A & P Chapter 11 & 12

The nervous system A. monitors internal and external stimuli. B. transmits information in the form of action potentials. C. interprets or assesses information. D. maintains homeostasis. E. All of these choices are correct.

All of these choices are correct

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

Chemical

In hyperpolarization

K+ ions tend to diffuse out of the cell

A change in resting membrane potential confined to a small area is called a(n)

Local potential

The motor neurons responsible for making a fist are

Multipolar

Identify the correct sequence of information in a chemical synapse.

Presynaptic terminal; synaptic cleft; postsynaptic membrane

Schwann cells differ from oligodendrocytes in which of the following ways?

Schwann cells form a myelin sheath around a portion of only one axon, while oligodendrocytes can surround portions of several axons

Depolarization of the nerve cell membrane occurs when there is a rapid influx (inflow) of

Sodium Ions

Axons contain:

trigger zone

A change in the resting membrane potential has the following characteristics (non-propagated, graded, can summate). This type of change can

be a local potential and a consequence of an increase in the permeability to Na+.

Neurons that have a single axon and a single dendrite are

bipolar

choose all that apply:Identify the phases of an action potential.

depolarization, hyperpolarization, repolarization

Monamine oxidase inhibitors (MAO inhibitors)

enhance the binding of norepinephrine to its receptors.

What inhibitory neurotransmitter is blocked in strychnine poisoning?

glycine

An IPSP is inhibitory because it

hyperpolarizes the postsynaptic membrane

Which of the following statements accurately describe events that occur as a result of a local potential reaching threshold?

A positive feedback cycle develops in which depolarization causes activation gates of Na+ ion channels to open.

A neuron within the central nervous system that carries action potentials from one neuron to another is called a(n)____________.

interneuron

A neuromodulator

is a substance released from neurons that influences the sensitivity of neurons to neurotransmitters.

The opening of more and more Na+ ion channels during depolarization

is an example of a positive feedback cycle.

During the absolute refractory period, the cell

is insensitive to further stimulation

The central nervous system

is the site for processing information

For the resting membrane potential, increasing the sodium ion concentration in the ECF results in

little change in membrane potential

microglia:

macrophages in CNS

Match the term with the correct definition.

membrane becomes more positive when sodium ions diffuse into cell

depolarization:

membrane becomes more positive when sodium ions diffuse into cell

choose 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.

If you cut bundles of axons and their myelin sheaths in the PNS, you cut

nerves

Compounds classified as ______ alter synaptic transmission by changing neurotransmitter receptor numbers or affecting the breakdown and/or removal of neurotransmitter.

neuromodulators

Clusters of gray matter deep within the brain are called

nuclei

potassium ions:

plasma membrane is more permeable to this ion because of leak ion channels

Neurotransmitters are released from the

presynaptic terminal

ependymal cells:

produce cerebrospinal fluid

What type of neuroglial cells provide support and nutrition to sensory ganglia in the PNS?

satellite cells (P)

Nissl bodies are

areas of rough endoplasmic reticulum.

LouAnn is being treated for a neurological condition with a specific drug that target neurons deep within the brain. Which glial cell must be bypassed by this drug in order for it to be effective?

astrocyte

There are _____ pairs of cranial nerves and _____ pairs of spinal nerves.

12;31

Viagra is used to treat erectile dysfunction by prolonging the effects of _____ on blood vessels

nitric oxide (NO)

Gaps or interruptions in the myelin sheath are called

nodes of ranvier

An action potential

occurs when the local potential reaches threshold level.

Multiple sclerosis is a neurological disorder in which myelin sheaths in the CNS are destroyed. Which of the following neuroglial cells is being damaged in multiple sclerosis?

oligodendrocyte

Continuous conduction of an action potential means that

one action potential stimulates the production of a new action potential at the adjacent site.

When repolarization of a neuron is complete, the

original polarity of the neuron is restored

Which type of circuit is associated with complex neuronal processes, such as solving mathematical equations?

parallel after-discharge

Digestion of food is regulated by the

parasympathetic division of the ANS

Synaptic vesicles contain neurotransmitters and are present in the

presynaptic terminals

repolarization:

return to the resting membrane potential

Neurons arranged in a circular pathway form

reverberating circuits

Which of the following is NOT a neuroglia of the CNS?

satellite cells

A neuron that conducts pain sensations to the central nervous system would be classified as a(n)

sensory or afferent neuron.

The junction between two neurons is a

synapse

The junction of a neuron with another cell is a/an

synapse

Gray matter on the surface of the brain is/are called

the cortex

The plasma membrane of a neuron is more permeable to potassium ions because

there are more leak ion channels for K+ than Na+.

In some cells, an afterpotential occurs because

there is prolonged, elevated permeability to potassium during repolarization.

In order for local potentials to trigger an action potential, the membrane must reach a level called the ______.

threshold

The motor (efferent) division of the peripheral nervous system

transmits impulses from the CNS to skeletal muscle.

Action potentials at a chemical synapse

travel from presynaptic terminal to presynaptic membrane.

True or False: The nervous system and the endocrine system are the major control systems of the body.

true

Which of the following is responsible for problem-solving skills?

