Action potentials

1. 1The following are the main steps involved in the generation of action potential:
   1. potassium channels open and potassium leaves the cell resulting in repolarization
   2. stimualtion of the neuron brings the membrane potential to threshold
   3. sodium channels open
   4. depolarization occurs
   5. sodium enters the neuron
   6. a temporary hyperpolarization occurs
   
   Which one of the following is the correct order?

   1. A3,5,6,1,4,2
   2. B 2,4,3,5,1,6
   3. C. 2,3,5,4,6,1
   4. D2,3,5,4,1,6
   5. E5,3,6,1,4,2
2. 2Action potentials signal different intensities of information by changing in:

   1. AConduction velocity relative to the strength of the stimulus
   2. BFrequency relative to the strength of the stimulus
   3. CShape relative to the strength of the stimulus
   4. D Duration relative to the strength of the stimulus
   5. EAmplitude relative to the strength of the stimulus
3. 3Once an action potential is initiated, the first major electrial change occuring is?

   1. APropagation of an action potential
   2. BAn increase in the negative charge inside the neuron
   3. CClosure of potassium channels
   4. D Reversal of membrane polarity and the inside of the neuron becomes positively charged
   5. EThe opening of potassium channels
4. 4The value of the membrane potential which must be reached to generate an action potential is called the?

   1. Athreshold
   2. B triggering voltage
   3. Cminimum voltage
   4. Dtriggering charge
   5. E voltage potential
5. 5Neurons are able to signal changes in the intensity of stimulation e.g. bright light/dim light by changes in?

   1. A the duration of action potentials
   2. Bthe shape of the action potential
   3. Cthe frequency at which action potentials are transmitted along an axon
   4. Dthe speed with which action potentials are transferred along the axon
   5. Ethe size of action potentials
6. 6Which one of the following statements about neurons is true?

   1. ADendrites are found in the myelin sheath
   2. B. Nodes of Ranvier convey action potentials towards the cell body
   3. CThe cell body houses the nucleus and other organelles
   4. DDendrites convey action potentials to other cells
   5. EDendrites release neurotransmitters
7. 7Opening of sodium channels in the neuronal membrane, results in which one of the following?

   1. Adepolarization
   2. Bincreased negative charge inside the cell
   3. Crepolariztion
      
   4. Dhyperpolarization
   5. Epolarization
8. 8The space between an axon terminal and dendrite is called the?

   1. Asynaptic knob
   2. B. synapse
   3. Cdendron
   4. Dgap junction
   5. Eterminal bouton
9. 9In comparison to action potentials, graded or receptor potentials?

   1. Aare all or none
   2. Bare always mediated by Na ions
   3. Cdo not require a stimulus
   4. Dvary in size
   5. E do not depend upon changes in membrane potential
10. 10For the inside a positively charged neuron to become negatively charged again takes how many long

    1. A2 minutes
    2. B5 seconds
    3. C30 second
    4. D1 hour
    5. EIt will not fully become negative following an action potential

11. 11 Which of the following initiate actions from the neurons;
    Sensory receptors or drug induced stimulus or electrically induced stimulus

    1. ANon of them
    2. BAll of them
    3. C Sensory receptors and drug induced stimulus only
    4. D Sensory receptors
    5. EDrug induced stimulus
    6. FElectrically induced stimulus
12. 12Which of the Following is NOT one of the 3 phases that make up an action potential

    1. ADepolarization
    2. BHyperdepolarization
    3. CAfter- hyperpolarization
    4. Drepolarization
13. 13Which phase action potential is responsible for the rapid opening of membrane Na+ channels and influx of Na+ ions

    1. ADepolarization
    2. BRepolarization
    3. CHyperpolarization
    4. DAfter-hyperpolarization
14. 14Which of the phase of the action potential is responsible for the closing of Na+ channel close and K+ channels open. The K+ and the Postive chrage leave the neuron. Causing the membrane potential begins to decrease.

    1. ADepolarization
    2. BRepolarization
    3. CHyperpolarization
    4. DAfter-hyperpolarization
15. 15Which of the ion channel are slowest to close

    1. ANa+
    2. BK+
    3. CCl-
    4. DCa2+
16. 16Which phase during an action potential cause more K+ leaves the neuron leaves than necessary to return to RMP causing the potential to fall below the RMP

    1. ADepolarization
    2. BRepolarization
    3. CHyperpolarization
    4. DAfter-Hyperpolarization
17. 17The threshold For a membrane potential is

    1. A-40mV
    2. B+40mV
    3. C-55mV
    4. D-70mV
    5. E-90mV
    6. F-15mV
18. 18The period during which the neuron is either unresponsive to a second stimulus or an increased stimulus intensity is required to generate an second action potential is known as the

    1. ARefraction period
    2. BRefractory period
    3. CReflection period
    4. DResponsive period
    5. EUnreponsive period
19. 19A neuron is unresponsive to a stimulus for a second time irrespective of increased intensity. What is this period known as?

