Anatomy Exam; (Unit 3) Nervous System

This potential travels through the dendrites and sometimes reaches the soma before fizzling out.

graded potential

Neurons communicate strength of signal by altering the amplitude of action potential deflection. True or False?

False

What are the proper steps in an action potential, from start to finish?

1. The membrane potential of the neuron shifts from resting membrane potential to threshold. 2. Voltage-gated Na+ channels open. 3. Na+ rushes into the cell and the cell depolarizes. 4. Voltage-gated Na+ channels inactivate. Voltage-gated K+ channels open. 5. K+ ions flow out of the neuron and the neuron repolarizes. 6. Voltage-gated K+ channels stay open beyond the resting membrane potential and the neuron hyperpolarizes. 7. Pumps return the neuron back to resting membrane potential.

Schwann cells are wrapped around multiple different axons. True or False?

False

The Chemicals of Neuronal Communication; Differentiate between the two main types of acetylcholine receptors.

Acetylcholine - most widely used neurotransmitter. - are called cholinergic neurons. - can bind to two main subtypes of acetylcholine receptors. ...two receptors... 1. nicotinic acetylcholine receptors; - are ligand-gated receptors. - produces EPSPs in the postsynaptic neurons. - found in brain, autonomic nervous system, and muscles. 2. muscarinic acetylcholine receptors; - are G-protein coupled receptors. - produces IPSPs in the postsynaptic neurons. - found in brain, smooth muscle, cardiac muscles, and glands.

The Chemicals of Neuronal Communication; Describe what happens when various toxins block or breakdown neuronal communication.

Acetylcholine Alterations - neurotoxin is injected into skeletal muscle. - the neurotoxins get endocytosed into the motor neuron that controls the skeletal muscle. - blocks release of acetylcholine. - cleaves SNARE proteins which function in exocytosis of neurotransmitters. - muscles relax and soften. 1. agonists; drugs or chemicals that activate receptors. - acetylcholine is an endogenous agonist. 2. antagonists; drugs or chemicals that inhibit receptors. - acetylcholine is an exogenous agonist.

The Chemicals of Neuronal Communication; Explain the importance of Acetylcholine Esterase and one of its blockers, nerve gas.

Acetylcholine Esterase - inactivates acetylcholine by breaking it down. - inhibited by nerve gas.

Electrical Communication of Neurons; Describe the events of the action potential.

Action Potential ...stages... 1. at rest (-70mV) 2. stimulus applied *voltage-gated Na+ opens, and Na+ in* 3. voltage rises *(repolarization) voltage-gated Na+ inactivates, voltage-gated K+ opens, K+ out* 4. voltage falls *voltage-gated K+ remains open* 5. end of action potential 6. return to rest

Action Potentials; Describe what is meant by "all or none," in relationship to action potentials.

All or None - depends if action potential is fired or not. - dependent on threshold. 1. none; (off neurons) depolarization of an axon membrane below threshold, and does not go past threshold. - action potential is not fired. 2. all; (on neurons) action potential of an axon, and goes past threshold. - action potential is fired.

___ forms the blood-brain barrier.

Astrocytes

The kinetics of voltage-gated potassium channels mandate that they open and close in a proper order. Which of the following properly illustrates the kinetics of voltage-gated potassium channels? a. At rest, voltage-gated potassium channels are closed. During the depolarization phase of the action potential, voltage-gated potassium channels are closed. At the peak of the action potential, voltage-gated potassium channels open. Because voltage-gated potassium channels are slow-acting, it takes a long time for them to close, so they stay open well into the hyperpolarization phase. b. At rest, voltage-gated potassium channels are closed. During the depolarization phase of the action potential, voltage-gated potassium channels are open. At the peak of the action potential, voltage-gated potassium channels inactivate. If a strong enough stimulus comes, the voltage-gated potassium channels can directly shift from being inactivated to being open. c. At rest, voltage-gated potassium channels act as leak channels and are open. They close throughout the duration of the action potential. d. At rest, voltage-gated potassium channels are closed. During the depolarization phase of the action potential, voltage-gated potassium channels are open. At the peak of the action potential, voltage-gated potassium channels inactivate. These channels MUST close again before reopening.