Central Nervous Sytem

choose all that apply:Identify the mechanisms by which neuromodulators alter synaptic transmission.

Changing neurotransmitter receptor numbers. Affecting breakdown of neurotransmitters. Affecting the removal of neurotransmitters.

When two or more presynaptic neurons synapse with a single postsynaptic neuron in the CNS, a(n) _______ pathway is formed.

Convergent

true/false: Gray matter consists of bundles of myelinated axons

False

A person who has seizures might have a deficit of which of the following?

GABA

Cell bodies of the peripheral nervous system are located in

Ganglia

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

Ganglia

Identify the statement that best differentiates gray matter and white matter.

Gray matter consists of cell bodies and dendrites whereas white matter consists mostly of myelinated axons

Mr. Miller has been hospitalized for the flu. The flu virus increases membrane permeability to potassium. You would expect his cells to

Hyper polarize

large molecules trapped inside cell

Negatively charged proteins

Which of the following statements regarding neuroglia is false?

Neuroglia produce action potentials for skeletal muscles

Which of the following is true?

The resting membrane potential is proportional to the tendency for K+ to diffuse out of the cell

resting membrane potential

a charge difference across the plasma membrane when the cell is in an unstimulated state

action potential:

a larger change in resting membrane potential that spreads over entire surface of a cell

If the ECF around a nerve cell is replaced with an isotonic saline solution that contains potassium ions and other solutes at concentrations very close to the ECF concentrations of a normal cell, the result is

a resting membrane potential close to its normal value.

local potential:

a small change in the resting membrane potential confined to a small area

What is the only neurotransmitter released at the neuromuscular junction?

acetylcholine

The absolute refractory period assures

completion of repolarization before another action potential.

higher on the inside of the cell membrane?

concentration of potassium

higher outside the cell

concentration of sodium and chloride

choose all that apply:Identify the functions of the nervous system.

controlling muscles and glands. integrating information. receiving sensory input.

The respiratory center of the brain (taking into account input from chemoreceptors, pulmonary stretch receptors and higher centers of the brain to determine respiratory output) is an example of a ______ circuit.

converging

The sensory (afferent) division of the peripheral nervous system

conveys action potentials to the CNS.

The gray matter of the cerebrum is composed of neuron cell bodies and makes up both the ______ and the ______.

cortex ; deep cerebral nuclei

The peripheral nervous system includes the

cranial nerves

Enkephalins produce presynaptic inhibition in neurons transmitting pain signals. Increased levels of enkephalins will

decrease awareness of pain

Receptor molecules

determine whether a neurotransmitter will be excitatory or inhibitory

An inhibitory postsynaptic potential (IPSP) can result from the

either influx of chloride or outflow of potassium ions.

Gap junctions are functional __________ synapses.

electrical

Synapses in which gap junctions allow ions to diffuse quickly from cell to cell are called ______ synapses.

electrical

Hydrocephaly is a condition whereby cerebrospinal fluid accumulates around the brain. What supportive cells continue CSF production despite it backing up in the subarachnoid space?

ependymal cells

oligodendrocyte:

form myelin sheath around axons in CNS

schwann cell:

form myelin sheath around part of the axon in the PNS

Action potentials are conducted more rapidly when transmission is

from node to node on a myelinated axon.

The autonomic nervous system

has two sets of neurons in a series

Axons:

have a distal portion that branches to form the presynaptic terminals.

Receptor molecules in synapses

have a high degree of specificity.

When a neuron releases a neuromodulator that _____ the release of neurotransmitters from another neuron, this is called presynaptic facilitation.

increases/facilitation

astrocytes:

influence function of blood-brain barrier

Local hyperpolarization in a synapse is called a(an)

inhibitory postsynaptic potential

Damage to a postsynaptic membrane would

interfere with the ability to respond to neurotransmitter.

In an EPSP (excitatory postsynaptic potential), there is a

local depolarization

Arrange the events of synaptic transmission in correct sequence. (1) sodium ions diffuse into the cell and cause a local potential (2) neurotransmitter binds with receptor on postsynaptic cell (3) neurotransmitter diffuses across the synaptic cleft (4) membrane permeability to sodium ions on postsynaptic cell increases (5) action potential causes release of neurotransmitter

5, 3, 2, 4, 1

The absolute refractory period ends when

A. inactivation gates of voltage-gated Na+ ion channels reopen.

Which of the following statements regarding voltage-gated K+ channels is true? A. These channels have only one gate. B. These channels open more slowly than Na+ channels. C. Once open, these channels remain open until repolarization is complete. D. These channels are specific for potassium. E. All of these statements are true.

All of these statements are true.

Neurotransmitter is being released at a synapse. Which of the following occurs last?

An action potential is produced in the postsynaptic membrane

Which of the following events is NOT a characteristic of an action potential?

As sodium ions enter, the inside of the plasma membrane becomes more negative

Each voltage-gated Na+ ion channel has two voltage sensitive gates: an activation gate and an inactivation gate. Which of the following would occur during depolarization?

Both activation and inactivation gates are open

What ion is necessary for the release of neurotransmitter from synaptic vesicles?

