Ch. 12 - nervous tissue

Typically, the resting membrane potential of a neuron is

-70 mV

Initially, the voltage-gated Na+ channels are closed and the membrane potential is ______ mV. As Na+ flows in the membrane potential changes to ______ mV and the threshold is reached. -70; -90 -70; -55 -90; -70 -55; -70

-70; -55

The voltage gated sodium channels undergo changes in activity during the depolarization phase of an action potential. Place them in order from firsr to last. 1. The membrane potential is -70 mv 2. Voltage gated sodium ion channels open 3. Sodium ions flow into the neuron 4. The membrane potential becomes more positive

1, 3, 4, 2

1 is 2 is 3 is 4 is

1. Bipolar neuron 2. Anaxonic neuron 3. Unipolar neuron 4. Multipolar neuron

1 is 2 is 3 is 4 is 5 is

1. Chemically gated channels 2. Leak channels 3. Pump 4. Voltage gated channels 5. Pump

Place the events of an EPSP in order. 3. The inside of the cell becomes more positive 1. Excitatory neurotransmitter binds to chemically gated cation channel 2. More Na+ enters the postsynaptic cell than K+ leaves 4. The local current of Na+ becomes weaker as it moves a towards the axon hillock

1. Excitatory neurotransmitter binds to chemically gated cation channel 2. More Na+ enters the postsynaptic cell than K+ leaves 3. The inside of the cell becomes more positive 4. The local current of Na+ becomes weaker as it moves towards the axon hillock

1 is 2 is 3 is

1. Sensory neuron 2. Interneuron 3. Motor neuron

A is B is C is D is E is

A- axon B- neurolemmocyte C- endoneurium D- perineurium E- epineurium

A is B is C is D is

A- dendrites B- axon C- axon collateral D- terminal extensions

A. B. C. D. E.

A. Dendrite B. Axon hillock C. Telodendria D. Nucleolus E. Synaptic knobs

Pain receptors in the skin send signals to the CNS for processing. These pain receptors are an example of ____ neurons Afferent Association Multipolar Efferent

Afferent

The fundamental physiological properties that enable nerve cells to communicate with other cells are The ability to respond to environmental changes. The ability to produce electrical signals that are quickly conducted to other cells at distant locations. The ability to secrete a chemical that will stimulate the next cell when an electrical signal reaches the end of an axon. All of these choices are correct.

All of these choices are correct

Glycine is a

Amino acid

Movement away from the cell body is

Anterograde transport

Which glial cells is starlike in shape and helps form the blood-brain barrier? Ependymal cells Astrocytes Oligodendrocytes Microglial cells

Astrocytes

Where are synaptic knobs located?

At the distal ends of an axons

Common types of neurons with where they can be found: Special senses

Bipolar neurons

The presence of ___ ions causes the synaptic vesicles to bind to the membrane, allowing neurotransmitters to be released Chloride Calcium Potassium Sodium

Calcium

When a neurotransmitter binds a protein channel, it opens and lets sodium diffuse down its concentration gradient. This is an example of Sodium pump Voltage gated sodium channel Leakage channel Chemically gated sodium channel

Chemically gated sodium channel

Synapses are classified as Electrical synapses Mechanical synapses Chemical synapses

Electrical synapses Chemical synapses

Neuropeptide is a

Enkephalin

____ is a responsiveness to a stimuli Amiotic Excitability Conductivity Secretion

Excitability

The functions of the astrocytes are to Help form the blood-brain barrier Produce cerebrospinal fluid Myelinate axons of the PNS Regulate the composition of the interstitial fluid Assist neuronal development

Help form the blood-brain barrier Assist neuronal development Regulate the composition of the interstitial fluid

Glial cells are found ___ In both the central and peripheral nervous systems Only within the peripheral nervous system Only within the central nervous system

In both the central and peripheral nervous system

The electrical gradient in a resting neuron is such that the ___ of the cell is negative relative to the ___