At rest, voltage-gated potassium channels are closed. During the depolarization phase of the action potential, voltage-gated potassium channels are closed. At the peak of the action potential, voltage-gated potassium channels open. Because voltage-gated potassium channels are slow-acting, it takes a long time for them to close, so they stay open well into the hyperpolarization phase.

The kinetics of voltage-gated sodium channels mandate that they open/close/inactive in a proper order. Which of the following properly illustrates the kinetics of voltage-gated sodium channels. a. At rest, voltage-gated sodium channels are closed. During the depolarization phase of the action potential, voltage-gated sodium channels are closed. At the peak of the action potential, voltage-gated sodium channels open. Because voltage-gated sodium channels are slow-acting, it takes a long time for them to close, so they stay open well into the hyperpolarization phase. b. At rest, voltage-gated sodium channels are closed. During the depolarization phase of the action potential, voltage-gated sodium channels are open. At the peak of the action potential, voltage-gated sodium channels inactivate. If a strong enough stimulus comes, the voltage-gated sodium channels can directly shift from being inactivated to being open. c. At rest, voltage-gated sodium channels are closed. During the depolarization phase of the action potential, voltage-gated sodium channels are open. At the peak of the action potential, voltage-gated sodium channels inactivate. These channels MUST close again before reopening. d. At rest, voltage-gated sodium channels act as leak channels and are open. They close throughout the duration of the action potential.

At rest, voltage-gated sodium channels are closed. During the depolarization phase of the action potential, voltage-gated sodium channels are open. At the peak of the action potential, voltage-gated sodium channels inactivate. These channels MUST close again before reopening.

Following an action potential, voltage-gated channels will open and ___ will flow into the presynaptic neuron, binding to ___ to form a complex. This complex will lead to the docking and fusion of vesicles that will cause ___ to be exocytosed from the presynaptic neuron.

Ca2+, synaptotagmin, neurotransmitters

Introduction to the Nervous System; Identify the components of the central nervous system verses the peripheral nervous system.

Central Nervous System - consists of the brain and spinal cord. - integrative and control centers. Peripheral Nervous System - consists of cranial nerves and spinal nerves. - communication lines from the central nervous system to the rest of the body. ..has two divisions.. 1. sensory (afferent) division; conducts impulses from sensory receptors to the central nervous system. 2. motor (efferent) division; conducts impulses from the central nervous system to effector tissues such as muscles and glands. ...has two segments... a. somatic nervous system; conducts impulses from the central nervous system to skeletal muscle. b. autonomic nervous system; conducts impulses from the central nervous system to cardiac muscle, smooth muscle, and glands.

Astrocytes line the cavities of the brain and spinal cord. True or False?

False

Over spring break, you traveled through South America with your friends. During a harmless game of truth or dare, you were dared to lick a random tree. Unfortunately for you, you digested some of the tree resin that contained curare. What will happen as curare travels throughout your body?

Curare acts as an antagonist and inhibits receptors in your CNS, causing your heart rate and breathing to slow and halting skeletal muscle contraction.

In unmyelinated axons, action potentials seemingly jump from node to node, in a process called "saltatory conduction". True or False?

False

___ brings a neuron closer to threshold and makes the neuron more ___.

Depolarization, positive

Two neurons synapse onto the dendrites of one neuron. One of these neurons is excitatory and causes EPSPs in the postsynaptic neuron and the other neuron is inhibitory and causes IPSPs in the postsynaptic neuron. If both presynaptic neurons fired at the same time, what would this cause in the postsynaptic neuron?

EPSP/IPSP cancellation

Electrical Communication of Neurons; Define important terms related to electrical flow.

