Air Passages: From 1 Different Sources
These are the nose, pharynx or throat (the large cavity behind the nose and mouth), larynx, trachea or windpipe, and bronchi or bronchial tubes. On entering the nose, the air passes through a high narrow passage on each side, the outer wall of which has three projections (the nasal conchae). It then passes down into the pharynx where the food and air passages meet and cross. The larynx lies in front of the lower part of the pharynx and is the organ where the voice is produced (see VOICE AND SPEECH) by aid of the vocal cords. The opening between the cords is called the glottis, and shortly after passing this the air reaches the trachea or windpipe.
The windpipe leads into the chest and divides above the heart into two bronchi, one of which goes to each lung, in which it splits into ?ner and ?ner tubes (see LUNGS). The larynx is enclosed in two strong cartilages: the thyroid (of which the most projecting part, the Adam’s apple, is a prominent point on the front of the neck), and the cricoid (which can be felt as a hard ring about an inch below the thyroid). Beneath this, the trachea – which is sti?ened by rings of cartilage so that it is never closed, no matter what position the body is in – can be traced down until it disappears behind the breastbone.
A condition in which the mucous membranes of the nose and breathing passages are inflamed, often chronically... catarrh
Aiding the secretion of the mucous membrane of the air passages and the removal of fluid by spitting... expectorant
A MASSAGE technique in which a part of the body is hit repeatedly and quickly with the hands. The technique is useful in helping patients with BRONCHITIS to loosen the MUCUS in the air passages of their lungs, thus helping them to cough it up.... tapotement
A collective term for the passages through which air enters and leaves the lungs (see respiratory system). The term is also applied to a tube inserted into the mouth of an unconscious person to prevent the tongue from obstructing breathing.... airway
Narrowing or blockage of the respiratory passages. The obstruction may be due to a foreign body, such as a piece of food, that becomes lodged in part of the upper airway and may result in choking. Certain disorders, such as diphtheria and lung cancer, can cause obstruction. Additionally, spasm of the muscular walls of the airway, as occurs in bronchospasm (a feature of asthma), results in breathing difficulty.... airway obstruction
Asphyxia means literally absence of pulse, but is the name given to the whole series of symptoms which follow stoppage of breathing and of the heart’s action. Drowning is one cause, but obstruction of the AIR PASSAGES may occur as the result of a foreign body or in some diseases, such as CROUP, DIPHTHERIA, swelling of the throat due to wounds or in?ammation, ASTHMA (to a partial extent), tumours in the chest (causing slow asphyxia), and the external conditions of su?ocation and strangling. Placing the head in a plastic bag results in asphyxia, and poisonous gases also cause asphyxia: for example, CARBON MONOXIDE (CO) gas, which may be given o? by a stove or charcoal brazier in a badly ventilated room, can kill people during sleep. Several gases, such as sulphurous acid (from burning sulphur), ammonia, and chlorine (from bleaching-powder), cause involuntary closure of the entrance to the larynx, and thus prevent breathing. Other gases, such as nitrous oxide (or laughing-gas), chloroform, and ether, in poisonous quantity, stop the breathing by paralysing the respiration centre in the brain.
Symptoms In most cases, death from asphyxia is due to insu?ciency of oxygen supplied to the blood. The ?rst signs are rapid pulse and gasping for breath. Next comes a rise in the blood pressure, causing throbbing in the head, with lividity or blueness of the skin, due to failure of aeration of the blood, followed by still greater struggles for breath and by general CONVULSIONS. The heart becomes overdistended and gradually weaker, a paralytic stage sets in, and all struggling and breathing slowly cease. When asphyxia is due to charcoal fumes, coal-gas, and other narcotic in?uences, there is no convulsive stage, and death ensues gently and may occur in the course of sleep.
Treatment So long as the heart continues to beat, recovery may be looked for with prompt treatment. The one essential of treatment is to get the impure blood aerated by arti?cial respiration. Besides this, the feeble circulation can be helped by various methods. (See APPENDIX 1: BASIC FIRST AID – Choking; Cardiac/respiratory arrest.)... asphyxia
Solid instruments for introduction into natural passages in the body – in order either to apply medicaments which they contain or with which they are coated, or, more usually, to dilate a narrow part or stricture of the passage. Thus we have, for example, urethral bougies, oesophageal bougies and rectal bougies, made usually of ?exible rubber or, in the case of the urethra, of steel.... bougies
See AIR PASSAGES; BRONCHUS; LUNGS.... bronchial tubes
Muscular contraction of the bronchi (air passages) in the LUNGS, causing narrowing. The cause is usually a stimulus, as in BRONCHITIS and ASTHMA. The result is that the patient can inhale air into the lungs but breathing out becomes di?cult and requires muscular e?ort of the chest. Exhalation is accompanied by audible noises in the airways which can be detected with a STETHOSCOPE. Reversible obstructive airways disease can be relieved with a BRONCHODILATOR drug; if the bronchospasm cannot be relieved by drugs it is called irreversible. (See CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD).)... bronchospasm
Casts of hollow organs are found in various diseases. Membraneous casts of the air passages are found in diphtheria and in one form of bronchitis, and are sometimes coughed up entire. Casts of the interior of the bowels are passed in cases of mucous colitis associated with constipation, and casts of the microscopic tubules in the kidneys passed in the urine form one of the surest signs of glomerulonephritis. (See KIDNEYS, DISEASES OF.)... casts
A natural re?ex reaction to irritation of the AIR PASSAGES and LUNGS. Air is drawn into the air passages with the GLOTTIS wide open. The inhaled air is blown out against the closed glottis, which, as the pressure builds up, suddenly opens, expelling the air – at an estimated speed of 960 kilometres (600 miles) an hour. This explosive exhalation expels harmful substances from the respiratory tract. Causes of coughing include infection – for example, BRONCHITIS or PNEUMONIA; in?ammation of the respiratory tract associated with ASTHMA; and exposure to irritant agents such as chemical fumes or smoke (see also CROUP).
The explosive nature of coughing results in a spray of droplets into the surrounding air and, if these are infective, hastens the spread of colds (see COLD, COMMON) and INFLUENZA. Coughing is, however, a useful reaction, helping the body to rid itself of excess phlegm (mucus) and other irritants. The physical e?ort of persistent coughing, however, can itself increase irritation of the air passages and cause distress to the patient. Severe and protracted coughing may, rarely, fracture a rib or cause PNEUMOTHORAX. Coughs can be classi?ed as productive – when phlegm is present – and dry, when little or no mucus is produced.
Most coughs are the result of common-cold infections but a persistent cough with yellow or green sputum is indicative of infection, usually bronchitis, and sufferers should seek medical advice as medication and postural drainage (see PHYSIOTHERAPY) may be needed. PLEURISY, pneumonia and lung CANCER are all likely to cause persistent coughing, sometimes associated with chest pain, so it is clearly important for people with a persistent cough, usually accompanied by malaise or PYREXIA, to seek medical advice.
