Sensation: Intro Sensation is the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment. Perception is the process of organizing and interpreting sensory information enabling us to recognize meaningful objects and events. Bottom-up processing is the analysis that begins with the sense receptors and works up to the brain’s integration of sensory information. Top-down processing is information processing guided by higher-level
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Muscular System Animations 1. How do nerve impulses cause muscle contraction? Skeletal muscle is under voluntary control. Nerve impulses that originate in the central nervous system cause muscles to contract. Both neurons and muscle tissue conduct electrical current by moving ions across cellular membranes. A motor neuron ends in a synapse with a muscle fiber. The neuron releases acetylcholine and transfers the action potential to the muscle tissue. The signal will travel through the tissue
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from scattering 5- Retina- the retina is a complex structure of photoreceptors (rods and cones) on the back of the eye. The retina’s function is that photoceptors allow us to see shape‚ movement and colour and the retinal nerve cells convert incoming light into nerve impulses. 6- Iris- the iris is a coloured part of the eye and it is a ring of muscle with a hole in the middle. 7- Lens- the lens is situated behind the iris and its function is to focus light onto the light sensitive cells. The lens
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During resting‚ peace and contentment the parasympathetic nervous system is active and it calms the heart output. During periods of fright‚ flight and fight the sympathetic nervous system is boosted by the hormone; adrenaline. The nerves of the adrenaline are the cardiac nerves. A special cluster
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A neuron is a nerve cell in the brain‚ it is essentially the building block of the nervous system. Each neuron is itself a miniature decision making device‚ reacting to signals it receives from hundreds‚ even thousands of other neurons. Each signal is either excitatory or inhibitory. Excitatory signals increase the likelihood of an action potential happening‚ inhibitory make an action potential in a nerve cell less likely. The action potential is a nerve impulse. Once the excitatory signals over
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of Leprosy is nerve infection. Nerve damage appears to result from the multiplication of bacilli within Schwann cells and damage to the perineurium. Most of the deformities occurring from Leprosy are in fact due to trauma or a secondary infection. In a Leprosy infection one of the first symptoms are anesthesia to heat and cold. Leprosy affects the peripheral nervous system by attacking the myelin sheath surrounding the axons which affects the reliability and speed of nerve impulses. In other words
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(thoracic and abdomino pelvic) by the diaphragm‚ which is a dome- shaped muscle important in the respiratory system. • The thoracic cavity is the upper ventral cavity which contains the heart‚ lungs‚ trachea‚ esophagus‚ large blood vessels‚ and the nerves. The ribs surround the organs of the thoracic cavity. • The lower part of the ventral cavity is divided into two parts‚ abdominal and pelvic portions. • The abdominal cavity contains most of the gastrointestinal tract‚ kidneys‚ and adrenal glands
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The other complex compartmentalized nervous system is found in arthropods (see the diagram). The arthropodan brain consists of three main regions: the protocerebrum‚deutocerebrum‚ and tritocerebrum. The anterior protocerebrum‚ which receives the nerves of the eyes and other organs‚ contains centres‚ or neuropils‚ such as the optic centres and bodies known as corpora pedunculata. The neuropils function as integrative systems for the anterior sense organs‚ especially the eyes‚ and in control of movement;
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’1 • Copyright © 1995 by Stephen A. Mitchell and Margaret J. Black. Published by BasicBooks‚ A Division of HarperCollins Publishers‚ Inc. All rights reserved. Printed in the United States of Amer ica. No part of this book may be re produced in any manner whatsoever without written permission except in the case of brief ^quotations embodied in critical articles and reviews. For informa tion‚ a4drcss BasicBooks‚ lO East 53rd Street‚ New York‚ NY 10022-5299. Designed by Elliott Beard _2 ^ Library
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(Generating) a Nerve Impulse 1. Why don’t the terms depolarization and action potential mean the same thing? Depolarization has to do with surfaces becoming more negative or positive and reaches a certain point called a threshold. When the threshold is reached‚ an action potential is initiated. 2. What was the threshold voltage in Activity 1? The threshold voltage in Activity 1 was 3.0. 3. What was the effect of increasing the voltage? How does this change correlate to changes in the nerve? There
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