Electrical Communication - occurs via graded potentials and action potentials. - neurons communicate chemically using neurotransmitters. ...notes... - cat ions (positive) attract to anions (negative). 1. potential energy; because ions attract, energy is required to separate opposite charges against a membrane. 2. kinetic energy; when opposite charges move toward one another energy is liberated, energy in motion. - Ohm's law states that current=voltage/resistance.

___ line ventricles and makes cerebrospinal fluid.

Ependymal cells

Voltage-gated Na+ channels and voltage-gated K+ channels do not exist within the axon terminal. Instead, the axon terminal has voltage-gated Cl- channels. True or False?

False

Which best describes an agonist? a. Foreign chemicals or drugs that activate neural receptors. b. Foreign chemicals or drugs that inhibit neural receptors. c. Natural chemicals that activate neural receptors. d. Natural chemicals that inhibit neural receptors.

Foreign chemicals or drugs that activate neural receptors.

Muscarinic acetylcholine receptors are ___ receptors that cause the opening of ___.

G-protein coupled, K+ channels

What does AChE do?

It breaks down ACh into acetate and choline.

After Valentine's day, you decided to take advantage of all the candy that went on sale. A few days ago, you went to your semiannual dentist appointment and found out that all that candy gave you a cavity and you need a root canal. The dentist gives you a shot of lidocaine before beginning the root canal. Which of the following best describes how lidocaine affects your gums?

Lidocaine binds to voltage-gated Na+ channels on the neuron in your gums, preventing depolarization.

What are ligand-gated channels?

Ligand-channels open and close in response to chemical stimulus.

Electrical Communication of Neurons; Describe resting membrane potential, graded potentials, and action potentials.

Membrane Potential 1. resting membrane potentials; - all cells have resting membrane potentials. - only neurons and muscles can alter it. - salts (Na+, K+, Cl-, Ca2+) play a role. - is -70 mV inside. - when a neuron is resting, it is polarized. a. Na+/K+ ATPase; pumps Na+ out and K+ into the cell, resulting in 3Na+ out and 2K+ in. 2. graded potentials; - short changes in membrane potential. - not strong enough to travel down the axon. - depends on stimulus size. - fizzle out over time. - occurs in dendrites and the cell body. a. hyperpolarization; moves further away from threshold causing inhibition, and is more negative than RMP. b. depolarization; moves closer to threshold excitation, and is more positive than RMP. 3. action potentials; - if graded depolarization is strong enough, action potential is triggered. - long distance electrical signal on an axon. - goes above threshold. - has six steps (1. at rest), (2. stimulus applied), (3. voltage rises), (4. voltage falls), (5. end of action potential), (6. return to rest). - occurs in the axon. a. repolarization; when voltage-gated Na+ inactivates and voltage-gated K+ opens, letting K+ out.

___ are specialized macrophages that phagocytize pathogen.

Microglia

In order for a second action potential to occur, what must happen first?

Na+ channels must inactivate and close.

Resting membrane potential is maintained by ___ which releases ___ out of the cell and brings ___ into the cell.

Na+/K+ ATPase, 3 Na+, 2 K+

___ inhibits AChE.

Nerve gas

Introduction to the Nervous System; Describe supporting cells according to structure and function.

Neuroglia 1. astrocytes; - abundant and versatile. - wrap around neurons, synapses, and capillaries. - support and anchor neurons. - a blood barrier. 2. ependymal cells; - consists of squamous and columnar cells. - are ciliated or non-ciliated. - line ventricles. - make cerebrospinal fluid (CSF). 3. microglial cells; - small cells with thorny processes. - migrate to injured neurons. - have macrophages that phagocytize neuronal debris and pathogens. 4. oligodendrocytes; - branched cells. - send processes around axons to form myelin sheaths. 5. satellite cells; - surround neuron cell body. - maintain proper chemical environment for the neuron. - supports and protects. 6. Schwann cells; - surrounds axons in peripheral neurons. - forms myelin sheaths. - regenerates damaged peripheral neurons.

Electrical Communication of Neurons; Differentiate between different channel types.