Treatment Treatment of coughs requires treatment of the underlying cause. In the case of colds, symptomatic treatment with simple remedies such as inhalation of steam is usually as e?ective as any medicines, though ANALGESICS or ANTIPYRETICS may be helpful if pain or a raised temperature are among the symptoms. Many over-the-counter preparations are available and can help people cope with the symptoms. Preparations may contain an analgesic, antipyretic, decongestant or antihistamine in varying combinations. Cough medicines are generally regarded by doctors as ine?ective unless used in doses so large they are likely to cause sedation as they act on the part of the brain that controls the cough re?ex.
Cough suppressants may contain CODEINE, DEXTROMETHORPHAN, PHOLCODINE and sedating ANTIHISTAMINE DRUGS. Expectorant preparations usually contain subemetic doses of substances such as ammonium chloride, IPECACUANHA, and SQUILL (none of which have proven worth), while demulcent preparations contain soothing, harmless agents such as syrup or glycerol.
A list of systemic cough and decongestant preparations on sale to the public, together with their key ingredients, appears in the British National Formulary.... cough
A condition in which the skin – usually of the face and extremities – takes on a bluish tinge. It accompanies states in which the blood is not properly oxygenated in the lungs, and appears earliest through the nails, on the lips, on the tips of the ears, and over the cheeks. It may be due to blockage of the air passages, or to disease in the lungs, or to a feeble circulation, as in heart disease. (See CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD); METHAEMOGLOBINAEMIA.)... cyanosis
The passages, one on each side, leading from the throat to the middle ear. Each is about 38 mm (1••• inches) long and is large at either end, though at its narrowest part it only admits a ?ne probe. The tubes open widely in the act of swallowing or yawning. The opening into the throat is situated just behind the lower part of the nose, so that a catheter can be passed through the corresponding nostril into the tube for in?ation of the middle ear. (See also EAR; NOSE.)... eustachian tubes
Epithelium is the cellular layer which forms the epidermis on the skin, covers the inner surface of the bowels, and forms the lining of ducts and hollow organs, like the bladder. It consists of one or more layers of cells which adhere to one another, and is one of the simplest tissues of the body. It is of several forms: for example, the epidermis is formed of scaly epithelium, the cells being in several layers and more or less ?attened. (See SKIN.) The bowels are lined by a single layer of columnar epithelium, the cells being long and narrow in shape. The air passages are lined by ciliated epithelium: that is to say, each cell is provided with ?agellae (lashes) which drive the ?uid upon the surface of the passages gradually upwards.... epithelium
Drugs which are claimed to help the removal of secretions from the AIR PASSAGES – although there is no convincing evidence that they do this. A simple expectorant may, however, be a useful placebo. Most preparations are available without a doctor’s prescription and pharmacists will advise on which might be helpful for particular patients with dry or congestive coughs.... expectorants
Expectoration means either material brought up from the chest by the AIR PASSAGES, or the act by which it is brought up.... expectoration
An escape of ?uid from the vessels or passages which ought to contain it. Extravasation of blood due to tearing of vessel walls is found in STROKE, and in the commoner condition known as a bruise. Extravasation of urine takes place when the bladder or the URETHRA is ruptured by a blow on the abdomen or on the crutch (PERINEUM), or torn in a fracture of the pelvis. Intravenous infusions frequently extravasate.... extravasation
Arcus senilis The white ring or crescent which tends to form at the edge of the cornea with age. It is uncommon in the young, when it may be associated with high levels of blood lipids (see LIPID).
Astigmatism (See ASTIGMATISM.)
Blepharitis A chronic in?ammation of the lid margins. SEBORRHOEA and staphylococcal infection are likely contributors. The eyes are typically intermittently red, sore and gritty over months or years. Treatment is di?cult and may fail. Measures to reduce debris on the lid margins, intermittent courses of topical antibiotics, steroids or systemic antibiotics may help the sufferer.
Blepharospasm Involuntary closure of the eye. This may accompany irritation but may also occur without an apparent cause. It may be severe enough to interfere with vision. Treatment involves removing the source of irritation, if present. Severe and persistent cases may respond to injection of Botulinum toxin into the orbicularis muscle.
Cataract A term used to describe any opacity in the lens of the eye, from the smallest spot to total opaqueness. The prevalence of cataracts is age-related: 65 per cent of individuals in their sixth decade have some degree of lens opacity, while all those over 80 are affected. Cataracts are the most important cause of blindness worldwide. Symptoms will depend on whether one or both eyes are affected, as well as the position and density of the cataract(s). If only one eye is developing a cataract, it may be some time before the person notices it, though reading may be affected. Some people with cataracts become shortsighted, which in older people may paradoxically ‘improve’ their ability to read. Bright light may worsen vision in those with cataracts.
The extent of visual impairment depends on the nature of the cataracts, and the ?rst symptoms noticed by patients include di?culty in recognising faces and in reading, while problems watching television or driving, especially at night, are pointers to the condition. Cataracts are common but are not the only cause of deteriorating vision. Patients with cataracts should be able to point to the position of a light and their pupillary reactions should be normal. If a bright light is shone on the eye, the lens may appear brown or, in advanced cataracts, white (see diagram).
While increasing age is the commonest cause of cataract in the UK, patients with DIABETES MELLITUS, UVEITIS and a history of injury to the eye can also develop the disorder. Prolonged STEROID treatment can result in cataracts. Children may develop cataracts, and in them the condition is much more serious as vision may be irreversibly impaired because development of the brain’s ability to interpret visual signals is hindered. This may happen even if the cataracts are removed, so early referral for treatment is essential. One of the physical signs which doctors look for when they suspect cataract in adults as well as in children is the ‘red re?ex’. This is observable when an ophthalmoscopic examination of the eye is made (see OPHTHALMOSCOPE). Identi?cation of this red re?ex (a re?ection of light from the red surface of the retina –see EYE) is a key diagnostic sign in children, especially young ones.
There is no e?ective medical treatment for established cataracts. Surgery is necessary and the decision when to operate depends mainly on how the cataract(s) affect(s) the patient’s vision. Nowadays, surgery can be done at any time with limited risk. Most patients with a vision of 6/18 – 6/10 is the minimum standard for driving – or worse in both eyes should
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bene?t from surgery, though elderly people may tolerate visual acuity of 6/18 or worse, so surgery must be tailored to the individual’s needs. Younger people with a cataract will have more demanding visual requirements and so may opt for an ‘earlier’ operation. Most cataract surgery in Britain is now done under local anaesthetic and uses the ‘phaco-emulsi?cation’ method. A small hole is made in the anterior capsule of the lens after which the hard lens nucleus is liqui?ed ultrasonically. A replacement lens is inserted into the empty lens bag (see diagram). Patients usually return to their normal activities within a few days of the operation. A recent development under test in the USA for children requiring cataract operations is an intra-ocular ?exible implant whose magnifying power can be altered as a child develops, thus precluding the need for a series of corrective operations as happens now.
Chalazion A ?rm lump in the eyelid relating to a blocked meibomian gland, felt deep within the lid. Treatment is not always necessary; a proportion spontaneously resolve. There can be associated infection when the lid becomes red and painful requiring antibiotic treatment. If troublesome, the chalazion can be incised under local anaesthetic.
