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Nervous system - Jocelyn Villa period 1, Drugs of Abuse, Nervous…

- - - - Memory and learning
- - - - CNS: made up of brain and spinal chord
        responsible for integration of information and decision making
- - - - Struct. Classification of neurons-
        Multipolar neurons: many dendrites +1 axon arising from cell body, most with cell body are multipolar.
        Bipolar neurons: 2 processes extending cell body, dendrite and axon; found in eyes, nose, and ears.
        Unipolar neurons: 1 process extending from cell body, soon splits into 2 parts that functions as 1 axon. (Sensory neurons)
        
        Neuroglia are cells that support neurons. They fill spaces, structurally support, protect, and insulate neurons, they do not generate or conduct nerve impulses. 4 types in CNS, 2 types in PNS.
- - - - Motor (efferent) neurons: Multipolar neurons that conduct impulses from the CNS to peripheral effectors which would be muscles or glands.
- - - - Cons of 31 segments, white matter, butterfly shaped core of gray matter.
        
        Functions:
        Major- transmit impulses to and from brain and or house spinal reflexes.
        Spinal reflexes controlled by reflex arcs that pass through spinal chord
- - - - Occurs when charge reaches -55mV, when the potential is reached the cell responds by returning to resting potential. At the end of repolarization something called hyperpolarization occurs
        
        Impulse conduction: Action potential at trigger zone causes and electrical current to flow to adjacent regions of axons membrane, refractory period occurs. Limits frequency and ensures impulse is transmitted in only one direction.
        
        Process of impulse conduction:
        
        Neuron membrane maintains resting potential
        
        Threshold stim recieved
        
        Sodium channels in the trigger zone of the axon open
        
        Sodium ions diffuse inward, depolarizing axon membrane.
        
        Potassium channels in axon membrane open
        
        Potassium ions diffuse outward, depolarizatiozing axon membrane
        
        The resulting action potential causes a local electric current that stims adjacent portions of axon membrane
        
        A series of action potentials.
        
        Types of impulse conduction: Continous conduction, Salatory conduction
- - - - The pairs are designated by # and name; the #’s are in order from superior to inferior.
- - - - ’d in sequence: 8 pairs of cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves and 1 pair of coccygeal nerves. Each arises from 2 roots: a sensory dorsal root and a motor ventral root