physiology final part 1

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physiology final part 1
2011-03-16 00:31:00
physiology final

moffat physiology final
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  1. The _____ is used in the production of excitatory postsynaptic potentials wereas the neurotransmitter ____ is used in the production of inhibitory postsynaptic potentials
    ACh (acetalcholine), and GABA
  2. Define what a membrane potential is
    A membrane potential is the different charges from the intracellular to the extracellular of the cell membrane then I drew a picture of a cell membrane with positive on the outside and negative on the inside.
  3. Ion Channels in cell membranes are
    A) are nonspecific
    B) may open in response to a change in the membrane potential
    C) may open in response to binding of a chemical
    D) Both B and C
  4. Which of the following statements is false concerning myelinated nerves?
    A) the nerve impulse is regenerated several times along the length of the axon.
    B) the impulse traveels faster in myelinated nuerons compared to unmyelinated neurons
    C) the impulse travels slower in myelinated neurons compared to unmyelinated neurons
    D) the myelination is due to schwann cells.
  5. When a axon is stimulated to threshold the voltage-gated
    A) K+ channels open before the voltage-gated Na+ channels.
    B) Ca2+ channels open first
    C) K+ channels open at the same time as the voltage-gated Na+ channels.
    D) Na+ channels open first
  6. In general polar molecules diffuse more easily through the lipid bilayer part of cell membranes than do nonpolar molecules. This statement is...
    A) true
    B) false. Polar molecules diffuse through less easily because the bilayer is completely hydrophilic
    C) false. Polar molecules diffuse through less easily because the bilayer is completely hydrophobic.
    D) false. Nonpolar molecules diffuse through more easily because much of the bilayer is hydrophobic
  7. During the hyperpolarization phase of an action potential (the "undershoot") how is the membrane potential returned to is normal resting membrane potential value?
    I got it wrong
  8. All of the following are true of grade potentials except they...
    A) are short-lived
    B) can be called postsynaptic potentials
    C) only form on dendrites
    D) increase in strength as they move away from where they started.
    E) Both C and D
    I think A
  9. Which of the following statements about the refactory period of a membrane is true?
    A) The absolute refactory period refers to the period of time during which another action potential cannot be initiated in that part of the membrane that has just undergone an action potential, no matter how great the strength of the stimulus.
    B)The relative refactory period is the period of time during which another action potential can be initiated in that part of the membrane that has just undergone an action potential, if the stimulus is strong enough.
    C) The refactory period places a limit on the number of (the frequency) action potentials that can take place in a second of time.
    D) All of these choices are correct.
  10. You place a cell into an unknown solution and the cell shrinks. What can you conclude about the unknown solution?
    A) the solutions were isotonic
    B) The solution was hypotonic to that of the cell
    C) The solution was hypertonic to than that of the cell
    D) Any of the choices are possible
  11. In a presynaptic inhibition the neurotransmitter called ____ leads to a decreased inflow of what ion?
    Gaba, Calcium
  12. How do we know that K+ ions compared to Na+ ions are more influential in establishing the value of a neuron cell's resting membrane potential value; what is your evidence for this?
    The regular resting equilibrium for a cell is -70mv you can tell that K+ has more influence because it's equilibrium is -90mv which is only a 20mv difference while sodiums equilibrium is +60mv which is more then 130mv difference being in the positive.
  13. Which of the following best explains the repolarization phase of the action potential?
    A) All of the voltage-gated Na+ channels are opened.
    B)The Na+/K+ pumps restores the ions to their original locations inside and outside of the cell.
    C) The permeability to Na+ has greatly increased.
    D)The permeability to K+ has greatly increased.
    I choose C but that was WRONG. I think its B but not sure
  14. The process of transporting neurotransmitters from the soma to the telodendria is specifically known as ____ movement and is one of two types of _____.
    retrograde, axoplasmic transport
  15. In a neuron with a resting membrane potential (RMP) what are the ions involved in establishing (creating) the RMP value? Which direction do these ions move across the membrane and what type of ion channels are allowing those ions to diffuse across the membrane?
    (I got a good on this) The ions involved with creating the RMP valve is sodium and potassium. These ions are diffusing across the membrane through the leaky channels. The potassium since there is a higher concentration of them in the cell it's trying to move out of the cell. While sodium has a higher concentration outside the cell, so Na+ is trying to move into the cell.
  16. List the factors besides temperature, affinity, surface area or the presence of an inhibitor of some type that influence the rate and how much of ion can enter a cell.
    (I got marked down for only putting leaky channels) The amount of CHANNELS for each ion (Na, K and Cl) and he chemical and electrical gradients. So how many ions are in the cell related to how many are outside the cell. Also the charge between in and out of the cell.
  17. explain the terms "temporal summation" and spatial summation." Be specific
    • Spatial summation: is 2 or more synapses simultaneously sending a stimulus for one big bang of stimulation.
    • Temporal summation: is when there's one synpase sending a stimulus to and dendrite and then sends another stimulus quickly after the first one to create a larger action potential. ( I got marked down for not saying quickly)
  18. Which of the following statements about a nerve cell with a resting membrane potential is true?
    A)The permeability to Na+ ions is a much greater than the permeability to K+ ions
    B) All of the K+ ion channels in the membrane are open.
    C) The activation gate of the voltage-gated Na+ ion channels is closed.
    D) None of the choices are true
    I got this wrong and I put A I THINK its B
  19. What effect does Black Widow venom have the function of a neuron, what does it cause to happen?
    The black Widow venom continually release acetylcholine so that it keeps going until it can't keep going anymore.
  20. Define the term hyperpolarize in terms of a membrane potential.
    Hyperpolatization is when it overshoots so for membrane potential. The membrane potential is more negative on the intracellular part of the membrane making it harder to get another action potential going without a big enough stimulus.
  21. Using the chart below the fill in the boxed areas to compare the neurotransmitters and the specific associated receptors found within the sympathetic and parasympathetic nervous system.
    • Parasympathetic- ach and muscerinic and nicerninic
    • Sympathetic- ALdosteron Alpha I and I, Beta BI, BII, BIII) I think got some points off so check everything
  22. A threshold level of stimulus applied to an excitable membrane is one that is just enough to
    A) trigger a graded potential in the membrane
    B) cause the membrane potential to become more negative
    C)Cause a large net inward movement of sodium ions through the membrane
    D) cause a large net outward movement of sodium ions through the membrane.
    I chose A but that was WRONG I would guess C
  23. fill in the boxed areas to compare excitatory postsynaptic and inhibitory postsynaptic potentials.
    I got a lot of these wrong see the test
  24. explain why the strength (intensity) of a stimulus needs to change in order to initiate (start) a 2nd action potential if that part of the membrane is still in the refractory period.
    You have more to overcome if you try and stimulate it again because the K+ voltage gated channel is still open making it (hyper or repolarized?) so its harder to create the brief transient positive change in the membrane potential needed to start the action potential again
  25. What does the term "Half- life" refer to?
    How long a substance take to degrade or metabolise so that only 50% or half of whatever the substance is is still there.
  26. Action potentials travel only in one direction in the body due to...
    A) the relative refractory phase has not ended
    b) the inactivation gate of K+ channels are still closed
    C) the absolute refractory phase has not ended
    D) both B and C
    I put D so thats WRONG, but I would guess B????