Conjunctivitis In?ammation of the conjunctiva (see EYE) which may affect one or both eyes. Typically the eye is red, itchy, sticky and gritty but is not usually painful. Redness is not always present. Conjunctivitis can occasionally be painful, particularly if there is an associated keratitis (see below) – for example, adenovirus infection, herpetic infection.
The cause can be infective (bacteria, viruses or CHLAMYDIA), chemical (e.g. acids, alkalis) or allergic (e.g. in hay fever). Conjunctivitis may also be caused by contact lenses, and preservatives or even the drugs in eye drops may cause conjunctival in?ammation. Conjunctivitis may addtionally occur in association with other illnesses – for example, upper-respiratory-tract infection, Stevens-Johnson syndrome (see ERYTHEMA – erythema multiforme) or REITER’S SYNDROME. The treatment depends on the cause. In many patients acute conjunctivitis is self-limiting.
Dacryocystitis In?ammation of the lacrimal sac. This may present acutely as a red, painful swelling between the nose and the lower lid. An abscess may form which points through the skin and which may need to be drained by incision. Systemic antibiotics may be necessary. Chronic dacryocystitis may occur with recurrent discharge from the openings of the tear ducts and recurrent swelling of the lacrimal sac. Obstruction of the tear duct is accompanied by watering of the eye. If the symptoms are troublesome, the patient’s tear passageways need to be surgically reconstructed.
Ectropion The lid margin is everted – usually the lower lid. Ectropion is most commonly associated with ageing, when the tissues of the lid become lax. It can also be caused by shortening of the skin of the lids such as happens with scarring or mechanical factors – for example, a tumour pulling the skin of the lower lid downwards. Ectropion tends to cause watering and an unsightly appearance. The treatment is surgical.
Entropion The lid margin is inverted – usually the lower lid. Entropion is most commonly associated with ageing, when the tissues of the lid become lax. It can also be caused by shortening of the inner surfaces of the lids due to scarring – for example, TRACHOMA or chemical burns. The inwardly directed lashes cause irritation and can abrade the cornea. The treatment is surgical.
Episcleritis In?ammation of the EPISCLERA. There is usually no apparent cause. The in?ammation may be di?use or localised and may affect one or both eyes. It sometimes recurs. The affected area is usually red and moderately painful. Episcleritis is generally not thought to be as painful as scleritis and does not lead to the same complications. Treatment is generally directed at improving the patient’s symptoms. The in?ammation may respond to NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS) or topical CORTICOSTEROIDS.
Errors of refraction (Ametropia.) These will occur when the focusing power of the lens and cornea does not match the length of the eye, so that rays of light parallel to the visual axis are not focused at the fovea centralis (see EYE). There are three types of refractive error: HYPERMETROPIA or long-sightedness. The refractive power of the eye is too weak, or the eye is too short so that rays of light are brought to a focus at a point behind the retina. Longsighted people can see well in the distance but generally require glasses with convex lenses for reading. Uncorrected long sight can lead to headaches and intermittent blurring of vision following prolonged close work (i.e. eye strain). As a result of ageing, the eye becomes gradually long-sighted, resulting in many people needing reading glasses in later life: this normal process is known as presbyopia. A particular form of long-sightedness occurs after cataract extraction (see above). MYOPIA(Short sight or near sight.) Rays of light are brought to a focus in front of the retina because the refractive power of the eye is too great or the eye is too short. Short-sighted people can see close to but need spectacles with concave lenses in order to see in the distance. ASTIGMATISMThe refractive power of the eye is not the same in each meridian. Some rays of light may be focused in front of the retina while others are focused on or behind the retina. Astigmatism can accompany hypermetropia or myopia. It may be corrected by cylindrical lenses: these consist of a slice from the side of a cylinder (i.e. curved in one meridian and ?at in the meridian at right-angles to it).
Keratitis In?ammation of the cornea in response to a variety of insults – viral, bacterial, chemical, radiation, or mechanical trauma. Keratitis may be super?cial or involve the deeper layers, the latter being generally more serious. The eye is usually red, painful and photophobic. Treatment is directed at the cause.
Nystagmus Involuntary rhythmic oscillation of one or both eyes. There are several causes including nervous disorders, vestibular disorders, eye disorders and certain drugs including alcohol.
Ophthalmia In?ammation of the eye, especially the conjunctiva (see conjunctivitis, above). Ophthalmia neonatorum is a type of conjunctivitis that occurs in newborn babies. They catch the disease when passing through an infected birth canal during their mother’s labour (see PREGNANCY AND LABOUR). CHLAMYDIA and GONORRHOEA are the two most common infections. Treatment is e?ective with antibiotics: untreated, the infection may cause permanent eye damage.
Pinguecula A benign degenerative change in the connective tissue at the nasal or temporal limbus (see EYE). This is visible as a small, ?attened, yellow-white lump adjacent to the cornea.
Pterygium Overgrowth of the conjunctival tissues at the limbus on to the cornea (see EYE). This usually occurs on the nasal side and is associated with exposure to sunlight. The pterygium is surgically removed for cosmetic reasons or if it is thought to be advancing towards the visual axis.
Ptosis Drooping of the upper lid. May occur because of a defect in the muscles which raise the lid (levator complex), sometimes the result of ageing or trauma. Other causes include HORNER’S SYNDROME, third cranial nerve PALSY, MYASTHENIA GRAVIS, and DYSTROPHIA MYOTONICA. The cause needs to be determined and treated if possible. The treatment for a severely drooping lid is surgical, but other measures can be used to prop up the lid with varying success.
Retina, disorders of The retina can be damaged by disease that affects the retina alone, or by diseases affecting the whole body.
