The central nervous system is that part of the nervous system that consists of the brain and spinal cord. It contains millions of neurons. If you slice through some fresh brain or spinal cord you will find some areas appear grey whilst other ares appear rather white. The white matter consists of axons, it appears white because it contains a lot of fatty material called myelin. The myelin sheath insulates an axon from its neighbors. This means that nerve cells can conduct electrical messages without interfering with one another. The grey matter consists of cellbodies and the branched dendrites which effectively connect them together. So this area is mainly cytoplasm of nerve cells which is why it appears white.
Central Nervous System Functions
Functions of the Spinal Cord
The spinal cord transmits sensory reception from the peripheral nervous system. It also conducts motor information to the body’s skeletal muscles, cardiac muscles, smooth muscles, and glands. There are 31 pairs of spinal nerves along the spinal cord. These nerves each contain both sensory and motor axons. The spinal cord is protected by vertebrae, and connects the peripheral nervous system to the brain, and it acts as a “minor” coordinating center.
Functions of the Brain
The brain apprehends signals from the spinal cord as well as the olfactory nerves and optic nerves. It allows the body to function. The brain is protected by the skull; however, if the brain is damaged, the results to the human body can be very consequential.
What are Central Nervous System Depressants
Central nervous system (CNS) depressants are drugs that can be used to slow down brain activity. CNS depressants may be prescribed by a physician to treat anxiety, muscle tension, pain, insomnia, acute stress reactions, panic attacks, and seizure disorders. In higher doses, some CNS depressants may be used as general anesthetics.
CNS depressants include a wide range of drugs such as alcohol, narcotics, barbiturates, benzodiazepines, chloral hydrate, and methaqualone, as well as newer CNS depressants developed in the 1990s, such as Buspirone and Zolpidem, which are thought to have the fewest side effects. Most CNS depressants activate a neurotransmitter called gamma-aminobutyric acid, which helps decrease brain activity. Street names for CNS depressants include Reds, Yellows, Blues, Ludes, Barbs, and Downers.
What are the side effects of Central Nervous System Depressants: Especially when taken in excess, CNS depressants can cause confusion and dizziness, and impair judgment, memory, intellectual performance, and motor coordination.
What are Central Nervous System Stimulants
Central nervous system (CNS) stimulants are medicines that speed up physical and mental processes. Central nervous system stimulants are used to treat conditions characterized by lack of adrenergic stimulation, including narcolepsy and neonatal apnea. Additionally, Ritalin and Dexedrine are used for their paradoxical effect in attention—deficit hyperactivity disorder (ADHD).
The anerexiants, benzphetamine, diethylpropion, phendimetrazine, phentermine, and sibutramine are CNS stimulants used for appetite reduction in severe obesity. Although these drugs are structurally similar to amphetamine, they cause less sensation of stimulation, and are less suited for use in conditions characterized by lack of adrenergic stimulation. Phenylpropanolamine and ephedrine have been used both as diet aids and as vasoconstrictors.
The majority of CNS stimulants are chemically similar to the neurohormone norepinephrine, and simulate the traditional “fight or flight” syndrome associated with sympathetic nervous system arousal. Caffeine is more closely related to the xanthines, such as theophylline.
What are the side effects of Central Nervous System Stimulants: Typical responses include overstimulation, dizziness, restlessness, and similar reactions. Rarely, hematologic reactions, including leukopenia, agranulocytosis, and bone marrow depression have been reported. Lowering of the seizure threshold has been noted with most drugs in this class.
Central Nervous System Disorders
Encephalitis is an inflammation of the brain. It is usually caused by a foreign substance or a viral infection. Symptoms for this disease include: headache, neck pain, drowsiness, nausea, and fever.
Meningitis is an inflammation of the meninges of the brain and spinal cord. It is most often caused by a bacterial or viral infection. Fever, vomiting, and a stiff neck are all symptoms of meningitis.
Tropical spastic paraparesis
Tropical spastic paraparesis (TSP) is a slight or partial paralysis or weakness in the legs. This is caused by a virus that can also cause leukemia.
Arachnoid cysts are cerebrospinal fluid covered by arachnoidal cells that may develop on the brain or spinal cord. They are a congenital disorder and in some cases may not show symptoms. However, if there is a large cyst, symptoms may include headache, seizures, ataxia, hemiparesis, and several others. Macrocephaly and ADHD are common among children, while pre-senile dementia, hydrocephalus, and urinary incontinence are symptoms for elderly patients.
Huntington’s disease is a rare neurological disorder that is inherited. Degeneration of neuronal cells in the frontal lobe of the brain occurs. There is a progressive decline which results in abnormal movements.
Alzheimer’s is a neurodegenerative disease typically found in people over the age of 65 years. Worldwide, approximately 24 million people have dementia; 60% of these cases are due to Alzheimer’s. The ultimate cause is unknown. The clinical sign of Alzheimer’s is progressive cognition deterioration.
