
Nerve Impulses - Tamalpais Union High School District
... outward causing inside of membrane to become negative again. K+ Potassium channels open ...
... outward causing inside of membrane to become negative again. K+ Potassium channels open ...
doc Lecture 5 practice Questions
... b. The ionic conductance of K is greatest at negative potentials c. An action potential can be initiated in the relative refractory period, but its peak will have a lower amplitude. true d. The Na channel has three conformation states while the K channel has two.true e. Two of the above f. None o ...
... b. The ionic conductance of K is greatest at negative potentials c. An action potential can be initiated in the relative refractory period, but its peak will have a lower amplitude. true d. The Na channel has three conformation states while the K channel has two.true e. Two of the above f. None o ...
Worksheet for Nervous Systems
... 29. Define each type of “graded potential”. Tell which ion channel is involved in each type of “graded potential”. ...
... 29. Define each type of “graded potential”. Tell which ion channel is involved in each type of “graded potential”. ...
Study Guide for Nervous System
... a. Voltage and potential energy b. Current and resistance c. Role of Ion Channels i. Leaky, voltage gated, chemical (ligand) gated d. Resting potential characteristics (voltage and permeability to Na+, K+ and Cl-) e. Depolarization ...
... a. Voltage and potential energy b. Current and resistance c. Role of Ion Channels i. Leaky, voltage gated, chemical (ligand) gated d. Resting potential characteristics (voltage and permeability to Na+, K+ and Cl-) e. Depolarization ...
Neurophysiology Resting membrane potential (Vr)
... the sodium inactivation gates. No new action potential can be generated during this time. Relative refractory period - sodium gates are closed and most have returned to their resting state. Potassium gates are open and repolarization is occurring. Conduction Velocities Conduction velocities of neuro ...
... the sodium inactivation gates. No new action potential can be generated during this time. Relative refractory period - sodium gates are closed and most have returned to their resting state. Potassium gates are open and repolarization is occurring. Conduction Velocities Conduction velocities of neuro ...
The Importance of the Nervous System
... Refractory Period • from the peak of an action potential until the membrane reaches resting potential again • a few milliseconds • ensures action potential travels in one direction only ...
... Refractory Period • from the peak of an action potential until the membrane reaches resting potential again • a few milliseconds • ensures action potential travels in one direction only ...
AP – All or nothing
... • With the Na+ / K+ channels closed, the cation pumps can now begin to restore the balance between the ions • Na+ is pumped out and K+ pumped in. • During this time a new action potential can not be set up until resting potential is achieved. ...
... • With the Na+ / K+ channels closed, the cation pumps can now begin to restore the balance between the ions • Na+ is pumped out and K+ pumped in. • During this time a new action potential can not be set up until resting potential is achieved. ...
Nervous System Class Overview Questions
... dendrite axon cell body synaptic vesicles presynaptic neuron postsynaptic neuron ...
... dendrite axon cell body synaptic vesicles presynaptic neuron postsynaptic neuron ...
Lecture #21 Date
... Intracellular/extracellular ionic concentration difference K+ diffuses out (Na+ in); large anions cannot follow….why not? Net negative charge of about -70mV ...
... Intracellular/extracellular ionic concentration difference K+ diffuses out (Na+ in); large anions cannot follow….why not? Net negative charge of about -70mV ...
Nervous System Review
... Three types of neurons are: Main parts of neurons and their functions: The main glial cells and their functions: Be able to identify and label neuron parts (Nodes of Ranvier, myelin sheaths, axon, dendrite, cell body) and what type of neuron. ...
... Three types of neurons are: Main parts of neurons and their functions: The main glial cells and their functions: Be able to identify and label neuron parts (Nodes of Ranvier, myelin sheaths, axon, dendrite, cell body) and what type of neuron. ...
PNS and Transmission
... inside -). The sodium potassium pumps are responsible for setting this up. • Action Potential: 1) depolarization (inside +); 2) repolarization (inside -). • If an axon is myelinated, the action potentials are stimulated between the nodes of Ranvier (faster potential) in non-myelinated it stimulates ...
... inside -). The sodium potassium pumps are responsible for setting this up. • Action Potential: 1) depolarization (inside +); 2) repolarization (inside -). • If an axon is myelinated, the action potentials are stimulated between the nodes of Ranvier (faster potential) in non-myelinated it stimulates ...
Nervous Systems - Western Washington University
... The membrane potential can be altered depending upon which ion channels are opened by a stimulus. These synaptic potentials are graded. ...
... The membrane potential can be altered depending upon which ion channels are opened by a stimulus. These synaptic potentials are graded. ...
11_45_48_SG
... Neurotrans binds with receptors associated with postsynaptic membrane Ca2+ ions rush into neuron’s cytoplasm Action potential depolarizes the synaptic terminal membrane Ligand-gated channels open Synaptic vesicles release nerutrans into the synaptic cleft ...
... Neurotrans binds with receptors associated with postsynaptic membrane Ca2+ ions rush into neuron’s cytoplasm Action potential depolarizes the synaptic terminal membrane Ligand-gated channels open Synaptic vesicles release nerutrans into the synaptic cleft ...
Nervous Systems - Western Washington University
... The membrane potential can be altered depending upon which ion channels are opened by a stimulus. These synaptic potentials are graded. ...