Retinopathy is a term used to denote an abnormality of the retina without specifying a cause. Some retinal disorders are discussed below. DIABETIC RETINOPATHY Retinal disease occurring in patients with DIABETES MELLITUS. It is the commonest cause of blind registration in Great Britain of people between the ages of 20 and 65. Diabetic retinopathy can be divided into several types. The two main causes of blindness are those that follow: ?rst, development of new blood vessels from the retina, with resultant complications and, second, those following ‘water logging’ (oedema) of the macula. Treatment is by maintaining rigid control of blood-sugar levels combined with laser treatment for certain forms of the disease – in particular to get rid of new blood vessels. HYPERTENSIVE RETINOPATHY Retinal disease secondary to the development of high blood pressure. Treatment involves control of the blood pressure (see HYPERTENSION). SICKLE CELL RETINOPATHY People with sickle cell disease (see under ANAEYIA) can develop a number of retinal problems including new blood vessels from the retina. RETINOPATHY OF PREMATURITY (ROP) Previously called retrolental ?broplasia (RLF), this is a disorder affecting low-birth-weight premature babies exposed to oxygen. Essentially, new blood vessels develop which cause extensive traction on the retina with resultant retinal detachment and poor vision. RETINAL ARTERY OCCLUSION; RETINAL VEIN OCCLUSION These result in damage to those areas of retina supplied by the affected blood vessel: the blood vessels become blocked. If the peripheral retina is damaged the patient may be completely symptom-free, although areas of blindness may be detected on examination of ?eld of vision. If the macula is involved, visual loss may be sudden, profound and permanent. There is no e?ective treatment once visual loss has occurred. SENILE MACULAR DEGENERATION (‘Senile’ indicates age of onset and has no bearing on mental state.) This is the leading cause of blindness in the elderly in the western world. The average age of onset is 65 years. Patients initially notice a disturbance of their vision which gradually progresses over months or years. They lose the ability to recognise ?ne detail; for example, they cannot read ?ne print, sew, or recognise people’s faces. They always retain the ability to recognise large objects such as doors and chairs, and are therefore able to get around and about reasonably well. There is no e?ective treatment in the majority of cases. RETINITIS PIGMENTOSAA group of rare, inherited diseases characterised by the development of night blindness and tunnel vision. Symptoms start in childhood and are progressive. Many patients retain good visual acuity, although their peripheral vision is limited. One of the characteristic ?ndings on examination is collections of pigment in the retina which have a characteristic shape and are therefore known as ‘bone spicules’. There is no e?ective treatment. RETINAL DETACHMENTusually occurs due to the development of a hole in the retina. Holes can occur as a result of degeneration of the retina, traction on the retina by the vitreous, or injury. Fluid from the vitreous passes through the hole causing a split within the retina; the inner part of the retina becomes detached from the outer part, the latter remaining in contact with the choroid. Detached retina loses its ability to detect light, with consequent impairment of vision. Retinal detachments are more common in the short-sighted, in the elderly or following cataract extraction. Symptoms include spots before the eyes (?oaters), ?ashing lights and a shadow over the eye with progressive loss of vision. Treatment by laser is very e?ective if caught early, at the stage when a hole has developed in the retina but before the retina has become detached. The edges of the hole can be ‘spot welded’ to the underlying choroid. Once a detachment has occurred, laser therapy cannot be used; the retina has to be repositioned. This is usually done by indenting the wall of the eye from the outside to meet the retina, then making the retina stick to the wall of the eye by inducing in?ammation in the wall (by freezing it). The outcome of surgery depends largely on the extent of the detachment and its duration. Complicated forms of detachment can occur due to diabetic eye disease, injury or tumour. Each requires a specialised form of treatment.
Scleritis In?ammation of the sclera (see EYE). This can be localised or di?use, can affect the anterior or the posterior sclera, and can affect one or both eyes. The affected eye is usually red and painful. Scleritis can lead to thinning and even perforation of the sclera, sometimes with little sign of in?ammation. Posterior scleritis in particular may cause impaired vision and require emergency treatment. There is often no apparent cause, but there are some associated conditions – for example, RHEUMATOID ARTHRITIS, GOUT, and an autoimmune disease affecting the nasal passages and lungs called Wegener’s granulomatosis. Treatment depends on severity but may involve NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS), topical CORTICOSTEROIDS or systemic immunosuppressive drugs.
Stye Infection of a lash follicle. This presents as a painful small red lump at the lid margin. It often resolves spontaneously but may require antibiotic treatment if it persists or recurs.
Sub-conjunctival haemorrhage Haemorrhage between the conjunctiva and the underlying episclera. It is painless. There is usually no apparent cause and it resolves spontaneously.
Trichiasis Inward misdirection of the lashes. Trichiasis occurs due to in?ammation of or trauma to the lid margin. Treatment involves removal of the patient’s lashes. Regrowth may be prevented by electrolysis, by CRYOTHERAPY to the lid margin, or by surgery.
For the subject of arti?cial eyes, see under PROSTHESIS; also GLAUCOMA, SQUINT and UVEITIS.... eye, disorders of
The narrow opening at the upper end of the LARYNX. The glottis is made up of the true vocal cords. (See AIR PASSAGES; CHOKING.)... glottis
An inflammatory disease of the genitourinary passages characterized by pain and discharge... gonorrhoea
The presence of blood pigment in the URINE caused by the destruction of blood corpuscles in the blood vessels or in the urinary passages. It turns urine a dark red or brown colour. In some people this condition, known as intermittent haemoglobinuria, occurs from time to time, especially on exposure to cold. It is also produced by various poisonous substances taken in the food. It occurs in malarious districts in the form of one of the most fatal forms of MALARIA: BLACKWATER FEVER. (See also MARCH HAEMOGLOBINURIA.)... haemoglobinuria
Hanging is a form of death due to suspension of the body from the neck – either suddenly, as in judicial hanging (although not in the United Kingdom, as the death penalty is not used in the UK justice system), so as to damage the spinal column and cord, or in such a way as to constrict the AIR PASSAGES and the blood vessels to the brain. Death is, in any case, speedy, resulting in 2–3 minutes if not instantaneously. Apart from judicial hanging, and in the absence of any signs of a struggle, hanging is usually due to SUICIDE. The resuscitation of people found hanging is similar to that for drowning. (See APPENDIX 1: BASIC FIRST AID – Cardiac/respiratory arrest.)... hanging
Insu?ation means the blowing of powder or vapour into a cavity, especially through the air passages, for the treatment of disease.... insufflation
The organ of voice which also forms one of the higher parts of the AIR PASSAGES. It is placed high up in the front of the neck and there forms a considerable prominence on the surface (Adam’s apple). The vocal cords vibrating in di?erent notes, according to their tenseness and the like, produce the sounds of VOICE AND SPEECH.... larynx
The general name given to the membrane which lines many of the hollow organs of the body. These membranes vary widely in structure in di?erent sites, but all have the common character of being lubricated by MUCUS – derived in some cases from isolated cells on the surface of the membrane, but more generally from de?nite glands placed beneath the membrane, and opening here and there through it by ducts. The air passages, the gastrointestinal tract and the ducts of glands which open into it, and also the urinary passages, are all lined by mucous membrane.... mucous membrane
The body’s defence against foreign substances such as bacteria, viruses and parasites. Immunity also protects against drugs, toxins and cancer cells. It is partly non-speci?c – that is, it does not depend on previous exposure to the foreign substance. For example, micro-organisms are engulfed and inactivated by polymorphonuclear LEUCOCYTES as a ?rst line of defence before speci?c immunity has developed.
Acquired immunity depends upon the immune system recognising a substance as foreign the ?rst time it is encountered, storing this information so that it can mount a reaction the next time the substance enters the body. This is the usual outcome of natural infection or prophylactic IMMUNISATION. What happens is that memory of the initiating ANTIGEN persists in selected lymphocytes (see LYMPHOCYTE). Further challenge with the same antigen stimulates an accelerated, more vigorous secondary response by both T- and B-lymphocytes (see below). Priming the immune system in this manner forms the physiological basis for immunisation programmes.
Foreign substances which can provoke an immune response are termed ‘antigens’. They are usually proteins but smaller molecules such as drugs and chemicals can also induce an immune response. Proteins are taken up and processed by specialised cells called ‘antigenpresenting cells’, strategically sited where microbial infection may enter the body. The complex protein molecules are broken down into short amino-acid chains (peptides – see PEPTIDE) and transported to the cell surface where they are presented by structures called HLA antigens (see HLA SYSTEM).
