Chapter 11 SB

Select all that apply Identify the phases of an action potential.

Afterpotential Depolarization Repolarization

Select all that apply Differentiate graded potentials and action potentials. Select all that apply.

-Graded potentials are conducted in a decremental fashion and action potentials are conducted with a constant magnitude. -The magnitude of graded potentials is variable and action potentials are all-or-none.

Click and drag on elements in order Place the events of action potential propagation in an unmyelinated axon.

1. Generation of an initial action potential. 2. generation of a local current in membrane adjacent to initial action potential. 3. Plasma membrane adjacent to initial action potential depolarizes. 4. Plasma membrane reaches threshold. 5. Generation of next action potential.

Which cell type is not found in the peripheral nervous system?

Astrocyte

Identify the descriptor that is NOT a structural type of neuron.

Afferent neuron

How do neurotransmitters move across a synaptic cleft?

Diffusion

Select all of the cell types that are components of the nervous system. Glial cells Neurons Myoglia Neurite

Glial cells Neurons

______ potentials are conducted in a decremental fashion, while ______ potentials are conducted with a constant magnitude.

Graded, action

Identify the primary site of protein synthesis within neurons.

Nissl bodies

Explain why the propagation of action potentials occurs in one direction.

The absolute refractory period prevents the generation of an action potential in the reverse direction.

Large, negatively charged proteins inside the cell ______ readily diffuse across the neuron membrane.

cannot

Proteins ______ easily diffuse across the cell membrane.

cannot

The brain and spinal cord are the two components of the ______.

central nervous system

Axoplasm

cytoplasm of an axon

Increasing the plasma membrane's permeability to calcium will cause the cell to ______.

depolarize

Cytoplasm ______ electrically neutral.

is

Central and peripheral are divisions of the ______

nervous system

In response to an action potential, voltage-gated calcium channels ______ in the presynaptic cell's axon terminal.

open

Multipolar is a ______ classification for a neuron.

structural

The intracellular fluid is considered to be electrically neutral because ______.

there are the same number of positively and negatively charged ions

Place in order the events of the propagation of an action potential in a myelinated axon. Start with the generation of an action potential.

1. An initial action potential is generated. 2. Local currents are generated. 3. Local currents flow to the next node of Ranvier. 4. Local currents promote depolarization. 5. Threshold is reached in the membrane. 6. The next action potential is generated.

Multipolar neuron

A neuron that has many dendrites and one axon

Unipolar neuron

A neuron with a single process that divides into two branches

Bipolar neuron

A neuron with one dendrite and one axon

The difference in electrical charge across the plasma membrane in an unstimulated cell is called the _______________ _________________ potential.

Blank 1: resting Blank 2: membrane

Select the components of the central nervous system.

Brain and spinal cord

Predict the effects on membrane potential if the membrane's permeability to calcium increases.

Calcium would diffuse into the cell, causing a depolarization.

Presynaptic terminal

Enlarged end of axon containing vesicles filled with neurotransmitters

True or false: During the absolute refractory period a neuron will be re-stimulated if it reaches threshold.

False

What is the nature of the signal that propagates along neurons that ultimately regulates and coordinates the functions of the body?

It is electrical.

______ is the electrolyte that has the greatest influence on resting membrane potential due to the greater permeability of the plasma membrane to this electrolyte.

Potassium

During an EPSP, an influx of ______ occurs.

Sodium

Which part of the central nervous system is with the vertebral canal?

Spinal cord

Select the item that best defines the soma of a neuron.

The cell body of neuron

Select all that apply Identify the characteristics of action potentials.

The strength of the stimulus determines the frequency of the action potentials. They are all-or-none. They are propagated in a non-decremental fashion.

True or false: The potential difference is caused by a difference in concentration of charged particles on either side of the cell membrane.

True

Which type of axon uses continuous conduction of action potentials?

Unmyelinated

Which channels are highly concentrated in the nodes of Ranvier?

Voltage-gated sodium channels

Electrical signals produced by the nervous system are called _______________ potentials.

action or graded

In the nervous system, the term ______ refers to signal conduction toward the CNS.

afferent

The sensory division is synonymous with the ______ division of the nervous system.

afferent

Glands, smooth muscles, and cardiac muscles are innervated by the ______ division of the motor nervous system.

autonomic

Within a chemical synapse, the receptors ______.

bind to very specific ligands

Closed voltage-gated sodium channels are stabilized ______.

calcium

The type of action potential conduction in an unmyelinated axon is ______ conduction.

continuous

An increase in a membrane's permeability to Na+ will result in ______ of the membrane.

depolarization

The concentrations of ions in the cytoplasm of neurons is ______ the concentrations of ions outside the cells.

different than

The motor division is also known as the _____________ division of the nervous system.

