Online Encyclopedia
Search over 40,000 articles from the original, classic Encyclopedia Britannica, 11th Edition.
LYMPHATIC SYSTEM
Online EncyclopediaEncyclopedia Home :: LUP-MAL
del.icio.us it!
|
LYMPHATIC See also:SYSTEM . In See also:anatomy, the lymphatic system (See also:Lat. lympha, clear See also:water) comprises the lymphoid or adenoid See also:tissue so plentifully distributed about the See also:body, especially in the course of the alimentary See also:canal (see CONNECTIVE TISSUES), See also:lymph spaces, lymphatic vessels of which the lacteals are modifications, lymphatic glands, haemolymph glands, and the thoracic and right lymphatic ducts by which the lymph (q.v.) finally reaches the See also:veins. Lymph spaces are See also:mere spaces in the connective tissue, which usually have no See also:special lining, though sometimes there is a layer of endothelial cells like those of the lymphatic and See also:blood vessels. Most of these spaces are very small, but sometimes, as in the See also:case of the sub-epicranial space of the See also:scalp, the See also:capsule of Tenon in the See also:orbit, and the retropharyngeal space in the See also:neck, they are large and are adaptations to allow See also:free See also:movement. Opening from these spaces, and also communicating with the serous membranes by small openings called stomata,' are the lymph capillaries (see VASCULAR SYSTEM), which converge to the lymphatic vessels. These resemble veins in having an See also:internal layer of endothelium, a See also:middle unstriped See also:muscular coat, and an See also:external coat of fibrous tissue, though in the smaller vessels the middle coat is wanting. They have numerous endothelial valves, formed of two crescentic segments allowing the lymph to pass toward the See also:root of the neck. When the vessels are engorged these valves are marked by a constriction, and so the lymphatics have a beaded See also:appearance. The vessels See also:divide and anastomose very freely, and for this See also:reason they do not, like the veins, increase in calibre as they approach their destination. It is usual to divide the lymphatic vessels into a superficial and a deep set; speaking generally, the superficial ones are found near the course of the superficial veins, while the deeper ones accompany the See also:arteries. Probably any single drop of lymph passes sooner or later through one or more lymphatic glands, and so those vessels which are approaching a gland are called afferent, while those leaving are spoken of as efferent lymphatics. The lacteals are special lymphatic vessels which carry the chyle from the See also:intestine; they begin in lymphatic spaces in the villi and See also:round the solitary and agminated glands, and pass into the mesentery, where they come in contact with a large number of mesenteric glands before reaching the receptaculum chyli. The lymphatic glands are See also:pink bodies situated in the course of the lymphatic vessels, to which they See also:act as filters. They are generally See also:oval in shape and about the See also:size of a See also:bean, but sometimes, especially in the See also:groin, they See also:form irregular flattened masses 2 in. See also:long, while, at other times, they are so small as almost to See also:escape See also:notice. They are usually found in See also:groups. Each gland has a fibrous capsule from which trabeculae pass toward the centre, where they break up and interlace, forming a See also:net-See also:work, and in this way a cortical and medullary region for each gland is distinguished; the intervals are nearly filled by lymphoid tissue, but See also:close to the trabeculae is a lymph path or sinus, which is only crossed by the reticular stroma of the lymphoid tissue, and this probably acts as a See also:mechanical See also:sieve, entangling See also:foreign particles; as an example of this the bronchial glands are See also:black from See also:carbon strained off in its passage from the lungs, while the axillary glands in a tattooed See also:arm are See also:blue. The blood-vessels enter at one spot, the hilum, and are distributed along the trabeculae. In addition to their See also:function as filters the lymphatic glands are probably one of the See also:sources from which the leucocytes are derived. The exact position of the various groups of glands is very important from a medical point of view, but here it is only possible to give a brief See also:sketch which will be helped by reference to the accompanying See also:diagram. In the See also:head are found occipital and mastoid glands (fig. 1, /3), which drain the back of the scalp; internal maxillary ' It has recently been stated that stomata do not exist in the peritoneum.glands, in the zygomatic fossa, draining the orbit, See also:palate, See also:nose and membranes of the See also:brain; preauricular glands (fig. 1, a), embedded in the parotid, draining the See also:side of the scalp, pinna, tympanum and See also:lower eyelid; and buccal glands, draining the cheek region. In the neck are the superficial cervical glands (fig. r, y), along the course of the external jugular vein, draining the See