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Lesson 8 blackboard

Lesson 8 blackboard - Neurons Hormones and the Brain...

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Unformatted text preview: Neurons, Hormones, and the Brain Organization of the Nervous System Central Nervous System Receives, processes, interprets, and stores incoming sensory information Sends out messages destined for muscles, glands, and internal organs Central Nervous System Comprised of the brain and the spinal cord Spinal cord collection of neurons and supportive tissue running from the base of the brain down the center of the back Spinal reflexes automatic behaviors produced by the spinal cord Peripheral Nervous System All portions of the nervous system outside the brain and the spinal cord Includes sensory and motor nerves Sensory nerves carry messages from skin, muscles, and other internal and external sense organs to the spinal cord. Motor nerves Carry orders from central nervous system to muscles, glands, and internal organs. Peripheral Nervous System Somatic Nervous System Permits voluntary actions Autonomic (Automatic) Nervous System Works without conscious control Biofeedback technique used to gain some control over autonomic nervous system function. Peripheral Nervous System Autonomic nervous system divided into two parts Sympathetic Nervous System Mobilizes body for action Parasympathetic Nervous System Slows the body down Communication in the Nervous System Neurons cells that conduct electrochemical signals; basic unit of the nervous system; also called a nerve cell. Glia cells that support, nurture, and insulate neurons, remove debris when neurons die, and modify neuronal functioning Structure of a Neuron Dendrites Receive information from other neurons and transmit toward the cell body Cell body Keeps the neuron alive and determines whether it will fire Axon Extending fiber that conducts impulses away from the cell body and transmits to other cells. Structure of a Neuron Myelin sheath Fatty insulation Surrounds the axon of a neuron Nerves Bundles of nerve fibers (axons and sometimes dendrites) Part of peripheral nervous system Human body has 43 pairs of peripheral nerves How Neurons Communicate Neurons not physically "connected" Synaptic cleft the space between the axon terminal of one neuron and the beginning of another. Synapse includes the synaptic cleft. End of preceding neuron and the beginning of the next Learning and stimulating environment produce new neurons and more complex connections Pruning when unused/seldom used synaptic connections disappear or die How Neurons Communicate Neurons communicate using an electrical and chemical "language" Stimulation of a nerve cell leads to an action potential, or change in electrical voltage Action potential produces an electrical current, or impulse Myelin sheath increases speed of impulse How Neurons Communicate Neural impulses travel to the axon terminal Synaptic vesicles open Neurotransmitters released Neurotransmitters travel across the synaptic cleft and bind with receptor sites on receiving cell's dendrites How Neurons Communicate Changes occur in receptor neuron's membrane Effect can be excitatory or inhibitory Thousands of messages, both excitatory and inhibitory, may be coming into a cell at any given time Firing is either all-or-none Major Neurotransmitters Serotonin sleep, appetite, sensory perception, temp. Dopamine lack of this = Parkinson's disease. Voluntary Acetylcholine (Ach) muscle action, cognitive Norepinephrine Gamma aminobutyric acid (GABA) Glutamate Endorphins p.125 functioning, memory, emotion movement, learning, memory, emotion regulation, pain suppression, mood ...
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