Question

9. Which is/are true about muscle spindle fibers?

    a. Muscle spindle fibers are a very bad model for studying mechanosensory receptors

    b. Single channel recordings from muscle spindle fibers show that increases in stretch causes individual channels to open more often and for longer durations.

    c. Muscle spindle fibers rely primarily on G-protein coupled receptors to transduce stretch.

    d. Muscle spindle fibers depolarize to the same extent in response to different amounts and rates of stretch (when action potentials are blocked with TTX).

    e. C and D

10. What does the second messenger cascade we discussed for taste receptors do?

    a. greatly amplifies very small signals

    b. indicates salty and bitter but not sweet

    c. inactivates otherwise leaky potassium channels.

    d. A and B

    e. A and C

11. How long does an action potential last?

    a. 1.0 millisecond

    b. 10.0 milliseconds

    c. 100.0 milliseconds

    d. 1,000.0 milliseconds

    e. 10,000.0 millisecond

12. What receptor cells can we (mammals) regenerate?

    a. auditory

    b. balance

    c. olfactory

    d. taste

    e. C and D

Answer 1

9. Option E - Muscle spindle fibers depolarize to the same extent in response to different amounts and rates of stretch (when action potentials are blocked with TTX). and primarily rely on G- proteins acetyl choline which acts as a ligand.

12. Option A Auditory receptor cells regenerate in mammals

10. Option A : Greatly amplifies very small signals

Option B is wrong because both salty and bitter cannot come into the same category. Bitter and sweet falls into same category. Salt and sour taste can be analyst by the ion channels whereas Bitter and sweet taste can be analyst by G- protein coupled receptors, where involves first messenger(Extra cellular signaling molecules) and second messenger (intracellular singaling molecules). There is no relation for ion channels and second messengers cascade (where phosphate group is transported by different molecules)

So obviously option C,D(as B comes in it), E (as C comes in it) is wrong

11. Answer : A. 1.0 millisecond

Imagine a neuron, which is consist of Cell body contains nucleus, ER, Golgi apparatus,mitochondria in it, AXON and synaptic terminals. An information which is passing from the Cell body and it travels down an axon.It is nothing but polaity changes in the membrane from the cell body to down the axon.This activity is rised by an ion channels which is present in the plasma membrane of neurons. This activity can be noticed in many of the animal cells like neurons , muscle cells, but the time taken for passing the impulse ,varies for each cells based on the ion channels.

Other names:- IMPULSE or SPIKES

Movement of action potential : in only one direction (from one neuron to neighbour neuron)

Voltage gated sodium channels - last for 1.0ms (nerve cells contains Na+ channels)

Voltage gated calcium channels - last for 100 ms

12.