Neuron Channels - open channels = decreased resistance and increased current flow. - closed channels = increased resistance and decreased current flow. 1. leak channels; are always opened and establish resting membrane potential. ex. K+ leak channel 2. voltage-gated channels; open or close in response to voltage. ex. voltage-gated Na+ channel 3. mechanically gated channels; open or close in response to physical deformation. ex. sensory touch receptors 4. ligand-gated channels; open or close when chemical binds to receptor. ex. nicotinic ACh receptor

Introduction to the Nervous System; Describe the structure of a neuron and know its parts.

Neurons - have extreme longevity. - are mitotic. - have high metabolic rates. - are electrically excitable, and the nerve impulses travel along the length of the axon. ...structures... 1. dendrites; receptive regions. 2. soma; cell body. 3. axon; impulse generating and conducting region. a. myelin; the axon may or may not have myelin, but it insulates the axon. b. nodes of ranvier; the small gaps between myelin sheaths, but control the speed of electrical signal. 4. axon hillock; junction between the cell body and axon. 5. synaptic knobs; the end of an axon, leading to the axon terminal.

Introduction to the Nervous System; Classify neurons according to structure (unipolar, bipolar, multipolar) and function (sensory neuron, interneuron, motor neuron).

Neurons ...structure classification... 1. unipolar neurons; - have a fused dendrite and axon. - make up majority of our sensory neurons. 2. bipolar neurons; - have one dendrite and one axon. - are the most rare and found in our interneurons. 3. multipolar neurons; - has many dendrites and one axon. - are the most abundant and make up majority of our motor neurons. ...function classification... a. sensory neurons; (afferent) receive input from a stimulus and relay the information to the central nervous system. b. interneurons; between afferent and efferent neurons within the central nervous system. c. motor neurons; (efferent) relay messages from the central nervous system to effectors to elicit a response.

The Chemicals of Neuronal Communication; Define neurotransmitters.

Neurotransmitters - bind to chemical receptors on the postsynaptic membrane. - binding of a neurotransmitter to its receptor protein on the postsynaptic membrane activates the postsynaptic neuron through two mechanisms. ...two mechanisms... 1. ligand-gated channel receptors; - use direct mechanism of activation. - the channel opens when a neurotransmitter binds to the binding site and allows the diffusion of ions. - produces EPSPs or IPSPs. 2. G-protein couple receptors; - activate enzymes and second messengers to open channels/activate genes/induce protein synthesis. - an activated receptor activates a G-protein. - the activated G-protein mobilizes and travels to an effector protein.

One of the ~100 billion neurons in your brain fires an action potential. During the repolarization phase of that action potential, while the voltage-gated sodium channels are still inactivated, your neuron decides it wants to fire another action potential. Can it do so? Why or why not?

No. The neuron is in absolute refractory period, so no additional action potentials can be fired.

___ myelinate axons in the central nervous system.

Oligodendrocytes

Leak channels are ___.

always open

The Synapse and Chemical Communication of Neurons; Differentiate between EPSP-IPSP cancellation, spacial summation, and temporal summation.

Postsynaptic Potentials - changes in the postsynaptic neuron's membrane potential in response to a neurotransmitter. 1. EPSP; depolarizations specific for the postsynaptic neurons. - results from neurotransmitters binding to excitatory receptors on the postsynaptic membrane. - anions out and cations in. - more positive. 2. IPSP; hyperpolarizations specific for the postsynaptic neurons. - results from neurotransmitters binding to inhibitory receptors on the postsynaptic membrane. - anions in and cations out. - more negative. 3. EPSP-IPSP cancellation; when both EPSP and IPSP fire at the same time they cancel out, and the wobble neuron does not fire. 4. spacial summation; two EPSPs fire an action potential at the same time, and both are enough for the wobble neuron to reach threshold. The wobble neuron then fires an action potential and we wobble. 5. temporal summation; two EPSPs from one neuron come close together for the postsynaptic neuron to reach threshold and fire action potential.