Locked-in syndrome is due to a lesion on the brain stem, damaging the pons. It is a condition where the patient is awake, but suffers from paralysis of all or nearly all voluntary muscles of the body and cannot communicate or move. Causes of locked-in syndrome may be: traumatic brain injury, circulatory system disease, nerve cell damage, and overdose of medication.
Parkinson’s affects the motor skills and speech. Symptoms may include bradykinesia, muscle rigidity, and tremors. Behavior, thinking, and sensation disorders are non-motor symptoms.
Tourette’s syndrome is an inherited neurological disorder. Early onset may be during childhood, and is characterized by physical tics and verbal tics.
Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disease, meaning that the myelin sheath of neurons is damaged. Symptoms of MS include: visual and sensation problems, muscle weakness, and depression.
Glossary of Definitions About the Central Nervous System
What are Neurons: a neuron is a nerve cell; it has a cell body, a very long axon sheathed in myelin, and many tiny branches called dendrites. There are three kinds of neurons: sensory (Sensory neurons are typically classified as the neurons responsible for converting external stimuli from the environment into internal stimuli.), intermediate (detect patterns of activity in the sensory neurons and send signals to groups of motor neurons as a result) and motor neurons (Upon adequate stimulation, the motor neuron releases a flood of neurotransmitters that bind to postsynaptic receptors and triggers a response in the muscle fiber.).
What are Axons: these are long cytoplasmic tubes, they carry electric impulses from one part of the body to another. They are insulated from each other by their myelin sheathes.
What are Dendrites: these are tiny branches on the cell body and at the ends of all neurons. The dendrites of one cell do not actually touch the dendrites of any other cell. There are very tiny gaps between them called synapses.
What are Synapses: these are the gaps between the dendrites of one neuron and the cell body of another one. There is no electrical connection between nerve cells. when one neuron stimulates another it does so by secreting a chemical into the synapse.
What is Grey Matter: this is the material in the brain and spinal cord which contains the cell bodies and dendrite of nerve cells. It is mainly cytoplasm.
What is White Matter: this is the material in the brain and spinal cord which contains the axons and myelin sheathes of nerve cells. It is mainly myelin which is a fat, so it appears white to the naked eye.
What is Agranulocytosis: An acute febrile condition marked by severe depression of the granulocyte-producing bone marrow, and by prostration, chills, swollen neck, and sore throat sometimes with local ulceration.
What is an Anorexiant: A drug that suppresses appetite.
What is Anxiety: Worry or tension in response to real or imagined stress, danger, or dreaded situations.
What is Attention-deficit hyperactivity disorder (ADHD): A condition in which a person has an unusually high activity level and a short attention span.
What is Depression: A mental condition in which people feel extremely sad and lose interest in life.
What is Leukopenia: A condition in which the number of leukocytes circulating in the blood is abnormally low and which is most commonly due to a decreased production of new cells in conjunction with various infectious diseases or as a reaction to various drugs or other chemicals.
What are Withdrawal symptoms: A group of physical or mental symptoms that may occur when a person suddenly stops using a drug on which he or she has become dependent.
How do amyl nitrates affect the central nervous system?
Amyl nitrate is a chemical compound with the formula CH3(CH2)4ONO2, and is a combination of amyl alcohol and nitric acid.
As a prescription medicine, amyl nitrate has traditionally been inhaled to relieve the pain of angina attacks or pain in the heart. It works by relaxing blood vessels so that the supply of blood and oxygen to the heart can increase without straining the heart. A doctor may also prescribe amyl nitrate for other conditions.
Amyl nitrate is a gold-colored liquid that comes in a glass vial covered by a protective cloth, which allows the glass to be popped open without causing injury. The vapors are then inhaled through the nose or mouth.
Amyl nitrate is also used as a street drug. Sometimes called “poppers” because of the way the glass capsule is opened, amyl nitrate has been known to cause a “high” or to heighten sexual arousal. Other slang words for amyl nitrate are “snappers,” “bold” and “rush.” Poppers are freely available through the Internet as well as in clubs and sex shops. The drug is especially popular among the gay community and teenagers. When amyl nitrate is distributed for illegal use, it is often sold in small, brown bottles and innocently labeled, for example, as “room odorizer” or “liquid aroma.”
Inhalants are usually made up of more than one chemical. Some chemicals tend to leave the body quickly while others remain and and are absorbed by fatty tissues in the central nervous system, which controls the brain and the spinal cord as well as the retina. All inhalants are absorbed through the lungs and spread throughout the body and brain within minutes. The nose, mouth, throat and lungs have a robust supply of blood vessels that carry the substance to the brain, and, therefore, an inhaled drug is felt more quickly than an ingested one. Regular abuse of inhalants can cause severe long-term damage to the liver, kidneys, brain and blood. While some of the damage can be reversed once the drug use is discontinued, some effects, like brain damage, are irreversible.
