Anatomy 1 ch 12 ***

Describe the events that occur with the voltage-gated sodium channel during the depolarizing phase of an action potential

At resting, the inactivation gate of the sodium voltage gate is open and the activation gate is closed. Voltage-gated Na+ channels activation gate opens rapidly allowing Na+ to rush into the cell driven by both the electrical and chemical gradient. The inward rush of Na+ causes the membrane potential to become less negative, resulting in depolarization.

) Depolarization is represented by [dropdown 1]. Repolarization is represented by [dropdown 2]. After-hyperpolarization is represented by [dropdown 3 ]. Dropdown 1, 2, & 3 choices: -70mV -90mV -55mV +30mV +30mV -70mV

Answer 1: -55mV +30mV Answer 2: +30mV -70mV Answer 3: -70mV -90mV

[dropdown 1] occur on unmyelinated axons. [dropdown 2] occur on cell bodies and dendrites. [dropdown 3] occur over short or long distances on myelinated axons. [dropdown 4] occur when ligand or mechanically-gated channels open. Dropdown 1, 2, 3&4 choices: Action potentials Graded potentials

Answer 1: Action potentials Answer 2: Graded potentials Answer 3: Action potentials Answer 4: Graded potentials

List the three ways that neurotransmitters can be removed from a synapse

Neurotransmitters can be removed by: 1) diffusion, 2) enzymatic degradation or 3) uptake by cells.

In the process of spatial summation, _____ are added together and _____ are subtracted from that total to determine whether _____ will be created at the trigger zone of the postsynaptic neuron. a) EPSPs; IPSPs; action potentials b) IPSPs; EPSPs; action potentials c) EPSPs; IPSPs; graded potentials d) IPSPs; action potentials; EPSPs e) EPSPs; action potentials; IPSPs

a) EPSPs; IPSPs; action potentials

List the three major factors that contribute to the creation of the resting membrane potential in excitable cells

The major factors that lead to creation of resting potential are: 1) unequal distribution of ions across the plasma membrane, 2) inability of most anions to leave the cell, and 3) the electrogenic nature of the Na+, K+ -ATPase.

Electrical excitability is seen in which cell? Select all that apply. a) Muscle cells b) Neurons c) Microglial cell d) Ependymal cell e) Satellite Cell

a b

With respect to neurons, the term "nerve fiber" refers to what structure? Select all that apply. a) an axon b) a dendrite c) a Nissl body d) microtubules e) neurofibrils

a b

Which is a function of the nervous system? Select all that apply. a) Sensory function b) Integrative function c) Motor function d) Contractility e) Elasticity

a b c

Which ion channelsare used in the production of electrical signals in neurons? Select all that apply a) Leak channel b) Voltage-gated channel c) Ligand-gated channel d) Mechanically gated channel e) Enzymatic channel f) Cell recognition channel

a b c d

The nervous system can distinguish between a light touch and a heavier touch because a) weak stimuli generate action potentials more often than strong stimuli. b) all action potentials are alike regardless of stimulus intensity. c) the frequency of impulses sent to sensory centers is changing. d) the threshold is lower for different sensations. e) the length of the refractory period is modified.

c) the frequency of impulses sent to sensory centers is changing.

Plasticity means the ability to a) regenerate after being damaged. b) communicate by hormones c) convert stimulus into an action potential. d) change based on experience. e) stretch and recoil without damage.

change based on experience

Chromatolysis refers to a) break up of lysosomes after neural injury. b) Wallerian degeneration after neural injury. c) plasticity of neuron. d) break up of Nissl bodies after neural injury. e) none of these choices

d) break up of Nissl bodies after neural injury.

After birth Schwanncells a) form myelin sheaths around axons in the central nervous system. b) stop myelinating neurons in the peripheral nervous system. c) lose their ability to regenerate neurons. d) increase their presence and amount of myelination in the peripheral nervous system. e) wrap around multiple parts of several axons forming nodes of Ranvier

d) increase their presence and amount of myelination in the peripheral nervous system.

____ is a neurotransmitter that is made on demand and can be used for microbial defense. _____is a neurotransmitter that is made on demand and is used for vasodilation and special sensory recognition. a) nitric oxide, enkephalins b) carbon monoxide, nitric oxide c) serotonin; carbon monoxide d) nitric oxide; carbon monoxide e) enkephalins; serotonin

d) nitric oxide; carbon monoxide

Acetylcholine is _________at the neuromuscular junctions and ________ at cardiac muscle in the parasympathetic pathway. a) excitatory; inhibitory b) excitatory; excitatory c) inhibitory; excitatory d) inhibitory; inhibitory

excitatory inhibitory

Which type of central nervous system tissue contains neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglial cells? a) Gray matter b) White matter c) Nissl bodies d) Ganglia

gray matter

In an action potential, the electric current that flows is generated by the movement of _____ across the membrane. a) electrons b) protons c) ions d) chemicals e) neutrons

ioins

Na+/K+-ATPase is considered to be an electrogenic pump because a) it contributes to the negativity of the resting membrane potential. b) the sodium ions are negatively charged. c) it exhibits low permeability. d) it hydrolyzes ADP into ATP. e) destroys the resting membrane potential

it contributes to the negativity of the resting membrane potential

Which of these allows more potassium to exit the neuron and helps in maintaining the resting membrane potential? a) leak channel b) ligand-gated channel c) mechanically gated channel d) voltage-gated channel

leak channel

A depolarizing graded potential a) makes the membrane more polarized. b) makes the membrane less polarized. c) occurs when chloride enters the cytosol. d) occurs when acetylcholine enters the cytosol. e) occurs on the axon.

