PCB3702 CHAPTER 7

Place the steps of neurotransmitter release in the correct chronological order from the point at which the action potential arrives at the terminal bouton to the diffusion of the neurotransmitter across the synaptic cleft.

1. action potential causes a change in the membrane potential of the terminal bouton2. voltage gated Ca++ channels open3. Ca++ binds to sensor proteins in cytoplasm4. Ca++ protein complex stimulates exocytosis

Place the events of an excitatory synaptic transmission in the correct order chronologically.

1: Action potential reaches the terminal bouton2: voltage gates Ca+++ channels open3: Ca+++ enters causing the release of excitatory neurotransmitter 4: neurotransmitter binds to the ligand-gated channel on the postsynaptic membrane causing it to open. 5: Na+ enter the postsynaptic cell causing a depolarization.

Which of the following is an EPSP or excitatory postsynaptic potential?

Depolarization of a CNS neuronal membrane in response to glutamate Depolarization of the muscle fiber due to acetylcholine binding at the neuromuscular junction

In order for neurotransmitters to be released from their synaptic vesicles, what must occur?

Calcium must diffuse into the terminal bouton through voltage gated channels.

What does an EPSP (excitatory postsynaptic potential) do in the postsynaptic cell?

Cause action potentials to be produced Cause the subsequent release of neurotransmitters

What is the convergence of neural pathways?

Convergence occurs when a number of axons synapse on a single neuron.

The neurotransmitter of somatic motor neurons and some autonomic nerve endings is ______.

acetylcholine

The inactivation of acetylcholine is done by an enzyme called ____ which is present on the postsynaptic membrane or in the synaptic cleft.

acetylcholinesterase

Which of the following are characteristics of EPSPs but not APs?

can be summed, has a loss of intracellular positive charges with time and distance

____ ____ ____ are proteins in the pre-and postsynaptic membranes that project from those membranes into the synaptic cleft to insure that the two cells remain in close proximity to one another.

cell adhesion molecules

When a single neuron has collateral axonal branches that synapse with a number of different neurons, this is called ___ of neural pathways

divergence

An _____ postsynaptic potential stimulates the postsynaptic cell to produce an action potential.

excitatory

A graded depolarization in the postsynaptic cell that causes the membrane to move towards threshold is called a(n) ____ ____ ____

excitatory postsynaptic potential

An ____ postsynaptic potential causes a cell to depolarize and makes it more likely to produce action potentials; while a ____ postsynaptic potential causes the cell to hyperpolarize and makes it less likely to produce action potentials.

excitatory, inhibitory

A graded change in the membrane potential is known as a(n) ___ ___

graded potential

____ are produced when ligand gated channels open allowing a localized flow of ions that changes the membrane potential in that small area.

graded potentials

_____ are produced when ligand gated channels open allowing a localized flow of ions that changes the membrane potential in that small area.

graded potentials

Which of the following are characteristics of APs but not EPSPs?

has a refractory period, are regenerated without decrement

An _____ postsynaptic potential prevents or inhibits the postsynaptic cell's production of an action potential.

inhibitory

A graded hyperpolarization of the postsynaptic membrane is called a(n) ____ ____ ___

inhibitory postsynaptic potential

Cell adhesion molecules (CAMs):

insure that the pre- and postsynaptic cell membranes are in close proximity to each other

Acetylcholine (ACh):

is a neurotransmitter is inhibitory is excitatory

A(n) ____ ____ gate in the cell membrane opens in response to the binding of a chemical to its receptor site.

ligand regulated

Neurotransmitter X is released from the terminal bouton of a neuron and binds to the receptors on a K+ channel in the postsynaptic cell causing the K+ channel to open. The K+ channel is classified as a(n) ____ ____ gate

ligand regulated

An excitatory postsynaptic potential (EPSP) causes the membrane potential to move towards threshold whereas an inhibitory postsynaptic potential (IPSP) causes it to become more ________.

negative

The connection from a muscle to a nerve is called a ______ junction.

neuromuscular

A neuromuscular junction or myoneural junction is a synapse between a(n) ____ and a(n) ______ cell (not second but a type of cell)

neuron, muscle

a chemical that is released from a presynaptic cell in response to a stimulus which then causes a change in the membrane potential of a postsynaptic cell.

neurotransmitter

Chemicals released at synapses are ______.

neurotransmitters

Which of the following are types of cholinergic receptors?

nicotinic muscarinic

The transmission of neurotransmitters across a small distance proceeds from the first cell to the second cell, which is called the _____ cell

postsynaptic

Synaptic vesicles ______.

release neurotransmitter by exocytosis

Presynaptic axon endings are called _______.

terminal boutons

The axons of neurons terminate in swollen button like structures called

terminal buttons

A synapse is ______.

the connection between a neuron and a second cell

The synaptic cleft is _____

the space between pre- and postsynaptic cells.

When ACh binds to a receptor on a sodium channel in the postsynaptic membrane, it causes the sodium channel to open and sodium ions enter the cell. What type of channel is this?

Ligand regulated or gated Chemically regulated

What type of gates or membrane channels in the postsynaptic membrane open in response to the binding of a chemical ligand to its receptor?

Ligand-regulated gates Chemically regulated gates

During excitatory synaptic transmission, neurotransmitters from the presynaptic cell bind to ligand gated channels on the postsynaptic cell causing:

Na+ to enter the postsynaptic cell, an EPSP

What does an IPSP (inhibitory postsynaptic potential) do in the postsynaptic cell?

Prevent the subsequent release of neurotransmitters, Prevent the production of action potentials

What is the space between the presynaptic cell and the postsynaptic cell called?

Synaptic cleft

Which of the following is correct about nerve signal transmission?

The signal travels from the presynaptic cell to the postsynaptic cell.

Which of the following is an IPSP or inhibitory postsynaptic potential?

Hyperpolarization of the postsynaptic membrane due to the opening of Cl- channels by glycine Hyperpolarization of the membrane in response to GABA