Foreign peptides presented by human leucocyte antigen (HLA) molecules are recognised by cells called T-lymphocytes. These originate in the bone marrow and migrate to the THYMUS GLAND where they are educated to distinguish between foreign peptides, which elicit a primary immune response, and self-antigens (that is, constituents of the person themselves) which do not. Non-responsiveness to self-antigens is termed ‘tolerance’ (see AUTOIMMUNITY). Each population or clone of T-cells is uniquely responsive to a single peptide sequence because it expresses a surface molecule (‘receptor’) which ?ts only that peptide. The responsive T-cell clone induces a speci?c response in other T-and B-lymphocyte populations. For example, CYTOTOXIC T-cells penetrate infected tissues and kill cells which express peptides derived from invading micro-organisms, thereby helping to eliminate the infection.
B-lymphocytes secrete ANTIBODIES which are collectively termed IMMUNOGLOBULINS (Ig)
– see also GAMMA-GLOBULIN. Each B-cell population (clone) secretes antibody uniquely speci?c for antigens encountered in the blood, extracellular space, and the LUMEN of organs such as the respiratory passages and gastrointestinal tract.
Antibodies belong to di?erent Ig classes; IgM antibodies are synthesised initially, followed by smaller and therefore more penetrative IgG molecules. IgA antibodies are adapted to cross the surfaces of mucosal tissues so that they can adhere to organisms in the gut, upper and lower respiratory passages, thereby preventing their attachment to the mucosal surface. IgE antibodies also contribute to mucosal defence but are implicated in many allergic reactions (see ALLERGY).
Antibodies are composed of constant portions, which distinguish antibodies of di?erent class; and variable portions, which confer unique antigen-binding properties on the product of each B-cell clone. In order to match the vast range of antigens that the immune system has to combat, the variable portions are synthesised under the instructions of a large number of encoding GENES whose products are assembled to make the ?nal antibody. The antibody produced by a single B-cell clone is called a monoclonal antibody; these are now synthesised and used for diagnostic tests and in treating certain diseases.
Populations of lymphocytes with di?erent functions, and other cells engaged in immune responses, carry distinctive protein markers. By convention these are classi?ed and enumerated by their ‘CD’ markers, using monoclonal antibodies speci?c for each marker.
Immune responses are in?uenced by cytokines which function as HORMONES acting over a short range to accelerate the activation and proliferation of other cell populations contributing to the immune response. Speci?c immune responses collaborate with nonspeci?c defence mechanisms. These include the COMPLEMENT SYSTEM, a protein-cascade reaction designed to eliminate antigens neutralised by antibodies and to recruit cell populations which kill micro-organisms.... immunity
Sited within some of the bones of the SKULL, these are spaces ?lled with air and lined by MUCOUS MEMBRANE. The sinuses comprise frontal and maxillary (a pair of each), ethmoidal (a group of small spaces), and two sphenoid sinuses. They drain into the nasal cavities (see NOSE). When a person has an upper respiratory infection, the sinuses sometimes become infected: this causes pain, purulent discharge from the nose and obstruction of the nasal passages (see SINUSITIS). Generally all that is required is a decongestant and antibiotic but, occasionally, infection may spread to produce a cerebral abscess or cerebral venous sinus thrombosis (see BRAIN, DISEASES OF).... paranasal sinus
A perverted sense of SMELL; everything may smell unpleasant to the affected individual. The most common cause is some septic condition of the nasal passages (see NOSE), but the condition may occasionally be due to a lesion in the BRAIN involving the centre responsible for the sense of smell.... parosmia
A popular name for MUCUS, particularly that secreted in the air passages. (See BRONCHITIS; EXPECTORANTS.)... phlegm
Sinusitis is in?ammation of the mucosal lining of a SINUS. The term is usually applied to in?ammation of the sinuses in the face. Most cases occur as a result of infection spreading to the sinuses from the NOSE along the passages that drain mucus secreted by the linings of the sinuses to the nose. The bacterial infection usually follows a viral infection of the upper respiratory tract. Treatment with ANTIBIOTICS is usually e?ective but the condition tends to recur. If the episodes are severe, they can be disabling, with bad headaches. Surgery is sometimes necessary to drain the sinuses. Rarely, sinusitis may lead to cerebral abscess or venous sinus thrombosis.... sinusitis
The process in which air passes into and out of the lungs so that the blood can absorb oxygen and give o? carbon dioxide and water. This occurs 18 times a minute in a healthy adult at rest and is called the respiratory rate. An individual breathes more than 25,000 times a day and during this time inhales around 16 kg of air.
Mechanism of respiration For the structure of the respiratory apparatus, see AIR PASSAGES; CHEST; LUNGS. The air passes rhythmically into and out of the air passages, and mixes with the air already in the lungs, these two movements being known as inspiration and expiration. INSPIRATION is due to a muscular e?ort which enlarges the chest, so that the lungs have to expand in order to ?ll up the vacuum that would otherwise be left, the air entering these organs by the air passages. The increase of the chest in size from above downwards is mainly due to the diaphragm, the muscular ?bres of which contract and reduce its domed shape and cause it to descend, pushing down the abdominal organs beneath it. EXPIRATION is an elastic recoil, the diaphragm rising and the ribs sinking into the position that they naturally occupy, when muscular contraction is ?nished. Occasionally, forced expiration may occur, involving powerful muscles of the abdomen and thorax; this is typically seen in forcible coughing.
Nervous control Respiration is usually either an automatic or a REFLEX ACTION, each expiration sending up sensory impulses to the CENTRAL NERVOUS SYSTEM, from which impulses are sent down various other nerves to the muscles that produce inspiration. Several centres govern the rate and force of the breathing, although all are presided over by a chief respiratory centre in the medulla oblongata (see under BRAIN – Divisions). This in turn is controlled by the higher centres in the cerebral hemispheres, so that breathing can be voluntarily stopped or quickened.
Quantity of air The lungs do not completely empty themselves at each expiration and re?ll at each inspiration. With each breath, less than one-tenth of the total air in the lungs passes out and is replaced by the same quantity of fresh air, which mixes with the stale air in the lungs. This renewal, which in quiet breathing amounts to about 500 millilitres, is known as the tidal air. By a special inspiratory e?ort, an individual can draw in about 3,000 millilitres, this amount being known as complemental air. By a special expiratory e?ort, too, after an ordinary breath one can expel much more than the tidal air from the lungs – this extra amount being known as the supplemental or reserve air, and amounting to about 1,300 millilitres. If an individual takes as deep an inspiration as possible and then makes a forced expiration, the amount expired is known as the vital capacity, and amounts to around 4,000 millilitres in a healthy adult male of average size. Figures for women are about 25 per cent lower. The vital capacity varies with size, sex, age and ethnic origin.
Over and above the vital capacity, the lungs contain air which cannot be expelled; this is known as residual air, and amounts to another 1,500 millilitres.
Tests of respiratory e?ciency are used to assess lung function in health and disease. Pulmonary-function tests, as they are known, include spirometry (see SPIROMETER), PEAK FLOW METER (which measures the rate at which a person can expel air from the lungs, thus testing vital capacity and the extent of BRONCHOSPASM), and measurements of the concentration of oxygen and carbon dioxide in the blood. (See also LUNG VOLUMES.)