... The membrane potential can be altered depending upon which ion channels are opened by a stimulus. These synaptic potentials are graded. ...
Polarised membrane A membrane with a potential difference across
... Channels in the cell membrane that allow the passage of charged particles or ions. They have a mechanism called a gate which can open and close the channel. In these channels the gates respond to changes in the potential difference across the membrane. ...
... Channels in the cell membrane that allow the passage of charged particles or ions. They have a mechanism called a gate which can open and close the channel. In these channels the gates respond to changes in the potential difference across the membrane. ...
Chapter 3
... 1. Know the main structures of neurons and the structural differences among neurons. 2. Know the main types of glia and their functions. 3. Be able to describe the advantages and disadvantages of the blood-brain barrier. Module 2.2 The Nerve Impulse 4. Understand why the neuron uses considerable ene ...
... 1. Know the main structures of neurons and the structural differences among neurons. 2. Know the main types of glia and their functions. 3. Be able to describe the advantages and disadvantages of the blood-brain barrier. Module 2.2 The Nerve Impulse 4. Understand why the neuron uses considerable ene ...
The Nervous System
... • 1. concentration difference of ions on either side of membrane represents potential energy-kind of like of cocked gun • 2. stacked dominoes waiting to fall over • 3. one domino falling over initiates a wave of action potentials spreading out like the ripples in a pond • 4. each action potential is ...
... • 1. concentration difference of ions on either side of membrane represents potential energy-kind of like of cocked gun • 2. stacked dominoes waiting to fall over • 3. one domino falling over initiates a wave of action potentials spreading out like the ripples in a pond • 4. each action potential is ...
Nervous System
... Membrane is more permeable to K+ than Na+ so diffusion more likely. Na+ channels often closed. ...
... Membrane is more permeable to K+ than Na+ so diffusion more likely. Na+ channels often closed. ...
MEMBRANE POTENTIALS
... (b) inside negative > Na+ attracted (electrical gradient) BUT: (a) membrane channels closed (voltage gated) (b) Na+ pumps to outside ...
... (b) inside negative > Na+ attracted (electrical gradient) BUT: (a) membrane channels closed (voltage gated) (b) Na+ pumps to outside ...
Cognitive Psychology
... • Passive currents are ones that simply pass through the cytoplasm, typically as a response to active currents; ex - within the cell body as a result of synaptic activity; within the axon as a result of action potentials. ...
... • Passive currents are ones that simply pass through the cytoplasm, typically as a response to active currents; ex - within the cell body as a result of synaptic activity; within the axon as a result of action potentials. ...
4-Calculate the Equilibrium Potential of Potassium, Sodium, and
... 3) When recording under voltage clamp, why are the measured Na+ currents outward at the command potential of 100mV? a. At 100mV there is more Sodium inside the cell than outside. b. At 100mV Sodium ions flow out of the cell down their electrochemical gradient. c. This is an artifact caused by damage ...
... 3) When recording under voltage clamp, why are the measured Na+ currents outward at the command potential of 100mV? a. At 100mV there is more Sodium inside the cell than outside. b. At 100mV Sodium ions flow out of the cell down their electrochemical gradient. c. This is an artifact caused by damage ...
Action potential

In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. Action potentials occur in several types of animal cells, called 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. In muscle cells, for example, an action potential is the first step in the chain of events leading to contraction. In beta cells of the pancreas, they provoke release of insulin. Action potentials in neurons are also known as ""nerve impulses"" or ""spikes"", and the temporal sequence of action potentials generated by a neuron is called its ""spike train"". A neuron that emits an action potential is often said to ""fire"".Action potentials are generated by special types of voltage-gated ion channels embedded in a cell's plasma membrane. These channels are shut when the membrane potential is near the resting potential of the cell, but they rapidly begin to open if the membrane potential increases to a precisely defined threshold value. When the channels open (in response to depolarization in transmembrane voltage), they allow an inward flow of sodium ions, which changes the electrochemical gradient, which in turn produces a further rise in the membrane potential. This then causes more channels to open, producing a greater electric current across the cell membrane, and so on. The process proceeds explosively until all of the available ion channels are open, resulting in a large upswing in the membrane potential. The rapid influx of sodium ions causes the polarity of the plasma membrane to reverse, and the ion channels then rapidly inactivate. As the sodium channels close, sodium ions can no longer enter the neuron, and then they are actively transported back out of the plasma membrane. Potassium channels are then activated, and there is an outward current of potassium ions, returning the electrochemical gradient to the resting state. After an action potential has occurred, there is a transient negative shift, called the afterhyperpolarization or refractory period, due to additional potassium currents. This mechanism prevents an action potential from traveling back the way it just came.In animal cells, there are two primary types of action potentials. One type is generated by voltage-gated sodium channels, the other by voltage-gated calcium channels. Sodium-based action potentials usually last for under one millisecond, whereas calcium-based action potentials may last for 100 milliseconds or longer. In some types of neurons, slow calcium spikes provide the driving force for a long burst of rapidly emitted sodium spikes. In cardiac muscle cells, on the other hand, an initial fast sodium spike provides a ""primer"" to provoke the rapid onset of a calcium spike, which then produces muscle contraction.