Calcium

Voltage-gated sodium channels are sensitive to changes in the extracellular concentration of

Calcium ions

Which of the following situations occurs in electrically excitable cells?

Depolarization causes voltage-gated sodium ion channels to open.

The enteric nervous system consists of plexuses within the walls of the

Digestive tract

Sensory neurons carrying action potentials from pain receptors synapse within the spinal cord with interneurons. These interneurons synapse with motor neurons leading back to an effector and ascending neurons that carry action potentials toward the brain. This is an example of a(n) _____ pathway.

Divergent

Low levels of ___ can have dire consequences on the functioning of neurons because of its role in membrane repolarization.

Potassium Ions

Why isn't an action potential transmitted from a postsynaptic membrane to a presynaptic terminal?

Presynaptic terminals have no acetylcholine receptors.

A decrease in the number of voltage-gated Ca2+ ion channels in the presynaptic terminal would

Reduce or inhibit transmission the synapse across

If five action potentials arrive at the same synapse in very close succession, which of the following would occur?

Temporal summation occurs.

The same neurotransmitter binds to a postsynaptic cell but produces a variety of different effects. What does this mean?

The postsynaptic cell is expressing different types of receptors for the same neurotransmitter.

Which of the following is NOT true about astrocytes?

They can aid in the regeneration of injured neurons.

true/false: Gray matter has little myelination, whereas white matter has abundant myelination.

True

Which of the following is true? A. Unmyelinated axons rest in invaginations of Schwann cells or oligodendrocytes.. B. Myelination will not influence the speed of conduction of action potentials. C. The myelin sheath inhibits the flow of electrical charges at nodes. D. The myelin sheath is a protein wrapping. E. The myelin sheath does not electrically insulate the axons from one another

Unmyelinated axons rest in invaginations of Schwann cells or oligodendrocytes..

Nervous tissue of the CNS that is composed primarily of myelinated axons is often referred to as ______ matter.

White

Saltatory conduction of an action potential means that

an action potential is conducted from one node of Ranvier to the next node.

A stimulus either causes an action potential or it doesn't. This is called

an all-or-none response.

When a neurotransmitter binds to its receptor and increases the permeability of the postsynaptic membrane to sodium ions,

an excitatory postsynaptic potential (EPSP) will result.

Which of the following events will lead to depolarization?

an increase in K+ ions in the extracellular fluid

Dendrites:

are the input part of the neuron

A local anesthetic such as Novocaine decreases membrane permeability to Na+ ions. The use of this anesthetic will

block sensory input into the CNS

The strength of a stimulus is communicated through

both the frequency and the length of time action potentials are produced.

The function of acetylcholinesterase is to

breakdown acetylcholine in the synapse.

White matter is composed of

bundles of myelinated axons

Neurotransmitters:

cause the production of action potentials in the postsynaptic membrane.

Which of the following is NOT true of reactive astrocytosis?

causes the spread of inflammation

Protein synthesis in neurons occurs in

cell bodies or soma

A local potential

increases or decreases in direct proportion to the stimulus strength.

Rapid removal or destruction of neurotransmitter in the synaptic cleft

may affect the ability of the postsynaptic membrane to generate action potentials

Which of the following is mismatched? A. microglia - provide support for the neuron cell body B. astrocytes - blood-brain barrier C. oligodendrocytes - form myelin sheaths D. ependymal cells - produce cerebrospinal fluid E. ependymal cells - choroid plexus

microglia - provide support for the neuron cell body

Fran has a microbial infection attacking his brain. Which cell type would you expect to proliferate and be most active during this time?

microglial cells

Identify the two functional sub-divisions of the peripheral nervous system.

motor division, sensory division

The blood-brain barrier

protects neurons from toxic substances in the blood.

Neurons in the skin that are responsible for detecting pain are

pseudo-unipolar

A decrease in the number of voltage-gated Ca2+ ion channels in the presynaptic terminal would

reduce or inhibit transmission across the synapse

A neuron is receiving a stimulus which gets stronger and stronger. The result is

requency of occurrence of action potentials increases.

During depolarization of the plasma membrane

sodium ions move rapidly into the cell.

What requires ATP?

sodium/potassium pump

Which of the following is mismatched? A. central nervous system - brain B. autonomic nervous system - sympathetic and parasympathetic divisions C. peripheral nervous system - spinal nerves D. somatic nervous system - sensory division of PNS E. peripheral nervous system - sensory and motor divisions

somatic nervous system - sensory division of PNS

When two action potentials arrive simultaneously at two different presynaptic terminals that synapse with the same postsynaptic neuron,

spatial summation occurs

The central nervous system includes the

spinal cord and brain

If the charge difference across the plasma membrane is decreased,

the membrane potential is more positive.

A series of local potentials causes the membrane potential to move to -80 mV. Predict the result.

the neuron is hyperpolarized

Suppose both excitatory and inhibitory neurons synapse with a single postsynaptic neuron. What determines if an action potential is initiated in the postsynaptic neuron?

the number of EPSPs in relation to the number of IPSPs

Chemical synapses are characterized by

the release of neurotransmitter by the presynaptic terminal.