The following are health and medical definitions of terms that appear in the Motion Sickness article.
Acetylcholine: A key chemical in neurons (nerve cells) that acts as a neurotransmitter and carries information across the synaptic cleft, the space between two nerve cells. Abbreviated ACh.
Antihistamines: Drugs that combat the histamine released during an allergic reaction by blocking the action of the histamine on the tissue. Antihistamines do not stop the formation of histamine nor do they stop the conflict between the IgE and antigen. Therefore, antihistamines do not stop the allergic reaction but protect tissues from some of its effects. Antihistamines frequently cause mouth dryness and sleepiness. Newer "non sedating" antihistamines are generally thought to be somewhat less effective. Antihistamine side effects that very occasionally occur include urine retention in males and fast heart rate.
Belladonna: An herbaceous plant bearing the scientific name Atropa belladonna or Atropa bella-donna, also known as deadly nightshade. The leaves and berries of the plant are highly toxic and can lead to hallucinations and delirium when ingested. Eating just a few berries from the plant can be fatal in children. The belladonna plant has a long history of use by humans for medicines, cosmetics, and poisons. It is native to Europe, Western Asia, and North Africa but has been naturalized in parts of North America. See the entire definition of Belladonna
Blind:1. Unable to see. Without part or all of the sense of sight. 2. In a clinical trial, not to know the treatment given or received. The participant is not told whether they are in the experimental or control arm of the study. Also called masked.
Brain: That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres."
Dizziness: Painless head discomfort with many possible causes including disturbances of vision, the brain, balance (vestibular) system of the inner ear, and gastrointestinal system. Dizziness is a medically indistinct term which laypersons use to describe a variety of conditions ranging from lightheadedness, unsteadiness to vertigo. See the entire definition of Dizziness
Ear: The hearing organ. There are three sections of the ear, according to the anatomy textbooks. They are the outer ear (the part we see along the sides of our head behind the temples), the middle ear, and the inner ear. But in terms of function, the ear has four parts: those three and the brain. Hearing thus involves all parts of the ear as well as the auditory cortex of the brain. The external ear helps concentrate the vibrations of air on the ear drum and make it vibrate. These vibrations are transmitted by a chain of little bones in the middle ear to the inner ear. There they stimulate the fibers of the auditory nerve to transmit impulses to the brain. See the entire definition of Ear
Ginger: A perennial tropical herb that has been used as a treatment for nausea and bowel spasms. See the entire definition of Ginger
Head injury: Damage to any of the structures of the head as a result of trauma. While the term "head injury" is most often used to refer to an injury to the brain, head injuries may also involve the bones, muscles, blood vessels, skin, and other organs of the face or head. A head injury does not always mean that there is an associated brain injury. Most head injuries are caused by blows to the head from numerous causes including motor vehicle accidents and falls. Head injuries are one of the most common causes of death and disability in the United States. See the entire definition of Head injury
Histamine: Substance that plays a major role in many allergic reactions. Histamine dilates blood vessels and makes the vessel walls abnormally permeable.
Horizontal: In anatomy, a plane passing through the standing body. A person lying on a bed is considered in a horizontal position. See the entire definition of Horizontal
Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person. See the entire definition of Infection
Injury: Harm or hurt. The term "injury" may be applied in medicine to damage inflicted upon oneself as in a hamstring injury or by an external agent on as in a cold injury. The injury may be accidental or deliberate, as with a needlestick injury. The term "injury" may be synonymous (depending on the context) with a wound or with trauma.
Inner ear: There are three sections of the ear. They are the external ear, the middle ear, and the inner ear. The inner ear is far and away the most highly complex. The essential component of the inner ear for hearing is the membranous labyrinth where the fibers of the auditory nerve (the nerve connecting the ear to the brain) end. The membranous labyrinth is a system of communicating sacs and ducts (tubes) filled with fluid (the endolymph). The membranous labyrinth is lodged within a cavity called the bony labyrinth. At some points the membranous labyrinth is attached to the bony labyrinth and at other points the membranous labyrinth is suspended in a fluid (the perilymph) within the bony labyrinth. See the entire definition of Inner ear
Joint: A joint is the area where two bones are attached for the purpose of motion of body parts. A joint is usually formed of fibrous connective tissue and cartilage. An articulation or an arthrosis is the same as a joint. See the entire definition of Joint
Labyrinth: The maze of canals in the inner ear. The labyrinth is the portion of the ear that is responsible for sensing balance. Inflammation of the labyrinth (labyrinthitis) can be accompanied by vertigo.
Malaise: A vague feeling of discomfort, one that cannot be pinned down but is often sensed as "just not right." See the entire definition of Malaise
Motion sickness: Motion sickness is a very common disturbance of the inner ear that is caused by repeated motion such as from the swell of the sea, the movement of a car, the motion of a plane in turbulent air, etc. In the inner ear (which is also called the labyrinth), motion sickness affects the sense of balance and equilibrium and, hence, the sense of spatial orientation. See the entire definition of Motion sickness
Muscle: Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and bowel is called "smooth muscle."
