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.
Aerosol:1. In general, a fine mist or spray which contains minute particles. 2. In medicine, a spray administered by a nebulizer and inhaled for treatment. 3. In medicine, a mist that causes disease as, for example, the hantavirus pulmonary syndrome. 4. In the environment, particles emitted into the air naturally as in volcanic eruptions and through human action such as burning fossil fuel. 5. In the environment, the pressurized gas used to propel substances out of a container.
Allergic reaction: The hypersensitive response of the immune system of an allergic individual to a substance. See the entire definition of Allergic reaction
Allergic rhinitis: Medical term for hay fever, a condition due to allergy that mimics a chronic cold. (Hay fever is a misnomer since hay is not a usual cause of this problem and there is no fever. Many substances cause the allergic symptoms in hay fever. Allergic rhinitis is the correct term for this allergic reaction. (Rhinitis means "irritation of the nose" and is a derivative of Rhino, meaning "nose.") Symptoms include nasal congestion, a clear runny nose, sneezing, nose and eye itching, and tearing eyes. Post-nasal dripping of clear mucus frequently causes a cough. Loss of smell is common and loss of taste occurs occasionally. Nose bleeding may occur if the condition is severe. Eye itching, redness, and tearing frequently accompany the nasal symptoms.
Allergy: A misguided reaction to foreign substances by the immune system, the body system of defense against foreign invaders, particularly pathogens (the agents of infection). The allergic reaction is misguided in that these foreign substances are usually harmless. The substances that trigger allergy are called allergen. Examples include pollens, dust mite, molds, danders, and certain foods. People prone to allergies are said to be allergic or atopic. See the entire definition of Allergy
Anti-: Prefix generally meaning "against, opposite or opposing, and contrary." In medicine, anti- often connotes "counteracting or effective against" as in antibacterial, anti-infective, and antiviral. Sometimes medical terms containing anti- take on new meanings as has occurred with antibiotic and antibody. As a prefix, anti- may be shortened to ant- as in antacid. "Anti" is the Greek word for "against."
Anticholinergic: The action of certain medications that inhibit the transmission of parasympathetic nerve impulses and thereby reduce spasms of smooth muscle (such as that, for example, in the bladder).
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.
Appendix: A small outpouching from the beginning of the large intestine (the ascending colon). Formally called the vermiform appendix because it was thought to be wormlike. See the entire definition of Appendix
Asthma: A common disorder in which chronic inflammation of the bronchial tubes (bronchi) makes them swell, narrowing the airways. Asthma involves only the bronchial tubes and does not affect the air sacs (alveoli) or the lung tissue (the parenchyma of the lung) itself. See the entire definition of Asthma
Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle. It's measurement is recorded by two numbers. The first (systolic pressure) is measured after the heart contracts and is highest. The second (diastolic pressure) is measured before the heart contracts and lowest. A blood pressure cuff is used to measure the pressure. Elevation of blood pressure is called "hypertension".
Blurred vision: Lack of sharpness of vision with, as a result, the inability to see fine detail. Blurred vision can occur when a person who wears corrective lens is without them. Blurred vision can also be an important clue to eye disease.
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."
Capsule: Capsule has many meanings in medicine including the following:
In medicine, a membranous structure that envelops an organ, a joint, tumor, or any other part of the body. It is usually made up of dense collagen-containing connective tissue.
In pharmacy, a solid dosage form in which the drug is enclosed in a hard or soft soluble container, usually of a form of gelatin.
In microbiology, a coat around a microbe, such as a bacterium or fungus.
Cavities: Holes in the two outer layers of a tooth called the enamel and the dentin. The enamel is the outermost white hard surface and the dentin is the yellow layer just beneath enamel. Both layers serve to protect the inner living tooth tissue called the pulp, where blood vessels and nerves reside. Small cavities may not cause pain, and may be unnoticed by the patient. Larger cavities can collect food, and the inner pulp of the affected tooth can become irritated by bacterial toxins, foods that are cold, hot, sour, or sweet - causing toothache. Also referred to as caries.
Common cold: A viral upper respiratory tract infection. This contagious illness can be caused by many different types of viruses, and the body can never build up resistance to all of them. For this reason, colds are a frequent and recurring problem. In fact kindergarten children average 12 colds per year, while adolescents and adults have around seven colds per year. See the entire definition of Common cold
Congestion: An abnormal or excessive accumulation of a body fluid. The term is used broadly in medicine. Examples include nasal congestion (excess mucus and secretions in the air passages of the nose) seen with a common cold and congestion of blood in the lower extremities seen with some types of heart failure.
