionic movement in the presynaptic cell?

calcium into the cell

A metabotropic synapse, by way of its second messenger, ____.

can influence activity in much or all of the postsynaptic cell

Insulin increases the entry of tryptophan into the brain by ____.

causing certain competing amino acids to enter other cells, outside the brain

the combined effects of EPSPs and IPSPs

chloride ions entering the cell

Protein hormones and peptide hormones

composed of chains of amino acids and attach to membrane receptors where they activate second messenger systems

. The primary method for disposal of peptide neurotransmitters is ____.

diffusion

The brain produces peptides called

endorphins

Metabotropic effects

events include such behaviors as taste, smell, and pain.

Otto Loewi's experiments

fluid from a stimulated frog heart caused the new heart to react as if stimulated.

An EPSP is a(n) ____.

graded depolarization

Affinity

how strongly the drug attaches to the receptor

Releasing hormones are synthesized in the ____ and released in the ____.

hypothalamus; anterior pituitary

agonist

increasing the effects of a neurotransmitter.

When a vertebrate animal contracts the flexor muscles of a leg, it relaxes the extensor muscles of the same leg. Sherrington considered this evidence for the existence of ____.

inhibitory messages

What ordinarily prevents extensor muscles from contracting at the same time as flexor muscles?

inhibitory synapses in the spinal cord

Ionotropic effects

neurotransmitter attaches to the receptor causing the immediate opening of an ion gate

Increased permeability to ____ would most likely result in an IPSP.

potassium

Sherrington studied ____, which are automatic muscular responses to stimuli

reflexes

The amino acid tryptophan is the precursor for

serotonin

Reuptake

taken by transporters located on the presynaptic neurons

What determines whether a neuron has an action potential?

the combined effects of EPSPs and IPSPs

Gap junction

the direct contact of the membrane of one neuron with the membrane of another

presynaptic neuron

the neuron that delivers the synaptic potential

postsynaptic neuron

the neuron that receives the message

What causes an EPSP?

the opening of sodium channels

Efficacy

the tendency of the drug to activate a receptor

Temporal summation is to ____ as spatial summation is to ____.

time; location

Neurotransmitters are stored in

vesicles