Topic 6.5 Neuron and Synapses
... Neurons • Dendrites receive chemical signals and produce an electrical signal • Axon transmits message • Axon covered with a layer of fat called myelin • Myelin does not completely cover the axon. • Gaps are called nodes of ranvier • Speeds up rate of impulse transmission • Saltatory conduction ...
... Neurons • Dendrites receive chemical signals and produce an electrical signal • Axon transmits message • Axon covered with a layer of fat called myelin • Myelin does not completely cover the axon. • Gaps are called nodes of ranvier • Speeds up rate of impulse transmission • Saltatory conduction ...
6.5 Nerves, Hormones and Homeostasis
... Explain how a nerve impulse passes along the membrane of a neuron ...
... Explain how a nerve impulse passes along the membrane of a neuron ...
Neurons, Neurons, Neurons!
... Information from one neuron flows to another neuron across a synapse. The synapse is a small gap separating neurons. The synapse consists of: 1. a presynaptic ending that contains neurotransmitters, mitochondria and other cell organelles, 2. a postsynaptic ending that contains receptor sites for ne ...
... Information from one neuron flows to another neuron across a synapse. The synapse is a small gap separating neurons. The synapse consists of: 1. a presynaptic ending that contains neurotransmitters, mitochondria and other cell organelles, 2. a postsynaptic ending that contains receptor sites for ne ...
chapter 48
... Astrocytes: are found within the CNS and provide structural and metabolic support as well as forming of tight junctions to help form the blood-brain barrier. They also communicate with one another via ...
... Astrocytes: are found within the CNS and provide structural and metabolic support as well as forming of tight junctions to help form the blood-brain barrier. They also communicate with one another via ...
File
... Neurons either fire maximally or not at all, this is referred to as the “all or none” response Increasing neuronal stimulation beyond a critical level will not result in an increased response Neurons response to increased stimulation by increasing the frequency of firing, not the intensity at wh ...
... Neurons either fire maximally or not at all, this is referred to as the “all or none” response Increasing neuronal stimulation beyond a critical level will not result in an increased response Neurons response to increased stimulation by increasing the frequency of firing, not the intensity at wh ...
The Nervous System
... Signal transmission along the length of a neuron depends of voltages created by ionic changes across the plasma membranes There is a difference in ion concentrations between the cell’s contents and the extracellular fluid – this is the membrane potential All cells have this membrane potential Only n ...
... Signal transmission along the length of a neuron depends of voltages created by ionic changes across the plasma membranes There is a difference in ion concentrations between the cell’s contents and the extracellular fluid – this is the membrane potential All cells have this membrane potential Only n ...
Electrical Communication #2
... Action potentials are designed for long-distance signaling, unlike graded changes in potential (i.e. depolarizations that do not reach threshold and do vary in amplitude, unlike action potentials). ...
... Action potentials are designed for long-distance signaling, unlike graded changes in potential (i.e. depolarizations that do not reach threshold and do vary in amplitude, unlike action potentials). ...
Clinical Case Activity Answers
... undergo action potentials. Describe the process of depolarization of a neuron to threshold. A neuron will depolarize when more positively charged ions enter the cell, as when sodium channels open and sodium enters the cell. This creates a local or graded potential that can spread across the cell (pl ...
... undergo action potentials. Describe the process of depolarization of a neuron to threshold. A neuron will depolarize when more positively charged ions enter the cell, as when sodium channels open and sodium enters the cell. This creates a local or graded potential that can spread across the cell (pl ...
For electrical signaling
... An action potential: a roughly 100 mV fluctuation in the electrical potential across the cell membrane that lasts for about 1ms Depolarization and hyperpolarization Absolute refractory period: a few milliseconds just after an action potential Relative refractory period: lasting up to tens of mill ...
... An action potential: a roughly 100 mV fluctuation in the electrical potential across the cell membrane that lasts for about 1ms Depolarization and hyperpolarization Absolute refractory period: a few milliseconds just after an action potential Relative refractory period: lasting up to tens of mill ...
Structure and Functions * Physiology of the Nerve
... Principle of dynamic polarization : electrical signals within a nerve flow only in one direction Principle of connectional specificity : nerve cells do not connect indiscriminately with one another to from a network ...
... Principle of dynamic polarization : electrical signals within a nerve flow only in one direction Principle of connectional specificity : nerve cells do not connect indiscriminately with one another to from a network ...
Nervous System
... Occurs in muscle cells and axons of neurons Does not decrease in magnitude over distance Principal means of long-distance neural communication ...
... Occurs in muscle cells and axons of neurons Does not decrease in magnitude over distance Principal means of long-distance neural communication ...