Action Potentials; List and describe factors that affect speed of conduction of action potentials.

Propagation - also known as conduction. ...speed... - increased diameter of the axon. - increased by myelination. *myelination causes no voltage-gated ion channels because there is no loss of current in the myelin* 1. axon hillock; opening of voltage-gated Na+ (depolarization) followed by an opening of voltage-gated K+ (repolarization). 2. nodes of ranvier; high levels of voltage-gated Na+ and K+ channels. a. saltatory conduction; "jumping", action potentials will spread quickly from node to node.

Action Potentials; Explain the process of interruption of action potential propagation due to local anesthetics and Multiple Sclerosis.

Propagation 1. local anesthetics; bind to voltage-gated Na+ channels in sensory axons, preventing depolarization of action potential. - - the pain message is not able to be sent to the brain. 2. Multiple Sclerosis; autoimmune disease where the immune system starts to attack part of their body, specifically the myelin sheaths. - myelin sheaths are destroyed with inflammation, scarring, and hardening making the neuron non-functional.

Action Potentials; Define and describe the differences between absolute and relative refractory periods.

Refractory Periods 1. absolute refractory period; period where action potential can not fire another action potential. - voltage-gated Na+ completely inactivates. 2. relative refractory period; if strong enough stimulus occurs, then voltage-gated Na+ opens and action potential fires until membrane potential reached back to RMP. - voltage-gated Na+ close and voltage-gated K+ open.

___ regulate chemical environment of PNS somas.

Satellite cells

___ myelinate axons in the peripheral nervous system.

Schwann cells

Action Potentials; Explain how neurons communicate strength of signal.

Signals - all about action potential frequency. - the neuron is stimulated with electricity. - greater the stimulus, the faster the frequency of action potentials. 1. weak stimulus; (sub-threshold) stimulation below threshold where no action potential is produced. 2. larger stimulus; (supra-threshold) voltage goes up and is enough to reach threshold. 3. strongest stimulus; same amplitude regardless the strength of the stimulus , but a full action potential is produced.

The Synapse and Chemical Communication of Neurons; Explain, in order, the step-by-step events that occur at the synapse.

Synapse ...stages... 1. presynaptic neuron fires an action potential. 2. action potential travels down neuron to the axon terminal. 3. voltage-gated calcium channels open in response to action potential . 4. calcium flows into the cell. 5. the synaptic terminals filled with neurotransmitters are exocytosed. 6. neurotransmitters are sent into the synaptic space. 7. neurotransmitters diffuse across the synaptic cleft and binds to receptors on postsynaptic membrane. 8. the postsynaptic neuron responds by opening ligand-gated channels where only certain ions can flow through. 9. graded potentials in the post synaptic cell. ...purpose... - get neurotransmitters out. 1. neurotransmitters can be broken down by enzymes that are in the synaptic space. 2. neurotransmitters can be taken back up into the presynaptic terminal through uptake transporters. 3. neurotransmitters can diffuse away from the synapse.

The Synapse and Chemical Communication of Neurons; Define synapse.

Synapse Intracellular junctions that exist between excitable cells (neurons and muscles) and transfer information from one neuron to the next.

The Synapse and Chemical Communication of Neurons; Identify the components of the synapse.

Synapses 1. electrical synapses; have gap junctions where the ions can pass from one cell to another cell. ex. smooth muscle and cardiac muscle 2. chemical synapses; have no gap junctions and rely on neurotransmitters. ex. neurons and effector tissues (muscles and glands) a. presynaptic; when the presynaptic terminal releases neurotransmitters from the presynaptic vesicles in the axon terminal. b. postsynaptic; (effector cell) receives the chemical signal. 1. axodendritic synapse; when the chemical signal takes place between the axons of the presynaptic neuron and the dendrites of the postsynaptic neuron. 2. axosomatic synapse; when the presynaptic neuron forms a synapse with the soma of a postsynaptic neuron. 3. axoaxonic synapse; when the axon of the presynaptic neuron forms a synapse with axon of the postsynaptic neuron.

