11. Neurophysio Set 2

08 #20 What happens during synaptic potential?

presynaptic cell is stimulated repeatedly or continuously, enhancing the release of neurotransmitter.

(3C) What term is used to define how Action Potentials are to be transmitted from the starting point along the axon toward terminals?

propagation

03. #30 A ___________________ neuron is a type of neuron which has two extensions. a. bipolar b. multipolar c. pseudounipolar

The correct answer is a. A bipolar neuron is a type of neuron which has two extensions.

04 #11 Another action potential can't occur before the end of the absolute refractory period because: a) The potassium channels are open b) The stimulus is not strong enough c) The sodium channels are inactivated

The correct answer is c) The sodium channels are still inactivated

Group 2 - #8 Let's think about a voltmeter attached to two terminals of a battery. If we take a difference of the voltages between the two terminals, what do you think it is? So If a voltmeter is used to measure the voltage across the cell membrane (inside versus being outside), the inside has a negative voltage and a positive voltage. What type of membrane potential would this be considered as?

resting membrane potential

When a neurotransmitter and its receptor result in hyperpolarization of the postsynaptic membrane it is called what? A) Inhibitory postsynaptic membrane B) Excitatory postsynaptic membrane C) Axoaxonic synapses

The answer is A, inhibitory postsynaptic membrane

In excitatory postsynaptic potential, action potentials occur where? A) Dendrites B) Axon hillock C) Schwann cell

The answer is B, axon hillock that is the trigger zone where all action potentials occur.

Can excitatory postsynaptic potential cause an action potential? A) Yes, right after depolarization B) No due to hyperpolarization C) Yes, after depolarization but only if it reaches threshold

The answer is C, excitatory postsynaptic potential will cause an action potential if depolarization reaches threshold

Can excitatory postsynaptic potential cause an action potential? A) Yes, right after depolarization B) No due to hyperpolarization C) Yes, after depolarization but only if it reaches threshold

The answer is C, excitatory postsynaptic potential will cause an action potential if depolarization reaches threshold.

Group 8, #4 What are the options for the integration of post-synaptic potentials be: A. spatial summation B. Temporal summation C. Neither D. Both

The answer is D: both The integration of post-synaptic potentials can be either spatial summation and temporal summation. Spatial summation: post-synaptic neuron is stimulated by different terminals simultaneously. Temporal summation: Post-synaptic occur in the same terminal in a rapid fire order.

As you are taking this exam, you perceive a "pit in your stomach." Your ability to sense this stems from the (P): A) somatic sensory (afferent) division B) visceral sensory (afferent) division C) sympathetic division D) parasympathetic division E) two of the above are correct

The correct answer is (B). The ability to perceive is a characteristic of the sensory, not motor, division, and the origin of this sensation is viscera.

Within an axodendritic synapse and along the axon membrane, one may find all except: A) voltage-gated channel B) mechanically gated channel C) ligand-gated channel D) leakage channel E) all of the above can be found in an axodendritic synapse and along the axon membrane

The correct answer is (E). Leakage channels are seen in all parts of all cell membranes, except for myelinating cells. Dendrites have receptors for stimuli (mechanical and chemical--or ligand) that are linked to ion channels that give rise to graded potentials, and along the axon membrane you will find voltage-gated ion channels which propagate action potentials.

Graded potentials can be: Polarized Hyperpolarized Interpolarized A and B

The correct answer is A and B. Graded potentials can be Polarized and Hyperpolarized at certain points.

Graded potentials that occur in RESPONSE to a neurotransmitter released from another neuron is called: Presynaptic Synaptic Sensory Postsynaptic

The correct answer is Postsynaptic. These occur in response (hence, post-) to a neurotransmitter.

Occurs on receptors of sensory neurons: Synaptic Postsynaptic Receptor potentials Presynaptic

The correct answer is Receptor potentials. Sensory neurons are called in from PNS receptors.

(04) #6 True or False During the relative refractory period, a second response can occur.

The correct answer is True After action potential, the cell is repolarizing. During this time period, a strong stimulus could trigger a second action potential.

11.7) 06 #24 When an action potential arrives at the pre-synaptic terminal, it causes which of the following... A. Ligand-gated sodium channels to open. B. Calcium ions to diffuse into the cell. C. Sodium ions to diffuse into the cell. D. None of the above.

