Describe the Structure of a Neuron A nervous system cell is constituted in such a way that it is specialized in receiving, processing, and/or transmitting information to other cells.
• Dendrites: Receivers of incoming signals; branch fibers extending outward from the cell body.
• Soma: The cell body containing the cytoplasm and the nucleus of the cell; cytoplasm keeps it alive.
• Axon: The nerve impulses travel from the soma to the terminal buttons through the extended fiber of a neuron i.e., axon. terminal Buttons: Swollen, bulblike structures at one end of the axon; the neuron stimulates the nearby glands, muscles, or other neurons
Connection between nerve cells
• Synapse: the gap between one neuron and the other.
• Synaptic Transmission: the procedure through which information is relayed from one neuron to another across the synaptic gap.
• Neurotransmitters: The post synaptic neuron is stimulated by the chemical messages released from neurons; they cross the synapse from one neuron to another.
The Chemical Messages
• The neurons follow an all-or-none law…. either a neuron will be firing or resting /off.
• Excitatory Message: The chemical message that makes it more likely that the receiving neuron will fire and the action potential will travel down its axon.
• Inhibitory Message: The chemical message that inhibits a receiving neuron from firing so that the action potential does not travel down its axon.
Major Varieties of Neurons
• Sensory Neurons (afferent): they carry messages toward the Central Nervous System from the sensory receptor cells.
• Motor Neurons (efferent): they carry messages away from the Central Nervous System toward the muscles and glands.
• Inter-Neurons: they relay messages from sensory neurons to other inter-neurons and/or to motor neurons.