Bio-210: Exam 3 Connect Assignment "Neuronal Communication"

Saltatory conduction means which of the following terms?

"Leaping"

Which are functions of astrocytes?

--Secrete nerve growth factors -Regulate chemical composition of tissue fluid -Convert blood glucose to lactate for neurons to use for fuel -Form blood-brain barrier

Choose all that are true about signal conduction in myelinated axons.

-Action potentials are only generated at the nodes of Ranvier. -The signal moves more rapidly through the internodes than it does through the nodes of Ranvier.

Select all that are categories of neurotransmitters based on chemical composition.

-Amino acids -Monoamines -Acetylcholine -Neuropeptides

Choose all the factors that influence the speed of nerve signal conduction.

-Diameter of axon -Presence of myelin

Beginning at the top, indicate the order of events that are initiated in an adrenergic synapse, after norepinephrine binds to its receptor

-G protein dissociates from receptor protein -G protein binds to adenylate cyclase -Adenylate cyclase is activated -ATP is converted to cyclic AMP by adenylate cyclase -Cyclic AMP induces multiple effects in the cell

Choose all the ways neuromodulators alter synaptic transmission.

-Increasing the release of neurotransmitters by presynaptic neurons -Altering the breakdown and/or reuptake of neurotransmitter -Adjusting the sensitivity of postsynaptic neurons to neurotransmitters

Beginning at the top, place these events into the order in which they occur during a single action potential.

-Local potential depolarizes membranes -Threshold is reached -Depolarization -Repolarization -HYperpolarization

Choose all that are usually found inside the cell body (or soma) of a mature neuron.

-Nucleus -Mitochondria -Rough endoplasmic reticulum

Which types of glial cells are found in the central nervous system?

-Oligodendrocytes -Astrocytes -Microglia -Ependymal cells

Choose all of the following that may be the result from inhibitory postsynaptic potentials.

-Opening Cl- channels -Opening K+ channels

Starting with a signal reaching the distal end of the presynaptic axon, indicate the correct order of events that occur during transmission at a cholinergic excitatory synapse.

-Opening of calcium gate sin synaptic knobs as nerve signal arrives -Exocytosis of ACh; diffusion across synaptic cleft -BInding of ACh to receptors on postsynaptic neuron -OPening of sodium gates post-synaptic membrane allowing influx of sodium -Depolarization of postsynaptic plasma membrane

Choose all that are names for the cell body of a neuron.

-Soma -Neurosoma

Choose all the statements that characterize neurotransmitters?

-They are synthesized by presynaptic neurons. -They are released in response to stimulation. -They bind to receptors and alter the physiology of the postsynaptic cell.

Choose all that are characteristics of neuroglia.

-They bind neurons together and provide a supportive scaffold. -They protect the neurons and help them function.

Choose all statements that are true about Schwann cells?

-They form the myelin sheath in the PNS. -They assist in the regeneration of damaged nerve fibers. -They form the neurilemma.

Which type of cell plays a role in the establishment of the blood-brain barrier?

Astrocyte

Which process of a neuron is specialized for rapid conduction of nerve signals to structures relatively far away from the neuron cell body?

Axon

Which term applies to the small swellings at the distal end of the axon of a neuron that contain synaptic vesicles?

Axon terminals

At a GABA-ergic synapse, the postsynaptic receptor for the GABA neurotransmitter is which type of channel?

Chloride

Inhibitory postsynaptic potentials is usually due to the opening of which type of ion channels?

Chloride or potassium

The processes of a neuron that usually receive signals from other neurons are called ___.

Dendrites

The processes that branch from the somas of most neurons are called ______.

Dendrites

The soma of a neuron gives rise to branch-like processes called what? They are the primary sites for receiving signals from other neurons.

Dendrites

Which term refers to the upward change in membrane potential during an action potential?

Depolarization

Which glial cell produces and helps circulate cerebrospinal fluid?

