See Graph 1: Maximal depolarization of membrane potential at axon hillock and axon after different stimulation voltages.…
During the action potential part of the neural membrane opens to let + charged ions in the cell and let – charged ions out. This causes a rapid increase in positive nerve fiber.…
-The resting membrane potential has the same value in the cell body and the axon because the typical resting membrane potential is the same throughout the entire neuron.…
|Action potential |A brief reversal of the resting potential across the cell surface membrane of a neurone. All action |…
What are the two processes that stop the potential from rising above +30 mV? a. Inactivation of voltage gated Na channels b. Opening of voltage gated K channels…
The nerve impulse caused by a charge in the electrical charge across the cell membrane of the axon. When the neuron "fires", this charge…
What are the important ions for most neurons when considering changes in membrane potential? (3 points)…
Channels can be classified as either gated or nongated channels. A sodium channel that is always open would be classified as a/an non-gated channel.…
Experiment Results Predict Question: Predict Question: Predict what will happen to the resting membrane potential if the extracellular K+ concentration is increased. Your answer : b. The resting membrane potential will become less negative. Stop & Think Questions: What is the polarity of the resting membrane potential (voltage)? You correctly answered: b. negative What does it mean that the voltage just inside the membrane is negative? You correctly answered: b. There are more negative charges than positive charges just inside the membrane. The membrane of most cells, including neurons, contains passive, open, K+ leak channels. Given the normal K+ concentrations and the resultant concentration gradient, which direction would K+ be expected to move (diffuse) through these leak channels? You correctly answered: b. out of the cell What effect does increasing extracellular K+ have on the net diffusion of K+ out of the cell? You correctly answered: b. It decreases the net diffusion of K+ . Which way would Na+ move across the membrane if there were open Na+ channels? You correctly answered: a. Na+ would diffuse into the cell. The membrane has open K+ channels, and changing extracellular K+ concentration results in a change in membrane potential. Changing the extracellular Na+ concentration does not significantly change the membrane potential. What do your results suggest about the number or state (open or closed) of Na+ channels in the resting membrane of a neuron? You correctly answered: b. Na+ channels are mostly closed. Experiment Data: Extracellular Fluid (ECF) Control Control Control Control High K+ High K+ High K+ High K+ Low Na+ Low Na+ Low Na+ Low Na+ Microelectrode Position Cell body extracellular Cell body intracellular Axon extracellular Axon intracellular Axon intracellular…
* An action potential is a very brief shift in a neuron’s electrical charge that travels along an axon.…
a. What acts as a chemical force that pushes K+ out of the cell? ___________…
A graded potential in physiology, is described as local changes in membrane potential that occur in varying grades or degrees of magnitude or strength. When compared to graded potential, an action potential is described as brief, rapid, large (100mV) changes in membrane potential during which the potential actually reverses so that the inside of the excitable cell transiently becomes more positive than the outside. As with a graded potential, an action potential involves only a small portion of the total excitable cell. Action potentials occur in several types of animal cells (excitable cells), which include neurons, muscle cells, and endocrine cells, as well as in some plant cells. In neurons, they play a central role in cell-to-cell communication. In other types of cells, their main function is to activate intracellular processes. Action potentials in neurons are also known as “nerve impulses” or “spikes”. A neuron that emits an action potential is often said to “fire”. Depending on the stimulus, graded potentials can be depolarizing or hyperpolarizing. Action potentials always lead to depolarization of the membrane and reversal of the membrane potential. Graded potentials amplitude is proportional to the strength of the stimulus. Amplitude is generally small (a few mV to tens of mV). The duration of graded potentials may be a few milliseconds to seconds. When compared to graded potentials, action potentials amplitude is all-or-none; strength of the stimulus is coded in the frequency of all-or-none action potentials generated (large amplitude). Nearly all cells from animals and plants function as batteries, in the sense that they maintain a voltage difference between the interior and the exterior of the cell, with the interior being the negative pole of the battery. The voltage of a cell is usually measured in millivolts(mV), or thousandths of a volt. A typical voltage for animal cell is -70mV. Because cells are so small, voltages of this magnitude give rise to…
11. When a neuron is resting, the outside of the cell has a net positive charge, and the inside of the cell has a net negative…
NERVOUS SYSTEM OUTLINE I. Nervous System = 2 Parts A. Central Nervous System (CNS) 1. Brain 2. Spinal Cord B. Peripheral Nervous System (PNS) 1. Nerves to parts of the body 2. Nerves from parts of the body C. Functions 1.…
Virtual Lab Stimulation Exercise 3 Activities 1-5 Study online at quizlet.com/_cfevi 1. 2. 3. 4. 5.…