Abnormal forms of respiration Apart from mere changes in rate and force, respiration is modi?ed in several ways, either involuntarily or voluntarily. SNORING, or stertorous breathing, is due to a ?accid state of the soft palate causing it to vibrate as the air passes into the throat, or simply to sleeping with the mouth open, which has a similar e?ect. COUGH is a series of violent expirations, at each of which the larynx is suddenly opened after the pressure of air in the lungs has risen considerably; its object is to expel some irritating substance from the air passages. SNEEZING is a single sudden expiration, which di?ers from coughing in that the sudden rush of air is directed by the soft palate up into the nose in order to expel some source of irritation from this narrow passage. CHEYNE-STOKES BREATHING is a type of breathing found in persons suffering from stroke, heart disease, and some other conditions, in which death is impending; it consists in an alternate dying away and gradual strengthening of the inspirations. Other disorders of breathing are found in CROUP and in ASTHMA.... respiration
The mucous secretions from the mouth, throat or back of the nose. Sputum is also expectorated by coughing from the lower air passages. Its production may be increased by respiratory-tract allergy (ASTHMA) or by breathing-in irritants such as tobacco smoke, smoke from a ?re, or fumes from chemical materials. Sputum is normally white, but infection will turn it to yellow or green, and blood from the lungs may produce pink frothy sputum. Treatment is to deal with the underlying disorder. Production of large quantities of sputum – for instance, in BRONCHIECTASIS – may require physiotherapy and postural drainage. (See also EXPECTORATION.)... sputum
A narrowing in any of the natural passages of the body, such as the GULLET, the bowel, or the URETHRA. It may be due to the development of some growth in the wall of the passage affected, or to pressure upon it by such a growth in some neighbouring organ, but in the majority of cases a stricture is the result of previous ulceration on the inner surface of the passage, followed by contraction of the scar. (See INTESTINE, DISEASES OF; URETHRA, DISEASES OF.)... stricture
Popularly known as the windpipe, this tube extends from the LARYNX above to the point in the upper part of the chest, where it divides into the two large bronchial tubes, one to each lung (see LUNGS). It is about 10 cm (4 inches) in length and consists of a ?brous tube kept permanently open by about 20 strong, horizontally placed hoops of cartilage, each of which forms about two-thirds of a circle, the two ends being joined behind by muscle-?bres. This ?brocartilaginous tube is lined by a smooth mucous membrane, richly supplied with mucous glands and covered by a single layer of ciliated epithelium. (See also AIR PASSAGES.)... trachea
A protozoon normally present in the VAGINA of about 30–40 per cent of women. It sometimes becomes pathogenic and causes in?ammation of the genital passages, with vaginal discharge. A man may become infected as a result of sexual intercourse with an infected woman and suffer from a urethral discharge; it may also cause prostatitis (see under PROSTATE GLAND, DISEASES OF). METRONIDAZOLE is usually an e?ective treatment, and to obtain a satisfactory result it may be necessary to treat both partners. Should metronidazole not work, then tinidazole may be tried.... trichomonas vaginalis
The popular name for the TRACHEA, which extends from the LARYNX above to the point in the upper part of the chest where it divides into the two large bronchial tubes, one to each lung. It is about 10 cm (4 inches) in length and consists of a ?brous tube kept permanently open by about 20 strong, horizontally placed hoops of cartilage, each of which forms about two-thirds of a circle, the two ends being joined behind by muscle ?bres. This ?brocartilaginous tube is lined by a smooth mucous membrane, richly supplied with mucous glands and covered by a single layer of ciliated epithelium. (See also AIR PASSAGES.)... windpipe
See: TEETH DECAY, TEETH EXTRACTION, ALOE VERA. DEOBSTRUENT. That which clears obstruction by dilating natural passages of the body. Usually of the intestines (Ispaghula seeds) or colon (Buckbean). ... dental problems
Terms applied to the sounds produced in the upper AIR PASSAGES which form one of the means of communication between human beings. Air passes through the LARYNX to produce the fundamental notes and tones known as voice. This is then modi?ed during its passage through the mouth so as to form speech or song.
Voice This has three varying characteristics: loudness, pitch, and quality or timbre. Loudness depends on the volume of air available and therefore on the size of the chest and the strength of its muscles. Pitch is determined by larynx size, the degree of tenseness at which the vocal cords are maintained, and whether the cords vibrate as a whole or merely at their edges.
In any given voice, the range of pitch seldom exceeds two and a half octaves. Typically, the small larynx of childhood produces a shrill or treble voice; the rapid growth of the larynx around PUBERTY causes the voice to ‘break’ in boys. Changes in the voice also occur at other ages as a result of the secondary action of the SEX HORMONES. Generally speaking, the adult voice is bass and tenor in men, contralto or soprano in women. Timbre is due to di?erences in the larynx, as well as to voluntary changes in the shape of the mouth.
Speech Rapid modi?cations of the voice, produced by movements of the PALATE, tongue and lips. Infants hear the sounds made by others and mimic them; hence the speech centres in the BRAIN are closely connected with those of hearing.
Defects of speech See below, and also SPEECH DISORDERS. MUTISM, or absence of the power to speak, may be due to various causes. LEARNING DISABILITY that prevents the child from mimicking the actions of others is most common; in other cases the child has normal intelligence but some neurological disorder, or disorder of the speech organs, is responsible. Alternatively, complete DEAFNESS or early childhood ear disease may be the cause. STAMMERING is a highly individual condition, but is basically a lack of coordination between the di?erent parts of the speech mechanism. (See also main entry on STAMMERING.) DYSPHASIA is the inability to speak or understand speech, most commonly following brain disease, such as STROKE. APHONIA or loss of voice may be caused by LARYNGITIS or, rarely, a symptom of conversion and dissociative mental disorders – traditionally referred to as HYSTERIA. It is generally of short duration.... voice and speech
The common cold. A virus droplet infection of the air passages.
Symptoms: Red itching eyes, clear nasal discharge progressing to yellow and thick, slight sore throat, sneezing, mild fever, headache, blocked or running nose, malaise.
The alternative school of medicine believes a cold should not be suppressed with popular drugs of the day but allowed to run its course. That course may be dramatically reduced by use of herbs. A cold is sometimes an acute healing crisis in which Nature expels accumulated wastes and toxins. Diaphoretics promote sweating, aiding this process.
Alternatives. Teas may be made from any of the following: Elderflowers, Peppermint, Catmint, Bayberry, Boneset, White Horehound, Feverfew, St John’s Wort.
Alternatives. Formulae:– Equal parts:– (1) Elderflowers and Peppermint. (2) Yarrow and Peppermint. (3) White Horehound and Hyssop. 1 teaspoon to each cup boiling water; infuse 5-15 minutes. 1 cup freely. A trace of Cayenne Pepper enhances potency and stimulates circulation.
Decoction. Prepared from Horseradish, Pleurisy root, Prickly Ash, Bayberry. Teaspoon, of any one, to two cups water gently simmered 20 minutes. Half-1 cup freely. Pinch of Cayenne enhances action.
