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The Nervous System: Neural Tissue
The Nervous System: Neural Tissue

... come down the axon – no matter how strong it is. 9. The __________________ __________________ __________________ is the time immediately after the Na gates close and repolarization is still occurring that a exceptionally strong stimulus may cause depolarization. F. Impulses 1. Impulses travel at dif ...
The Nervous System
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unit 2 – nervous system / senses - Greater Atlanta Christian Schools
unit 2 – nervous system / senses - Greater Atlanta Christian Schools

... -“polarized” b/c of electrical charge difference that exists on each side of the cell membrane - inside cell: -ve ; high amt. of K+ - outside cell: +ve; high amt of Na+ - cell membrane permeability  K+ > Na+ - Na+/ K+ exchange pump  maintains RMP 3. Stimulated Neuron (action potential) a. nerve (e ...
Learning Objectives
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The Nervous System: Neural Tissue
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... a. Each neuron will have only one axon, however it may be branched. b. At the end of the axon will be axon terminal (AKA - synaptic knobs or synaptic boutons). c. Some axons will be covered by white, fatty insulation called a myelin sheath. Myelin sheaths increase the speed of impulse transmission. ...
Jürgen R. Schwarz
Jürgen R. Schwarz

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touch and pain - Stark home page
touch and pain - Stark home page

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Peripheral Nervous System (PNS)
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Neurons, Synapses and Signaling

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Peripheral Nervous System
Peripheral Nervous System

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How the Nervous System Works

... The nervous system receives information about what is happening both inside and outside your body. It also directs the way in which your body responds to this information. In addition, the nervous system helps maintain homeostasis. A stimulus is any change or signal in the environment that can make ...
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Biol 155 Human Physiology - University of British Columbia
Biol 155 Human Physiology - University of British Columbia

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Overview Functions of the Nervous System

... • travel across the synapse to the postsynaptic cells, where they are converted back into electrical signals • Axon terminal: contains many tiny, membrane-bounded sacs (synaptic vesicles) containing thousands of neurotransmitter molecules • Neurotransmitter receptor region on the membrane of a dendr ...
Babylon university Medical physics exam
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... inside go positive to 50 mV. The action potential last few m sec for most neuron and muscles, and last 150-300 m sec for cardiac muscle. The membrane of some axons is covered with fatty insulating layer called myelin has small uninsulated gaps called nodes of ranvier. The action potential decreases ...
axonal terminals
axonal terminals

... 1. Polarization of the neuron's membrane: Sodium is on the outside, and potassium is on the inside. • When a neuron is not stimulated — it's just sitting with no impulse to carry or transmit — its membrane is polarized. • Being polarized means that the electrical charge on the outside of the membran ...
Nervous System Chapter 11 Answers
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... Chemical gradient is formed when ions diffuse across a membrane (High to low concentration) Electrical gradient is formed when ions move toward an area of opposite charge An electrochemical gradient occurs on neural membranes due to BOTH chemical & electrical gradients 11. What is the resting membra ...
In Pursuit of Ecstasy - Heartland Community College
In Pursuit of Ecstasy - Heartland Community College

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NEUROPHYSIOLOGY

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Plants and Pollinators
Plants and Pollinators

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Rheobase



Rheobase is a measure of membrane excitability. In neuroscience, rheobase is the minimal current amplitude of infinite duration (in a practical sense, about 300 milliseconds) that results in the depolarization threshold of the cell membranes being reached, such as an action potential or the contraction of a muscle. In Greek, the root ""rhe"" translates to current or flow, and ""basi"" means bottom or foundation: thus the rheobase is the minimum current that will produce an action potential or muscle contraction.Rheobase can be best understood in the context of the strength-duration relationship (Fig. 1). The ease with which a membrane can be stimulated depends on two variables: the strength of the stimulus, and the duration for which the stimulus is applied. These variables are inversely related: as the strength of the applied current increases, the time required to stimulate the membrane decreases (and vice versa) to maintain a constant effect. Mathematically, rheobase is equivalent to half the current that needs to be applied for the duration of chronaxie, which is a strength-duration time constant that corresponds to the duration of time that elicits a response when the nerve is stimulated at twice rheobasic strength.The strength-duration curve was first discovered by G. Weiss in 1901, but it was not until 1909 that Louis Lapicque coined the term ""rheobase"". Many studies are being conducted in relation to rheobase values and the dynamic changes throughout maturation and between different nerve fibers. In the past strength-duration curves and rheobase determinations were used to assess nerve injury; today, they play a role in clinical identification of many neurological pathologies, including as Diabetic neuropathy, CIDP, Machado-Joseph Disease, and ALS.
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