The Nervous System Essays

The Nervous System Essays The Nervous System Essay The Nervous System Essay The Nervous System is a complex System that has been broken into two major sections. One is the Central Nervous System also known as the CNS. This system consists of the brain and the Spinal cord. The second system is the Peripheral Nervous System which is known as the PNS. The PNS consist of all the other neural elements. The CNS and PNS work together to play a major role in the control of behavior. They receive and respond to the elements in the external and internal environment that’ll cause a nervous response. The CNS represents the largest part of the nervous system. The complete CNS is in the dorsal cavity the brain sits in the cranial sub cavity which is protected by the skull and the spinal cord is in the spinal cavity that is protected by the vertebrae. The nerves in the spinal cord carry messages to and from the brain. This system is for information processing where the motor output is computed to the response of the sensory input. The brain receives messages through the CNS and the PNS through special neurons. Each message travels to the brain or the spinal cord. Messages received through the spinal cord causes a response to the stimuli (elements in the external and internal environment strong enough to cause a nervous reaction) that does not cause any interpretation. The stimuli that are then received in the brain causes the response. The response is generated through the sense organs that interact with the 5 senses (hearing, seeing, smelling, tasting and touching). There are also general senses that are associated with the 5 senses, they are: pressure sense (sensed by the pressure receptors beneath the skin), Temperature senses (for the hot and the cold. This sends messages through the nerves to the brain), touch senses (receptors called tactile corpuscles), and the sense of pain (this is a protectant against something being wrong) these receptors for the general senses are found in the skin, muscles, joints and the internal and external organs. The PNS is subdivided into the sensory Somatic nervous system and the autonomic nervous system. The sensory somatic system consists of 12 pairs of cranial nerves and 31 pairs of spinal nerves. The cranial nerves all send and respond to the different nerves in the system. The olfactory (sensory) nerve is for smell, the optic nerve (sensory) is for vision, oculomotor (motor) nerve controls the eye lid and the eyeball muscles. Thetrochlear (motor) nerve is strictly for the eyeball muscles. The trigeminal nerve (mixed) is for facial and mouth sensations also for chewing. Abducens nerve (motor) is for eyeball movement. Facial nerve (mixed) is for taste and facial muscles and salivary glands. Aditory (sensory) controls the hearing and balance. Glossopharyngeal (mixed) for taste and swallowing functions. Vagus (mixed)is the main nerve of the parasmpathetic nervous system this motor is for swallowing and movement of the head and shoulders. The tongue muscles are controlled by the Hypoglossal nerves (motor). The Spinal nerves are mixed with both sensory and motor neurons. When exposed to the environment all conscious and motor activity deals with and operates through the Sensory somatic division. The Autonomic Nervous System consists of both sensory and motor neurons the travel between the CNS. The internal organs that are associated with the nervous system are the heart, the lungs, the viscera and the glands. This system is responsible for the monitoring conditions of the internal environment. The autonomic nervous system has two subdivisions the sympathetic and the parasympathetic nervous system. With the release of adrenaline into the blood ensures that all the cells of the body will be exposed to the sympathetic stimulation even if no postganglionic neurons reach them directly. The sympathetic nervous system prepares the body for violent activity and the parasympathetic system reverses these changes when the danger is over. The PNS is not protected by bone so that leaves it exposed to mechanical injuries. There are many disorders associated with nervous system such as vascular (stroke and hematoma’s), infections (meningitis and polio), structural (brain and spinal injury), functional (headache’s and epilepsy), degeneration (Parkinson’s and Alzheimer’s). The signs and symptoms to look for are head aches, loss of feeling, sudden loss of sight, memory loss, tremors, seizers and back pain that radiates to the feet, toes and other body parts. As you can see the nervous system play’s a large part in your day to day life. It keeps you moving, functioning and sending messages trying to protect you from the day to day incidents by using your sensory and you motor abilities. This part of the body should definitely be taken care of and kept out of harms way.