makes the membrane less polarized

__________open and close in response to physical deformation of receptors. a) Leak channels b) Ligand-gated channels c) Mechanically gated channels d) Voltage-gated channels

mechanically gated channels

Which of the following types of neurons is the most common type of neuron found in the brain and spinal cord? a) bipolar neuron b) multipolar neuron c) unipolar neuron d) pseudounipolar

multipolar neuron

Which electrical signal can allow for rapid long-distance communication within the nervous system? a) resting potential b) nerve action potential c) muscle action potential d) graded potential

nerve action

Which organelle is a common site of protein synthesis in neurons? a) mitochondria b) nucleus c) Nissl body d) Golgi apparatus e) nucleolus

nissl body

What specific type of unipolar neuron detects a sharp pain? a) tactile epithelial cells (Merkel disc) b) corpuscle of touch (Meissner corpuscle) c) lamellated (Pacinian) corpuscle d) nociceptor

nociceptor

Which of the neurons is located deep in the dermis or hypodermis and detect deep pressure? a) corpuscle of touch b) nociceptor c) pacinian Corpuscle d) tactile epithelial cell

pacinian corpuscle

All of the following statements are true for which type of cell? • has a charge imbalance across its membrane. • includes most cells of the body. • exhibits a membrane potential. inside is more negative relative to outside. a) Nonpolarized cell b) Polarized cell c) Neutral cell d) Electrogenic cell

polarized cell

Which of the following types of neurons is exclusively found in the cerebellum? a) bipolar neuron b) multipolar neuron c) Purkinje cells d) unipolar neuron e) pyramidal cells

purkinje cells

These statements describe what part of an action potential? • Sodium activation gates are closed • Sodium inactivation gates are open • Potassium gates are open • Repolarization is occurring a) Latent period b) Absolute refractory period c) Relative refractory period d) depolarizing phase e) repolarizing phase

relative refractory period

Diffusion, enzymatic degradation, and uptake by cells are all ways to a) remove a neurotransmitter b) stop a spatial summation c) continue a temporal summation d) inhibit a presynaptic potential e) excite a presynaptic potential

remove a neurotransmitter

Hearing your cell phone ring in an quiet lecture hall is an example of which nervous system functions? a) Sensory function b) Integrative function c) Motor function d) More than one of the types of nervous system functions

sensory function

Excitatory postsynaptic potentials can occur if there is an influx of [dropdown 1] ions. Inhibitory postsynaptic potentials can occur if there is an influx of [dropdown 2 ] ions or an efflux of [dropdown 3] ions. Dropdown 1, 2 & 3 choices: phosphate chloride potassium sodium

sodium chloride potassium

As the action potential nears its peak, the voltage-gated [dropdown 1] channels close, and voltage-gated [dropdown 2] channels open, allowing cations to flow out of the cell to restore the resting membrane potential. Dropdown 1& 2 choices: calcium chloride potassium sodium

sodium potassium

The motor portion of the autonomic nervous system can be divided into a) somatic and sympathetic divisions. b) somatic and parasympathetic divisions. c) enteric and somatic divisions. d) sympathetic and parasympathetic divisions. e) voluntary and involuntary divisions

sympathetic and parasympathetic

Describe four ways drugs can modify the effects of neurotransmitters

: Drugs can modify neurotransmitter effects by: 1) stimulating or inhibiting their synthesis, 2) enhancing or blocking their release, 3) activating or blocking their receptor, and 4) stimulating or inhibiting their removal.

What factors limit neurogenesis in the CNS of adults?

: Neurogenesis in adults is limited by: 1) Inhibitory influences from neuroglia, mainly from oligodendrocytes, and 2) the absence of growth-stimulating cues present during fetal development.

During the resting state of a voltage-gated Na+ channel, 1. the inactivation gate is open. 2. the activation gate is closed. 3. the channel is permeable to Na+. a) 1 only b) 2 only c) 3 only d) both 1 and 2 are true. e) all of these choices are true.

1 and 2 are true

Describe the difference between spatial and temporal summation in a postsynaptic neuron.

