Nervous System 2-o Dendrites: Input location. Receptors are located. Responds to neurotransmitterso Cell body: nucleus and metabolic machinery located o Axons: propagate signals away from cell body Surrounded by a myelin sheath Conducting zone. Responsible for generating and transmitting action potential signals to the axon terminalo Axon terminal: neurotransmitter chemicals are locatedo Nervous tissue: composed of neurons and glia cells (produce myelin sheath)- Neuronso Afferent Neurons: Sensory neurons and nerves that convey info into the central nervoussystem (CNS)o Efferent neuros: convey info away from the interneurons and affect or response to the original stimuluso Interneurons: CNS; 99% integrative centers for decisions underlying our responses- Speed of action potentialo Depended on Axon diameter: the bigger the mre rapidly itconducts the signal Myelin sheath: Provides insulation, and the the more insulated, the more efficient because prevents leakage- Nodes on the sheath from which act. Pot. Jumps from one toto another called saltatory conduction- Graded potentialo Long-distant signaling = act. Pot.o Short-distance signaling = graded pot.o Occurs in the input portion of t he nerve (at dendrites)o Differs from act. Pot. Amplitude variable, based on stimulus strength- Not all or noneo Receptor potential: response to change in environment R = special endings of afferent neurons or cells attached to afferent neurns Based on sodium ion. Soft touch = minimal sodium ion and vice versa Info from environment  graded potential = receptor pot. Frequency modulation: Absolute refractory period is short, so any stimulus that remains above threshold at the first node of the axon can setoff a string of action pot. - The more intense the stimulus, the more longer and higher graded pot.  If stimulus is not intense, act. Pot. Will slow down and body will adapt. If it is very intense, then the opposite will happeno Synaptic potential: response to NT(chem) at synapse Nerve to nerve Dendrite of second nerve action pot. Travels down the axon of the first nerve and depolarization at end of fist nerve allows the calcium to move in and exocytosis. This releases the neurotransmitter which diffuses across the gap and binds to the postsynaptic membrane receptors on the dendrites of the second nerve. This will open the sodium gatesn the sub synaptic membrane and result in a depolarizing graded potential that can cause action potential at the end nodes of the axon of the second