Ependymal cells

List the fundamental physiological properties of neurons.

Excitability, conductivity, secretion

True or false: Signal conduction is faster in unmyelinated axons because myelin increases the capacitance of the membrane.

False

cells protect the neurons and help them function.

Glial

The opposite of facilitation is presynaptic ___. This is a mechanism in which one presynaptic neuron suppresses another one.

Inhibition

The trigger zone includes the axon hillock and the ___ segment, a region between the axon hillock and the first glial cell.

Initial

Which term refers to the segment of an axon between the axon hillock and the first glial cell?

Initial segment

The myelin sheath is a spiral layer of ______ around a nerve fiber.

Insulation

Between the nodes of Ranvier are myelin-covered segments of axon encircled by Schwann cells. Which term refers to these segments?

Internodes

The myelin sheath is composed mostly of which of the following?

Lipids

Neuroglial cells that act as macrophages within the CNS are ______.

Microglia

Which type of glial cells in the central nervous system fight microorganisms and destroy foreign matter and dead nervous tissue?

Microglia

Which alter synaptic transmission by adjusting the sensitivity of postsynaptic neurons to neurotransmitters or by affecting the breakdown and/or removal of a neurotransmitter?

Neuromodulators

Which term refers to the gaps between segments of myelin along an axon?

Nodes of Ranvier

Which glial cell insulates nerve fibers from extracellular fluids and speeds up signal conduction in the brain?

Oligodendrocyte

In the CNS, myelin is produced by glial cells called

Oligodendrocytes

GABA has an inhibitory effect on postsynaptic neurons because it does which of the following?

Opens chloride channels

At a synapse, the neuron that responds to the neurotransmitter is the ______ neuron.

Postsynaptic

At a synapse, the neuron that releases neurotransmitter is the ______ neuron.

Presynaptic

The ability of a neuron to enhance the effect of another neuron is called what?

Presynaptic facilitation

Propagation of an action potential down a myelinated axon in which the action potential appears to "jump" from node to node is called ___ conduction.

Saltatory

Glial cells in the peripheral nervous system that surround somas of neurons in the ganglia, provide electrical insulation, and regulate the chemical environment of neurons are which of the following?

Satellite

Match each glial cell type with its location and function.

Satellite cells <--> In the PNS; surround somas of neurons in ganglia, provide electrical insulation, and regulate the chemical environment of neurons Schwann cells <--> In the PNS; form neurilemma around all PNS fibers and myelin around most of them; aid in regeneration of damaged nerve fibers. Ependymal cells <--> In the CNS; line cavities of the brain and spinal cord; secrete and circulate CSF Microglia <--> In the CNS; phagocytize microorganisms, foreign matter, and dead nervous tissue

Which type of glial cell produces the myelin sheath in the PNS?

Schwann cell

Which two types of neuroglia are found only in the peripheral nervous system?

Schwann cells and satellite cells

The release of a neurotransmitter is an example of which physiological property exhibited by a neuron?

Secretion

Which is true about a neuron with a large diameter, myelinated axon as compared to a neuron with a small diameter, unmyelinated axon?

Signal conduction will be faster

Excitatory postsynaptic potentials (EPSPs) are usually due to the entry of which type of ion?

Sodium

What type of summation results when EPSPs occurring at multiple synapses add up to threshold at the axon hillock?

Spatial

When EPSPs from several synapses add up to threshold at the axon hillock, this process is called what?

Spatial summation

Which term refers to summation that results from a single synapse firing rapidly in sequence?

Temporal

When a single synapse generates EPSPs so quickly that each is generated before the previous one fades, what is this process called?

Temporal summation

At its distal end, an axon has an extensive complex of fine branches called what?

Terminal arborization

Which of the following are characteristic of presynaptic inhibition?

The inhibiting neuron causes the stimulating neuron to release less neurotransmitter onto the responding neuron.

When do EPSPs usually occur?

When sodium channels open