Practice Quizzes for Lecture #12

Which neurotransmitter is used to initiate skeletal muscle contraction?

Acetylcholine

Step 3: Place the events that activate a chemical synapse in the correct order.

Calcium enters the cell and triggers exocytosis of synaptic vesicles

In a ________ neuronal circuit, a single neuron receives input from many different neurons.

Convergent

Step 2: Place the events that activate a chemical synapse in the correct order.

Depolarization opens voltage-gated calcium channels in the axon terminal

In a ___________ neuronal circuit, a single neuron sends signals out to multiple target cells.

Divergent

In most neurons, a higher frequency of action potentials leads to a decrease in the amount of neurotransmitter released. T or F

False

Neuron excitability does not require a continuous supply of oxygen. T or F

False

What is the main inhibitory neurotransmitter in the spinal cord?

Glycine

___________ receptors are ligand-gated ion channels that increase or decrease the chance of an action potential firing when activated.

Ionotropic

What is the main function of the neurotransmitter glutamate?

It is the main excitatory neurotransmitter in the brain.

What is the main function of gamma-aminobutyric acid (GABA)?

It is the main inhibitory neurotransmitter in the brain.

Step 5: Place the events that activate a chemical synapse in the correct order.

Neurotransmitter binds with receptors on the postsynaptic cell and initiates a response

___________ are small sections of bare axon between the myelinated regions.

Nodes of Ranvier

What prevents an action potential from traveling backwards through the axon?

Sodium channel inactivation during the absolute refractory period

A __________ is a structure where a neuron transmits a signal to another cell.

Synapse

The __________ is the gap between the two cells at a chemical synapse.

Synaptic Cleft

_________ occurs when the neuron is stimulated at a rapid rate and loses the ability to fire signals.

Synaptic fatigue

Step 4: Place the events that activate a chemical synapse in the correct order.

Synaptic vesicles release neurotransmitter into the synaptic cleft

Step 1: Place the events that activate a chemical synapse in the correct order.

The action potential depolarizes the axon terminal

What causes the action potential to move from the trigger zone towards the axon terminal?

The movement of sodium ions from an area that is depolarized into an adjacent area that is at the resting potential

Which of the following statements about myelin is TRUE?

Action potentials skip over myelinated sections of an axon.

Which of the following statements about synapses is TRUE?

All of these answers are true

Which of the following is a category of neurotransmitter?

All of these are categories of neurotransmitter

Which of the following is a method to remove neurotransmitter from a chemical synapse?

All of these are method for removing neurotransmitter from a chemical synapse.

Which of the following factors can affect action potential formation and conduction?

All of these factors can affect the formation and conduction of action potentials

Which factors influence the speed of action potential conduction?

Axon diameter and the amount of myelin on the axon.

__________ receptors are G protein coupled receptors that activate enzymes, open ion channels, and/or initiate intracellular signaling cascades

Metabotropic

__________ is a lipid-rich substance created by glial cells to insulate the axons.

Myelin

Which structure insulates sections of an axon and allows for saltatory conduction?

Myelin Sheath

What is saltatory conduction?

The way an action potential skips from node to node down the full length of an axon

A low concentration of extracellular calcium (hypocalcemia) increases the excitability of a neuron. T or F

True

Alkalosis (high blood pH) increases the activity of neurons while acidosis (low blood pH) decreases their activity. T or F

True

Myelin increases the speed of an action potential. T or F

True

Stimulus strength and duration is encoded by the frequency of the action potentials. T or F

True

pH can influence the activity of neurons. T or F

True