As a party drug, amyl nitrates produce an immediate effect when inhaled. Within 30 to 40 seconds, the face becomes flushed, the head and neck perspire, blood pressure drops and heart rate accelerates, causing a “rush” sensation. The quick reduction in blood pressure can result in loss of balance and fainting. Some people also experience acute nausea and dizziness. Poppers increase pressure within the eyeball and are especially dangerous to those with glaucoma. The effects of amyl nitrate are short lived, as the “high” lasts only from 30 seconds to five minutes.
To prolong the high, users often inhale again and again, a dangerous practice called “huffing.” Another common practice is to spray or pour the liquid into a bag or other container and breathe in and out with the bag pressed to the face. This causes users to rebreathe their exhaled air and increase the “high.” Regular abuse can also lead to infections around the nose and mouth and impaired respiration. If a high dose of amyl nitrate is inhaled, it can lead to unconsciousness or death, which can occur even in someone using the drug for the first time. More than one-third of deaths from inhalants involve first-time users.
In the United States, inhalants are the most abused substance after alcohol and tobacco. Statistics show that the abuse of inhalants is on the rise, especially in poverty-stricken areas. Young, white males are the most common users. Aside from the chemically related risks, the abuse of amyl nitrate is associated with unsafe sexual practices that put users at increased risk for contracting and spreading infectious diseases such as HIV and hepatitis.
How does tuberculosis affect the central nervous system?
Tuberculosis (TB) is a disease caused by bacteria known as Mycobacterium tuberculosis. Discovered by Dr. Robert Koch in 1882, this infectious bacteria is also called Koch’s bacillus. The bacteria usually affect the lungs, but it can also affect other parts of the body such as the brain, kidneys or spine.
TB is an airborne disease. This means that the germs that cause tuberculosis are spread from person to person through the air. Germs can enter the air when someone with TB of the lungs coughs, sneezes, laughs, speaks or sings. These germs can stay in the air up to several hours. Anyone who breathes in this contaminated air can become infected. Tuberculosis cannot be contracted via physical contact, like handshaking, or via body fluids from sharing food or toothbrushes, or even kissing.
Not everyone infected with TB bacteria becomes sick. There are two different types of TB: latent and active. In latent TB infection, the bacteria can live in a person’s body for years without making him or her sick because the body’s immune system can successfully stop the bacteria from multiplying. Individuals who have the latent form of TB have no symptoms, do not feel sick, are not contagious and, therefore, cannot spread the bacteria to others. However, they are at higher risk for eventually contracting active TB, if the latent bacteria manage to overcome the immune system and begin to multiply. For this reason, people with compromised immune systems, such as those with the HIV virus, are more likely to contract active TB.
In active TB, people feel sick because the TB germs are actively multiplying and destroying tissue in their bodies. These people experience a number of symptoms and are contagious. The symptoms of TB depend on where in the body the TB is located. The most common place for the TB to grow is in the lungs. This is called pulmonary TB. People with ulmonary TB may have a long-lasting cough that produces blood or phlegm as well as chest pain. Sufferers may also feel weak and experience weight loss, lack of appetite, chills, fever and night sweats.
When the TB is located in the brain or spine, it is called TB of the central nervous system (CNS). Research shows that as many as 10 percent of people with pulmonary TB develop CNS TB, which can manifest itself as meningitis or the inflammation of the protective membranes covering the brain and spinal cord. CNS TB can also cause lesions (abnormal tissue) to grow on the brain or spine. This form of TB is particularly devastating as it is often disguised as a neurological disorder and is harder to diagnose. The antibiotic treatment for TB of the CNS is also not as effective, and, therefore, those with CNS TB have a high rate of death due to the disease.
With appropriate antibiotic treatment, TB can usually be cured. Treatment is typically a specific drug regimen that combines several different antibiotics during the course of months or even a year. Since one out of every 10 people with latent TB infection develops TB at some point, individuals with latent TB are advised to seek treatment even though they do not feel sick. The drug used to treat latent TB infection is called isoniazid; it is generally taken for nine months or even longer. However, even after being treated for as short a time as two weeks, those infected are no longer contagious.
Bacille Calmette-Guerin (BCG) is a vaccine for TB disease. While not recommended in the United States, the BCG vaccination is widely used in many other countries. The vaccine does not completely prevent people from contracting TB, nor has it been found to be effective in eliminating CNS tuberculosis.
According to the World Health Organization, there are more than 8 million new cases of TB each year, and 3 million people die annually of the disease. Further research is currently being conducted about tuberculosis, aiming to develop better diagnostic tools, more effective vaccines and reduced treatment times.