Advanced Physiology Chapter 2

Synaptic transmission is made possible by ____________. saltatory conduction membrane transport neurotransmitters an ion pump

neurotransmitters

A threshold stimulus immediately ________. inactivates voltage-gated sodium channels opens voltage-gated sodium channels closes voltage-gated sodium channels opens voltage-gated potassium channels closes voltage-gated potassium channels

opens voltage-gated sodium channels

Neurotransmitters are removed from the synaptic cleft by all of the following except: ___________. simple diffusion presynaptic inhibition reuptake by a presynaptic neuron enzymatic degradation

presynaptic inhibition

One of the following only represents spatial summation. The other choices could represent either spatial or temporal summation. Which one only represents spatial summation? (+ 5 mV) + (+ 10 mV) (+ 1 mV) + (+ 2 mV) (- 5 mV) + (+ 10 mV) (- 1 mV) + (- 2 mV)

(- 5 mV) + (+ 10 mV)

A nerve fiber has a RMP of -80 mV and a threshold potential of -60 mV. Which of the following is most likely to generate an action potential? - 15 mV IPSP and - 20 mV IPSP + 15 mV EPSP - 20 mV IPSP and + 5 mV EPSP + 15 mV EPSP and + 5 mV EPSP

+ 15 mV EPSP and + 5 mV EPSP

__________________ studies seek to identify the patterns, causes, and control of disorders in groups of people. Prevention Epidemiological Quality of life Diagnostic

Epidemiological

The hyperpolarization phase of the action potential is caused by too much __________ leaving the cell. Ca2+ Na+ water K+

K+

The hyperpolarization phase of the action potential is caused by too much __________ leaving the cell. K+ water Ca2+ Na+

K+

Which of the following enters the postsynaptic terminal and initiates an EPSP at an electrochemical synapse? Ca2+ H- Cl- K+ Na+

Na+

Which of the following is NOT a characteristic of neurons? In general, neurons cannot be replaced if destroyed. Neurons can function optimally for over 100 years. Neurons require continuous and abundant supplies of oxygen, and cannot survive for more than a few minutes without it. Neurons are relatively small, simple-structured cells.

Neurons are relatively small, simple-structured cells.

Which of the following statements is true? For any given effector (muscle or gland), the postsynaptic membrane has receptors for only one kind of neurotransmitter. Most of the neurotransmitters are manufactured in the axon terminal region. Neurotransmitter molecules are stored in vesicles located in the axon terminal region of the presynaptic cell. For any given neuron, synaptic vesicles may contain more than one type of neurotransmitter.

Neurotransmitter molecules are stored in vesicles located in the axon terminal region of the presynaptic cell.

Which of the following statements concerning inhibitory synapses (IPSPs) is correct? The postsynaptic membrane becomes less permeable to potassium. The permeability of the postsynaptic membrane to sodium, potassium, and chloride is not changed. Channels allow both sodium and potassium ions to diffuse simultaneously through the membrane. The postsynaptic membrane becomes more permeable to potassium and/or chloride. The postsynaptic membrane becomes less permeable to sodium.

The postsynaptic membrane becomes more permeable to potassium and/or chloride.

Saltatory conduction refers to: conduction or electrical current through body water conduction between presynaptic and postsynaptic membranes conduction of a nerve impulse by a myelinated axon conduction of a signal between nerve and muscle

conduction of a nerve impulse by a myelinated axon

The most probable site on a neuron where incoming information is received is the ___________. axon neurosoma myelin sheath dendrite axon terminal

dendrite

A change in membrane potential from -70 mV to -40 mV would be termed __________. repolarization hypopolarization hyperpolarization depolarization

depolarization

A graded, non-propagated potential the increased sodium conductance into a postsynaptic cell which is not skeletal muscle is a(n) _____________. action potential inhibitory postsynpatic potential end plate potential excitatory postsynaptic potential

excitatory postsynaptic potential

According to the "all-or-none" law: the amplitude of the action potential is inversely proportional to the strength of the applied stimulus partial depolarization of the neuron's plasma membrane never occurs for a given nerve fiber, the amplitude of the action potential does not vary with the strength of stimulus the amplitude of the action potential is directly proportional to the strength of the applied stimulus

for a given nerve fiber, the amplitude of the action potential does not vary with the strength of stimulus

In a neuron, a membrane potential of -90 mV is considered __________. a graded potential hyperpolarized The resting membrane potential of a neuron is -70 mV so a potential of -90 mV would be due to hyperpolarization. a normal resting potential depolarized

hyperpolarized

A graded, non-propagated potential that increased chloride conductance into a postsynaptic cell is a(n) _____________. inhibitory postsynaptic potential excitatory postsynaptic potential resting membrane potential action potential end plate potential

inhibitory postsynaptic potential

The speed of a nerve impulse is determined by all of the following except the _______________. presence of myelin diameter of a nerve fiber intensity of a stimulus

intensity of a stimulus

Acetylcholinesterase : is an enzyme essential for the synthesis of acetylcholine is the neurotransmitter always found at the neuromuscular junction is an enzyme that cleaves acetylcholine from the postsynaptic receptor is an enzyme that cleaves acetyl from choline

is an enzyme that cleaves acetyl from choline

The normal AP exhibited by a single neuron: may or may not be propagated (conducted) has a variable amplitude is conducted without decrement (decreased velocity/amplitude) has a variable threshold potential

is conducted without decrement (decreased velocity/amplitude)