The correct answer is: B. Calcium ions to diffuse into the cell.

the myelin sheath

What allows the action potential to stay the same during Saltatory Conduction? (Group 5, #23)

A neuron with many nerve fibers arising from its cell body and that carries impulses away from the brain would be classified as___________________? (03-#13) a) multipolar b) bipolar c)unipolar and sensory d) multipolar and motor

d) multipolar and motor

03c Action Potentials happen over a short distance. True or False

03c False Graded potentials happen over a short distance since there is a decaying of the neurotransmitter.

03c True or False There are 3phases that happen during the generation of an action potential. 1) depolarization 2) Repolarization 3)Hyperpolarization

03c True Depolarization : Opening of the sodium gated channels increasing the millivolts to -55.( Threshold) Repolarization : closing of gated Na+ and opening K+ voltage gated channels causing the membrane potential to repolarized bring it back to resting potential -70mV Hyperpolarization: voltage gated K+ channels remain open after the potential reaches resting level.

In Saltatory Conduction, action potentials are only generated in which part of the neuron? A. Dendrite B. Myelin Sheath Gaps C. Axon Terminal D. Axon Hillock

B - APs are only generated in myelin sheath gaps because the myelin sheath insulates the charges riding along the axon.

Which of the following is true about TEMPORAL SUMMATION? (Group 8 #19) A) 2 Simultaneous stimuli at different locations cause ESPSs that add together. B) 2 Excitatory stimuli close in time cause ESPSs that add together.

B) 2 Excitatory stimuli close in time cause ESPSs that add together.

Which of the following is NOT true of the elimination on a neurotransmitter effect in the synapse? (Group 6 #29) A) Elimination of effect will diffuse out of the synapse B) Neurotransmitter effect will stay within the synapse C) Enzymes can eliminate graded potentials D) Astrocytes reuptake neurotransmitter effect

B) Neurotransmitter effect will stay within the synapse

Group 7 #20 What is Depolarization? A) Negative charge neuron B) Positive charge neuron C) Neutral charge neuron

B) Positive charge neuron It's the first stimulus that causes sodium channels to open. Since sodium has a positive charge, the neuron becomes more positive and becomes depolarized.

During saltatory conduction, which type of channel is located at myelin sheath gaps? A. Mechanically-gated channels B. Electrically-gated channels C. Voltage-gated channels D. None of the above

C - Voltage-gated channels open in response to changes in membrane potential.

The site for triggering action potential by excitatory postsynaptic potential (EPSP) is at the _______. A. Ganglia B. Nodes of ranvier C. Axon hillock D. Nucleus (8)

C. Axon hillock

In which way does the spread of ions occur in a graded potential? (02 #17) A. forward only B. Backward only C. Bidirectionally

C. Bidirectionally.

(Group 4, #35) At the membrane of an axon, the initial threshold potential is -30 mV, resting potential is -50 mV and the membrane is currently in a hyperpolarized state. If a second stimulus of +20 mV is presented, will the initial threshold be reached? A. Yes, because the current action potential at the membrane is in its relative refractory period phase and the voltage of the 2nd stimulus is sufficient enough to initiate response. B. No, because the current action potential at the membrane is in its absolute refractory period phase. C. No, because the current action potential at the membrane is in its relative refractory period phase and the voltage of the 2nd stimulus is not sufficient enough to initiate response. D. There's not enough data to determine.

C. No, because the current action potential at the membrane is in its relative refractory period phase and the voltage of the 2nd stimulus is not sufficient enough to initiate response: the membrane is currently hyperpolarized, which tells us that the minimum threshold voltage of 20mV [-30-(-50) = 20] wouldn't be great enough.

Which two parts are required to make up a chemical synapse? a. axon terminal, myelin sheath b. dendrite, neurotransmitter receptor c. axon terminal, neurotransmitter receptor d. none of the above (Group6, #6)

C. axon terminal, neurotransmitter receptor

01C In the autonomic nervous system which cranial nerves do the preganglionic parasympathetic axons run in or exit? A.) Trochlear, Hypoglossal and Olfactory nerves. B.)Facial, Abducens and Trigeminal nerves C.) Oculomotor, glossopharyngeal, facial, sacral spinal and vagus nerve. D.) None of the above (27)

C.) Oculomotor nerve, glossopharyngeal nerve, facial nerve, sacral spinal nerve and vagus nerve.

