Nerve and muscle signalling
... Hodgkin Cycle • Stimulus depolarisation opens a small fraction of voltage-gated Na+ channels • Increase in inward current through these Na+ channels further depolarises the membrane • As membrane depolarises more, a greater fraction of the Na + channels open leading to more depolarisation etc ...
... Hodgkin Cycle • Stimulus depolarisation opens a small fraction of voltage-gated Na+ channels • Increase in inward current through these Na+ channels further depolarises the membrane • As membrane depolarises more, a greater fraction of the Na + channels open leading to more depolarisation etc ...
9.3 Synaptic Transmission
... Excitatory neurotransmitters cause an action potential in the postsynaptic neuron to continue the transmission of the nerve impulse. ...
... Excitatory neurotransmitters cause an action potential in the postsynaptic neuron to continue the transmission of the nerve impulse. ...
Nervous System: General Principles
... • Can be chemical (with neurotransmitters) or electrical (gap junctions) ...
... • Can be chemical (with neurotransmitters) or electrical (gap junctions) ...
on micro principles
... The axon is a long and thin extension of the cell membrane (and cytosol). The composition of the axonal membrane and cytoplasm is different than the rest of the cell. The Axon begins at the axon hillock, and can branch in multiple directions, ending at an axon terminal. Important molecules are trans ...
... The axon is a long and thin extension of the cell membrane (and cytosol). The composition of the axonal membrane and cytoplasm is different than the rest of the cell. The Axon begins at the axon hillock, and can branch in multiple directions, ending at an axon terminal. Important molecules are trans ...
Neural_Tissue_notes
... Electrical events of the action potential include resting potential, rising phase of act. pot., falling phase of act. pot., period of hyperpolarization. What properties of the nerve cell membrane cause or account for each of the phases? Voltage-gated Na and K channels play key roles. APs are self-pr ...
... Electrical events of the action potential include resting potential, rising phase of act. pot., falling phase of act. pot., period of hyperpolarization. What properties of the nerve cell membrane cause or account for each of the phases? Voltage-gated Na and K channels play key roles. APs are self-pr ...
Biology 251 17 September 2015 Exam One FORM G KEY PRINT
... corresponding letter on the accompanying answer sheet. Each correct answer is worth 2 points. Partial credit of ½ point may be available for questions that have answers such as “all the above”, “both a and b are true”, etc. 1. Temporal summation is caused by multiple excitatory presynaptic neurons f ...
... corresponding letter on the accompanying answer sheet. Each correct answer is worth 2 points. Partial credit of ½ point may be available for questions that have answers such as “all the above”, “both a and b are true”, etc. 1. Temporal summation is caused by multiple excitatory presynaptic neurons f ...
Biology 3201
... This causes outside of membrane to have an abundance of + charges compared to inside. The inside of the membrane is negative compared to the outside (this is helped by the (-)’ly charged proteins, etc. on the inside) The “sodium-potassium” pump pulls 2 K+ ions in for 3 Na+ ions sent out. This furthe ...
... This causes outside of membrane to have an abundance of + charges compared to inside. The inside of the membrane is negative compared to the outside (this is helped by the (-)’ly charged proteins, etc. on the inside) The “sodium-potassium” pump pulls 2 K+ ions in for 3 Na+ ions sent out. This furthe ...
View Lymnea Poster - Wellesley College
... during psps and between psps by injecting current pulses long enough to come to a new steady-state voltage. The amplitudes are compared. Smaller amplitude indicates reduced resistance and increased conductance. In this way, students can determine whether channels are opening or closing during the ps ...
... during psps and between psps by injecting current pulses long enough to come to a new steady-state voltage. The amplitudes are compared. Smaller amplitude indicates reduced resistance and increased conductance. In this way, students can determine whether channels are opening or closing during the ps ...
AP Biology Reading Guide Chapter 48 Neurons synapses and
... In this section you will need to recall information about the structure and function of the plasma membrane. Ions are not able to diffuse freely through the membrane, because they are charged and so must pass through protein channels specific for each ion. ...
... In this section you will need to recall information about the structure and function of the plasma membrane. Ions are not able to diffuse freely through the membrane, because they are charged and so must pass through protein channels specific for each ion. ...
Neurons, Synapses, and Signaling
... Sensory neurons transmit information from the eyes and other sensors that detect stimuli to the brain or spinal cord for processing. Interneurons connect sensory and motor neurons or make local connections in the brain and spinal cord. Motor neurons transmit signals to effectors, such as muscl ...
... Sensory neurons transmit information from the eyes and other sensors that detect stimuli to the brain or spinal cord for processing. Interneurons connect sensory and motor neurons or make local connections in the brain and spinal cord. Motor neurons transmit signals to effectors, such as muscl ...