Inside; outside

During an action potential, voltage-gated potassium channels open after voltage-gated sodium channels. The effect this had on the membrane potential is It becomes less positive and more negative It becomes more positive It has no effect on the membrane potential

It becomes less positive and more negative

Common types of neurons with where they can be found: Most common type; innervate muscles and glands

Multipolar neurons

The threshold is reached when the ____ ions flow into the cell Ca2+ Cl- Na+ K+

Na+

The nerve impulse has the voltage-gated ______ channels opened first followed by the opening of the voltage-gated ______ channels. Na+; K+ K+; Na* Na+; Cl- K+; Cl-

Na+ and K+

Which of the following pumps can you find in the plasma membrane? Ca2+ H+ Na+/K+ Cl-

Na+/K+ Ca2+

A ___ is the propagation of an action potential along an axon Depolarized neuron Graded potential Depolarized neuron Nerve impulse

Nerve impulse

What type of cels produce the myelin sheath in the central nervous system (CNS)? Neurolemmocytes Astrocytes Oligodendrocytes Microglia

Oligodendrocytes

The sequential opening of voltage gated sodium channels is followed by the sequential opening of voltage gated ___ channels

Potassium

The flow of ______ ion is the most common cause of depolarization. Sodium Chloride Calcium Potassium

Sodium

Which of the following membrane transporters are present throughout the membrane of a neuron? Potassium leak channels Voltage gated sodium channels Voltage gated potassium channels Sodium leak channels Na+/K+ pumps

Sodium leak channels Na+/K+ pumps Potassium leak channels

Which part of the neuron contains the nucleus?

Soma

Which part of a neuron contains calcium pumps and channels? Synaptic bulbs Soma Dendrites Axon

Synaptic bulbs

"An action potential either happens or it doesn't" this statement could also be called ___ The threshold law The all-or-none-law The refractory law

The all-or-none law

The two factors that affect PNS regeneration are ____ The amount of damage The distance between injury site and the effector organ Rate of microglial cell division Presence of ependymal cells

The amount of damage The distance between injury and the effector organ

The myelin sheath covers ___ The axon The choroid plexus The nerve The cell body

The axon

Which describes the propagation of depolarization down an axon? Sodium flows into the cell in one region and backs out again at another region The flow of Na+ into adjacent regions causes potassium channels to open Sodium influx triggers sodium efflux The flow of Na+ to downstream regions cause depolarization of adjacent regions

The flow of Na+ to downstream regions causes depolarization of adjacent regions.

What do all glial cells have in common?

They assist neurons in their respective functions

The all-or-none law refers to the fact that action potential will only occur if the initial segment reaches ___

Threshold

TRUE OR FALSE For regeneration of a damaged axon in the PNS, the cell body must be intact

True

True or false: Graded potentials vary in size depending on the stimulus

True

True or false: Voltage gated sodium ion channels are closed initially and the membrane potential is -70 mv

True

Common types of neurons with where they can be found: Most neurons in the PNS

Unipolar neurons

If extracellular calcium was absent, which would likely be true? Vesicles containing Neurotransmitter would not merge with the plasma membrane Voltage gated calcium channels would not open on the synaptic knob An action potential could not propagate itself down the axon The electrochemical gradient for sodium would be destroyed

Vesicles containing neurotransmitter would not merge with the plasma membrane.

Membrane pumps require ___ energy A lot of No

a lot of

Conductive activity in a neuron generally causes it to secrete

a specific neurotransmitter that either excites or inhibits its target.

