An In Depth Look at Your Incredible Nervous System
Your body relies entirely on your nervous system for the operation of all other systems. Different from other body systems that have one or two functions, the nervous system is a hype of activities.
Your nervous system is in full command of everything happening in your body, whether voluntary or involuntary. The system sends signals to every part of the body for different activities.What is the Nervous System?
The nervous system, in a simple definition, is a network of nerves and nerve cells called neurons that send signals to and from the body parts from the system. The system, which is at the center of every physical and mental activity is sensitive to environmental changes.
The system then responds to environmental changes accordingly through its receptors and with the help of the endocrine system.
Amazing Facts of the Nervous system
Your brain utilizes the most energy of the entire body energy than any other organ. It accounts for energy usage of 20% in sending signals and nerve cell maintenance.
The speed of the fastest neurons, the alpha motor of the spinal cord, is 268 mph. The slowest is the skin's neural receptors at 1 mph.
The nerve cells do not go through cell division like other cells, and neither do they repair or regenerate. It is not possible to reverse a damaged neuron. However, other neurons adapt to the functions of the damaged one.
The largest nerve is called the sciatic nerve. It is the nerve of the toe that connects to the spinal cord.
The Two Parts of the Nervous System
The nervous system has two different parts that work together harmoniously to serve the entire body in all the sensory and motor activities. They are the central nervous system and peripheral nervous system.
The Central Nervous System or CNS
The central nervous system has the name "central" because it is at the center of the nervous system. The CNS receives messages from parts of the body to formulate responses and sends back the messages to the body.
The central nervous system consists of the brain and the spinal cord. The brain and the spinal cord are both encased for protection. The skull protects the brain while the vertebra protects the spinal cord. Some cerebrospinal fluid immerses the entire CNS structure for further protection against any damage.
The cerebrospinal fluid also provides a chemical environment conducive and suitable for the nerve fibers to affect the transmission of information.
The spinal cord and the brain are both responsible for conveying sensory and motor signals to other parts of the body. The signals are passed through a specific nerve or neuron of the peripheral nervous system for a particular action.
The appearance of the brain is bumpy because of the ridges and grooves of its tissue called gyri and sulci.
Gyri and sulci's primary function is to increase the cerebral cortex surface area and to form divisions of the brain, which then allows more room for neurons activities.
The brain is responsible for coordinating some body functions such as thoughts, feelings, memory, movement, and other activities of the body organs. It is also the responsibility of the brain to interpret messages from the five senses.
The Three Main Parts of the Brain
The brain is divided into three main parts, which play different roles in the central nervous system.
The brain's largest part is the cerebrum. The responsibilities of the cerebrum are controlling the senses, emotional response, speech, and memory. The outer layer of the cerebrum is called the cerebral cortex, which is a gray matter tissue.
The cerebral cortex is made of four lobes that have different functions.
The frontal lobe – It controls cognitive skills such as language, memory, problem-solving, and judgment.
The parietal lobe – It is responsible for touch sense and pain. It also controls your understanding and how you feel or your emotions on other people and things.
The temporal lobe – It creates memories to remember visual activities such as recognizing faces, memorizing languages, and controlling emotions.
The occipital – Its primary responsibility, among others, is vision and processing eyes visual input.
The cerebellum, which is in two halves (hemispheres), is situated next to the brain stem at the meeting point of the brain and the spinal cord.
The right and the left cerebral hemispheres are connected by a fissure called the corpus callosum. Each region controls the nervous functions of the opposite body side. For instance, the right hemisphere controls the left side of the body.
The cerebellum controls the motor nerves of the muscles to coordinate and balance the movements. It also helps to learn new movements such as dancing, riding a bicycle, and other coordinated actions.
At first, you might think it is the stem of the brain. You are not far from the truth. The brainstem works as a stem between the brain and the spinal cord. Besides that, the brainstem has other essential functions such as regulating the circulatory and the respiratory systems.
One part of the brainstem is involved in the visual and auditory process as well as eye movement. The brainstem is also responsible for most reflex activities such as sneezing, yawning, coughing, vomiting, swallowing, and others.
The Spinal Cord
The spinal cord runs from the medulla of the brain stem to the lumbar vertebrae. It is the path for neurons signals between the brain and the body. The spinal bone or the vertebral column protects the spinal cord.
Some membranes further protect both the spinal cord and the brain. Three different types of protective membranes or meninges cover the delicate parts of the spinal cord.
Dura mater – It is the outer most meninges which has a thick and tough protective coating. Dura mater lies directly below the vertebral column. The epidural space separates the dura mater from the arachnoid mater. It is the space that the doctors apply anesthetic in preparation for surgery or childbirth to reduce pain.
Arachnoid mater – The next tissue, which is the middle layer, is arachnoid mater that has connective tissue layers. Underneath it, there is a space called subarachnoid. Subarachnoid separates the arachnoid mater from pia mater, the tissue that follows. Subarachnoid contains cerebrospinal fluid, which doctors use as a sample when testing for meningitis (an infection of meninges).
Pia mater – This is the layer that lies directly on the spinal cord. It is the thinnest layer among the other two and adheres to the spinal cord surface or the brain. The pia mater has a lot of blood vessels that pass through it to supply the neural tissue with blood.
The spinal cord performs its duties by the help of spinal nerves or neurons, and the nerve fibers also called axons.
The spinal nerves are the messengers that convey different signals from the brain to the body and vice versa. The spinal nerves which are made of some bound together nerve fibers or axons are grouped in the five regions of the spinal cord.
5 Sections of the Spinal Nerves
Your spinal cord has five parts, and each section has some pairs of nerve fibers totaling to 31 pairs. Each pair of nerve fiber is a connection between the specific body they serve and the spinal cord.