Nerve cells - Spark (e
... The neurons are the nerve cells involved in the production and exchange of signals. They represent the functional unit of the nervous system. The majority of the neurons is characterized by 3 main areas: the cell body (also called soma), the dendrites and the axons. ...
... The neurons are the nerve cells involved in the production and exchange of signals. They represent the functional unit of the nervous system. The majority of the neurons is characterized by 3 main areas: the cell body (also called soma), the dendrites and the axons. ...
Nervous System Study Guide
... and potassium amount inside and outside of neuron cell. 6. When a neuron at rest, what is the amount of sodium amount outside and inside the cell? 7. When a neuron at rest, what is the amount of K+ ions inside and outside the neuron cell? 8. Functions of sodium-potassium pumps during action potentia ...
... and potassium amount inside and outside of neuron cell. 6. When a neuron at rest, what is the amount of sodium amount outside and inside the cell? 7. When a neuron at rest, what is the amount of K+ ions inside and outside the neuron cell? 8. Functions of sodium-potassium pumps during action potentia ...
Chapter 48: Nervous System
... o Gated ion channels: ion channels that allow neurons to change membrane potential in response to stimuli o Hyperpolarization: increase in the electrical gradient (i.e., membrane potential becomes more negative) K+ channels release potassium from inside the cell, making it more negative o Depolari ...
... o Gated ion channels: ion channels that allow neurons to change membrane potential in response to stimuli o Hyperpolarization: increase in the electrical gradient (i.e., membrane potential becomes more negative) K+ channels release potassium from inside the cell, making it more negative o Depolari ...
NERVES
... Action Potential- the reversal and restoration across the plasma membrane of a cell, as an electrical inpulse passes along it (depolarization and repolarization). A stimulus strong enough to produce a depolarization that reaches the threshold triggers the action potential When an impulse passes alon ...
... Action Potential- the reversal and restoration across the plasma membrane of a cell, as an electrical inpulse passes along it (depolarization and repolarization). A stimulus strong enough to produce a depolarization that reaches the threshold triggers the action potential When an impulse passes alon ...
Nervous System - Mohawk Medicinals
... o Cl- ions take their places Depolarization moves away from stimulus area ...
... o Cl- ions take their places Depolarization moves away from stimulus area ...
ppt of nervous system slides
... o Cl- ions take their places Depolarization moves away from stimulus area ...
... o Cl- ions take their places Depolarization moves away from stimulus area ...
Resting membrane potential
... Larger diameter neurons conduct nerve impulses faster Larger diameter neurons present less resistance to current flow ...
... Larger diameter neurons conduct nerve impulses faster Larger diameter neurons present less resistance to current flow ...
Nervous Tissue - MrsSconyersAnatomy
... Explain depolarization and repolarization, including the relationship between them. ...
... Explain depolarization and repolarization, including the relationship between them. ...
Nervous System Ch 10 Notes - Reading Community Schools
... threshold intensity or above is applied to an axon • All impulses carried on an axon are the same strength ...
... threshold intensity or above is applied to an axon • All impulses carried on an axon are the same strength ...
SBI4U - 9.2
... • Nerve cell membrane more permeable to Na+ than K+ • Na+ ions rush into nerve cell through diffusion and charge attraction • Sodium inflow causes charge reversal depolarization • A sodium-potassium pump restores the original polarity of the nerve membrane repolarization ...
... • Nerve cell membrane more permeable to Na+ than K+ • Na+ ions rush into nerve cell through diffusion and charge attraction • Sodium inflow causes charge reversal depolarization • A sodium-potassium pump restores the original polarity of the nerve membrane repolarization ...
13. Electrochemical Impulse
... Chemicals called neurotransmitters are stored and released from the end plates of axons An impulse moves along the axon and releases neurotransmitters from the endplate (called the presynaptic neuron) ...
... Chemicals called neurotransmitters are stored and released from the end plates of axons An impulse moves along the axon and releases neurotransmitters from the endplate (called the presynaptic neuron) ...
Nervous System Function
... Action Potentials and Myelinated Neurons Myelinated neurons allow action potentials to ‘jump’ between unmyelinated gaps (Node of Ranvier) along the neuron Action potential and nerve impulse are faster Myelin sheath acts as insulation prevents depolarization Nodes of Ranvier are not insulated and ca ...
... Action Potentials and Myelinated Neurons Myelinated neurons allow action potentials to ‘jump’ between unmyelinated gaps (Node of Ranvier) along the neuron Action potential and nerve impulse are faster Myelin sheath acts as insulation prevents depolarization Nodes of Ranvier are not insulated and ca ...
Nerve Cell Impulses
... Membrane not permeable to (-) ions in cell – however, negative anions (-Cl, -Proteins) – attract to K+ and Na+ ...
... Membrane not permeable to (-) ions in cell – however, negative anions (-Cl, -Proteins) – attract to K+ and Na+ ...
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.