Constipation: Infrequent (and frequently incomplete) bowel movements. The opposite of diarrhea, constipation is commonly caused by irritable bowel syndrome, diverticulosis, and medications (constipation can paradoxically be caused by overuse of laxatives). Colon cancer can narrow the colon and thereby cause constipation. The large bowel (colon) can be visualized by barium enema x-rays, sigmoidoscopy, and colonoscopy. Barring a condition such as cancer, high-fiber diets can frequently relieve the constipation.
Contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.
Decongestant: A drug that shrinks the swollen membranes in the nose and makes it easier to breath. Decongestants can be taken orally or by nasal spray. Decongestant nasal sprays should not be used for more than five days without the doctor's advice, and if so, usually only when accompanied by a nasal steroid. Many decongestant nasal sprays often cause a rebound effect if taken too long. A rebound effect is the worsening of symptoms when a drug is discontinued. This is a result of a tissue dependence on the medication. Decongestants should not be used by patients with high blood pressure (hypertension) unless under doctor's supervision.
Drip: In medical usage, a drip is not a dull, unattractive person but a device for administering a fluid drop-by-drop into a vein. It is an intravenous (IV) fluid dripping into a vein, an intravenous fluid drip, a solution (usually a balanced electrolyte solution) administered directly into the venous circulation. It is, for short, an IV.
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
Eczema: A particular type of inflammatory reaction of the skin in which there are typically vesicles (tiny blister-like raised areas) in the first stage followed by erythema (reddening), edema (swelling), papules (bumps), and crusting of the skin followed, finally, by lichenification (thickening) and scaling of the skin. Eczema characteristically causes itching and burning of the skin. See the entire definition of Eczema
Eustachian tube: The tube that runs from the middle ear to the pharynx. The function of the Eustachian tube is to protect, aerate and drain the middle ear (and mastoid). Occlusion of the Eustachian tube leads to the development of middle ear inflammation (otitis media). The Eustachian tube is also called the otopharyngeal tube (because it connects the ear to the pharynx) and the auditory tube (and in Latin, the tuba acustica, tuba auditiva, and tuba auditoria). See the entire definition of Eustachian tube
Fever: Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.). See the entire definition of Fever
Generic:1. The chemical name of a drug. 2. A term referring to the chemical makeup of a drug rather than to the advertised brand name under which the drug may be sold. 3.A term referring to any drug marketed under its chemical name without advertising.
Glaucoma: A common eye condition in which the fluid pressure inside the eyes rises because of slowed fluid drainage from the eye. If untreated, it may damage the optic nerve and other parts of the eye, causing the loss of vision or even blindness. See the entire definition of Glaucoma
Hay fever: A seasonal allergy to airborne particles characterized by itchy eyes, runny nose, nasal congestion, sneezing, itchy throat, and excess mucus. See the entire definition of Hay fever
Headache: A pain in the head with the pain being above the eyes or the ears, behind the head (occipital), or in the back of the upper neck. Headache, like chest pain or back ache, has many causes. See the entire definition of Headache
Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest. See the entire definition of Heart
High blood pressure: Also known as hypertension, high blood pressure is, by definition, a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90. See the entire definition of High blood pressure
Histamine: Substance that plays a major role in many allergic reactions. Histamine dilates blood vessels and makes the vessel walls abnormally permeable.
Hives: A raised, itchy area of skin that is usually a sign of an allergic reaction. It can be rounded or flat-topped but is always elevated above the surrounding skin. It reflects circumscribed dermal edema (local swelling of the skin). The hives are usually well circumscribed but may be coalescent and will blanch with pressure. They typically last less than 4 hours but they may stay for days or weeks. Approximately 20% of the population has experienced a bout of hives. See the entire definition of Hives
Inflammation: A basic way in which the body reacts to infection, irritation or other injury, the key feature being redness, warmth, swelling and pain. Inflammation is now recognized as a type of nonspecific immune response. See the entire definition of Inflammation
Inflammatory response: A fundamental type of response by the body to disease and injury, a response characterized by the classical signs of "dolor, calor, rubor, and tumor" -- pain, heat (localized warmth), redness, and swelling. See the entire definition of Inflammatory response
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
Insomnia: The perception or complaint of inadequate or poor-quality sleep because of one or more of the following: difficulty falling asleep; waking up frequently during the night with difficulty returning to sleep; waking up too early in the morning; or unrefreshing sleep. Insomnia is not defined by the number of hours of sleep a person gets or how long it takes to fall asleep. Individuals vary normally in their need for, and their satisfaction with, sleep. Insomnia may cause problems during the day, such as tiredness, a lack of energy, difficulty concentrating, and irritability. See the entire definition of Insomnia
Intractable: Unstoppable. For example, intractable diarrhea or intractable pain.