After an action potential, the membrane becomes more negative than -70 mV. This period is called: A)depolarization. B)hyperdepolarization. C)hyperpolarization. D)repolarization.

C:hyperpolarization.

03c What is the resting potential of a neuron? A) +30 mV B) 0 mV C) -70 mV D) +70 mV

Correct answer C) -70 mV

Group 1(#13) Where does the graded potential occur ? A. dendrites, cell bodies, sensory receptors ; B. dendrites, cell bodies; C. axon ; D. dendrites, sensory receptors.

Correct answer is A Graded potentials occur in dendrites, cell bodies and sensory receptors. Graded potentials dissipate with distance from stimulus.

Which of the following is NOT correct regarding saltatory conduction? A. Continuous conduction moves slower than Saltatory conduction B. In Saltatory conduction, signals appear to jump from gap to gap C. Myelin sheaths insulate and prevent leakage of charges D. All of the above are correct

D - All of the above are correct

Once an action potential has been triggered, which of these phases takes place: A. Depolarization B. Re-polarization C. Hyper-polarization D. All the above (23)

D) All the above.

(3C) The soma, also known as the cell body of the neuron, contains the typical organelles found in a cell except which of the following? A) Nissl granules B) Rough ER C) Golgi complex D) Centrioles E) Mitochondria

D) centrioles

(3C) Action potentials are long distance signal formed on receptor endings True or False

False Explanation: Although action potentials are long distance signals, they are NOT found on receptor endings. Those are GRADED potentials.

True or False During an Action Potential, Na+, K+, and H+ channels are involved.

False H+ is not involved in during the Action Potential. Gated Na+ channels open during depolarization. K+ channels open and Na+ channels close when the membrane tries to restore resting potential during repolarization.

Group 7 :Does the excitatory post synaptic potential's (EPSP), drive the neuron away from AP thershold ? True or False

False, The EPSP brings the neuron closer to AP thershold.

Group 7, #14 True or False At excitatory synapses, neurotransmitters hyper polarize the membrane by making more permeable K+ or moving membrane potential away from threshold, and making generation of an action potential less likely.

False, the above explanation corresponds with inhibitory synapses. At excitatory synapses, neurotransmitters bond to chemically gated ion channels, causing depolarization of the membrane, and generation of excitatory postsynaptic potentials that can trigger action potentials at the axon hillock if they are of adequate strength.

When depolarization occurs, IPSPs occurs. True or False? (33)

False. EPSP occurs. the response is stimulatory.

IPSPs are generated due to increase in permeability to Na+ of the plasma membrane. True or False?(33)

False. IPSPs are generated due to increase in permeability to K+ or Cl- of the plasma membrane. (33)

True or false: Graded potentials and action potentials both depolarize in one direction (02, 22)

False: Both action potentials and graded potentials depolarize bidirectionally

05C: T/F: Continuous Conduction is faster than Saltatory conduction

False; Saltatory conduction is about 50x's faster than continuous conduction due to the nature of how it travels between the gaps of the node of ranvier.

What is saltatory conduction and how is it different from continuous conduction ? 05/#23

In saltatory conduction, the nerve impulse will jump between the spaces between the nodes of Ranvier (the pieces of insulation that surround the neuron). This is faster than continuous conduction, where the nerve impulse travels down the whole unmyelinated neuron.

what is the process of Neurotransmitter? (28)

Neurotransmitter opens chemically gated ion channels which allows NA+ and K+ to pass simultaneously.

(3C) Myelin sheaths are key components in increasing the strength of a signal. It surrounds the axon and facilitates the transmission of an impulse by acting as a conductor. What cells form the sheaths in the CNS?

Oligodendrocytes In the PNS the cells that create the myelin sheath are Schwann cells

________________ Conduction occurs in Myelinated axons and is faster, while __________________ Conduction occurs in nonmyelinated axons and is much slower.

