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Neurons. Answers to the outline are bold , italic , and underlined. Neurons. The nervous system is your body’s electrochemical communication system Comprised of your brain, spinal cord, and nerves- all of which are formed from neurons Perform 3 tasks:
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Neurons Answers to the outline are bold, italic, and underlined
Neurons • The nervous system is your body’s electrochemical communication system • Comprised of your brain, spinal cord, and nerves- all of which are formed from neurons • Perform 3 tasks: • Receive information from the other neurons that feed into it • Carry this information down its length • Pass the information on to the next neuron in line
Neurons • Very limited in function- their main capability is transmitting an impulse, or firing • While neurons come in a variety of shapes and sizes, they all have similar structures
Structure of a Neuron Dendrite – The branching extensions of a neuron that receive information and conduct impulses toward the cell body
Structure of a Neuron Soma – The cell body of a neuron, which contains the nucleus and other parts that keep the cell healthy
Structure of a Neuron Axon – The extension of a neuron through which neural impulses are sent
Structure of a Neuron Axon terminals – The endpoint of a neuron where neurotransmitters are stored
Transfer of Information • The impulse that occurs when a neuron fires is called an action potential • This is followed by a brief recharging period known as a refractory period • At that point, a neuron is capable of another firing impulse if stimulated- as it rests and waits to fire again, it exists in a state of resting potential
Action Potential Resting Potential Refractory Period
Transfer of Information • All neurons exist under the all-or-nothing principle, which means that each neuron fires with the same intensity no matter what the stimulation is that causes the action potential
Transfer of Information • No two neurons are in contact with one another- so the information has to find a way to get from one neuron to the next • The fluid-filled gap that exists between the dendrites of one neuron and the axon terminal of another is called the synapse or synaptic gap • The information crosses the gap aboard a chemical messenger called neurotransmitters
Transfer of Information • The neurotransmitter will cause the receiving neuron to do one of two things: • If it causes the receiving neuron to fire, it creates an excitatory effect • If it causes the receiving neuron to stay at rest, it creates an inhibitory effect
Transfer of Information • Receptor cells located in the sensory systems of the body gather information such as sight, smells, and sounds. • This information is then sent to the brain and spinal cord by sensory nerves where it is processed by billions of interneurons • If an action of a muscle is needed due to the results of that processing, a new signal is sent to that muscle through motor nerves where an action takes place
Transfer of Information • Certain chemicals can get in the way of this transfer of information: • Antagonists can block the effects of a neurotransmitter (ex. Paralyzing poison darts) • Agonists boost the effects of a neurotransmitter (ex. Black Widow spider venom)