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The Nervous System
Biology 30-1
Term | Definition |
---|---|
Autonomic System | Invertebrates, the division of the peripheral nervous system that is under involuntary control |
Somatic System | Invertebrates, division of the peripheral nervous system that controls voluntary movement of skeletal muscle |
Sympathetic Nervous System | Division of the autonomic system that regulates involuntary processes in the body |
Norepinephrine | Neurotransmitter released by sympathetic neurons of the autonomic system to produce an excitatory effect on target muscles |
Parasympathetic Nervous System | -Rest & Digest -Dominates during times of relaxation -Stimulates activity in digestive system, salivation and tears |
Thalamus | Shuttles vision, auditory and touch sensory info to cerebrum & limbic system |
Midbrain | -very reduced in humans -relays auditory & visual information -role in eye movement & control of skeletal muscle |
Pons | Relay between left and right sides of cerebellum as well as relay to forebrain |
Medulla Oblongata | Controls automatic functions -breathing, heart rate, blood pressure, swallowing -large extension of spinal cord |
Cerebellum | coordination of voluntary movements, balance & equilibrium receives input about body position from specialized sensors called proprioceptors located in muscles and joints |
Meninges | three laters of tough, elastic tissue with the skill & spinal column which directly enclose the brain & spinal cord |
White Matter | Part of the nervous system that is made up of tracts of myelinated nerve fibers. Forms the inner region of some areas of the brain & the outer area of the spinal cord |
Gray Matter | Part of the nervous system that contains mostly cell bodies, dendrites & short unmyelinated nerve fibers. Forms the outer areas of the brain & the H-shaped core of the spinal cord |
Acetylcholine | the primary neurotransmitter of both the somatic nervous system & the parasympathetic nervous system. -open Na+ channels in the postsynaptic neuron |
Nodes of Ranvier | Gap in the myelin sheath insulating the axon of the myelinated nerve cell The membrane of the axon is exposed & action potentials occure only at the nodes Nerve impulses jump from one node of Ranvier to the next. |
Myelin Sheath | Layer of fatty protein wrapped around axon Myelin speeds movements of nerve impulses by insulating axons |
Axon | Projection of cell body Conducts impulses away from cell body to synaptic |
Cell Body | Contains nucleus & cytoplasm Carries on normal metabolic activities of nerve cells Integrates signals from the dendrites & initiates nerve impulses down the axon |
Dendrites | Projections of cell body Receives signals & transmit towards cell body |
Glial Cells | Non conducting "support" cells that are involved in support & metabolism of neurons |
Neurons | Functional unites of nervous system Specialized to conduct electrochemical impusles |
Corpus Callosum | Halves communicate through a band of myelinated axons |
Cerebrum | Controls higher-level thinking Intellect, memory, personality, language, interpretation of sensory information & control of voluntary muscles movement |
Hypothalamus | Released hormones Directs Autonomic nervous system Controls internal body environment Controls "primitive" drives (thirst, hunger, sleep) & emotions |
Cerebral Cortex | Responsible for language, memory, personality, conscious thought & other activities that are associated with thinking & feeling |
Wernicke's Area | Stores the information involved in language comprehension |
Broca's Area | Coordinates the muscles for speaking & translates thought into speech |
Temporal Lobes | Auditory, Memory |
Polarization | Lowering the membrane potential of the cell below its equilibrium value |
Nervous System | System made up of cells & organs that let an animal detect changes & respond to them. Made up of the brain & spinal cord, as well as the nerves that emerge from them & connect them to the rest of the body |
Homeostasis | The tenancy of the body to maintain a relatively constant internal environment |
Peripheral Nervous System | Network of nerves that carry sensory messages to the central nervous system & send information from the CNS to the muscles & glands |
Central Nervous System | Network of nerves that includes the brain & spinal cord; integrates & processes information sent by nerves |
Sodium-Potassium Exchange Pump | System involving a carrier protein in the plasma membrane that uses the energy of ATP to transport sodium ions out of & potassium ions into animal cells |
Frontal Lobes | Control precise, voluntary motor skills including speech production Reasoning, critical thinking, memory & personality Inhibition of unsuitable behaviours |
Nerves | Macroscopic structures Made up of many neurons grouped into bundles Message pathway of the nervous system |
Cerebrospinal Fluid | Circulates between meninges and throughout the brain & spinal cord providing cushioning & shock absorption Transports hormones, nutrients & white blood cells |
Refractory Period | Na/K pump active K channels open Na channels shut Restores ion concentrations necessary for resting potential Neuron is not receptive to another stimulus until resting potential of -70mV is established -90mV to -70mV |
Parietal Lobes | Touch, pain, pressure, temperature, help process body position information |
Occipital Lobes | Primary visual processing |
Repolarization | K channels open Na channels shut Na/K pump inactive -40mV to -90mV |
Depolarization | Neuron receives stimulus K channels shut Na channels are open Na/K pump stops Neuron becomes positively charged Once the neuron reaches +40mV the sodium channel is shut -70mV to +40mV |
Resting Membrane Potential | Na/K Pump active K channels open "leaky" Na channels closed More positive ions are moving out of the neuron than are coming in, creates negative resting potential -70mV |
Cholinesterase | Enzyme that breaks down the neurotransmitter acetylcholine in a synapse |
Neuromuscular Junction | The synapse connection a motor neuron to a muscular fiber. The neurotransmitter acetylcholine causes an action potential which triggers muscle fiber contraction |
Synapse | Tiny junction between neurons or between a motor neuron & an effector (ex. muscle) |
Neurotransmitter | Chemicals released by the presynaptic neuron that influence the activity of the postsynaptic neuron. The receptor on the postsynaptic neuron determines th NTs effect |
Schwann Cells | A type of insulating glial cell that wraps around the axon of a neuron, creating a myelin sheath |
Reflex Arcs | Involuntary movement initiated without brain control Ex. pain-withdrawal reflex |
Blood-Brain Barrier | Protective barrier formed by selectively permeable blood vessels that controls entrance of substances into the brain from the blood |
Membrane Potentail | Measure of the charge inside of a cell relative to the outside |
Action Potential | In an axon, the change in charge that occues when the gates of the K+ channels close & the gates of Na+ channels open after a wave of depolarization is triggered |