Activity: Action Potentials Name: Caitlin Magnacca Instructor: Date: 03.19.2015 Predictions Exceeding threshold depolarization at the trigger zone______the likelihood of generation of an action potential. increases Action potential amplitude decreases with distance Increasing frequency of stimulation to the trigger zone increases number of action potentials Materials and Methods Experiment 1: Effect of Stimulus Strength on Action Potential Generation Dependent Variable membrane potential Independent
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The Action Potential Graphics are used with permission of: Pearson Education Inc.‚ publishing as Benjamin Cummings (http://www.aw-bc.com) ** If this is not printed in color‚ it is suggested you color code the ion channels and ions as you go through this topic. Ions channels and ions should be color coded as follows: Red: Sodium ion channels and sodium ions Blue: Potassium ion channels and potassium ions Page 1. Introduction • Neurons communicate over
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ckingmotherCoordination by Neural Signaling 26.1 Invertebrates reflect an evolutionary trend toward bilateral symmetry and cephalization * Invertebrate Nervous Organization * In simple animals‚ such as sponges‚ the most common observable response is closure of the osculum (central opening) * Hydras (cnidarians) have a nerve net that is composed of neurons * Planarians‚ (flatworms) have a ladderlike nervous system * In annelids (earthworm)‚ arthropods (crab)‚ and
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stimulate both ___ and ___. Synapses‚ cell bodies‚ dendrites Signals from other neurons are received at junctions called ___‚ located primarily on the ___ ___and ___‚ the receptive and integrative regions of the neuron. Axon hillock‚ action potential The area where the axon emerges from the soma (cell body) is called the ___ ___. This is also where the outgoing signal‚ called a/an ___ ___ is generated. Collaterals‚ terminals An axon can branch‚ forming many axon ___. At the end‚ axons
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Exercise 3: Neurophysiology of Nerve Impulses: Activity 2: Receptor Potential Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. Assuming that the resting potential of a sensory neuron is -70 mV‚ which of the following represents a depolarization? You correctly answered: c. a change to -60 mV 2. Which of the following is a sensory modality (type of sense)? You correctly answered: e. all of the above 3. Which of the following is a sensory stimulus
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The Ionic mechanism and propagation of action potentials. The action potential is the result of a large‚ sudden increase in sodium permeability of the membrane. The resulting rush of sodium ions into the membrane and accumulation of positive charge on its inner surface drives the potential towards Ena. This is followed by repolarisation‚ whereby there is a large increase in the membranes permeability to potassium ions‚ hence the membrane returns to Ek. Explanation of the (ionic) mechanisms underlying
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1. a. The action potential changes the membrane potential from -70 mV (resting) to +30 mV and back again to the resting membrane potential. b. This results from a change in membrane permeability first to Na then to K due to the opening of what type of ion channels? Voltage gated channels 2. a. Where is the density of voltage-gated Na+ channels the greatest? Axon hillock b. What areas of the neuron generate signals that open these voltage-gated channels? Dendrites and the cell body c. Opening
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The action potential is started when the membrane is very slightly ‘depolarised’‚ meaning that the charges inside and outside the cell become more similar. This happens when a stimulus causes a small influx of sodium ions into the cell. For an action potential to occur‚ the voltage has to pass a threshold value of -58mV. at this point‚ in a cycle of positive feedback‚ the action potential will always occur. Once the threshold value has been reached
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different electrode sites. The amplitude and the shape of the signals depend upon the position of the electrodes (Brown‚ 1999) (Conover‚ 1992). The SA node produces the pacemaker potential and if this reaches the threshold then an action potential is generated. There are five stages involved during cardiac action potentials‚ during these stages there is a flow of ions through
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Name: Christina Hale Exercise 3: Neurophysiology of Nerve Impulses: Activity 4: The Action Potential: Importance of Voltage-Gated Na+ channels Lab Report Pre-lab Quiz Results You have not completed the Pre-lab Quiz. 02/28/15 page 1 Experiment Results You have not completed the Experiment. Experiment Data: 02/28/15 page 2 Post-lab Quiz Results You have not completed the Post-lab Quiz. 02/28/15 page 3 Review Sheet Results 1. What does TTX do to voltage-gated Na+ channels? Your answer: It
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