Saltatory / Continuous Saltatory conduction is about 30 times faster than Continuous conduction because the Myelin Sheaths provide electrical insulation, preventing leakage of charge.

objective 11.7 0.6 #15 Which of the following are the true on synapse, the structure and the way it transmits information? A) space between two cells that allows for communication B) You can find synapse in the heart C) Synapse goes by the name of synaptic cleft or synaptic junction D) Pre synaptic region, post synaptic region and synaptic cleft E) Neurotransmitters are use to communicate the signal from one cell to the next. and then rebuild to recreate it and destroy it for later used, which is called re uptake mechanism F) All of he above

F) All of the above

Membranes have gated and leakage channels, can Na+ go through a K+ channel ? TRUE or FALSE (13)

FALSE the action gate and inaction gate potential can only consist of the NA+ gate. Same goes for K+.

What is the difference between a nerve and a tract? (2).

A nerve delivers information to and from the Central Nervous System, where as a tract is part of the circuit where decisions are being made.

05C: What is the main difference between Saltatory conduction and Continuous conduction?

A. In Saltatory conduction, nerve impulses jump between the spaces of the nodes of ranvier, whereas in Continuous conduction, nerve impulses travel down the entire length of the unmyelinated neuron

What usually returns the membrane potential back to the resting membrane potential? A. Repolarization B. Depolarization C. Hyperpolarization D. Polarization

A. Repolarization

When a postsynaptic neuron reaches threshold and triggers action potential due to release of stimuli from multiple presynaptic neurons is called ________? A. Spatial summation B. Temporal summation C. Excitatory synapse D. Inhibitory synapse (8)

A. Spatial summation

Group 7, #36 An information transfer across chemical synapses can not occur without what happening first?

An action potential arriving at the axon terminal.

How long is the relative refractory period of neurons?(04.#12) a) 1-3 ms b) 5-10 ms c) 10-100 ms d) 3-5 ms

Answer D- 3-5 ms

A stronger-than-threshold stimulus can initiate another action potential during the absolute refractory period. (Group 4, #32) True or False

Answer is False. It can only happened during the relative refractory period. While complete insensitivity exists to another stimulus occurs in the absolute refractory period.

(06c) List the following in order: 1. Ca2+ entry causes synaptic vesicles to release neurotransmitter by exocytosis. 2. Neurotransmitter effects are terminated. 3. An AP arrives at the presynaptic terminal. 4. Neurotransmitters diffuses across synaptic cleft and binds to specific receptors on the postsynaptic membrane. 5. Voltage-gated Ca2+ channels open, Ca2+ enters the presynaptic terminal. 6. Binding of neurotransmitter causing (ligand-gated Na+) ions channels opens, Na+ diffuses into/out to the cell, creates a change in membrane (graded) potential.

Answer: 3, 5, 1, 4, 6, 2

List the following in order: 1. Ca2+ entry causes synaptic vesicles to release neurotransmitter by exocytosis. 2. Neurotransmitter effects are terminated. 3. An AP arrives at the presynaptic terminal. 4. Neurotransmitters diffuses across synaptic cleft and binds to specific receptors on the postsynaptic membrane. 5. Voltage-gated Ca2+ channels open, Ca2+ enters the presynaptic terminal. 6. Binding of neurotransmitter causing (ligand-gated Na+) ions channels opens, Na+ diffuses into/out to the cell, creates a change in membrane (graded) potential.

Answer: 3, 5, 1, 4, 6, 2

(Group 4 Roster #7) Which of the following refers to a cluster of axons in the PNS? A) Ganglion B) Nerve C) Nucleus D) Tract

Answer: B - Nerve Ganglion = cluster of cell bodies in PNS Nucleus = cluster of cell bodies in CNS Tract = cluster of axons in CNS

(3C) What step must occur in order for potassium (K+) channels to open when generating an action potential? A) Depolarization B) Hyperpolarization C) Repolarization D) Na+ channels inactivate E) Both C and D

Answer: C and D Repolarization is what allows the membrane potential to go back to its resting state. This occurs just as the sodium channels are inactivated which thus allows the K+channels to open

Graded potentials in dendrites are characterized by: (01) A)Short distance signals B)leakage of current through Na+ leakage channels C)voltage increasing with distance from the stimulus D)A&B E)A&C (18)

Answer: D) Graded Potentials are characterized by short distance signals. Voltage decreases with distance from the stimulus due to the Na+ leakage channels in the membrane.