Which occurs first? Absolute refractory period Relative refractory period

absolute refractory period

Glutamate is an ______

amino acid

Action potentials are always propagated along an axon at the same ____ but ___ can vary depending on the strength of the stimulus Amplitude; frequency Frequency; amplitude

amplitude; frequency

The nerve impulse causes ___ in the number of calcium ions that enter the synaptic knob An increase A decrease

an increase

What is the most abundant glial cell in the CNS?

astrocyte

___ are star shaped Ependymal cells Astrocytes Satellite cells Microglial cells

astrocytes

A nerve is a bundle of parallel

axons

Cytoplasm within an axon is called Axoplasm Axolemma Nissl substance

axoplasm

A synapse is a junction Between cell bodies Between neurotransmitters Between a neuron and another cell

between a neuron and another cell

Many excitatory neurotransmitters cause the opening of channels that allow for the flow of ______. Both Na+ and K+ Cl- only K+ only Na+ only

both Na+ and K+

The central nervous system is made of the ____ and spinal ___

brain; cord

Acetylcholinesterase Binds to nicotinic receptors Catalyzes hydrolysis of ACh to remove it from the synaptic cleft Blocks muscarinic receptors Catalyzes resynthesis of ACh

catalyzes hydrolysis of ACh to remove it from the synaptic cleft.

Consists of the brain and spinal cord

central nervous system

The brain and spinal cord are part of the ____ Peripheral nervous system Sensory nervous system Motor nervous system Central nervous system

central nervous system

Ependymal cells help produce An immune response against pathogens Cerebrospinal fluid The blood-brain barrier Myelin in the CNS

cerebrospinal fluid

The ependymal cells help produce ___ Urine White blood cells Cerebrospinal fluid Blood plasma

cerebrospinal fluid

Receptors are parts of the nervous system that allow it to

collect information

The total length of the axon is called the ___ segment

conductive

The main activity of the ___ is the propagation of an action potential along the axolemma Terminal segment Initial segment Conductive segment

conductive segment

A positive change in the membrane potential is called Inactivation Depolarization Repolarization Hyperpolarization

depolarization

Another way for the neurotransmitter to be removed from the synaptic cleft is by ___ where there is uptake by surrounding glial cells Reuptake Extrusion Diffusion

diffusion

Glial cells ______ transmit electrical impulses. Do not Do

do not

The nervous system controls the activity of muscles and glands. Muscles and glands can generate changes and are therefore called

effectors

Neurons that carry signals from the CNS to skeletal muscle for contraction would be classified as ___ neurons Unipolar Bipolar Efferent Afferent

efferent

Creating and transmitting ___________ currents is central to the function of neuron physiology

electrical

A difference in the number of charged particles between two sides of the membrane forms a(n) ___ Electrical gradient Sodium gradient Chemical gradient

electrical gradient

The choroid plexus is made from capillaries and ___ Ependymal cells Astrocytes Microglial cells Ogliodendrocytes

ependymal cells

A larger axon transmits an impulse ______ than a smaller axon. Slower Faster

faster

A potential that is a temporary change in membrane potential which lasts only as long as the stimulus that causes it and can vary in size is called a ___ potential

graded

Neuronal pools are made of ___ Sensory neurons Interneurons Motor neurons

interneurons

The myelin sheath is made of a high percentage of ____ Nucleic acids Lipids Carbohydrates

lipids

Which glial cell acts as a phagocyte? Ogliodendrocytes Ependymal cells Astrocytes Microglial cells

microglial cells

The vagus nerve contains afferent and efferent neurons, therefore it is an example of a(n) __________ nerve. Mixed Afferent Sensory Motor

mixed

Dopamine is a

monoamine

Norepinephrine is a __

monoamine

The brain interprets the increased frequency of nerve signals as a ___ stimulus More intense Less intense

more intense

If there were no sodium leak channels, the resting membrane potential of a neuron would be:

more negative

Based on structure, the most common type of neuron is the _______ neuron.

