* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download PNS and Transmission
Multielectrode array wikipedia , lookup
Central pattern generator wikipedia , lookup
Long-term depression wikipedia , lookup
Patch clamp wikipedia , lookup
Caridoid escape reaction wikipedia , lookup
Apical dendrite wikipedia , lookup
Microneurography wikipedia , lookup
Optogenetics wikipedia , lookup
Endocannabinoid system wikipedia , lookup
Activity-dependent plasticity wikipedia , lookup
Development of the nervous system wikipedia , lookup
Axon guidance wikipedia , lookup
Premovement neuronal activity wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
Signal transduction wikipedia , lookup
Circumventricular organs wikipedia , lookup
Neuroregeneration wikipedia , lookup
Membrane potential wikipedia , lookup
Spike-and-wave wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Neuroanatomy wikipedia , lookup
Biological neuron model wikipedia , lookup
Pre-Bötzinger complex wikipedia , lookup
Neuromuscular junction wikipedia , lookup
Channelrhodopsin wikipedia , lookup
Action potential wikipedia , lookup
Resting potential wikipedia , lookup
Electrophysiology wikipedia , lookup
Single-unit recording wikipedia , lookup
Nonsynaptic plasticity wikipedia , lookup
Node of Ranvier wikipedia , lookup
Nervous system network models wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Synaptogenesis wikipedia , lookup
Synaptic gating wikipedia , lookup
Neurotransmitter wikipedia , lookup
Stimulus (physiology) wikipedia , lookup
Chemical synapse wikipedia , lookup
PNS and Transmission February 09, 2010 PNS • Composed of neurons and ganglia. Ganglia are swellings associated with nerves that contain collections of cell bodies. • Somatic division: serves the skin, skeleton, and tendons. • Autonomic division: regulates the activity of cardiac and smooth muscles and glands. Types of PNS Nerves • Cranial: 12 pairs; many belong to the somatic division; includes the vagus nerve which has branches to most of the internal organs. • Spinal: 31 pairs; associated with the 3 regions of the vertebral column; Somatic Division • Most actions are voluntary which means they originate in the cerebral cortex. • Others are reflexes: cranial (blinking) and spinal reflexes (hand on stove). Autonomic Division • Sympathetic: most arise from the lower thoracic or lumbar region. Highly involved in the fight or flight reflex. • Parasympathetic: Craniosacral; promotes all the internal responses we associated with a relaxed state. • Commonalities: 1) they function automatically and usually involuntary, 2) they innervate all internal organs, and 3) they utilize 2 motor neurons and 1 ganglion for each impulse. Nerve Impulses • Resting Potential: membrane is polarized (outside + inside -). The sodium potassium pumps are responsible for setting this up. • Action Potential: 1) depolarization (inside +); 2) repolarization (inside -). • If an axon is myelinated, the action potentials are stimulated between the nodes of Ranvier (faster potential) in non-myelinated it stimulates another part of the axomembrane. • All or None event. One way from cell body to axion terminal. Transmission • Every axon terminates in an axon terminal. All of these lie close to a dendrite or the cell body of another neuron. • Pre-synaptic and Postsynaptic region. Between them is the Synaptic cleft. Transmission • Transmission is carried out by molecules called neurotransmitters. These are stored in vesicles in the axon terminals. • Impulse reaches terminal opens calcium channels Calcium enters the terminal vesicles move toward membrane for exocytosis neurotransmitters are released and diffuse through synaptic cleft neurotransmitters bind with receptors on postsynaptic membrane. • Depending on the neurotransmitter and receptor the response will be excitation or inhibition. Integration • Neurons can have many dendrites and can synapse with many other neurons. • An excitatory NT produces a potential change called a signal. The signal drives the polarity of a neuron closer to an action potential. An inhibitory NT does the opposite. • Integration is the summing up of all of the excitatory and inhibitory signals. Which ever side wins determines if an Action Potential will be transmitted.