there. The human body contains billions of neurons. They are found in the brain‚ spinal cord‚ and peripheral ganglia. No two neurons are identical in form; the numerous kinds of neurons differ widely in size and shape. Many have globe-shaped or pyramid-shaped cell bodies; short‚ branching dendrites; and single‚ long axons that branch only at the ends. Neurons may be classified by the direction in which they carry nerve impulses. Afferent‚ or sensory‚ neurons carry nerve impulses to the brain or spinal
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Organization of the human body Human anatomy and physiology – study of the structure and function of the human body. Anatomy- the scientific discipline that investigates the structure of the human body. Physiology – The scientific discipline that investigates the process of functions of living things. 6 Structural levels 1. Chemical level – atoms combine to form molecules 2. Cell level – Molecule form organelles 3. Tissue level – similar and surrounding material make up tissues
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organize‚ remember‚ and use knowledge to guide their behavior. Neuron Cell body- cell’s life support center Dendrites-receive messages from other cells Axon-passes messages away from the cell body to other neurons‚ muscles‚ or glands Neural impulse-electrical signal traveling down the axon Terminal branches-form junctions with other cells Myelin sheath covers the axon of some neurons and helps speed neural impulses How a neuron fires-threshold:the minimal level of stimulation needed to trigger
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Alzheimer’s dementia is a neurodegenerative disease that is characterized by several brain abnormalities that are selective and only affect neurons in specific regions of the brain. This disease is characterized by a progressive decrease in neuronal activity and neuronal survival. Historically‚ researchers have used Magnetic Resonance Imaging (MRI) machines to scan patients with Alzheimer’s disease and the unaffected old adults and then use supercomputers to create color-coded maps which revealed
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sympathetic and parasympathetic systems. These are opposing actions and create a check and balance system. The nervous system uses electrical impulses to communicate external conditions to the brain; the electrical impulses travel along the length of the neurons (the nervous system’s primary network of cells) and
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Amyotrophic lateral sclerosis‚ usually referred to as ALS or Lou Gehrig’s disease‚ is a condition that continually deteriorates motor neurons in the brain and spinal cord. Motor neurons are nerve cells that control muscle movements. When these nerves fail‚ the muscles they are supposed to communicate with don’t receive the full messages that are being carried from the brain or spinal cord‚ causing the muscles to stop working properly. Early symptoms of this disease include cramping or twitching of
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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 and trigger the contraction of individual sarcomeres. One synapse generally controls an entire muscle fiber. One motor neuron usually controls several adjacent muscle fibers
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information on Neurons and how they function. Module eight contains information about the nervous system and the endocrine system‚ and it also explains how the body communicates from within. Module nine is the last module and contains information on the brain. The different parts and functions of the brain are also found in module nine. Module 7 Neurons are the most basic elements of the nervous system. They are tasked with relaying messages from the central nervous system. Neurons are a web that
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to answer these questions: a) Identify the parts labeled a and b and describe their functions. a = dendrites b = axon b) What is c? c = myelin sheath c) How would a signal travel through this neuron differently if c were not present? The myelin sheath is a layer of insulation. It forces the nerve impulse to leap from node to node as shown above. This allows the nerve impulse to travel much faster. If the myelin sheath were missing‚
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slowly terminates motor neutrons in the brain and spinal cord. Motor neurons are an important part of the body’s neuromuscular system; the neuromuscular system is what aids our body’s movement. It is made up of the brain‚ muscles‚ and nerves. Upper motor neurons send messages from the brain to the spinal cord‚ while the lower motor neurons send messages from the spinal cord to our muscles. Over time the disease causes these motor neurons in the brain and spinal cord to shrink‚ and finally disappear‚
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