Itching: An uncomfortable sensation in the skin that feels as if something is crawling on the skin or in the skin, and makes the person want to scratch the affected area. See the entire definition of Itching
Lactation: The process of milk production. Human milk is secreted by the mammary glands, which are located within the fatty tissue of the breast. The hormone oxytocin is produced in response to the birth of a new baby, and it both stimulates uterine contractions and begins the lactation process. For the first few hours of nursing, a special fluid called colostrum is delivered, which is especially high in nutrients, fats, and antibodies to protect the newborn from infection. Thereafter the amount of milk produced is controlled primarily by the hormone prolactin, which is produced in response to the length of time the infant nurses at the breast. See the entire definition of Lactation
Mold: A very large group of microscopic fungi that live on plant or animal matter. Most are filamentous organisms and produce spores that can be air-, water-, or insect-borne. A common trigger for allergies. See the entire definition of Mold
Mouth:1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.
Mucous: Pertaining to mucus, a thick fluid produced by the lining of some tissues of the body. See the entire definition of Mucous
Mucus: A thick slippery fluid produced by the membranes lining certain organs such as the nose, mouth, throat, and vagina. Mucus is the Latin word for "a semifluid, slimy discharge from the nose." Note that mucus is a noun while the adjective is mucous.
Nasal: Having to do with the nose. Nasal drops are intended for the nose, not (for example) the eyes. The word "nasal" came from the Latin "nasus" meaning the nose or snout.
Nasal decongestant: A drug that shrinks the swollen membranes in the nose, making it easier to breath. Decongestants can be taken orally or by nasal drops or spray. Nasal decongestants should not be used for more than five days in a row without the doctor's consent, and then usually only when accompanied by a nasal steroid. When nasal decongestants are used for a long time and then discontinued, symptoms often worsen (a rebound effect) because the tissues become dependent on the medication.
Nasal passage: The walls of the nasal passages are coated with respiratory mucous membranes which contain innumerable tiny hair-like cells that act to move waves of mucus toward the throat. Dust, bacteria, and other particles inhaled from the air are trapped by the mucus in the nose, carried back, swallowed and dropped into the gastric juices to nullify any potential harm they might do. See the entire definition of Nasal passage
Nasal polyps: Benign growths that originate in the mucous membranes lining the nasal passages or paranasal sinuses. Polyps are believed to arise in the nasal mucosa as a result of chronic inflammation. Up to 4% of adults have nasal polyps; they can also occur in children, particularly those with chronic respiratory conditions such as cystic fibrosis. Symptoms include postnasal drainage, snoring, headaches, sinusitis, and a reduced sense of smell and taste. Therapy can include oral and topical steroid medications or surgical removal. See the entire definition of Nasal polyps
Nasal septum: The dividing wall within the nose. The nasal septum runs down the middle of the nose creating two sides to the nose, each containing a passageway that ends in a nare (nostril). See the entire definition of Nasal septum
Nasopharynx: The area of the upper throat that lies behind the nose. In contrast to the oropharynx, the area of the throat that lies behind the mouth. See the entire definition of Nasopharynx
Nerve: A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another. See: Nervous system.
Nose: The external midline projection from the face. See the entire definition of Nose
Nostril: One of the openings in the nose that allows air to flow in and out of the nasal cavities. The word nostril comes from the Old English nosu, nose + thyrel, hole = the nose hole.
Onset: In medicine, the first appearance of the signs or symptoms of an illness as, for example, the onset of rheumatoid arthritis. There is always an onset to a disease but never to the return to good health. The default setting is good health. See the entire definition of Onset
Palpitations: Unpleasant sensations of irregular and/or forceful beating of the heart. In some patients with palpitations, no heart disease or abnormal heart rhythms can be found. In others, palpitations result from abnormal heart rhythms (arrhythmias). Arrhythmias refer to heartbeats that are too slow, too rapid, irregular, or too early.