HONORS BIOLOGY Chapter 28 Nervous Systems
... Synapses are junctions where signals are transmitted between Two neurons or between neurons and effector cells Electrical synapses ...
... Synapses are junctions where signals are transmitted between Two neurons or between neurons and effector cells Electrical synapses ...
Nervous System
... positive magnitude of +0.5 mV, for a neuron with initial membrane potential of -70 mV, the net effect of 5 IPSP’s and 2 EPSPs spatially would be to move the membrane potential to? Would the impulse continue? ...
... positive magnitude of +0.5 mV, for a neuron with initial membrane potential of -70 mV, the net effect of 5 IPSP’s and 2 EPSPs spatially would be to move the membrane potential to? Would the impulse continue? ...
Anatomy and Physiology of the Neuromuscular Junction
... depolarization is called an end-plate potential. It then spreads along the sarcolemma, creating an action potential as voltage-dependent (voltage- ...
... depolarization is called an end-plate potential. It then spreads along the sarcolemma, creating an action potential as voltage-dependent (voltage- ...
The Neuron - Austin Community College
... local depolarization which opens more activation gates and cell interior becomes progressively less negative. Threshold – a critical level of membrane potential (~ -55 mV) where depolarization becomes self-generating ...
... local depolarization which opens more activation gates and cell interior becomes progressively less negative. Threshold – a critical level of membrane potential (~ -55 mV) where depolarization becomes self-generating ...
refractory period
... (milliseconds), long-distance (up to meters) communication in the body • As opposed to • chemical messages - which can be longdistance, but slow (seconds to minutes) • decremental electric currents - which are rapid, but can only operate over short distances (a few tens of microns) ...
... (milliseconds), long-distance (up to meters) communication in the body • As opposed to • chemical messages - which can be longdistance, but slow (seconds to minutes) • decremental electric currents - which are rapid, but can only operate over short distances (a few tens of microns) ...
Module 17 / Anatomy and Physiology of the
... at the motor-end plate, this depolarization is called an end-plate potential. It then spreads along the sarcolemma, creating an action potential as voltage-dependent (voltage-gated) sodium channels adjacent to the initial depolarization site open. The action potential moves across the entire cell me ...
... at the motor-end plate, this depolarization is called an end-plate potential. It then spreads along the sarcolemma, creating an action potential as voltage-dependent (voltage-gated) sodium channels adjacent to the initial depolarization site open. The action potential moves across the entire cell me ...
PowerPoint
... Review “resting membrane potential” (Ch 5) Factors influencing membrane potential ...
... Review “resting membrane potential” (Ch 5) Factors influencing membrane potential ...
Doktryna neuronu
... The arrow next to each current record reflects the magnitude of the net Na+ flux at that membrane potential. B. The end-plate current actually reverses at 0 mV because the ion channel is permeable to both Na+ and K+, which are able to move into and out of the cell simultaneously. The net current is ...
... The arrow next to each current record reflects the magnitude of the net Na+ flux at that membrane potential. B. The end-plate current actually reverses at 0 mV because the ion channel is permeable to both Na+ and K+, which are able to move into and out of the cell simultaneously. The net current is ...
Phases
... This positive feedback continues until the sodium channels are fully open ,The sharp rise in Vm and sodium permeability correspond to the rising phase of the action potential. The critical threshold voltage for this runaway condition is usually around −45 mV, but it depends on the recent activity o ...
... This positive feedback continues until the sodium channels are fully open ,The sharp rise in Vm and sodium permeability correspond to the rising phase of the action potential. The critical threshold voltage for this runaway condition is usually around −45 mV, but it depends on the recent activity o ...
Chapter 2
... Mitochondria – an organelle that is responsible for extracting energy from nutrients (and thus providing cells with ATP) Endoplasmic reticulum – contains ribosomes (rough) and provides channels for segregation of molecules involved in cellular processes (smooth); lipid ...
... Mitochondria – an organelle that is responsible for extracting energy from nutrients (and thus providing cells with ATP) Endoplasmic reticulum – contains ribosomes (rough) and provides channels for segregation of molecules involved in cellular processes (smooth); lipid ...
Lecture_29_noquiz
... which the concentration and electrical gradients acting on that ion balance out. • The Nernst equation is a formula that converts energy stored in a concentration gradient to the energy stored as an electrical potential. This is calculated independently for each ion. ...
... which the concentration and electrical gradients acting on that ion balance out. • The Nernst equation is a formula that converts energy stored in a concentration gradient to the energy stored as an electrical potential. This is calculated independently for each ion. ...
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.