In _________ synapses, neurotransmitters cause the membrane to become permeable to __ions, which makes an action potential less likely to occur. (17) A. Excitatory, K+ B. Inhibitory, Na+ C. Excitatory, Na+ D. Inhibitory, K+

Answer: D, Inhibitory, K+ Inhibitory synapses cause the membrane to become more permeable to potassium (K+) which is a slower moving ion that moves the membrane further from threshold. This, in turn, makes it less likely to generate an action potential along the following neuron or receptor site.

(06c) What is correct concerning a depolarization at a synapse? A. It is an excitatory synapse B. associated with a neurotransmitter acetylcholine and norepinephrine C. It could lead with a production of an action potential that occur at the trigger zone of a post synaptic neuron D. Includes a creation of EPSP E. All of the Above

Answer: E. All of the above

(06c) In a chemical synapse, A. Action potentials in the presynaptic terminal cause voltage-gated Ca+ channels to open B. Neurotransmitters can be broken down by enzymes C. Neurotransmitters can cause ligand-gated Na+ channels to open D. Neurotransmitters can be taken up by the presynaptic terminal E. All of the above are correct

Answer: E. All of the above are correct

True or False? Graded potentials and action potentials are both long distance? group 2 (#6)

Answer: False, action potentials are long distance found in the axon while graded potentials are short distance found in synapses.

What is Graded Potentials?(2)

Answer: Graded potentials (local potentials) occur in the receptive (dendrites & cell bodies) due to opening of chemically gated channels that allow small ion amounts to cross the membrane and the altered charge may result in a change in polarization. Degree of change depends on how many molecules make it through and decreases intensity over distance-usually only lasting a short time.

In the Peripheral Nervous System (PNS) what is the name of the Neuroglial cells? and what is their function in the PNS and their characteristics. A). Oligo dendrocytes- Insulate the axons, one cell mylenate- several axons. B). Schwann Cells-Insulate the axons, several cells mylenate- one axon cell. C). Non-ciliated ependymal cells-secrete spinal fluid. (Group 2, #15)

B). Schwann Cells- Insulate the axons by using several cells to mylenate one axon cell.

(O2) #2 Action Potential only occurs in a ____________________ direction A. Backward B. Forward C. All the above

B. AP occurs only in a Forward direction

05C: What ions are associated with: depolarization, repolarization, and hyperpolarization? (De-, Re-, Hyper-)

B. De- Sodium; Re- Potassium; Hyper- Chloride

05C: What cells are myelinated in the CNS?

B. Oligodendrocytes; Oligodendrocytes are the myelinated nerve cells in the CNS. Schwann cells are also myelinated but reside in the PNS

05C: Schwann cells are myelin producing cells of what system?

B. Peripheral nervous system; Schwann Cells are myelin producing cells of the PNS which includes all nerves aside from the brain and spinal cord.

When a membrane potential (Vm) reaches threshold and triggers action potential due to multiple release of a neurotransmitter over time it is called _____. A. Spatial summation B. Temporal summation C. Excitatory synapse D. Inhibitory synapse (8)

B. Temporal summation

All but which of the following describe graded potentials? A. The amplitude is proportional to the strength of the stimulus B. Voltage-gated Na+ and K+ channels are responsible for the potential C. No refractory period is associated with graded potentials D. Amplitude diminishes as the potential travels away from the initial site

B. Voltage-gated Na+ and K+ channels are responsible for the potential *Ion channels responsible for graded potentials may be ligand-gated, mechanosensitive, or temperature sensitive channels

Action potential ___________ occurs in ________ direction(s) because the recently depolarized area of the membrane is in an _______ refractory period and cannot generate an action potential. (02,12) A. depolarization, two, absolute B. propagation, one, absolute C. stimulus, one, relative D. threshold, both, potassium

B. propagation, one, absolute

01C An adrenergic nerve fiber is a neuron for which the neurotransmitter released is either: A.)Serotonin or Acetycholine B.) Adrenaline (Epinephrine), Noradrenaline or Dopamine. C.) Just Endorphins D.) Gaba, Glutamate or Adrenaline (Epinephrine) (27)

B.) Adrenaline (Epinephrine), Noradrenaline or Dopamine.

