Parasympathic nervous system

Parasympathic nervous system (link) is one of the two major nervous systems under the the Autonomic nervous system(link). It has a ‘rest and repose’ effect on the targeted organs as compared to Sympathic(link) nervous system(1Ref.Dic). It mainly serves the salivary gland(link), thoracic and viscera, bladder and genitalia  and plays a part in less vigorous activities(2Ref.Dic)(3Ref.BLU 351) .

Functions

Most of the time performs constriction in and secretion functions in several organs, except in the regulation of heart rate, which is constricted by the Sympathic nervous system(4Ref.Pharm 27). It is not involved in regulating the blood vessel(link) and the brain. (5Ref.RD 274) It maintains and returns the body to relatively stable internal environment. (6Ref.RD 274) 

Structure

Preganglionic neurons(link) are located in the gray matter and its dendrites being distanced far away from the CNS(link). It synapses with one postganglionic neuron in the peripheral ganglia situated near or within the effector tissue. It is important to know that only one organ is affected by a Parasympathic neuron during signal transduction when a signal is transmitted from one preganglionic neuron to a postganglionic neuron that attaches itself to only one effector tissue in the organ. In contrast, Sympathic nervous system can have several effectors(7Ref.RD 267-8). 

Preganglionic neurons contain nicotinic acetylcholine(link) ion channel(link) receptors at and Postganglionic neurons contain muscarinic acetylcholine(link) G-protein(link) receptors at their respective presynaptic terminals(link).

Disease and Treatment

A defective in the longest neuron in the system is most evident to account for a neuronal disease(8Ref.BLU 288). This usually causes a 'stocking and glove' defect and parathsias in patients. Individuals with diabetes(link) are more prone to be affected.

The most prominent accountable disease-causing factor is stress, which upsets the Parasympathic pathway, thus having an adverse effect on the overall metabolic system(9Ref.RD 269) (10Ref.Pubmed2) .

According to d'Alessio et al. (2013), it is known that d-Limonene is capable of counteracting the stress changes in Parasympathic pathway(Ref.PubMed1). The Parasympathic nervous system has the ability to respond to mechanisms that could lead stroke or brain damage. Despite the severity of the diseases, only a minute number of stroke cases can be treated. With minimal treatments in stroke patients, a further study in the neuroprotective mechanism is vital. From the research conducted by Cheyuo et al. (2011), neuroprotection could be attained by several approaches. Ideally a treatment which utilises mutiple drugs and with a less damaging and simplistic approach would be the most effective way to treat stroke patients(11Ref.Pubmed2).

1Ref.Dic

2Ref.Dic

3Ref.BLU 351

4Ref.Pharm 27

5Ref.RD 274

6Ref.RD 274

7Ref.RD 267-8

8Ref.BLU 288

9Ref.RD 269

10Ref.Pubmed2

PubMed1 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3099641/

PubMed2 http://www.ncbi.nlm.nih.gov/pubmed/24125633

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