efferent

The somatic and autonomic nervous systems are subdivisions of the ______.

efferent division

Supporting cells such as oligodendrocytes and ependymal cells are examples of ______ cells

glia

The support cells of the nervous system are called ______.

glia cells

Hyperpolarization of a postsynaptic neuron in response to a neurotransmitter is called an ______ postsynaptic potential.

inhibitory

An excitatory local potential will make the neuron _____ likely to generate a nerve impulse.

more

Action potentials are conducted more rapidly along ______ axons.

myelinated

When the resting membrane potential becomes more ______ the condition is referred to as hyperpolarization.

negative

Action potentials propagate in ______ along the axon.

one direction

During an EPSP, sodium channels ______.

open

All of the nervous tissue outside the central nervous system is categorized as belonging to the ______ nervous system.

peripheral

The subdivision of the nervous system that is responsible for detecting stimuli in and around the body and sending that information to the central nervous system is the ______.

peripheral nervous system

When a charge difference exists across the plasma membrane, this difference is referred to as the membrane _______________.

potential

A period of time after a nerve cell has responded to a stimulus in which it cannot be re-excited by a threshold stimulus is called a(n) ______ period.

refractory

Propagation of an action potential down a myelinated axon requires that the action potential "jumps" from node to node in a process called ______ conduction.

saltatory

The propagation of action potentials from one node of Ranvier to another along a myelinated axon is called ______ conduction.

saltatory

Dendritic spines are ______ of dendrites.

small extensions

Indicate the correct order of events that occur during a single action potential.

1. Local potential decreases membrane potential. 2. Threshold is reached. 3. Depolarization spike occurs. 4. Repolarization occurs. 5. Afterpolarization occurs. 6. Resting membrane potential re-established.

The general types of cells that make up the nervous system are __________and ____________cells.

Blank 1: neurons or neuron Blank 2: neuroglia, glial, supportive, nonneural, or glia

On myelinated axons, small gaps exist between adjacent Schwann cells; these gaps are known as __________of _____________ .

Blank 1: nodes Blank 2: Ranvier

True or false: Na+ has the greatest influence on resting membrane potential due to its high permeability in the membrane.

False

True or false: Once achieved, a single action potential can travel the distance of the entire axon of the neuron.

False

True or false: Summation of all incoming signals occurs at the axon terminus of a neuron.

False

What are the divisions of the motor division of the peripheral nervous system?

Somatic and autonomic

The central nervous system is ______.

a key decision maker

Dendrites are extensions of ______ of a neuron.

cell body

soma

cell body

The highly branched cytoplasmic extensions of a neuron cell body that are specialized to receive input and conduct signals toward the cell body are called ______.

dendrites

The speed of action potential conduction along an axon ______ on the myelination of the axon. Multiple choice question.

depends

Sodium ions move into a neuron during ______.

depolarization

During an action potential, an increase in membrane permeability to Na+ leads to a(n) ______ followed by an increase in permeability to K+ that leads to a(n) ______ of the membrane and a slight afterhyperpolarization.

depolarization, repolarization

When the neuron membrane becomes less negative than the resting membrane potential, it is said to be ______.

depolarized

Depolarization of a postsynaptic neuron in response to a neurotransmitter is called an __________________ postsynaptic potential.

excitatory or excited

The entry of calcium into the synaptic knob triggers ______.

exocytosis of neurotransmitter

A group of related nerve cell bodies is located outside of the central nervous system. It is called a ______.

ganglia

Groups of nerve cell bodies located outside the central nervous system are called

ganglia

The knotlike swelling in a nerve where neuron cell bodies are found is called a ______.

ganglion

As the strength of a stimulus increases, the magnitude of a graded potential will ______.

increase

During depolarization, the ______ of the cell becomes more positive.

inside

Neurons that are found between an afferent pathway and an efferent pathway are called

interneurons

A synapse is a

junction between two cells

A hyperpolarizing local potential will make the neuron ______ likely to generate a nerve impulse.

less

A refractory period is a time in which the plasma membrane becomes ______ to further stimulation.

less sensitive

An excitatory local potential will make the neuron ______ likely to generate a nerve impulse.

more

Glial cells are ______ numerous than neurons in the brain.

more

The efferent division of the peripheral nervous system is also called the ______ division.

motor

Action potentials are conducted more rapidly along ______ axons. Multiple choice question.

myelinated

The cells that account for over half of the brain's weight and outnumber neurons by at least 10 times are called ___________ cells.

neuroglial, neuroglia, glial, or glia

Synaptic vesicles within synaptic knobs contain chemicals called

neurotransmitters

Resting membrane potential is measured using a(n) ______.

oscilloscope

Schwann cells and satellite cells are examples of neuroglial cells in the ______ nervous system.