Which of the following factors is associated with increased conduction velocity in an axon? large diameter small diameter presence of collaterals increased number of dendrites the absence of the myelin sheath

large diameter

Which of the following membrane ion channels in the neuron are always open? ligand-gated channels leakage channels mechanically gated channels voltage-gated channels

leakage channels

Which type of ion channel opens when a chemical binds to it? ligand-gated channel mechanically gated channel leakage channel voltage-gated channel

ligand-gated channel

Depolarization of a dendrite results in current flow between the dendrite and the __________ resulting in propagation of a nerve impulse. adjacent dendrites axon terminals neurosoma myelin sheath

neurosoma

Synaptic transmission is made possible by ____________. neurotransmitters an ion pump membrane transport saltatory conduction

neurotransmitters

In the sodium-potassium pump, sodium and potassium both leave the cell. potassium enters and sodium leaves the cell. sodium enters and potassium leaves the cell. sodium and potassium both enter the cell.

potassium enters and sodium leaves the cell.

In the sodium-potassium pump, sodium and potassium both leave the cell. sodium and potassium both enter the cell. potassium enters and sodium leaves the cell. sodium enters and potassium leaves the cell.

potassium enters and sodium leaves the cell.

Neurotransmitters are removed from the synaptic cleft by all of the following except: ___________. enzymatic degradation presynaptic inhibition simple diffusion reuptake by a presynaptic neuron

presynaptic inhibition

The sodium-potassium ion pump will __________. pump three potassium ions out of the cell for every two sodium ions it brings into the cell pump three sodium ions out of the cell for every two ions of potassium it brings into the cell pump one sodium ion out of the cell for every ion of potassium it brings into the cell pump one potassium ion out of the cell for every ion of sodium it brings into the cell

pump three sodium ions out of the cell for every two ions of potassium it brings into the cell

The period of excitability during which a greater than normal strength of stimulus is required to elicit a cell response is termed the ____________. hyperexcitable period absolute refractory period relative refractory period interphase period

relative refractory period

During which phase of an action potential are voltage-gated K+ channels open, while voltage-gated Na+ channels are closed? depolarization repolarization resting state threshold

repolarization

Which part of the action potential occurs when the voltage-gated Na+ channels are inactivating and voltage-gated K+channels open? repolarization depolarization resting state hyperpolarization

repolarization

A stable potential that is maintained by K+ leak channels and the Na+/K+ pump is a(n) ____________. excitatory postsynaptic potential resting membrane potential action potential inhibitory postsynaptic potential

resting membrane potential

You would expect a neuron that depolarizes to -65 mV would __________. fire a much less intense action potential with a peak of +15 mV fire a much more intense action potential with a peak of +100 mV hyperpolarize return to resting membrane potential without generating an action potential

return to resting membrane potential without generating an action potential

Which of the following characteristics is NOT associated with a myelinated nerve fiber? slow conduction of nerve impulses the presence of nodes of Ranvier rapid conduction of nerve impulses formation by oligodendrocytes in the central nervous system formation by Schwann cells in the peripheral nervous system

slow conduction of nerve impulses

During the repolarization phase of the action potential, there is a decrease in the membrane permeability to which ion? potassium sodium both sodium and potassium calcium

sodium

Somatic integration involving the additive effect of 2 or more EPSP's produced in rapid succession at one synapse defines: spatial summation temporal summation motor unit summation mechanical summation

temporal summation

If energy input (in the form of ATP) to the Na+-K+ pump ceases: the RMP goes to zero the cell loses sodium an EPSP develops the RMP becomes larger

the RMP goes to zero

In a neuron, where does an action potential first appear after the neuron has been adequately stimulated on a dendrite? the neurosoma the dendrite the axon terminal the axon hillock

the axon hillock

The membrane potential returns to the resting state due to ________. the bulk transport of ions the diffusion of K+ through voltage-gated K+ channels the facilitated diffusion of K+ the diffusion of ions through leak channels the active transport of ions

the diffusion of ions through leak channels

The resting membrane potential of a neuron is dependent on: active transport of potassium ions out of the cell the presence of non-diffusible anions inside the cell active transport of sodium ions into the cell the opening of electrically operated sodium channel gates

the presence of non-diffusible anions inside the cell

A membrane maintains its resting potential mainly due to _________. calcium leak channels ligand-gated sodium channels potassium leak channels the sodium-potassium pump