The pairs of the spinal nerves according to their sections are:
Cervical in the neck – 8 pairs
Thoracic in the chest – 12 pairs
Lumbar in the abdomen – 5 pairs
Sacral in the pelvic – 5 pairs
Coccygeal in the tailbone – 1 pairThe Axon or Nerve Fiber
The nerve fiber or axon is a process that acts as a connection between its cell body and another nerve or neuron. Each axon serves only one neuron.
The Peripheral Nervous System
The peripheral nervous system is the other part of the nervous system apart from the central nervous system. This part of the nervous system, like its name 'peripheral,' includes the nerves outside the CNS (central nervous system). It connects the rest of the body to the brain and the spinal cord.
The peripheral nervous system has the axons or the nerve fibers that connect to the nerve cells.
The peripheral nervous system consists of two parts:Somatic Nervous System
The somatic nervous system carries signals to and from the central nervous system. The system has the sensory neurons and motor neurons. The sensory neurons serve the sensory part of the body, while the motor neurons serve the entire muscle fibers of the body.Autonomic Nervous System
The autonomic system regulates involuntary, or 'automatic' body functions. The heartbeat, blood flow, digestion are some of the services controlled by the system.
The autonomic nervous system has other smaller systems:Sympathetic Nervous System
The sympathetic nervous system regulates the danger response during environmental threats. In such moments, the sympathetic system can trigger 'fight or flight' and other reactions such as the increase of heartbeat, sweat secretion, blood flow to the muscles in readiness of 'fight or flight.'Parasympathetic Nervous System
The system brings back things to normalcy after the 'fight or flight' response once the threat situation is over. The body resumes its normal state of regular breathing and heartbeat, steady blood flow to the muscles, and other body functions.Enteric Nervous System
The enteric nervous system, also known as 'the second brain' controls the functions of the gastrointestinal tract. Although the first two systems can influence the functions of the enteric nervous system, it can work independently without the need of the brain or spinal cord.
The nerves of the system connect directly to neurotransmitters in the gut, dopamine, serotonin, and acetylcholine making the system independent.
Health Disorders of the Nervous System
The nervous system, like any other system, is susceptible to various health conditions. Some of the nervous system disorders are classified as follows:Infections
Most of the infections of the nervous system can be life-threatening. Some of the infections include:
Meningitis – The swelling of meninges or the membrane covering the brain and the spinal cord. Mainly caused by bacteria or virus infection.
Polio – Polio is caused by poliovirus, which spreads from one infected person to another healthy one. The disease affects the spinal cord or the brain and can lead to paralysis, meningitis, or paresthesia (legs prickly feeling).Vascular Disorders
Some vascular disorders that affect the nervous system include:
Stroke – Stroke is the brain cell disease where the cells die gradually due to lack or deficiency of oxygenated blood.
Acute Spinal Cord Ischemia Syndrome – This is a vascular disease of the spinal cord even though rare, it can happen and lead to severe neurologic morbidity.The Nervous System Degenerative Disorders
Some of the most common nervous system degenerative diseases include:
Parkinson's disease – The condition is a degeneration or progressive disease of the nervous system. It can begin with slight hand tremors and then develop gradually to Parkinson's disease.
Amyotrophic Lateral Sclerosis – It is a motor neuron disease which can affect the nerves that control the voluntary muscle movement.
Alzheimer's disease – The disease is irreversible and degenerative. It is a brain disorder that affects thinking skills and memory. Alzheimer's disease can degenerate to change the ability to perform the usual simple activities eventually.
Functional Neurological Diseases
The dysfunction of the nervous system to communicate between the brain and the body can cause functional neurological diseases. Some of such disorders are:
Shingles – A virus called varicella-zoster that causes chickenpox is also the cause of shingles. If at one time you had chickenpox, some inactive varicella-zoster virus can hide in nerve tissue. If for some reason, your immunity gets compromised, the virus reactivates, causing shingles.
Neuralgia – Neuralgia is a sensational sharp tingling pain at a particular nerve path. The condition can happen due to a tumor, bone, or a ligament pressing on the nerve.
Epilepsy – Epilepsy is a disorder of the brain. Some of its symptoms are seizures and twitching of arms or legs during epilepsy seizure.
Your nervous system is an organized system that works systematically with every nerve serving the end part of the body efficiently. However, it can take only one health condition to crumble a big part of the system.
Since you are the custodian of your nervous system by taking care of it, you can help it serve you effectively for ages. Eating a healthy diet and keeping an active stress-free life are some of the ways you can take care of your nervous system.
Some of the nervous system diseases can encroach 'silently', which you can easily escape you. For instance, Parkinson's disease may have sporadic early symptoms that you can fail to notice. Some of the nervous system disorders 'raise alarm' by revealing some signs when out of control.
Don't wait until when it is too late, get tested to rest your worries about your health. Visit Island Healthworks Clinic, where we use modern technology for your entire body examination.
You can also call us on 250-468-7685 for over-the-phone consultation with our Natural Health Practitioner – Yvonne Dollar Perc.
Did you get informed about the nervous system, how it operates, and the disorders that affect the system? You won't want to miss out on our next series of the 10 body systems.
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Editor: Yvonne Dollard Perc
Research Assistant: Elizabeth Njuguna
Designer: Sherry Robb
To learn more, contact Yvonne Dollard Perc at Island Healthworks. Yvonne offers phone consultations where she will develop an individualized health care program and lifestyle plan tailored to your specific needs through a personal health and lifestyle analysis.
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This article is intended for educational purposes and the information contained within is not intended to treat, diagnose or cure any disease or health problem. Please seek appropriate medical attention for any health complaints. We cannot take responsibility for your health care decisions. Our intent is only to offer health information to help you with your search for better health.