What STIMULUS caused resting potential to move towards 0mv and what occurs at -55mv?
An action potential is a change in membrane potential in response to a stimulation. A stimulation can be a heat shock or pain which was received by receptor present in the skin or the place where shock has been given. An action potential divied into four phases that correlate with changes in sodium and potassium ion permeability of the plasma membrane of nerve cell. These are resting, depolarization, repolarization, and hyperpolarization phases. The resting phase of action potential where neuron has a membrane potential of -70 mV, which is maintained by the potassium leaky channels. When any stimulus stimulate the opening of the gate of potassium voltage gated channels, potassium ions will move into the cell acroos membrane through the voltage gated channels which causes membrane potential to decrease beyond theshold level -50mV. This decrease in membrane potential is called depolarisation phase of the action potential. The action potential can be generated only when the reduction in membrane potential beyond the threshold level (-50 mV). If the initial depolarization does not exceed the threshold level, then the action potential will not proceed and the membrane potential will return to the resting potential. If the threshold is exceeded, then the voltage-gated sodium channels are opened and there is a rapid inflow of sodium ions, reversing the membrane potential from a negative value to a positive value. Depolarization occurs only in less than one millisecond, then the voltage-gated sodium channels are inactivated. Depolarization triggers the voltage-gated potassium channels to open, to set back the membrane potential to resting value, this phase is called repolarization. The voltage-gated potassium channels are slow to close after the change in membrane potential which cause the membrane potential to reach more that resting value, reaching more than resting of membrane potential is called hyperpolarization. The potassium leaky channels reestablish the resting membrane potential, during this period, the sodium channels are restored to the active, but closed state and this axon portion is ready to undergo next action potential in response to further stimulation.
What STIMULUS caused resting potential to move towards 0mv and what occurs at -55mv?
The process of changing the resting membrane potential towards its threshold is called Facilitation Direct conduction inhibition Salutatory conduction
The resting membrane potential of a neuronal axon is -70 mV. When an action potential is triggered, Na+ ions move into the axon, which reverses the voltage, bringing it towards 0 mV. Which of the following is the correct term for this sequence of events? a. Repolarization b. Hyperpolarization c. Depolarization d. Hypopolarization e. Isopolarization
The neuron has a resting potential of – 60 mv and a threshold
potential at -40 mv. The ENa is approximately at +40 mv. In every
case, the stimulus is initiated at 2 ms, and lasts for 1 ms. Draw
the membrane potentials from 0 to 10 ms for the following scenarios
in each of the boxes above.
a) 15 mv depolarizing stimulus
b) 25 mv hyperpolarizing stimulus
c) 30 mv depolaring stimulus
d) 30 mv depolarizing stimulus after the...
1. Consider a typical cell at its resting membrane potential
(rest Vm). The membrane temporarily becomes more permeable to Na+.
Ena = +55mV, resting Vm = -60mV How would the change in membrane be
represented in a graph of Vm vs. time?
a. no change b. Graph B c. Graph
C
Please explain why the right answer is correct and why the wrong
answers are incorrect.
Opening a sodium channel during the resting potential would cause sodium ions to move along an electrical gradient and along a concentration gradient. (T/F: Explain)
What is a resting potential? Is it positive or negative? The resting potential is mainly due to the main _____-charged large molecules stuck inside the neuron. The Na+/K+ pump pushes Na+ _____ of the cell and K+ ____ of the cell (in or out for each ion) Where is K+ concentrated, inside or outside of the neuron? Where is Na+ concentrated, inside or outside of the neuron? The action potential starts with an rise in membrane voltage. This is due...
A neuron has a resting membrane potential of -70 mV; it’s trigger threshold for firing an action potential is -50 mV. Two competing signals arrive simultaneously in the trigger zone: one is a depolarizing stimulus of +40 mV, the other a hyperpolarizing stimulus of -25 mV. Will the neuron fire an action potential after integrating these signals? Why?
Which statements are true of summation?
a) A second nerve stimulus occurs before the muscle has had time
to relax (i.e., before cell Ca2+ concentration has been
restored to resting values).
b) A second stimulus is delivered while the nerve axon is
depolarized.
c) A second stimulus occurs while the muscle cell membrane is
depolarized.
d) More motor units are recruited.
Draw the appropriate force/tension response of skeletal muscles in the images below. 4 pts Twitch Summation Incomplete tetanus Complete...
QUESTION 11 . THE RESTING POTENTIAL IS CAUSED BY . . A. . the rotation of charged particles . . B. . the uneven distribution of ions inside and outside the cell . . C. . the release of ions by neighboring neurons . . D. . the axon hillock . 1 points QUESTION 12 . WHICH NEUROTRANSMITTER PLAYS A ROLE IN REINFORCEMENT AND ADDICTION . . A. . dopamine . . B. . acetyl choline . . C....
Which statements are true of summation? 1 pt O A second nerve stimulus occurs before the muscle has had time to relax (1.e., before cell Ca2+ concentration has been restored to resting values). O A second stimulus is delivered while the nerve axon is depolarized. O A second stimulus occurs while the muscle cell membrane is depolarized. More motor units are recruited. Draw the appropriate force/tension response of skeletal muscles in the images below. 4 pts Twitch Summation Incomplete tetanus...