Buy essay on The Sensory Nervous System

The nervous system is an integral functional totality of different interconnected nervous structures, which provides the interrelated regulation of activities of all the systems of a human body and reaction to the changing conditions of internal and external environment.
Speaking about the sensory nervous system, it connects the central nervous system with organs and extremities. Neurons of the peripheral nervous system are located beyond the limits of the central nervous system (brain and spinal cord) (Peripheral nervous system, 2007). The peripheral system is classified into somatic, vegetative and sensory systems (Rang, 2003).
Functionally, the peripheral nervous system is responsible for body movements coordination, receiving of external stimuli, as well as for the reactions to approaching danger or stress, assisting in increasing of the level of the adrenaline. In order to analyze the way peripheral nervous system senses on a definite stimulus, types of nerves, which are the instruments of the reactions to some stimuli, are to be mentioned. To begin with, there are 12 pairs of nerves that perform sensible and motional functions. These are: an olfactory nerves, visual (optic) nerve it comes to the retina and transfers visual senses, oculomotorious nerve assures the movements of the bulb of eye (optic bulb), block which assures the movements of one of the eye muscles, trigeminus that adds a sensibility to the whole face and assures the work of mastication muscles, abductoral (makes a bulb of eye turn to the internal side), and facial nerves provide for the movements of one of the facial muscles.
An olfactory nerve transfers to the brain olfactory feeling from the mucous tunic of the nasal cavity. When an organism or some part of it senses a stimulus the reciprocal reaction on it is called a reflex.
The way, with the help of which impulses of the stimulation are transferred to the brain, is called a reflex arc. So, one of the stimulus and the process of sensing it to describe in this paper is a smell stimulus. An olfactory analyzer is presented by two systems – main and nasal each of which has three parts: peripheral (olfactory organs), an intermediate system that consists of axons, sensorineural olfactory cells, and nerve cells of olfactory bulbs, and the central, that is localized in a cerebral hemispheres for main olfactory system. The main smelling organ is organum olfactus localized in the mucous membrane of the nose, particularly in the olfactory region.
Nerve olfactorius provides a reaction. There are a lot of receptive olfactory cells in the epithelium of the mucous membrane of the nose. Thin central cellular processes of this cells are gathered into olfactory filaments, that are, as a matter of fact, an olfactory nerve.
So, when a stimulus (smell) is felt by the olfactory nerve which acts as a sensory neuron. A process of reaction takes places then through the nerve that goes to the brain’s ethmoid bone and ends in the olfactory bulb. Neuron receives a stimulus then the impulse is sent through the nerve to the brain that sends a message back to the olfactory filaments. The body responses according to the message – it feels a smell.
All in all, the peripheral nervous system is a very complex system that performs different functions and is responsible for body movements, the olfactory system provides the reaction to the stimulus (smell) and makes an organism feel different odors.

Works cited:

Johnson G. & Losos J. (2009). The Living World – Sixth Edition. McGraw-Hill Higher Education.
Peripheral nervous system (2007). Powered by Dorland’s Medical Dictionary for Healthcare Consumers. Retrieved May 10, 2010, from Resource Library
Poarch M. (2002). Stimulus – Response: Reaction Time. Retrieved May 10, 2010 from Science class website
Rang, Dale, Ritter & Moore (2003). Pharmacology – Fifth Edition. Churchill Livingstone.