peripheral

The second neuron at a synapse (where the neurotransmitter binds) would be the ______ neuron.

postsynaptic

The target cell receiving a signal from a cell is called the __________cell.

postsynaptic

Nissl bodies in neurons are the primary site of ______ synthesis.

protein

Action potentials are produced when graded potentials ______

reach threshold

The afferent division of the peripheral nervous system is also called the ______ division.

sensory

Excitable cells operate through the movement of ions across ______.

the plasma membrane

Afferent neurons carry information ______.

toward the CNS

Once stimulated, a single action potential ______.

travels only a short distance before stimulating another action potential

The normal site for action potential generation for most neurons is the

trigger zone

The normal site for action potential generation for most neurons is the ______.

trigger zone

Within a neuron, summation of all incoming signals occurs at the

trigger zone

Within a neuron, summation of all incoming signals occurs at the ______.

trigger zone

An action potential is initiated immediately adjacent to where the last action potential terminated in ______ axons.

unmyelinated

An ion channel that opens when a specific electrical current is present on the cell membrane would be categorized as _______________ -gated.

voltage

The movement of ions across the cell membrane can change the charge difference across that membrane and stimulate ______.

voltage gated channels to open

The central nervous system consists of the_____________ , which is found within the__________________ skull, and the_______________ , which is found within the vertebral column.

1: brain 2: spinal 3: cord

Identify the type of synapse that includes a presynaptic cell, synaptic cleft, and postsynaptic cell.

Chemical

Motor neuron

Conducts impulses away from the CNS

Interneuron

Conducts impulses from one neuron to another neuron within the CNS

Sensory Neuron

Conducts impulses towards the CNS

______ occurs when the inside of the plasma membrane becomes more negative, and ______ occurs when the inside of the plasma membrane becomes less negative.

Hyperpolarization, depolarization

Which of the following is NOT one of the phases of an action potential?

Hyperpotential

Name the type of neuron found between an afferent pathway and an efferent pathway.

Interneuron

When Na+ channels open, what happens to the Na+ ions?

Na+ diffuses into the cell.

Explain why Na+ ions diffuse into the neuron when the Na+ channels open.

Na+ is more concentrated outside the cell than inside; hence, the concentration gradient causes diffusion into the cell.

What is the name of the gaps found between segments of myelin along an axon?

Nodes of Ranvier

Identify the correct sequence of information in a chemical synapse.

Presynaptic terminal, synaptic cleft, postsynaptic membrane

Select all that apply Identify the structural types of neurons. Interneuron Pseudo-unipolar Efferent neuron Multipolar neuron Bipolar neuron Afferent neuron

Pseudo-unipolar Multipolar neuron Bipolar neuron

Nissl body

Rough endoplasmic reticulum of a neuron responsible for protein synthesis

Select all that apply Describe characteristics of receptors at the synapses. Select all that apply.

They are ligand activated receptors Only specific molecules are able to bind to the receptors

Identify the statement that best describes the characteristics of a voltage-gated ion channel.

They open and close in response to a specific voltage change across the plasma membrane.

Myelin sheaths are ______ in nodes of Ranvier.

absent

The electrical signals that are propagated along axons, regulating and coordinating body activities, are known as ______.

action potentials

The self-governing division of the motor division of the nervous system is the ______ nervous system.

autonomic

Entry of ______ ions into the synaptic knob triggers exocytosis of neurotransmitters.

calcium

Acetylcholine ______ bind to norepinephrine receptors.

cannot

The division of the nervous system that is the key decision maker of the body is the ______ nervous system.

central

The ______ are the two major subdivisions of the nervous system.

central and peripheral nervous systems

Synapses in which neurotransmitters are released are called ______ synapses.

chemical

The type of synapse that occurs when a neurotransmitter is used to communicate a message to an effector is called a(n) _________ synapse.

chemical

In the region of the plasma membrane immediately adjacent to the area where the last action potential occurred, the entry of positive ions stimulates a new action potential. This kind of conduction is known as ______ conduction.

continuous

During an action potential of a neuron, the type of ion that enters the cell and causes depolarization is the _________ ion.

sodium, Na, or Na+

During an action potential, depolarization is due to ______ ions ______ the cell.

sodium, entering

The cell body of a neuron is also known as the

soma, neurosoma, or perikaryon

Select all that apply The motor divisions of the peripheral nervous system is further divided into the ______ subdivisions. afferent somatic autonomic efferent

somatic autonomic

Small extensions off a dendrite surface are called dendritic

spines

The point of contact between an axon and its target is called a(n) ______.

synapse

The small, membrane-bound organelles that are found in the presynaptic terminals and which contain neurotransmitters are called

synaptic vesicles