brain contains an estimated 1011 (100 billion) neurons. Each neuron may communicate with thousands of other neurons in complex information-processing circuits. Recently developed technologies can record brain activity from outside the skull. One technique is functional magnetic resonance imaging (fMRI)‚ which reconstructs a 3-D map of the subject’s brain activity. The results of brain imaging and other research methods show that groups of neurons function in specialized circuits dedicated to different
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Chapter 3 review components of a neuron (i.e.‚ dendrites‚ axons‚ terminal buttons) dendrites A branched fiber that extends outward from the main cell body and carries information into the neuron. axon In a nerve cell‚ an extended fiber that conducts information from the soma to the terminal buttons. Information travels along the axon in the form of an electric charge called the action potential. terminal buttons Tiny bulblike structures at the end of the axon‚ which contain neurotransmitters
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___________________________‚ which brings the membrane potential closer to the point at which the action potential will occur. If (12) ___________________ (the voltage at which an action potential is generated) is reached at the (13) ______________ ________ (area) of the neuron‚ then an action potential will be generated because (14) ________________________-gated (15) ________________ (ion) channels will open. The – (16) efflux / influx (circle or highlight one) – of these ions will cause more channels to open‚ moving the
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information sent by neurons. Spinal nerves refer to a mixture of spinal nerves‚ which carry motor‚ sensory‚ and autonomic signals between the spinal cord and the body. 2. Define the terms reflex and spinal reflex‚ and identify the components of the reflex arc. * A reflex is an involuntary physiological response to a stimulus. A spinal reflex is any reflex action mediated through the center of the spinal cord. The components of the reflex arc include the receptor‚ sensory neuron‚ the integration
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potential. b. This results from a change in membrane permeability first to _______ then to _______ due to the opening of what type of ion channels? _______ 2. a. Where is the density of voltage-gated Na+ channels the greatest? b. What areas of the neuron generate signals that open these voltage-gated channels? c. Opening of these channels causes the membrane to ______________ (voltage change). 3. a. If the membrane reaches the trigger point‚ known as ___‚ what electrical potential will be generated
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Neurotransmitters Neurotransmitters are chemicals made by neurons and used by them to transmit signals to the other neurons or non-neuronal cells (e.g.‚ skeletal muscle; myocardium‚ pineal glandular cells) that they innervate. The neurotransmitters produce their effects by being released into synapses when their neuron of origin fires (i.e.‚ becomes depolarized) and then attaching to receptors in the membrane of the post-synaptic cells. This causes changes in the fluxes of particular ions across
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maintain the feeling of happiness; however‚ these drugs are extremely dangerous to the human body and are unhealthy for humans. `The brain is a complex organ that has a complex‚ but quick process of delivering the neurotransmitters to the receptors. Neurons communicate with each other by sending electrical signals‚ nerve impulses‚ through tube like structures called axons.
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flow back and fourth across the cell membrane Na cl ‚K and Ca ions and they just flow back and fourth without any gate keeper or obstruction‚ When the neuron is at rest its 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
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Nervous System Made up of neurons‚ which are the nerve cells. These send electrical impulses to one another ( through a process known as firing) telling the body what to do. The parts of a neuron include: Cell Body (a.k.a. soma) – Main part of neuron; contains basic cell parts such as nucleus‚ ER‚ etc.; also has dendrites extending from it. Dendrites – bushy fibers which extend from the soma; receives impulses and directs them towards soma Axon – an extension of the neuron from the soma which ends
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What are the three (3) types of brain tissue? ~Gray matter‚ white matter‚ and Cerebrospinal fluid (CSF) 2. List the two (2) neurodegenerative disorders that destroy cell bodies. ~Alzheimer’s and Parkinson’s 3. What does the cell body do for the neuron? ~Performs basic command functions 4. Why does “cerebral cortex” mean “bark of the brain”? ~The nerve cell bodies are highly concentrated on the surface of the brain‚ causing it to look like tree bark 5. What does “subcortical” literally mean
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