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NERVOUS SYSTEM. Main function and components…. The Nervous System is composed of The _________________ Brain and Spinal Cord The ___________________ Peripheral nerves carrying information from the periphery to the spinal cord to be relayed to the brain for interpretation .
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Main function and components…. • The Nervous System is composed of • The _________________ • Brain and Spinal Cord • The ___________________ • Peripheral nerves carrying information from the periphery to the spinal cord to be relayed to the brain for interpretation
The neuron…. • ____________ are the main _______________ of the ________________ that are responsible for relaying information to and from the ________ • There are 3 different types • _________ • sends messages to the body dictated by the brain • _________ • receives messages from periphery ( via receptor cells) and sends them to the CNS • ______________ (aka relay neurons) • The junction between motor and sensory neurons
Nerve impulses • Neuronal function is almost 100% dependent on _______________ • Every nerve cell has an _____________ both inside and outside of the cell - those charges are different in that one is overall (-) and the other is overall (+) in nature • These charges are provided by specific ions that are both in/out of the cell • This difference in charge is referred to as “_________________” and is measured in voltage • The state of charge of membrane potential - can change from ______ ____________ to ____________ to _________________ • The “state” change is a result of ion movement via ion channels in the neuron’s axon
Nerve Firing – Resting Potential • Four different types of ______ are involved in the transmission of neural impulses; (Cl-), (Na+), (K+), and organic anions (A-). • A neuron at rest normally charges __________ inside the cell and ___________ outside the cell
Nerve firing – Action potential • Due to the opening of "gated" sodium (Na+) channels. • The inside of the axon becomes more __________ • This change of potential opens the “______" of further sodium channels. This occurs in an "explosive" manner leading to a sudden change from a _______________ across the membrane to a ____________ • This potential difference results in ________ the sodium channels and opening current "gated" potassium channels allowing outflow of potassium to areas outside the axon where potassium is at a lower concentration. • As a consequence the potential across the membrane is _______as the inside of the axon becomes more ______ and the outside more ______________.
Neuron firing – Refractory Period • After the cell fires, it goes through a _________________ • it will not fire again • the cell will fire during the relative refractory period, but only if it receives a very strong stimulus. • This is called and “____________” response
The Synapse and release of neurotransmitter • When a neuron fires it releases chemicals called _______________. • Neurotransmitters are found in the ___________ • The neurotransmitters then travel across a small space called the ___________________ to attach to the neuron that will receive their message.