also:surface of the neck; the sub-maxillary glands (fig. 1, 6), lying just above the salivary gland of the same name and draining the front of the See also:face and scalp; the sub-See also:mental glands (fig. 1, e), beneath the See also:chin, draining the lower See also:lip, as well as sometimes the upper, and the front of the See also:tongue; the retropharyngeal glands, draining the naso-pharynx and tympanum; the pretracheal glands, draining the trachea and lower See also:part of the See also:thyroid body; and the deep cervical glands, which are by far the most important and form a See also:great See also:mass close to the internal jugular vein; they receive afferent vessels from most of the glands already mentioned and so are liable to be affected in any trouble of the head or neck, especially of the deeper parts. Into them the lymphatics of the brain pass directly. The lower part of this mass is sometimes distinguished as a See also:separate See also:group called the supra-clavicular glands, which drain the back of the neck and receive afferents from the occipital and axillary glands. The efferents from the deep cervical glands join to form a See also:common See also:vessel known as the jugular lymphatic See also:trunk, and this usually opens into the thoracic duct on the See also:left side and the right lymphatic duct on the right. In the See also:thorax are found intercostal glands (fig. 2, I.), near the vertebral See also:column draining the back of the thoracic walls and pleura; internal mammary glands, draining the front of the same parts as well as the inner part of the See also:breast and the upper part of the abdominal See also:wall; diaphragmatic glands, draining that structure and the See also:convex surface of the See also:liver; anterior, middle, posterior and See also:superior mediastinal glands, draining the contents of those cavities. The bronchial glands, draining the lungs, have already been referred to. In the See also:abdomen and See also:pelvis the glands are usually grouped round the large arteries and are divided into visceral and parietal. Among the visceral are the gastric glands, draining the, See also:stomach (these are divided into coronary, subpyloric FIG. r.—Superficial Lymphatic and retropyloric groups) ; the splenic Vessels and Glands. glands at the hilum of the See also:spleen, a, Preauricular. draining that See also:organ, the tail of the ,B, Mastoid. See also:pancreas and the fundus of the y, Superficial cervical. stomach; the hepatic glands in the S, Submaxillary. small omentum, draining the lower e, Submental. surface and deep parts of the liver; Infraclavicular. the pancreatic glands, behind the rt, Anterior axillary. lesser See also:sac of the peritoneum, drain- g, Supratrochlear. See also:ing the head and body of the r, Antecubital. pancreas, the superior mesenteric Ic, Inguinal. lands; from one to two See also:hundred 1, Superficial femoral. in number, lying in the mesentery and receiving the lacteals; the ileo-caecal glands, draining the caecum, one of which is known as the appendicular gland and drains the vermiform appendix and right ovary; the See also:colic glands along the right and middle colic arteries, draining the ascending and transverse See also:colon ; the inferior mesenteric glands in the course of that artery, draining the descending iliac and pelvic colons; the rectal glands, behind the rectum, draining its upper part. Among the parietal glands are the external iliac glands, divided into a lateral and mesial set (see fig. 2, E.I.), and receiving the inguinal efferent vessels and lymphatics from the See also:bladder, prostate, cervix uteri, upper part of the vagina, glans penis vel clitoridis and urethra. The supra and infra-umbilical glands receive the deep lymphatics of the abdominal wall, the former communicating with the liver, the latter with the bladder. From the latter, vessels pass to the epigastric gland lying in front of the termination of the external iliac artery. The internal iliac glands (fig. 2, I. I.) are situated close to the branches of this artery and drain the rectum, vagina, prostate, urethra, buttock and perinaeum. Common iliac glands (fig. 2, C.I.) See also:lie around that artery and receive afferents from the external and internal iliac glands as well as a few from the pelvic viscera.' The 2 For further details of the pelvic glands see " Seventh See also:Report of the See also:Committee of Collective Investigation," Journ. Anat. and Phys. xxxii. 