A. RESPONSES TO NERVE STIMULATION Figure 1.0 Spontaneous contractions of rabbit ileum at 20Hz. Figure 1‚1 Contractions of rabbit ileum at 20Hz‚ with a stimulation of 2V applied to produce a moderate reaction. Figure 1.2 Contractions of rabbit ileum at 20Hz‚ with a stimulation of 3V applied to produce a maximal contractile response. 1) Briefly describe the response of the ileum when it is unstimulated and during stimulation
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Action Potentials An action potential is the change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell. An action potential occurs when a neuron sends information down an axon‚ away from the cell body. A threshold is the minimum amount of stimulation needed to start a neural impulse (you know‚ the electrical impulses that travel throughout your body carrying important information). Action potentials generated by neural impulses are
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The formation of an action potential can be divided into five steps. (1) A stimulus from a sensory cell or another neuron causes the target cell to depolarize toward the threshold potential. (2) If the threshold of excitation is reached‚ all Na+ channels open and the membrane depolarizes. (3) At the peak action potential‚ K+ channels open and K+ begins to leave the cell. At the same time‚ Na+ channels close. (4) The membrane becomes hyperpolarized as K+ ions continue to leave the cell. The
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Phase 2 of the cardiac action potential‚ when the calcium channels remain open and potassium channels are closed‚ is called the You correctly answered: a. plateau phase. 3. Which of the following is true of the cardiac action potential? You correctly answered: b. The cardiac action potential is longer than the skeletal muscle action potential. 4. The main anatomical difference between the frog heart and the human heart is that the frog heart has You correctly answered: c. a single‚ fused ventricle.
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cytoplasm is Negatively charged. That means that it is not going under depolarization‚ we use the term resting potential. Modality gated channels- specific to sensory neurons‚ open in response to mechanical forces (i.e. stretch‚ touch‚ pressure‚ temperature changes or chemicals) Ligand- is a particular molecule that causes a receptor to open. The ligand gated channels open in response to a neurotransmitter binding to the surface of a channel receptor on a postsynaptic cell membrane‚ when open
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3810-504 Compound Action Potentials Date Performed: 15FEB2011 Date Due: 01MAR2011 Introduction Neurons are the cells that receive and transmit electrical signals (University of North Texas‚ 2010). The ability of the neuron to conduct these impulses is because of an electrochemical voltage across the plasma membrane of that neuron. An action potential is an all or nothing response to a stimulus along a single axon. A compound action potential is a graded response that results from the
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What is an action potential? To put it simply‚ it is a message that is sent down the nervous line. The message is written and is sent from the central nervous system. That message is addressed to muscles or glands. This essay will explain what happens before‚ during‚ and after an interneuron action potential. To accurately define an action potential‚ it is part of the incredible course of events that occur during the firing of a neuron. When a neuron is not firing signals‚ the interior of the
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allow an Action potential to occur in a neuron. This will be achieved by firstly‚ defining the purpose of neurons in the body along with a description of the components within a neuron and how they enable information to be passed through the cell membrane and on to other neurons. Secondly‚ the resting potential of a neuron will be explored with relation to the concept of selective permeability and the purpose of the Sodium - Potassium pump. Thirdly‚ the molecular basis of the Action Potential will
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A graded potential in physiology‚ is described as local changes in membrane potential that occur in varying grades or degrees of magnitude or strength. When compared to graded potential‚ an action potential is described as brief‚ rapid‚ large (100mV) changes in membrane potential during which the potential actually reverses so that the inside of the excitable cell transiently becomes more positive than the outside. As with a graded potential‚ an action potential involves only a small portion of
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RESTING POTENTIAL Resting potential is the membrane potential when a neuron is not conducting any electrical impulse or signal. The resting potential is around -75 mV. During resting potential‚ the inside of the axon is negative GRADED POTENTIAL ACTION POTENTIAL Action potential is a fleeting reversal of the membrane potential‚ caused by changes in permeability of the plasma membrane of neuron to potassium and sodium ions causing an electrical impulse to be transmitted along the axon.
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