Which of the following statements about the conduction velocity of action potentials along myelinated axons as compared to that along unmyelinated axons, is false? A)Conduction velocity is very fast, approaching 225 miles per hour. B)Cable properties within the axon help increase the conduction velocity. C)Nodes of Ranvier increase the conduction velocity by saltatory conduction. D)Thinner fibers conduct action potentials faster than thicker fibers.

D)Thinner fibers conduct action potentials faster than thicker fibers.

Group 7: What charge difference is a dam like at rest A. -100 mV B.-80 mV C. 70 mV D. -70mV

D: -70 mV

(06c) In a chemical synapse, A) Action potentials in the presynaptic terminal cause voltage-gated Ca+ channels to open B) Neurotransmitters can be broken down by enzymes C) Neurotransmitters can cause ligand-gated Na+ channels to open D) Neurotransmitters can be taken up by the presynaptic terminal E) All of the above are correct

E) All of the above

(06c) What is correct concerning a depolarization at a synapse? A) It is an excitatory synapse B) associated with a neurotransmitter acetylcholine and norepinephrine C) It could lead with a production of an action potential that occur at the trigger zone of a postsynaptic neuron D) Includes a creation of EPSP E) All of the above

E) All of the above

05C: What is the purpose of Myelin in nerve cells?

E. B and C (B. to insulate electrical impulses & C. to increase the speed of electrical communication between neurons); Myelin expedites the transmission of electrical impulses by insulating and containing their energy as they travel from neuron to neuron. A lack of myelin would allow the electrical impulses to disperse and lose their electrostatic level/properties.

Which of the following is true about the structure of Chemical Synapses? (Group 6 #16) A. Axon terminals have a single synaptic vesicle to store and secrete neurotransmitters. B. Axon terminals have numerous synaptic vesicles to store and secrete neurotransmitters. C. Neurotransmitter receptor region is located on a dendrite D. Both A and C E. Both B and C

E. Both B and C

Continuous conduction occurs in unmyelinated nerves. True or false?(05 - 21)

True! Continuous conduction occurs in unmyelinated cells and involved step my step depolarization and repolarization.

A graded potential is produced when a ligand opens a ligand-gated channel in the dendrites? True or false? (01),#22

True. A graded potential is produced when a ligand opens a ligand-gated channel in the dendrites, allowing ions to enter (or exit) the cell making both reach equilibrium.

A EPSP occurs due to a change in membrane permeability. True or false? (33)

True. A EPSP occurs because the membrane has become more permeable to Na+. The negative charge in inside the cell attracts Na+

(04-9) True or false? The absolute refractory period is the first part of the refractory period during which complete insensitivity exists to another stimulus.

True. A refractory period is when once an action potential is produced at a given point on the plasma membrane, that area becomes less sensitive to further stimulation. The absolute refractory period is indeed the first part of the refractory period.

True or False, Leak channels allow leakage of ions to diffuse and decrease in magnitude. (class EG, Group 1, Roster#22)

True. Leak channels allow leakage of ions to decrease magnitude while Voltage channels allow an increase of magnitude.

During saltatory conduction, a nerve impulse jumps from one ___________ to another. (#21 group 5) a. Myelin sheath b. synapse c. node of ranvier d. dendrite e. axon

answer c. Node of Ranvier

(3C) The three structural classes of neurons include: multipolar, bipolar, and unipolar neurons. What is one distinguishing characteristic that varies amongst the three? a) Number of somas b) Number of dendrites/processes c) Location of the soma d) None of the above

b) Number of dendrites/processes

Action potentials can spread across the plasma membrane because a. they bind with receptors in adjacent cells of the membrane. b. an action potential produced at one point of the plasma membrane stimulates the production of action potentials at adjacent points. c. the local current produced by an action potential activates electrical synapses in the plasma membrane, stimulating surrounding cells. d. neurotransmitters are released, causing a positive feedback effect in which neurotransmitters are released to stimulate more action potentials across the plasma membrane. (32)

b. an action potential produced at one point of the plasma membrane stimulates the production of action potentials at adjacent points.