    1. AReflection period
    2. BAbsolute reflection period
    3. CAbsolute refractory period
    4. DRefractory period
    5. EThis doesnt usually occur
20. 20Where are action potenital generated from

    1. ADendrites
    2. BAxon terminals
    3. CNucleus
    4. DAxon hillock
    5. EMylinated sheath
21. 21The local current change takes place outside the cell

    1. AVerdadero
    2. BFalso
22. 22The depolarization of one section of the membrane depolarizes the one next to it down the axon

    1. AVerdadero
    2. BFalso
23. 23The relative___________ period corresponds to the depolarizing and after ______________ phase of the action potential. During this phase a second stimulus of __________ magnitude than that generated after the first action potenial , this may generate a second action potenial

    1. ARefractory, after hyperpolarization, greater
    2. BRepolarization, hyerpolarization, lower
    3. CRefractory, hyperpolarization, lower
24. 24The presence of the relative __________ period ensures that the movement of the action potential is______________

    1. ARefractory, unidirectional
    2. BRefractory, bidirectional
    3. CReflection, bidirectional
25. 25Which two are the most important factors of an axon that influence the speed of the conduction of the action potential

    1. ALength
    2. BMyelinated sheath
    3. CDiameter
    4. DEnergy
    5. EStrength of the stimulus
    6. FNone of them
26. 26What is the name given to the zone in which action potentials take place within myelinated axons

    1. ANodes of Ranvier
    2. BLoop of Henle
    3. CNodes of Yesod
    4. DNode of Cloquet
27. 27Myelinated axons cause the conduction velocity to

    1. AIncrease
    2. BDecrease
    3. CStagnate
    4. DFluctuate
28. 28In comparison what is the ratio in m/s for the conduction velocity of the a non myelinated axon to a myelinated axon

    1. A2.5:120 m/s
    2. B5:125 m/s
    3. C30:80 m/s
29. 29Ligand-gated channels found within the membrane of the axon open in response to ligand binding of __________________

    1. AProteins
    2. BNa+
    3. CDrugs/neurotransmitters
    4. DHormones
30. 30Which of the following statements concerning the action potentials of nerve cells is correct?

    1. AThey result from a large increase in the membrane permeability to sodium ions
       
    2. BThey can summate one with another
    3. CThey may vary considerably in amplitude
    4. DThey become larger as stimulus strength increases
31. 31Which of the following statements concerning the velocity of action potential propagation is correct?

    1. AIs independent of an axon's diameter
    2. BDepends on the thickness of the myelin around the axon
    3. CWill be unaffected if the axon becomes demyelinated
    4. DIs fastest in unmyelinated axons
32. 32If a motor nerve has a conduction velocity of 50 m s-1 how long will it take an action potential to reach a muscle 0.5 m from the spinal cord?

    1. A10ms
    2. B15 ms
    3. C2 ms
    4. D20 ms
33. 33There is large quantities of Na+ ions are found within the membrane

    1. AVerdadero
    2. BFalso
34. 34What is the effect of painkillers on voltage gated channels in the cell

    1. AThey cause the channels to open wider letting increasing the influx of Na+
    2. BThey block the channels stopping the influx of Na+
35. 35How many type of Na+ channels are in the membrane

    1. A4
    2. B7
    3. C9
    4. D2
36. 36Pathology associated channel dysfunction with headaches

    1. AVerdadero
    2. BFalso
37. 37How long does the Depolaization stage of take before the sodium channel open

    1. A~1μs
    2. B~10μs
    3. C~50μs
    4. D~20μs
38. 38If you remove the Na+ in the ECF what will happen

    1. AAction potential will increase
    2. BNo action potential will occur
    3. CNa+ from ICF will will move in to the ECF
39. 39An Absolute refractory period is between 0.4-1.0 msec

    1. AVerdadero
    2. BFalso
40. 40Nerve impulses that travel down towards the axon terminaln from the axon hillock is known as what?

    1. ASalutatory conduction
    2. BOrthodromic propagation
    3. CAction potential
41. 41Another name given to the depolarization of the membrane between myelinated sheath is also known as

    1. AAction potential
    2. Bsalutatory conduction
    3. CNodes of Ranvier
    4. DOrthodromic propagation

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Test sobre Action potentials, creado por michelle simms el 31/03/2015.

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michelle simms

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