* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Studying the concepts pg 344 1-7 Motor neurons are located in the
Holonomic brain theory wikipedia , lookup
Neural coding wikipedia , lookup
Patch clamp wikipedia , lookup
Multielectrode array wikipedia , lookup
Embodied language processing wikipedia , lookup
Neuroscience in space wikipedia , lookup
Signal transduction wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Central pattern generator wikipedia , lookup
Premovement neuronal activity wikipedia , lookup
Neural engineering wikipedia , lookup
Caridoid escape reaction wikipedia , lookup
Membrane potential wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
Microneurography wikipedia , lookup
Action potential wikipedia , lookup
Axon guidance wikipedia , lookup
Electrophysiology wikipedia , lookup
Resting potential wikipedia , lookup
Development of the nervous system wikipedia , lookup
Neuromuscular junction wikipedia , lookup
Single-unit recording wikipedia , lookup
Nonsynaptic plasticity wikipedia , lookup
Node of Ranvier wikipedia , lookup
Biological neuron model wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Synaptic gating wikipedia , lookup
Neuroanatomy wikipedia , lookup
Neuroregeneration wikipedia , lookup
Nervous system network models wikipedia , lookup
Neurotransmitter wikipedia , lookup
Chemical synapse wikipedia , lookup
Molecular neuroscience wikipedia , lookup
End-plate potential wikipedia , lookup
Synaptogenesis wikipedia , lookup
Studying the concepts pg 344 1-7 1. Motor neurons are located in the central nervous system (CNS) they project their axons outside the CNS and directly or indirectly control muscles. A typical neuron is divided into three parts: the soma or cell body, dendrites, and axon. The soma is usually compact; the axon and dendrites are filaments that extrude from it. The dendrites of a neuron are processes that send signals towards the cell body. The cell body is a part of a neuron that contains the nucleus and other organelles. An axon conducts nerve impulses along its entire length. There are three classes of neurons: motor neurons, sensory neurons and interneurons. In relation to the CNS a sensory neuron takes information to the CNS while a motor neuron takes information away from the CNS. An interneuron conveys information between neurons in the CNS. 2. The sodium-potassium pump is an enzyme located in the plasma membrane in all animals. The pump helps maintain resting potential, avail transport, and regulate cellular volume. In order to maintain the cell membrane potential, cells must keep a low concentration of sodium ions and high levels of potassium ions within the cell thru the sodium-potassium pump. When an axon is not conducting an impulse and the inside of the axon is negative compared to the outside it is called resting potential. 3. Action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls. It is a rapid change in polarity across an axonmembrane as the nerve impulse occurs. The first part of action potential is the sodium gates opening; this is when the gates of the sodium channels open and Na+ flows in the axon. This is depolarization because the axon changes from negative to positive. The second part is the Potassium gates opening, this is when the potassium channels open and K+ flows to the outside of the axon. This is repolarization because the inside of the axon resumes a negative charge from positive. 4. Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. A synapse is a region between two nerve cells, usually an axon and dendrite. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side (of a synapse, and are released into the synaptic, where they bind to receptors in the membrane on the postsynaptic side of the synapse. Release of neurotransmitters usually follows arrival of an action potential at the synapse. Neurotransmitters are 5. 6. 7. either destroyed by specific Enzymes in the Synapse, diffuse out, or are reabsorbed by the Neuron. Two well-known neurotransmitters are acetylcholine (Ach) and norepinephrine (NE). The peripheral nervous system lies outside the central nervous system and contains nerves which are bundles of axons. The PNS contains 3 types of nerves: sensory nerves, motor nerves and mixed nerves. Mixed nerves contain motor and sensory fibres. The Somatic Reflex: stimulus – sensory receptor (skin)generate nerve impulses – sensory nerve fibre pass signals to many interneurons – spinal nerve – dorsal root ganglion – interneuron – motor transmission carry impulses to effector – motor nerve fibre – effector (muscle) response to stimulus. The autonomic system of the PNS regulates the activity of cardiac and smooth muscles and glands. Its two major divisions are the sympathetic division and the parasympathetic division. Sympathetic Parasympathetic -Arise from middle portion of spinal cord -Arise from the sacral portion of spinal cord -Terminated by ganglion immediately -Craniosacral portion -Preganglionic fibres are short -Preganglionic fibres are long -Postganglionic fires are long -Postganglionic fires are short -Emergency state “fights or flight” -Relaxed state “housekeeper division -Uses NE neurotransmitters -Uses Ach neurotransmitters