Nausea:Nausea, is the urge to vomit. It can be brought by many causes including, systemic illnesses, such as influenza, medications, pain, and inner ear disease. When nausea and/or vomiting are persistent, or when they are accompanied by other severe symptoms such as abdominal pain, jaundice, fever, or bleeding, a physician should be consulted.
Neck: The part of the body joining the head to the shoulders. Also, any narrow or constricted part of a bone or organ that joins its parts as, for example, the neck of the femur bone.
Otolaryngology: A medical and surgical specialty concerned with the diagnosis, management, and treatment of diseases and disorders of the ear, nose, throat (ENT) and related structures of the head and neck, including the sinuses, larynx (voice box), oral cavity, and upper pharynx (mouth and throat). Subspecialty areas within otolaryngology include pediatric otolaryngology (children), otology/neurotology (ears, balance, and tinnitus), allergy, facial plastic and reconstructive surgery, head and neck, laryngology (throat), and rhinology (nose). Some otolaryngologists limit their practices to one or more of these seven areas. Otolaryngology is commonly called ENT. It is the oldest medical specialty in the US.
Scopolamine: A venerable drug that is a naturally occurring member of a large chemical class of compounds called alkaloids. Scopolamine was first introduced into medical usage in 1902. The name comes from that of the 18th-century Italian naturalist Giovanni Scopoli. See the entire definition of Scopolamine
Sensation: In medicine and physiology, sensation refers to the registration of an incoming (afferent) nerve impulse in that part of the brain called the sensorium, which is capable of such perception. Therefore, the awareness of a stimulus as a result of its perception by sensory receptors. (Sensory is here synonymous with sensation.) See the entire definition of Sensation
Sensory: Relating to sensation, to the perception of a stimulus and the voyage made by incoming (afferent) nerve impulses from the sense organs to the nerve centers. See the entire definition of Sensory
Spinal cord: The major column of nerve tissue that is connected to the brain and lies within the vertebral canal and from which the spinal nerves emerge. Thirty-one pairs of spinal nerves originate in the spinal cord: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. The spinal cord and the brain constitute the central nervous system (CNS). The spinal cord consists of nerve fibers that transmit impulses to and from the brain. Like the brain, the spinal cord is covered by three connective-tissue envelopes called the meninges. The space between the outer and middle envelopes is filled with cerebrospinal fluid (CSF), a clear colorless fluid that cushions the spinal cord against jarring shock. Also known simply as the cord. See the entire definition of Spinal cord
Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office. See the entire definition of Surgery
Sweating: The act of secreting fluid from the skin by the sweat (sudoriferous) glands. These are small tubular glands situated within and under the skin (in the subcutaneous tissue). They discharge by tiny openings in the surface of the skin. See the entire definition of Sweating
Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease. See the entire definition of Syndrome
Vertical: In anatomy, upright. As opposed to horizontal. See the entire definition of Vertical
Vertigo: Aside from being the name of a classic 1958 Alfred Hitchcock film (with Jimmy Stewart and Kim Novak), vertigo is a feeling that you are dizzily turning around or that things are dizzily turning about you. Vertigo is usually due to a problem with the inner ear. Vertigo can also be caused by vision problems. See the entire definition of Vertigo
Dizziness is a symptom that is often applies to a variety of sensations including lightheadedness and vertigo. Causes of dizziness include low blood pressure, heart problems, anemia, dehydration, and more. Treatment of dizziness depends on the cause.
Nausea is an uneasiness of the stomach that often precedes vomiting. Nausea and vomiting are not diseases, but they are symptoms of many conditions. The causes of vomiting differ according to age, and treatment depends upon the cause of nausea and vomiting.
Vertigo is a feeling of spinning movement, and at times accompanied by nausea and vomiting occur. Vertigo is most often associated with an inner ear problem. The treatment for vertigo can be lifestyle changes and medication if necessary.
Nausea and vomiting are symptoms that may be caused by many conditions. Antiemetics are drugs that treat nausea and vomiting. Though some antiemetics for motion sickness and mild nausea are available over the counter (OTC), most require a medical evaluation and prescription.
Balance is a state of body equilibrium or stability. We often take for granted how dependent we are on a healthy balance system. When the system breaks down, however, patients will describe symptoms such as dizziness, vertigo, lightheadedness, or motion sickness.
Travelers should prepare for their trip by visiting their physician to get the proper vaccinations and obtain the necessary medication if they have a medical condition or chronic disease. Diseases that travelers may pick up from contaminated water or food, insect or animal bites, or from other people include malaria, meningococcal meningitis, yellow fever, hepatitis A, typhoid fever, polio, and cholera.
Dizziness is one of the most common symptoms that will
prompt a person to seek medical care. The term dizziness (or dizzy) means
different things to different people, so it is difficult to define. Does "feeling dizzy"
mean lightheadedness or the feeling of weakness and almost passing out?
Or does it
refer to the sensation of vertigo, in which a person feels as if they have just
gotten off a merry-go-round?
Dizziness (lightheadedness) is often caused by a decrease in blood supply to the brain,
while vertigo may be caused by disturbances of the inner ear and the balance centers
of the brain. It is important that the health care practitioner understand what
you mean when you complain of dizziness. You may be asked additional questions
so that the proper direction can be taken for a diagnosis and treatment.