Spatial summation is summation of postsynaptic potentials in response to stimuli that occur at different locations in the membrane of a postsynaptic cell at the same time. This typically occurs when multiple presynaptic neurons synapse with one postsynaptic neuron and fire simultaneously. Temporal summation is summation of postsynaptic potentials in response to stimuli that occur at the same location in the membrane of the postsynaptic cell but at different times. This typically occurs when one presynaptic neuron fires in rapid succession leading to a summing of the resulting EPSPs, which then triggers the generation of action potentials in the postsynaptic neuron as it moves above threshold

What events must occur for the creation of an action potential? Select all that apply. a) Neurotransmitters must be released into the synaptic cleft. b) Summation of depolarizing graded potential. c) Threshold at the trigger zone. d) Summation of hyperpolarizing graded potential. e) Glycine attaches to a ligand gate.

b c

Which types of membrane channels can cause an IPSP on a neuron when acetylcholine binds to the receptor? Select all that apply. a) leakchannel b) ionotropic ligand-gated channels c) mechanically gated channels d) voltage-gated channels e) metabotropic ligand-gated channels

b e

During an action potential's ___________, a second stimulus will not produce a second action potential (no matter how strong that stimulus is). This event corresponds to the period when the __________ remain open and the sodium inactivation gates have not reopened. a) absolute refractory period; voltage-gated sodium channels b) absolute refractory period; voltage-gated potassium channels c) relative refractory period; voltage-gated sodium channels d) relative refractory period; voltage-gated potassium channels

b) absolute refractory period; voltage-gated potassium channels

Wallerian degeneration refers to a) degeneration of the proximal end of axon and myelin sheath after neural injury. b) degeneration of the distal end of axon and myelin sheath after neural injury. c) break of Nissl bodies after neural injury. d) plasticity of neuron.

b) degeneration of the distal end of axon and myelin sheath after neural injury.

In temporal summation, a single presynaptic neuron stimulates the creation of action potentials in a postsynaptic neuron when it a) stops firing long enough to allow the postsynaptic neuron to recover. b) fires at a fast enough rate that the sum of EPSPs in the postsynaptic neuron moves above threshold. c) fires at a steady rate that allows the postsynaptic neuron to return to resting potential. d) recruits other presynaptic neurons to begin to fire.

b) fires at a fast enough rate that the sum of EPSPs in the postsynaptic neuron moves above threshold.

Which neurotransmitters are used in virtually all of the inhibitory synapses found in the spinal cord? a) gamma aminobutyric acid (GABA) and acetylcholine b) gamma aminobutyric acid (GABA) and glycine c) epinephrine and norepinephrine d) serotonin and melatonin e) glutamate and aspartate

b) gamma aminobutyric acid (GABA) and glycine

Manic-depressive illness is associated with a) major depression. b) dysthymia. c) bipolar disorder. d) seasonal affective disorder. e) all of these disorders

bipolar disorder

This type of neuron has one dendrite and one axon emerging from the cell body. a) Multipolar neuron b) Bipolar neuron c) Unipolar neuron d) Purkinje cell e) Pyramidal cell

bipolar neuron

During an action potential's ___________, a second stimulus can be produced only if the stimulus is greater than the threshold stimulus. This event corresponds to the period when the __________ remain open and sodium inactivation gates have reopened. a) absolute refractory period; sodium voltage-gated channels b) absolute refractory period; potassium voltage-gated channels c) relative refractory period; sodium voltage-gated channels d) relative refractory period; potassium voltage-gated channels

d) relative refractory period; potassium voltage-gated channels

When a graded potential summates to threshold at the axon hillock, a) ligand-gated Ca+2 channels close rapidly. b) voltage-gated Ca+2 channels open rapidly. c) ligand-gated Na+ channels close rapidly. d) voltage-gated Na+ channels open rapidly. e) ligand-gated K+ channels open rapidly.

d) voltage-gated Na+ channels open rapidly.

An excitatory neurotransmitter _____ the postsynaptic membrane. a) depolarizes b) repolarizes c) hyperpolarizes d) does not affect the polarity of e) creates a synaptic delay at

depolarizes

This type of neural circuit consists of a single presynaptic neuron synapsing with several postsynaptic neurons. a) Diverging circuit b) Converging circuit c) Reverberating circuit d) Parallel after-discharge circuit e) Simple series circuit

diverging circuit

Saltatory conduction is described by which statements? 1) current passes through the entire unmyelinated axon membrane 2) current passes through a myelinated axon only at the nodes of Ranvier 3) current occurs at faster rates 4) voltage-gated channels are concentrated in unmyelinated regions 5) More energy is used to increase speed of conduction a) 1, 3, 4 b) 2, 4, 5 c) 1, 2, 3, 4, 5 d) 1, 5 e) 2, 3, 4

e) 2 3 4

A postsynaptic neuron responds to acetylcholine neurotransmitter by creating a) EPSP b) IPSP c) either EPSP or IPSP d) neither EPSP or IPSP

either epsp or ipsp

Faster communication and synchronization are two advantages of a) chemical synapses b) electrical synapses c) graded potentials d) action potentials e) Na+-K+ ATPases

electrical synapses

Which division of the peripheral nervous system only innervates the gastrointestinal tract's wall? a) Somatic nervous system b) Autonomic nervous system c) Enteric nervous system d) Parasympathetic nervous system e) Sympathetic nervous system

enteric nervous