the sodium-potassium pump

All of the following are true of action potentials except: ______________. they travel more slowly on myelinated fibers they need a threshold stimulus they are inhibited by IPSPs they exhibit an all-or-none response

they travel more slowly on myelinated fibers

Which of the following is NOT a function of the myelin sheath? to increase the speed of transmission of nerve impulses to protect nerve fibers to recapture and recycle released neurotransmitters to electrically insulate nerve fibers

to recapture and recycle released neurotransmitters

Information is coded in the nervous system by: increasing the velocity of impulse conduction changing the type of neurotransmitter used by a neuron varying the frequency of the APs altering the amplitude of the AP

varying the frequency of the APs

The cell body is the enlarged portion of the neuron that contains the nucleus and nucleolus surrounded by cytoplasm. True False

True

Neurotransmitters are important in functioning of ______ synapses. elecretical converging gap chemical

chemical

Which of the following are the main receptive or input regions found in neurons? neurofibrils ganglia dendrites axons

dendrites

During transmission at an electrochemical synapse, neurotransmitter molecules are released from the presynaptic neuron by: exocytosis endocytosis active transport phagocytosis facilitative diffusion

exocytosis

An action potential is a phenomenon that either happens completely or doesn't happen at all. True False

True

Dendrites and axons are both armlike processes that extend from neuron cell bodies. True False

True

IPSPs never generate APs. True False

True

What type of ion channel opens in response to an action potential arriving at the axon terminal? Voltage-gated potassium Voltage-gated sodium Voltage-gated calcium

Voltage-gated calcium

The time interval during which no stimulus can elicit an action potential in a nerve fiber is called ______________. repolarization period relative refractory period absolute refractory period latent period

absolute refractory period

A non-graded, propagated potential that follows the "all-or-none" law is a(n) ____________. action potential excitatory postsynaptic potential inhibitory postsynaptic potential end plate potential

action potential

Which of the following electrical events occurs when a certain threshold is reached? resting membrane potential IPSP EPSP action potential

action potential

Which type of potential does not decay with distance? receptor potential end-plate potential action potential graded potential

action potential

According to the "all-or-none" law: saltatory conduction is faster either all of the fibers in a nerve are active at the same time or none of them are action potential amplitude for a given neuron is constant the stronger the stimulus the greater the amplitude of the action potential

action potential amplitude for a given neuron is constant

Synaptic transmission can be blocked by: blocking the release of neurotransmitter all are ways of blocking synaptic transmission blocking the postsynaptic receptor blocking the synthesis of neurotransmitter

all are ways of blocking synaptic transmission

The establishment and maintenance of a cell's resting membrane potential is dependent on: all listed are correct action transport of ions the presence of non-diffusible anions inside the cell selective permeability of the membrane to ions energy expenditure

all listed are correct

The principal cause of depolarization of a nerve fiber when threshold is reached is an increase in the inward conductance of K+ an decrease in the inward conductance of Na+ an increase in the inward conductance of Na+ an increase in the outward conductance of Na+

an increase in the inward conductance of Na+

The principal cause of depolarization of a nerve fiber when threshold is reached is an increase in the inward conductance of Na+ an increase in the inward conductance of K+ an increase in the outward conductance of Na+ an decrease in the inward conductance of Na+

an increase in the inward conductance of Na+

The presynaptic neuron releases neurotransmitters in response to an influx of _______ ions potassium calcium sodium sodium and potassium

calcium

Which of the following statements is INcorrect concerning a nerve impulse? It is the actual movement of Na and K ions. It always progresses from dendrites, to cell body, to axon. It travels in only one direction. It is an all-or-none response. All of the statements are true.

All of the statements are true.

Which of the following statements best describes the resting membrane state in the neuron? All of the voltage-gated Na+ and K+ channels are closed. Only the voltage-gated Na+ channels are open. Only the voltage-gated Na+ channels are closed. Only the voltage-gated K+ channels are open. Only the voltage-gated K+ are closed.

All of the voltage-gated Na+ and K+ channels are closed.

Synaptic vesicles are induced to migrate toward and blend with the presynaptic membrane and then to release neurotransmitter into the synaptic cleft as a result of an increase in the concentration of free ____ in the presynaptic terminal. Cl- ACh K+ Na+ Ca2+

Ca2+

Which of the following is NOT true of neurons? They all conduct nerve impulses. They cannot divide mitotically. They respond to physical and chemical stimuli. They all release chemical regulators. They are the most abundant cells of nervous tissue.

They are the most abundant cells of nervous tissue.

Which of the following is FALSE regarding chemical synapses? Each is composed of an axon terminal and a receptor region. They possess pre- and postsynaptic membranes separated by a synaptic cleft. They transmit nerve impulses directly from one neuron to another. They communicate unidirectionally.

They transmit nerve impulses directly from one neuron to another.