* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Your Nervous System
Neural engineering wikipedia , lookup
Mirror neuron wikipedia , lookup
Signal transduction wikipedia , lookup
Action potential wikipedia , lookup
Caridoid escape reaction wikipedia , lookup
Neural coding wikipedia , lookup
Metastability in the brain wikipedia , lookup
Axon guidance wikipedia , lookup
Central pattern generator wikipedia , lookup
Multielectrode array wikipedia , lookup
Patch clamp wikipedia , lookup
Premovement neuronal activity wikipedia , lookup
Neuromuscular junction wikipedia , lookup
Node of Ranvier wikipedia , lookup
End-plate potential wikipedia , lookup
Resting potential wikipedia , lookup
Optogenetics wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Development of the nervous system wikipedia , lookup
Nonsynaptic plasticity wikipedia , lookup
Neuroregeneration wikipedia , lookup
Neurotransmitter wikipedia , lookup
Circumventricular organs wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
Synaptogenesis wikipedia , lookup
Chemical synapse wikipedia , lookup
Single-unit recording wikipedia , lookup
Molecular neuroscience wikipedia , lookup
Electrophysiology wikipedia , lookup
Channelrhodopsin wikipedia , lookup
Synaptic gating wikipedia , lookup
Biological neuron model wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Nervous system network models wikipedia , lookup
Your Nervous System Engage Lorenzo’s Oil Discussion Explore Quick Communications Neuron Models Explain Nervous System Four Major Parts of the Nervous System Neurons Nerves Brain Spinal Cord Two Major Nervous System Central Nervous System Peripheral Nervous System Nerves and Neurons are found in both and this is where we will begin Neuron ”Nerve Cell” Functional Unit of Nervous System 1. 2. Cell Body – center part of the cell containing the nucleus Dendrites 3. Carries messages toward the cell body. Fingerlike projections Axon Carries messages away from the cell body. Elongated extension of the cell body End of the axon is divided into fingerlike projections called axon terminals. Neuron Model To check for understanding you will need to construct a neuron model that contains dendrites, a cell body (soma), axon, and axon terminals. Types of Neurons Sensory Neurons – picks up the stimuli (nerve impulse) and carries it to the spinal cord and brain. Interneurons- Found within the brain and spinal cord. Relays the message between the sensory neurons and the motor neurons. Motor Neurons – transfers impulses away from the brain to the spinal cord How Neurons Work 1. Reception 2. Transmission 3. Information is sorted and interpreted Transmission 5. Sensory neurons transmit the touch message Data Interpretation 4. Receptors in the skin sense stimuli Motor Neurons transmit a response message to a muscle Response Muscles are activated causing a response Impulse Transmission Start with a RESTING neuron – one NOT transmitting an impulse Plasma membrane controls [ ] of ions inside the cell Na+ and K+ on both sides of membrane Na+ Higher Conc Outside K+ Higher Conc Inside Remember Na+/K+ ATPase Pump Sodium Potassium Pump How an Impulse Travels Stimulus excites a neuron Na+ channels open, Na+ build up inside Inside more + that outside Change in charge (depolarization) Membrane immediately behind depolarization returns to RESTING STATE RESTING STATE – inside negative, outside positive 1. Resting State A neuron is not conducting an impulse The K+ concentration is much higher inside the cell than out The Na+ concentration is much higher outside the cell than in 2. Depolarization A nerve cell is stimulated Membrane becomes permeable to Na+ for an instant and they quickly move into the cell The inner surface of the cell membrane is now more positively charged then the outside. 3. Repolarization When the cell membrane becomes depolarized, K+ automatically leaves the cell until the cell is back to its resting state. 4. The Impulse Travels “Wave” of depolarization – transmission of an impulse along length of axon All or None Principle – must reach a threshold level or the impulse dies Covered by a white covering called a myelin sheath (Schwann Cells), an insulator Myelin sheath causes the ion exchange to occur only at the nodes which speeds up the process For a short time after depolarization; the neuron cannot be stimulated 5. Transmission Across a Synapse Neurons do not actually touch. This gap between the two cells is call a SYNAPSE Impulses are carried across a synapse by chemical messengers called neurotransmitters. Approximately 30 different neurotransmitters; do one of two things: 1. 2. Stimulate the action potential in a second cell Inhibit the action potential in the next cell 6. Refractory Period The period of time it takes a neuron to return to its resting potential after being stimulated A neuron cannot be stimulated during this period This period of time is about 0.0004 of a second Elaboration Neurotransmission: Nifty Neurons and Muscle Messages Evaluation Parts of Nervous System List the Four Major Parts of the Nervous System Neurons Nerves Brain Spinal Cord