- The human nervous system may be categorized into two divisions namely PNS and CNS. The nervous system has three broad functions which include sensing changes in the body as well as within outside environment; interpreting changes as well as establishing suitable response depending on reflexes, current conditions and experiences; and responding to interpretation through initiating action by glandular secretions (Paxinos, 2010). The PNS link the spinal cord and brain with receptors, glands, and muscles.
- Nerve impulse or action potential is an electrical signal which travels along the neuron resulting from entry of ions into neuron and altering voltage along the membrane. Myelin, synthesized by oligodendrocytes, is significant in the process of action potential because it increases the speed of impulse. Neurotransmitters are chemicals released by a neuron that change membrane potential of a different neuron to either inhibit an action or cause it.
- ANS (Autonomic Nervous System) have motor neurons, which transmit impulses, from central nervous system to cardiac muscle tissue, smooth muscle tissue, as well as glands. The sympathetic division increases alertness, stimulates metabolism and prepares a person for abrupt, extreme physical activity (Paxinos, 2010). On the contrary, parasympathetic division centers on food processing, relaxation, as well as energy absorption. Parasympathetic system is stimulated throughout the day for the body to process energy needed by cell activities (Paxinos & Mai, 2008).
- Injury to PNS and CNS may impair various functions of the nervous system such as cognition, memory, voluntary movement, and language (Paxinos, 2010). This always occurs through the crush of nerve systems. This lead to communication interruption between the nervous system and their organ targets. In worse situations, damage of PNS and CNS may lead to permanent disability or death (Uchida, 2009, p. 15).
- Damage to the frontal lobe may lead to impairments in attention span, organizational ability, and judgment and motivation loss. Additionally, a patient can become impulsive, take on risky behaviors and act rashly (Uchida, 2009, p. 10). Injury to the cerebellum may lead to dizziness, ataxia, vertigo, staggering gait and unsteady movement (Paxinos, 2010). Damage to Broca area and Wernicke area leads to difficulty in speech while injury to cranial nerve VII results into partial or complete facial paralysis and impaired taste. Injury at the back of the head can lead to impaired consciousness, inability to store or retrieve fresh information (Paxinos & Mai, 2008).
Paxinos, G., & Mai, J. K. (2008). The human nervous system. Amsterdam: Elsevier Academic Press.
Paxinos, G. (2010). The Human nervous system. San Diego: Academic Press.
Uchida, N. (2009). Direct isolation of human central nervous system stem cells. Proceedings of The National Academy of Sciences, 5, 10-15. doi:10.1073/pnas.97.26.14720