Irish Moss. 1 teaspoon to 2 cups water simmered gently 20 minutes. Do not strain. Eat with a spoon with honey.
Powders. Composition. 1 teaspoon to cup of tea, or hot drink.
Powders. Formula. Bayberry bark 2; Ginger 1; Pleurisy root 1. Cayenne quarter. Sift. 500mg (two 00 capsules or one-third teaspoon) thrice daily.
Tablets/capsules. Lobelia. Iceland Moss. Vitamin C. Feverfew.
Essence of Cinnamon. Popular traditional herbal expectorant to help relieve symptoms of cold and flu. Composition essence and Elderflowers and Peppermint. 2 teaspoons in hot water or cup of tea every 3 hours. Children less according to age.
Life Drops. See entry.
Practitioner. Colds with fever, cardiac excitability and distress out of all proportion to the infection: Tincture Gelsemium, 3-5 drops.
Laxative. A mild laxative may be advised (5-7 Senna pods, infused in cup of boiling water, or Senacot). A healthy bowel movement may cut short a cold by assisting elimination.
Aromatherapy. Few drops of any of the following antiseptic oils added to a bowl of boiling water, head covered with a towel, steam inhaled: Eucalyptus, Peppermint, Marjoram, Thyme, Niaouli. Oil of Camphor is most effective, but as it antidotes all other medicaments, should be used alone. Oil of Scots Pine (5-10 drops) used in bath. Tiger Balm. Olbas oil.
Diet. 3-day fast; no solid food, herb teas and fruit juices only. Citrus fruits (Vitamin C) in abundance. Hot lemon and honey.
Supplementation. Daily. Vitamin A (7500iu), B-complex (50mg), C (3 grams at onset: 2 grams every 3 hours thereafter).
Prophylaxis, winter months. Daily: Vitamin C (Rose Hip, Acerola, etc), Echinacea. 2 Garlic capsules at night to build-up body’s resistance. ... colds
An acute contagious notifiable disease with catarrh of upper respiratory passages and watery eyes, characterised by papular eruption. Incubation: 1-2 weeks. Usually affects children. Common spring and autumn. Fever may reach 40°C (104°F), with coughing and sore throat. About two days before the rash, white spots (Koplik’s spots) may appear in mouth, but which fade when rash disappears.
Rash: blotchy and orange-red. Commencing behind the ears, it rapidly invades the whole body. Complications: inflammation of the middle ear, brain, and eyes.
Prophylactic: Pulsatilla.
A Danish study confirms that suppression of measles with drugs and vaccines can contribute to dermatitis, arthritis and cancer later in life.
Treatment by or in liaison with a general medical practitioner.
Alternatives. Marigold petal tea popular: 2-6 teaspoons to 1 pint boiling water. Make in vacuum flask. Consume 1-2 flaskfuls daily.
Other teas. Lime flowers, Chamomile, Elderflowers and Peppermint, Vervain. Formula (France): equal parts, German Chamomile, Catmint, Thyme. 2 teaspoons to each cup boiling water; infuse 15 minutes. 1 cup freely. Children: 2-5 teaspoons each year to 5 years; quarter to half cup to 10 years.
Jethro Kloss. 1 teaspoon Pleurisy root; quarter of a teaspoon powdered Ginger. Steep in 1 pint boiling water. For hyperactive child, add 1 teaspoon Skullcap. Infuse 20 minutes. Dose: half-1 cup freely. Children: 2-5 teaspoons each year to 5 years; quarter to half cup to 10 years.
Traditional. First give laxative to clear stomach and bowels. Then, bruise Houseleek, adding equal weight of honey. Dessertspoon every 2 hours. Cup of Balm tea assists reduction of temperature.
Topical. Wash with warm Elderflowers or Chamomile tea. Aloe Vera juice.
Aromatherapy. To inhale or for bath: Lavender essential oil.
Enema. Constipation. Injection of warm Chamomile tea.
Eyes. Impairment of sight possible. For inflamed eyes and lids bathe with warm Elderflowers or Chamomile tea.
Note: There is always debility and chilliness followed by a throwing out of the skin morbific materials. Diaphoretic drinks are important so that no undue stress is placed on the kidneys. These include teas of Yarrow, Lemon Balm, Lime flowers, Hyssop, Ginger, Elderflowers and Peppermint.
Tincture. Echinacea. Adults: 1 teaspoon. Child: 1 drop each year to 5; thereafter 2 drops each year to 12 years.
Diet. 3-day fast, if possible. No solid food. Abundant Vitamin C drinks, fruit juices. All cases should receive Vitamin A supplements, halibut liver oil. Foods rich in beta-carotene (carrots). ... measles
One of a large number of tiny, balloon-like sacs at the end of a bronchiole (one of many small air passages in the lungs) where gases are exchanged during respiration.... alveolus, pulmonary
A rarely used X-ray procedure for examining the bronchi, the main air passages of the lungs. Once used to diagnose bronchiectasis, it has now been largely replaced by other imaging techniques, such as CT scanning, and by the use of bronchoscopy.... bronchography
Infection of the breathing passages, which extend from the nose to the alveoli. This type of infection is divided into upper and lower respiratory tract infections. Upper respiratory tract infections affect the nose, throat, sinuses, and larynx. They include the common cold, pharyngitis, tonsillitis, sinusitis, laryngitis, and croup. Lower respiratory tract infections, which affect the trachea, bronchi, and lungs, include acute bronchitis, acute bronchiolitis, and pneumonia.... respiratory tract infection
A surgical procedure that involves cutting the muscle that closes a body opening or that constricts the opening between body passages.... sphincterotomy
n. a drug that relaxes smooth muscle and stimulates respiration. It is widely used to dilate the air passages in the treatment of severe asthma and some cases of chronic obstructive pulmonary disease. Side effects may include nausea, vomiting, dizziness, and fast heart rate. See also theophylline.... aminophylline
n. a hollow or solid cylindrical instrument, usually flexible, that is inserted into tubular passages, such as the oesophagus (gullet), rectum, or urethra. Bougies are used in diagnosis and treatment, particularly by enlarging *stricture(s) (for example, in the urethra).... bougie
n. a drug that causes narrowing of the air passages by producing spasm of bronchial smooth muscle.... bronchoconstrictor
n. an agent that causes widening of the air passages by relaxing bronchial smooth muscle. *Sympathomimetic drugs that stimulate ?2 adrenoceptors, such as *formoterol, *salbutamol, and *terbutaline, are potent bronchodilators and are used for relief of bronchial asthma and chronic obstructive pulmonary disease. These drugs are often administered as aerosols, giving rapid relief, but at high doses they may stimulate the heart. Some antimuscarinic drugs (e.g. *ipratropium and *theophylline) are also used as bronchodilators.... bronchodilator
(beta-adrenergic receptor blocker) a drug that prevents stimulation of the beta *adrenoceptors at the nerve endings of the sympathetic nervous system. Blockade of ?1 receptors causes a decrease in heart rate and force; blockade of ?2 receptors causes constriction of the airways and the arteries. Beta blockers include *acebutolol, *atenolol, *bisoprolol, *oxprenolol, *propranolol, and *sotalol; they are used to control abnormal heart rhythms, to treat angina, and to reduce high blood pressure (although they are no longer regarded by some experts as the first choice of drug for treating hypertension in the absence of heart disease, being less effective than newer antihypertensive drugs). Beta blockers that block both ?1 and ?2 receptor sites cause constriction of air passages in the lungs, and these drugs should not be used in patients with asthma and bronchospasm. Other beta blockers are relatively selective for the heart (cardioselective) and are less likely to constrict the airways. Some beta blockers (e.g. *carteolol, *levobunolol, and *timolol) reduce the production of aqueous humour and therefore the pressure inside the eye; they are taken as eye drops in the treatment of *glaucoma.... beta blocker