Your Aunt Selena is very concerned about her wrinkles. Though you try assuring her that wrinkles are beautiful and are a sign of a life well lived, your aunt decides to get a botox treatment. How does botox work?

The botulinum neurotoxin from Claustridum botulinum is injected into skeletal muscle. Botulinum is endocytosed into the motor neuron and it cleaves the SNARE proteins. Because SNARE proteins have been destroyed, vesicles containing neurotransmitters can not dock and fuse, and no neurotransmitters are released. This then prevents muscle contraction and the skeletal muscle relaxes and softens, and wrinkles are minimized.

Which of the following are true of the central nervous system? a. The brain and spinal cord are part of the CNS. b. The autonomic nervous system falls under the CNS. c. The CNS is the integration and control center. d. Satellite cells are abundant in the CNS.

The brain and spinal cord are part of the CNS. The CNS is the integration and control center.

What happens when an excess of acetylcholine (ACh) is in the synapse?

The enzyme acetylcholinerase breaks acetylcholine into acetic acid and choline.

Which of the following are true of myelination? a. The spaces between myelination are called "nodes of ranvier". b. Myelination increases speed of action potential propagation. c. Areas of the brain and spinal cord that have high density of myelination are called "gray matter" regions. d. Myelination is made by Schwann cells in the central nervous system and by oligodendrocytes in the peripheral nervous system. e. Myelination protects and electrically insulates axons.

The spaces between myelination are called "nodes of ranvier". Myelination increases speed of action potential propagation. Myelination protects and electrically insulates axons.

Electrical Communication of Neurons; Define threshold and explain the importance of the axon hillock as it pertains to action potentials.

Threshold - point of no return, all or none. 1. axon hillock; where action potentials are generated. 2. propagation; when that action potential travels down the axon to the axon terminals. - the speed of propagation can be increased by thicker diameter of the axon and myelination. 3. neurotransmitters; vesicles filled with chemicals at the end of the axon terminals.

Ependymal cells are found in the central nervous system. True or False?

True

Choose the best description of hyperpolarization during an action potential. a. Voltage gated K channels remain open after initially opening during repolarization. This causes the neuron to become more negative than resting membrane potential. b. Voltage gated Na channels go directly from being open to being closed after staying open during the entirety of repolarization. This causes the neuron to become more negative. c. Voltage gated K channels stay closed after closing during repolarization. This causes the neuron to become more negative than resting membrane potential. d. Voltage gated Ca channels open once hyperpolarization begins. This causes the neuron to become more positive and closer to threshold.

Voltage gated K channels remain open after initially opening during repolarization. This causes the neuron to become more negative than resting membrane potential.

A neuron is firing an action potential. Before it fires a second action potential, which of the following must occur? a. The neuron must fully return to resting membrane potential before firing another action potential. b. Voltage gated K channels must close in order to fire another action potential. c. Voltage gated Na channels must inactivate then close in order for another action potential to be fired. d. Na channels must remain open in order for the neuron to continue to become more positive so that another action potential can be fired.

Voltage gated Na channels must inactivate then close in order for another action potential to be fired.

What are voltage-gated channels?

Voltage-gated channels open and close in response to electrical stimulus.

What is the most common neurotransmitter in the body?

acetylcholine

Satatory conduction is when ___.

action potential jumps from node to node

Multiple Sclerosis is ___.

an autoimmune disease in which one's own immune system attacks the myelin sheaths, causing them to become sclerotic (hard) and then non-functional

Which of the following neuroglia cells help make the blood brain barrier? a. Schwann cells b. oligodendrocytes c. ependymal cells d. satellite cells e. astrocytes f. microglial cells

astrocytes

Which type of neuroglia controls the extracellular environment around neuron cell bodies in the central nervous system?

astrocytes

In the CNS, ___ maintain the proper chemical environment for neurons while ___ maintain the chemical environment for neurons in the PNS.

