A neuron is a specialized type of cell that helps in impulse conduction in the body. It is a basic unit of communication in the body. It receives and initiates the information reception and transmission to all parts of the body. The structure of the neuron is made of several parts that include dendrites, Soma (cell body), nucleus, cell membrane, axon, myelin sheath, a node of Ranvier and terminal Buttons or axon terminal (Marieb, 2004). The figure below shows the structure of the neuron.
Figure 1: structure of neuron (Shonkoff & Phillips, 2010).
For neural impulse to occur, the stimulus depolarizes the cell membrane causing the action potential. Depolarization occurs as results of disruption of K+ or Na+ caused by an electrical signal. The action potential results to conduction of signal in electrical or chemical form to the receptors. The electrical signal travels through axon via the membrane channels that contain voltage-gated ions (Euler, Skoglund, & Söderberg, 1968).
Stages in the neural impulses
Neural impulses have two stages which include resting potential and action potential. Resting potential is the stage in which neuron is not signaled for transmission. The membrane of the neuron is actively charged on both sides leaving inside in negative charge condition with respect to the outside.
The action potential is the stage in the neuron that is actively signaled and ready for transmission. It is characterized by a rapid change of polarity that takes place along the nerve fiber from one neuron to another. The change of stage from resting potential to action potential is initiated by the electrical change that allows the electrical signal from one neuron to the next. Types of stimuli that can activate the neuron include pressure, electricity or chemical. For the activation to take place, stimuli must reach the required threshold (Shonkoff & Phillips, 2010).
Functions of primary neurotransmitters
The primary neurotransmitters include γ-aminobutyric acid (GABA), serotonin (SE, 5-HT), dopamine, Norepinephrine and Acetylcholine.
Acetylcholine: It stimulates the contraction of muscles by sending cholinergic neurons.
γ-aminobutyric acid (GABA): It stabilizes the stimulation over firing.
Serotonin (SE, 5-HT): It plays the role of balancing the excitatory secretion in the brain.
Dopamine: It is both excitatory and inhibitory and controls depression as well as focus.
Norepinephrine helps in the stimulatory process in the body as well as producing epinephrine.
The neuropathic damage that causes malfunction to the nerves system is a good example that contrasts neural conduction.
References
Marieb, E. (2004). Human anatomy & physiology. San Francisco, Calif.: Pearson Benjamin Cummings.
Shonkoff, J. & Phillips, D. (2010). From neurons to neighborhoods. Washington, D.C.: National Academy Press.
Euler, C., Skoglund, S., & Söderberg, U. (2008). Structure and function of inhibitory neuronal mechanisms. Oxford: Pergamon Press.