n. (pl. bronchi) any of the air passages beyond the *trachea (windpipe) that has cartilage and mucous glands in its wall (see illustration). The trachea divides into two main bronchi, which divide successively into five lobar bronchi, 20 segmental bronchi, and two or three more divisions. See also bronchiole. —bronchial adj.... bronchus
(conjugate diameter, true conjugate) n. the distance between the front and rear of the pelvis measured from the most prominent part of the sacrum to the back of the pubic symphysis. Since the true conjugate cannot normally be measured during life it is estimated by subtracting 1.3–1.9 cm from the diagonal conjugate, the distance between the lower edge of the symphysis and the sacrum (usually about 12.7 cm). If the true conjugate is less than about 10.2 cm, delivery of an infant through the natural passages may be difficult or impossible, and *Caesarean section may have to be performed.... conjugate
(rale) n. a soft fine crackling sound heard in the lungs through the stethoscope. Crepitations are made either by air passages and alveoli (air sacs) opening up during inspiration or by air bubbling through fluid. They are not normally heard in healthy lungs.... crepitation
n. a drug that causes constriction of blood vessels and widening of the bronchial passages (see sympathomimetic). It is used mainly as a nasal *decongestant but also to reverse hypotension following epidural or spinal anaesthesia. It may cause nausea, insomnia, headache, and dizziness.... ephedrine
n. the forcible removal of secretions from the air passages by some form of suction apparatus.... exsufflation
cancer arising in the epithelium of the air passages (bronchial cancer) or lung (see also non-small-cell lung cancer; small-cell lung cancer). It is a very common form of cancer, particularly in Britain, and is strongly associated with cigarette smoking and exposure to industrial air pollutants (including asbestos). There are often no symptoms in the early stages of the disease, when diagnosis is made on X-ray examination. Treatment includes surgical removal of the affected lobe or lung (less than 20% of cases are suitable for surgery), radiotherapy, and chemotherapy.... lung cancer
n. a genus of spherical Gram-negative aerobic nonmotile bacteria characteristically grouped in pairs. They are parasites of animals, and some species are normal inhabitants of the human respiratory tract. The species N. gonorrhoeae (the gonococcus) causes *gonorrhoea. Gonococci are found within pus cells of urethral and vaginal discharge; they can be cultured only on serum or blood agar. N. meningitidis (the meningococcus) causes meningococcal *meningitis. Meningococci are found within pus cells of infected cerebrospinal fluid and blood or in the nasal passages of carriers. They too can only be cultured on serum or blood agar.... neisseria
n. acute inflammation and obstruction of the respiratory tract, involving the larynx and the main air passages (trachea and bronchi), in young children (usually aged between six months and three years). The usual cause is a virus infection but bacterial secondary infection can occur. The symptoms are those of *laryngitis, accompanied by signs of obstruction – harsh difficult breathing (see stridor), a characteristic barking cough, a rising pulse rate, restlessness, and *cyanosis. Treatment is by reassurance and humidification of the inspired air. In severe cases the obstruction may require treatment by steroid nebulizers, *intubation, or *tracheostomy. See also epiglottitis.... croup
n. an acute highly contagious infection, caused by the bacterium Corynebacterium diphtheriae, generally affecting the throat but occasionally other mucous membranes and the skin. The disease is spread by direct contact with a patient or carrier or by contaminated milk. After an incubation period of 2–6 days a sore throat, weakness, and mild fever develop. Later, a soft grey membrane forms across the throat, constricting the air passages and causing difficulty in breathing and swallowing; a *tracheostomy may be necessary. Bacteria multiply at the site of infection and release a toxin into the bloodstream, which damages heart and nerves. Death from heart failure or general collapse can follow within 4 days but prompt administration of antitoxin and penicillin arrests the disease. An effective immunization programme has now made diphtheria rare in most Western countries (see also Schick test).... diphtheria
n. a severe and almost exclusively viral infection of the respiratory tract, especially of young children, in whom there may be a dangerous degree of obstruction either at the larynx (see croup) or main air passages (bronchi) due to the thickness and stickiness of the fluid (exudate) produced by the inflamed tissues. Symptoms normally start at night. Treatment is supportive until the condition resolves naturally. In mild and moderate cases the child may benefit from being kept in a humid atmosphere (e.g. a steamy room). Nebulized medications and oxygen can help in more severe cases. In extreme cases endotracheal *intubation may be necessary. The condition may recur.... laryngotracheobronchitis
n. an infestation of a living organ or tissue by maggots. The flies normally breed in decaying animal and vegetable matter; myiasis therefore generally occurs only in regions of poor hygiene, and in most cases the infestations are accidental. Various genera may infect humans. *Gasterophilus, *Hypoderma, *Dermatobia, and Cordylobia (see tumbu fly) affect the skin; Fannia invades the alimentary canal and the urinary system; *Phormia and *Wohlfahrtia can infest open wounds and ulcers; *Oestrus attacks the eyes; and Cochliomyia invades the nasal passages. Treatment of external myiases involves the destruction and removal of maggots followed by the application of antibiotics to wounds and lesions.... myiasis
n. the branch of medicine concerned with disorders of the nose and nasal passages.... rhinology
(deglutition) n. the process by which food is transferred from the mouth to the oesophagus (gullet). Voluntary raising of the tongue forces food backwards towards the pharynx. This stimulates reflex actions in which the larynx is closed by the epiglottis and the nasal passages are closed by the soft palate, so that food does not enter the trachea (windpipe). Lastly, food moves down the oesophagus by *peristalsis and gravity.... swallowing
n. 1. a device to ensure a supply of fresh air. 2. (respirator) equipment that is manually or mechanically operated to maintain a flow of air into and out of the lungs of a patient who is unable to breathe normally. Positive-pressure ventilators blow air into the patient’s lungs; air is released from the lungs when the pressure from the ventilator is relaxed (see BiPAP; Nippy; noninvasive ventilation). Negative-pressure ventilators are airtight containers in which the air pressure is decreased and increased mechanically. This draws air into and out of the patient’s lungs through the normal air passages. The original devices, known colloquially as iron lungs, had a seal around the neck and enclosed the whole body except the head. They have been replaced by cuirass ventilators, which work on a similar principle but enclose the chest only; there may be a role for these in adults and children with claustrophobia.... ventilator
n. a machine used to generate vibrations of different frequencies, which have a stimulating effect when applied to different parts of the body. A vibrator may also be used to loosen thick mucus in the sinuses or air passages.... vibrator
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