Please help with the following questions STAT, will rate. Provide complete answe
ID: 301873 • Letter: P
Question
Please help with the following questions STAT, will rate. Provide complete answers. Thank you Please help with the following questions STAT, will rate. Provide complete answers. Thank you
Pufferfish (Fugu) are a delicacy in Japan, but must be cleaned very carefully as their liver contains tetrodotoxin which blocks voltage-gated Na+ channels. Imagine you are testing for the presence of this toxin using a neuron in a dish. You apply an electrical stimulus to the neuron that should produce an action potential. What will you observe if tetrodotoxin levels are high enough to block the neuron's voltage-gated Na+ channels? The neuron will exhibit a slow depolarization even before the stimulus is applied, followed by a normal action potential The neuron will exhibit a slow hyperpolarization even before the stimulus isapplied. The neuron will show a normal resting potential, but will not exhibit depolarization when the stimulus is applied. The neuron will exhibit rapid depolarization, but will not repolarize. The neuron will depolarize normally, but then become hyperpolarized such that the membrane potential is much lower than usual. Question 40 .67 pts How does myelination affect the propagation of an action potential? O It speeds propagation by increasing the density of voltage-gated ion channels OIt speeds propagation by increasing electrochemical gradients favoring Na+ entry O It speeds propagation because cations do not leak out of the membrane as they spread down the axon O It slows down propagation because Na+ channels exist only at unmyelinated nodes (nodes of Ranvier).
Explanation / Answer
Question 40: the myelination greatly speeds up the action potential conduction by acting as an electrical insulator (i.e. saltatory conduction) therefore, option 'A' is correct
question 42 : the artificial electical stimulation will produce a sensation of the cold temperature as the cold is related to TRP (transient receptor potentials) where the menthol activates the Cfibres type 2 receptors only.
Question 43: the tuning of pupil size to wide and the increased pulse thereby increasing respiration or heartbeat is the result of sympathetic nervous system as it is the fight or flight system so the immediate response or sudden change in hormone levels (epinepherine or adrenaline).