A&P 1 - SB Chapter 12

During axonal transport, motor proteins transport material as they crawl along microtubules. Match the type of axonal transport with its corresponding motor protein. -Kinesin -Dyein -Retrograde transport -Anterograde transport

-Kinesin: Anterograde transport -Dyein: Retrograde transport

Beginning at the top, place these events into the order in which they occur during a single action potential. -Repolarization -Depolarization spike -Hyperpolarization -Local potential depolarizes membrane -Threshold is reached

-Local potential depolarizes membrane -Threshold is reached -Depolarization spike -Repolarization -Hyperpolarization

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

-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.

Choose all of the following statements that are true about signal conduction along unmyelinated fibers. -A zone of depolarization excites voltage-gated channels immediately distal to the action potential. -The signal conduction in unmyelinated fibers is saltatory. -Unmyelinated fibers have voltage-gated channels along their entire length.

-A zone of depolarization excites voltage-gated channels immediately distal to the action potential. -Unmyelinated fibers have voltage-gated channels along their entire length.

What is the approximate ratio of glial cells to neurons?

10:1

Which best describes an electrical potential? -The movement of charged particles like ions -A positively or negatively charged atom or molecule -A form of potential energy that can produce current -The opposition to the flow of electrical current across a membrane

A form of potential energy that can produce current

Description of Axon hillock

A mound located on one side of the soma from which the axon originates

A local potential is what type of change in voltage?

A short-range change only

Which best describes signal conduction in unmyelinated axons? -The entire axon depolarizes at the same time. -A local potential is passively conducted down the entire length of the axon. -A wave of depolarization opens more voltage-gated channels immediately distal to the action potential. -The signal is transmitted from one node of Ranvier to the next through saltatory conduction.

A wave of depolarization opens more voltage-gated channels immediately distal to the action potential.

Choose all that would cause postsynaptic stimulation to end. -Diffusion of neurotransmitters from the synaptic cleft into ECF. -Addition of receptors onto the presynaptic membrane. -Enzymatic degradation of neurotransmitters in the synaptic cleft. -Cessation of signals in the presynaptic nerve fiber. -Reuptake of neurotransmitter into the presynaptic knob.

All but: Addition of receptors onto presynaptic membrane

Movement away from the neuron cell body toward an axon ending is called _____ transport.

Anterograde

Which cells of the CNS can absorb stray neurontransmitters?

Astrocytes

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

Axon terminals

Description of Axon collateral

Branch that originates from an axon

Which are the sites of learning and memory? Chemical or electrical synapses

Chemical synapses

Which fundamental physiological property of neurons allows them to send signals quickly over long distances?

Conductivity

Description of Axoplasm

Cytoplasm of the axon

The processes of a neuron that usually receives signals from other neurons are called _____.

Dendrites

Which two organ systems are primarily responsible for coordinating the other bodily systems so as to maintain homeostasis? -Cardiovascular system -Endocrine system -Nervous system -Immune system

Endocrine system and nervous system

Two organ systems are dedicated to internal coordination, communication between the other systems, and maintaining the overall homeostasis of the body. They are the _____ system, which communicates by means of hormones, and the _____ system which sends quick electrical and chemical messages from cell to cell.

Endocrine; Nervous

True or false: Damaged nerve fibers in the CNS regenerate very fast whereas damaged nerve fibers in the PNS never regenerate.

False: Damaged nerve fibers in the CNS cannot regenerate at all, but since the CNS is enclosed in bone, it suffers less trauma than the PNS. Regeneration in the PNS is facilitated by Schwann cells. It may be slow and not always perfect process.

True or false: Electrical synapses are able to integrate information and make decisions more rapidly than chemical signals.

False: Electrical synapses have the advantage of quick transmission, but they cannon integrate information and make decisions.

In electrical synapses, electrical signals move more quickly from cell to cell through which of the following? -Gap junctions -Na+-K+ pumps -Voltage-gated ion channels -Neurotransmitter receptors

Gap junctions

Where are unmyelinated axons found?

In both the central and peripheral nervous system

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

Insulation

Choose the three functional classes of neurons. -Interneurons -Multipolar neurons -Motor neurons -Unipolar neurons -Sensory neurons

Interneurons Motor neurons Sensory neurons

Which of the following would have the fasted conduction speed? -Small unmyelinated axon -Small myelinated axon -Large myelinated axon

Large myelinated axon

Which term refers to decremental changes in electrical potential along a dendrite or the soma?

Local potentials

The structure that consists of spiral layers of insulation around an axon is called a(n) _____ sheath.

Myelin

Sensory, inter, and motor are three classes of _____.

Neurons

Which type of glial cells are found in the central nervous system? -Oligodendrocytes -Satellite cells -Microglia -Astrocytes -Ependymal cells -Schwann cells

Oligodendrocytes Microglia Astrocytes Ependymal cells

Description of Axolemma

Plasma membrane of the axon

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

Postsynaptic

The neuron that responds to the presynaptic neuron is called the _____ neuron.

Postsynaptic

The plasma membrane is most permeable to which of the following ions?

Potassium

Which ion has the greatest influence on the resting membrane potential of most neurons?

Potassium

An electrical potential is a form of what type of energy?

Potential energy

Choose all the factors that influence the speed of nerve signal conduction. -Presence of myelin -Size of soma -Diameter of axon -Type of neuron (multipolar vs. unipolar)

Presence of myelin and diameter of axon

Which term refers to the period of time after a nerve cell has responded to a stimulus in which it cannot be excited by a threshold stimulus?

Refractory period

The refractory period in which it is possible to trigger a new action potential, but only with an unusually strong stimulus is the _____ refractory period.

Relative

Choose all that are usually found inside the cell body (or soma) of a mature neuron. -Rough ER -Mitochondria -Synaptic vesicles -Centrioles -Nucleus

Rough ER Mitochondria Nucleus

Which type of glial cell aids in regeneration of damaged peripheral nerve fibers by forming a regeneration tube to help reestablish the former connection?

Schwann cells

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

Secretion

What are dendrites or neurons?

Sites for receiving signals from other neurons

Choose all that are names for the cell body of a neuron. -Ganglion -Inclusion -Soma -Astrocyte -Neurosoma

Soma and neurosoma

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

Terminal arborization

Choose all that are characteristics of neuroglia. -They are less numerous than neurons -They protect the neurons and help them function -They bind neurons together and provide a supportive scaffold -Their main properties are excitability and conductivity

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

The minimum amount of voltage needed to open voltage-gated channels on an axon is called what?

Threshold

An axon lacking a myelin sheath is said to be what?

Unmyelinated