multipolar

If a neuron has many dendrites and a single axon, it is called a(n) ______ neuron. Bipolar Unipolar Multipolar

multipolar

The most common type of neuron contains many dendrites and a single axon. Structurally, this is classified as a(n) ___ neuron Bipolar Anaxonic Unipolar Multipolar

multipolar

___ neurons are most common Bipolar Multipolar Unipolar

multipolar

What is the primary tissue of the nervous system? Epithelial tissue Connective tissues Nervous tissue Muscle tissue

nervous tissue

Nerve growth factors that stimulate outgrowth of severed axons are secreted by Microglial cells Astrocytes Neurolemmocytes Oligodendrocytes

neurolemmocytes

The ability to alter the response of neurons to neurotransmitters is known as

neuromodulation

Neuronal pools are also called Axosomatic synapses Neuronal pathways Neuronal circuits Synaptic vesicles

neuronal circuits Neuronal pathways

Neuromodulation alters the response of ______ to neurotransmitters. Neurons Glial cells

neurons

The components of nervous tissue that conduct electrical impulses are Blood vessels Neurons Ganglia Glial cells

neurons

______ are released from neurons in response to conductive activity. Electrons Neurotransmitters Mitotic cells Graded potentials

neurotransmitters

The glial cell that myelinates and insulates axons within the CNS is the

oligodendrocyte

A nerve is part of the ______ nervous system. Central Peripheral

peripheral

Includes cranial nerves, spinal nerves, and ganglia

peripheral nervous system

Nerves and ganglia are structures found in the

peripheral nervous system

Myelin sheaths mainly consist of which part of the glial cells that form them? Nucleus Perivascular feet Plasma membranes Cytoplasm

plasma membranes

When sodium enters the neuron via chemically gated sodium channels, the membrane will depolarize. Therefore, the membrane potential will become more Negative Positive

positive

Voltage represents ______ energy. Potential Kinetic Chemical

potential

Propagation of depolarization only flows away from the cell body towards the synaptic knob because ______. Previous regions in the axon have only potassium channels Previous regions of the axon are already repolarized Previous regions in the axon have sodium channels in the inactive state

previous regions in the axon have sodium channels in the inactive state

Chemically gated ion channels are mainly found in the ___ segment of a neuron

receptive

A return of the membrane potential towards the resting membrane potential immediately following depolarization is called _____. depolarization Repolarization Summation

repolarization

______ is the return of polarity from positive back to negative (the RMP). Summation Depolarization Depolarization

repolarization

The function of a neuron is dependent on ___ Resting membrane potentials changing Resting membrane potentials staying the same

resting membrane potentials changing

Na+ and K+ leak channels and Na+/K+ pumps on the neuron are responsible for establishing and maintaining the ____ membrane ____.

resting potential

Removal of neurotransmitters from the synaptic cleft by transport into the synaptic knob is known as Diffusion Reuptake Degradation

reuptake

A mixed nerve is one that contains both

sensory and motor neurons

The portion of the nervous system that conducts impulses from the skin, joints, skeletal muscles, and special senses is the ___ division

somatic sensory

A damaged axon within the PNS can regenerate if ______. Part of the cell body remains Some Neurilemma remains Some dendrocytes remain Some oligodendrocytes

some neurilemma remains

When threshold is reached, depolarization occurs with the same amplitude of potential change. This is known as Cable properties of axons Saltatory conduction A graded response The all or none principle

the all or none principle

If all the sodium leakage channels were removed from the cell membrane of a neuron, The membrane potential would become more positive. The membrane potential would be about -90 mV. Intracellular sodium levels would increase. Sodium would diffuse out of the neuron.

the membrane potential would be about -90 millivolts.

As a neuron's refractory period ends, its sodium channels are changing from

their inactivated state to their resting state.

In retrograde transport, substances are moved ___ the cell body

toward

Vesicles involved in retrograde transport are moving ______ the cell body. Away from Toward Toward and away from

toward

A graded potential is one that

varies in size depending on the magnitude of the stimulus (larger voltage change for stronger stimulus).

The measure of the difference in electrical charge between two areas is called a ___

voltage

The type of voltage-gated channel that possesses an inactivation gate that temporarily closes after the channel is active is the

voltage gated sodium channel

If a subthreshold value is reached on an axon membrane, an action potential ______. Will not occur Will occur

will not occur