Pasteur Institute: A non-profit private foundation which contributes to the prevention and treatment of disease, primarily infectious diseases, through research, education, and public health activities. See the entire definition of Pasteur Institute
Pharmacist: A professional who fills prescriptions, and in the case of a compounding pharmacist, makes them. Pharmacists are familiar with medication ingredients, interactions, cautions, and hints. See the entire definition of Pharmacist
Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist.
Post-nasal drip: Mucous accumulation in the back of the nose and throat leading to or giving the sensation of mucus dripping downward from the back of the nose.
Pregnancy: The state of carrying a developing embryo or fetus within the female body. This condition can be indicated by positive results on an over-the-counter urine test, and confirmed through a blood test, ultrasound, detection of fetal heartbeat, or an X-ray. Pregnancy lasts for about nine months, measured from the date of the woman's last menstrual period (LMP). It is conventionally divided into three trimesters, each roughly three months long. See the entire definition of Pregnancy
Prescription: A physician's order for the preparation and administration of a drug or device for a patient. A prescription has several parts. They include the superscription or heading with the symbol "R" or "Rx", which stands for the word recipe (meaning, in Latin, to take); the inscription, which contains the names and quantities of the ingredients; the subscription or directions for compounding the drug; and the signature which is often preceded by the sign "s" standing for signa (Latin for mark), giving the directions to be marked on the container.
Prostate: A gland within the male reproductive system that is located just below the bladder. Chestnut shaped, the prostate surrounds the beginning of the urethra, the canal that empties the bladder. See the entire definition of Prostate
Rebound: Return of the original symptoms when maneuvers or treatment is discontinued.
Receptor:1. In cell biology, a structure on the surface of a cell (or inside a cell) that selectively receives and binds a specific substance. There are many receptors. There is a receptor for (insulin; there is a receptor for low-density lipoproteins (LDL); etc. To take an example, the receptor for substance P, a molecule that acts as a messenger for the sensation of pain, is a unique harbor on the cell surface where substance P docks. Without this receptor, substance P cannot dock and cannot deliver its message of pain. Variant forms of nuclear hormone receptors mediate processes such as cholesterolmetabolism and fatty acid production. Some hormone receptors are implicated in diseases such as diabetes and certain types of cancer. A receptor called PXR appears to jump-start the body's response to unfamiliar chemicals and may be involved in drug-drug interactions. 2. In neurology, a terminal of a sensorynerve that receives and responds to stimuli.
Residual: Something left behind. With residual disease, the disease has not been eradicated.
Rhinitis: Irritation of the nose. Derived from the Greek word rhinos meaning of the nose.
Runny nose: Rhinorrhea is the medical term for this common problem. From the Greek words "rhinos" meaning "of the nose" and "rhoia" meaning "a flowing."
Septum: A word borrowed from the Latin "saeptum" meaning a "dividing wall or enclosure."
Sinus:1. An air-filled cavity in a dense portion of a skull bone. The sinuses decrease the weight of the skull. The sinuses are formed in four right-left pairs. The frontal sinuses are positioned behind the forehead, while the maxillary sinuses are behind the cheeks. The sphenoid and ethmoid sinuses are deeper in the skull behind the eyes and maxillary sinuses. The sinuses are lined by mucous-secreting cells. Air enters the sinuses through small opening in bone called ostia. If an ostium is blocked, air cannot pass into the sinus and likewise mucous cannot drain out. See also: Sinusitis. See the entire definition of Sinus
Sinusitis: Sinusitis is inflammation of the lining membrane of any of the hollow areas (sinuses) of the bone of the skull around the nose. The sinuses are directly connected to the nasal cavities. See the entire definition of Sinusitis
Sodium: The major positive ion (cation) in fluid outside of cells. The chemical notation for sodium is Na+. When combined with chloride, the resulting substance is table salt. See the entire definition of Sodium
Soothing: Bringing comfort, solace, reassurance, peace, composure, quietude. See the entire definition of Soothing
Stage: As regards cancer, the extent of a cancer, especially whether the disease has spread from the original site to other parts of the body. See also: Staging.
