cell B‚ which cell has the larger resting membrane potential? Explain. If the permeability to K is higher in A than in B‚ then the resting membrane potential (rmp) will be closer to the equilibrium potential in cell A‚ which means the rmp will be more negative in cell A than in cell B; or in other words‚ the potential difference will be LARGER in cell A. 2. Predict the effect of a reduced extracellular concentration of Na+ on the magnitude of the action potential in an electrically excitable cell
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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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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 branch to form many axon ___. Schwann cells What support cell forms the myelin sheath? Integral proteins What structures in the cell membrane function as ion channels?
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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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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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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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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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fundamental unit of the nervous system. These neurons work together with other excitable cells to produce action potentials when they receive electrical or chemical stimuli. Action potentials can be thought of as an “all-or-nothing” event and occur as a large-scale depolarization when sodium and other positive ions rapidly enter the neuron through membrane channel proteins. Once initiated‚ action potentials travel down the length of the axon and when it reaches the end a neurotransmitter is released into
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THE WORK DONE BY A CONSERVATIVE FORCE ALWAYS HAS FOUR PROPERTIES: 1. It can be expressed as the difference between the initial and final values of a potential-energy function. 3. It is independent of the path of the body and depends only on the starting and ending points. 2. It is reversible. 4. When the starting and ending points are the same‚ the total work is zero. The total mechanical energy ME = K + U is constant. Object moving in a uniform gravitational field gravitational a
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Potential Energy • Definition and Mathematics of Work • Calculating the Amount of Work Done by Forces • Potential Energy • Kinetic Energy • Mechanical Energy • Power An object can store energy as the result of its position. For example‚ the heavy ball of a demolition machine is storing energy when it is held at an elevated position. This stored energy of position is referred to as potential energy. Similarly‚ a drawn bow is able to store energy as the result of its position. When assuming
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