astrocytes, satellite cells

When a presynaptic neuron synapses on the axon of a postsynaptic neuron, it is called ___.

axoaxonic synapse

An action potential is created in the ___.

axon hillock

When a presynaptic neuron synapses on the cell body of a postsynaptic neuron, it is called ___.

axosomatic synapse

Local anesthetics (lidocaine) work by ___.

blocking voltage-gated Na+ channels

Postsynaptic potentials are ___.

changes in membrane potential of the postsynaptic neuron in response to a neurotransmitter binding to a receptor on the postsynaptic neuron

Neurons communicate via ___ signals in the synaptic cleft.

chemical

Neurons that have acetylcholine are called ___.

cholinergic neurons

How is the strength of stimulus determined?

frequency

According to Ohm's law, if resistance increases then ___.

current decreases

Which of the following factors will not increase the speed of an action potential? a. increased axon diameter b. high amounts of myelination d. decrease the axon diameter e. a and b

decrease the axon diameter

Nicotinic acetylcholine receptors are ___ receptors that cause the opening of ___.

direct ligand-gated, Na+ channels

Cerebrospinal fluid flows through the ventricles of the brain and supplies nutrients to the brain while also offering the brain buoyancy. Which of the following neuroglia cells help make cerebrospinal fluid? a. astrocytes b. oligodendrocytes c. microglial cells d. ependymal cells e. satellite cells f. Schwann cells

ependymal cells

Refer to the image. Point D is which phase of an action potential?

hyperpolarization

Which of the following increases the magnitude of an action potential? a. increasing frequency b. increasing amplitude c. decreasing amplitude d. higher voltage

increasing frequency

Bipolar neurons are for ___.

interneurons

Which ion channel type opens in response to chemicals binding to it?

ligand-gated channels

While taking this test, you accidentally drop your pencil and hit your knee on the table while trying to pick it up. Physically bumping into the table likely activated what channels in your knee?

mechanically mediated channels

Motor neurons send information from the Central Nervous System to target organs and glands. Motor neurons can correctly be classified as which of the following? a. multipolar neurons b. unipolar neurons c. bipolar neurons d. afferent neurons e. efferent neurons f. interneurons

multipolar neurons, efferent neurons

Which of the following influences the speed of action potential propogation? a. myelination b. diameter of an axon c. diameter of a dendrite d. diameter of a neuron cell body

myelination, diameter of an axon

___ ACh receptors are ligand-gated ion channels, and ___ ACh receptors are G-protein coupled receptors.

nicotinic, muscarinic

The spaces between myelination on an axon are called ___ and contain a high concentration of voltage-gated ___ channels that allow for saltatory conduction.

nodes of ranvier, Na+ and K+

At resting membrane potential, the cell has a high concentration of which ion due to the Na+/K+ ATPase?

potassium, K+

Action potential flows down the axon via ___.

saltatory conduction

Which type of neuralgia controls the extracellular environment around neuron cell bodies in the peripheral nervous system?

satellite cells

What branch of the nervous system is responsible for communicating stimulation from afferent receptors to the central nervous system?

sensory divison

A postsynaptic neuron receives two excitatory postsynaptic potentials from two different neurons. What type of stimulation is this?

spatial summation

One presynaptic neuron releases two excitatory postsynaptic potentials (EPSP) on the postsynaptic neuron. What type of summation is this?

temporal summation

This neuron has a fused dendrite and axon and makes up the majority of sensory neurons.

unipolar neuron

Sensory neurons gather information from the external and internal environments, and send that information to the Central Nervous System for processing. Sensory neurons can also correctly be classified as which of the following? a. multipolar neurons b. unipolar neurons c. bipolar neurons d. afferent neurons e. efferent neurons f. interneurons

unipolar neurons, afferent neurons

What channels are found on the nodes of ranvier?

voltage-gated Na+ and voltage-gated K+

Which ion channel type opens in response to changes in membrane potential?

voltage-gated channels

Refer to the image. Which channels are opening during point B?

voltage-gated sodium channels