Steroid: A general class of chemical substances that are structurally related to one another and share the same chemical skeleton (a tetracyclic cyclopenta[a]phenanthrene skeleton). See the entire definition of Steroid
Stuffy nose: The presence of increased secretions and mucus in the nasal passages, most commonly arising as a result of a common cold, allergic reaction, or inflammation or infection of the paranasal sinuses (sinus infection).
Symptom: Any subjective evidence of disease. Anxiety, lower back pain, and fatigue are all symptoms. They are sensations only the patient can perceive. In contrast, a sign is objective evidence of disease. A bloody nose is a sign. It is evident to the patient, doctor, nurse and other observers.
Systemic: Affecting the entire body. A systemic disease such as diabetes can affect the whole body. Systemic chemotherapy employs drugs that travel through the bloodstream and reach and affect cells all over the body.
Taste: Taste belongs to our chemical sensing system, or the chemosenses. The complicated process of tasting begins when molecules released by the substances stimulate special cells in the mouth or throat. These special sensory cells transmit messages through nerves to the brain where specific tastes are identified. See the entire definition of Taste
Throat: The throat is the anterior (front) portion of the neck beginning at the back of the mouth, consisting anatomically of the pharynx and larynx. The throat contains the trachea and a portion of the esophagus.
Thyroid:1. The thyroid gland. Also, pertaining to the thyroid gland. 2. A preparation of the thyroid gland used to treat hypothyroidism. 3. Shaped like a shield. (The thyroid gland was so-named by Thomas Wharton in 1656 because it was shaped like an ancient Greek shield.) See the entire definition of Thyroid
Topical: Pertaining to a particular surface area. A topical agent is applied to a certain area of the skin and is intended to affect only the area to which it is applied. Whether its effects are indeed limited to that area depends upon whether the agent stays where it is put or is absorbed into the blood stream.
Trigger: Something that either sets off a disease in people who are genetically predisposed to developing the disease, or that causes a certain symptom to occur in a person who has a disease. For example, sunlight can trigger rashes in people with lupus.
Tubes: The "tubes" are medically known as the Fallopian tubes. There are two Fallopian tubes, one on each side, which transport the egg from the ovary to the uterus (the womb). The Fallopian tubes have small hair-like projections called cilia on the cells of the lining. See the entire definition of Tubes
Allergic rhinitis symptoms include an itchy, runny nose, sneezing, itchy ears, eyes, and throat. Seasonal allergic rhinitis (also called hay fever) is usually caused by pollen in the air. Perennial allergic rhinitis is a type of chronic rhinitis and is a year–round problem, often caused by indoor allergens, such as dust, animal dander, and pollens that may exist at the time. Treatment of chronic rhinitis and post nasal drip are dependant upon the type of rhinitis condition.
An allergy refers to a misguided reaction by our immune system in response to bodily contact with certain foreign substances. When these allergens come in contact with the body, it causes the immune system to develop an allergic reaction in people who are allergic to it. It is estimated that 50 million North Americans are affected by allergic conditions. The parts of the body that are prone to react to allergies include the eyes, nose, lungs, skin, and stomach. Common allergic disorders include hay fever, asthma, allergic eyes, allergic eczema, hives, and allergic shock.
Hay fever (allergic rhinitis) is an irritation of the nose caused by pollen and is associated with the following allergic symptoms: nasal congestion, runny nose, sneezing, eye and nose itching, and tearing eyes. Avoidance of known allergens is the recommended treatment, but if this is not possible, antihistamines, decongestants, and nasal sprays may help alleviate symptoms.
Common sources of indoor allergens include dust mites, cockroaches, molds, pets, and plants. Managing allergies caused by indoor allergens means reducing your exposure to them.
What is hay fever? What are the symptoms and signs?
Hay fever is a misnomer. Hay is not a usual cause of this problem, and it does not cause fever. Early descriptions of sneezing, nasal congestion, and eye irritation while harvesting field hay promoted this popular term.
Allergic rhinitis is the correct term used to describe this allergic reaction, and many different substances cause the allergic symptoms noted in hay fever.
Rhinitis means "irritation of the nose" and is a derivative of rhino, meaning nose. Allergic rhinitis which occurs during a specific season is called "seasonal allergic rhinitis." When it occurs throughout the year, it is called "perennial allergic rhinitis." Rhinosinusitis is the medical term that refers to inflammation of the nasal lining as well as the lining tissues of the sinuses. This term is sometime used because the two conditions frequently occur together.
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