164. aortic glands are grouped all round the length of the aorta, and are divided into pre-, retro- and lateral aortic groups (fig. 2 P.A. and L), all of which communicate freely. The upper preaortic glands are massed round the coeliac See also:axis, and receive afferents from the gastric, hepatic, splenic and pancreatic glands; they are known as coeliac glands. The lateral aortic glands drain the See also:kidney, See also:adrenal, testis, ovary, fundus of uterus and lateral abdominal walls. In the upper extremity a few small glands are sometimes found near the deep arteries of the forearm. At the See also:bend of the See also:elbow are the antecubital glands (fig. i ?) and just above the internal condyle, one or two supra-trochlear glands (fig. 1, 0). The axillary glands (fig. 1, r,) are perhaps the most practically important in the body. They are divided into four sets: (I) external, along the axillary vessels, draining the greater part of the arm; (2) anterior, behind the lower border of the See also:pectoralis See also:major muscle, draining the surface of the thorax including the breast and upper part of the abdomen; (3) posterior along the subscapular artery, draining the back and side of the trunk as See also:low as the umbilical See also:zone; (4) superior or infra-clavicular glands (fig. 1, 1), receiving the efferents of the former groups as well as lymphatics accompanying the cephalic vein. In the lower See also:limb all the superficial lymphatics pass up to the groin, where there are two sets of glands arranged like a T. The superficial femoral glands (fig. 1, a) are the See also:vertical ones, and are grouped round the internal saphenous vein; they are very large, drain the surface of the See also:leg, and are usually in two parallel rows. The inguinal glands form the See also:cross See also:bar of the T (fig. i, K), and drain part of the buttock, the surface of the abdomen below the umbilicus and the surface of the genital See also:organs. The deep lymphatics of the leg drain into the anterior tibial gland on that artery, the popliteal glands in that space, and the deep femoral glands surrounding the common femoral vein. The thoracic duct begins as an irregular See also:dilatation known as the receptaculum chyli, opposite the first and second lumbar vertebrae, which receives all the abdominal lymphatics as well as those of the lower intercostal spaces. The duct runs up on the right of the aorta through the posterior mediastinum and then traverses the superior mediastinum to the left of the See also:oesophagus. At the root of the neck it receives the lymphatics of the left arm and left side of the neck and opens into the beginning of the left innominate vein, usually by more than one opening. The right lymphatic duct collects the lymphatics from the right side of the neck and thorax, the right arm, right See also:lung, right side of the See also:heart and upper surface of the liver; it is often represented by several ducts which open separately into the right innominate vein. Haemolymph glands are structures which have only been noticed since 1884. They differ from lymphatic glands in their much greater vascularity. They assist the spleen in the destruction of red blood corpuscles, and probably explain or help to explain the fact that the spleen can be removed without effects. In See also:man they extend along the vertebral column from the coeliac axis to the pelvis, but are specially numerous close to the renal arteries. T. See also:Lewis suggests that lymphatic and haemolymph glands should be classified in the following way: Haemal glands. See also:Simple. Specialized (Spleen). Haemolymph '1. Blood and lymph Glands. Haemal lymphatic sinuses separate. glands. 2. Blood lymph sinuses. 3. Other combined forms. L Lymphatic glands. Details and references will be found in papers by T. Lewis, J. Anat. & Phys. vol. xxxviii. p. 312; W. B. See also:Drummond, Journ. Anat. and Phys. vol. xxxiv. p. 198; A. S. Warthin, Journ. Med. See also:Research, 1901, p. 3, and H. See also:Dayton, Am. Journ. of Med. Sciences, 1904, p. 448. For further details of man's lymphatic system see The Lymphatics by See also:Delamere, Poirier and See also:Cuneo, translated by C. H. See also:Leaf (See also:London, 1903). See also:Embryology.—The lymphatic vessels are possibly See also:developed by the hollowing out of mesenchyme cells in the same way that the arteries are; these cells subsequently coalesce and form tubes (see VASCULAR SYSTEM). There is, however, a See also:good See also:deal of See also:evidence to show that they are originally offshoots of the venous system, and that their permanent openings into the veins are either their See also:primary points of communication or are secondarily acquired. The lymphatic and haemolymph glands are probably formed by the proliferation of lymphocytes around networks of lymphatic vessels; the dividing lymphocytes form the lymphoid tissue, and eventually the network breaks up to form distinct glands into which blood vessels penetrate. If the blood vessels enlarge more than the lymphatic, haemolymph glands result, but if the lymphatic vessels become predominant See also:ordinary lymphatic glands are formed. At an See also:early See also:stage in the embryo See also:pig two thoracic ducts are formed, one on either side of the aorta, and the incomplete See also:fusion of these may See also:account for the See also:division often found in man's duct. In the embryo pig too there have been found two pairs of lymph See also:hearts for a See also:short See also:period. See A. S. Warthin, Journ. Med. Research, vol. vii. p. 435; F. R. Sabin, Am. Journ. of Anat. i., 1902; and, for literature, Development of the Human Body, by J. P. McMurrich (London, 1906), and See also:Quain's Anatomy (vol. i., London, 1908). See also:Comparative Anatomy.—A lymphatic system is recognized in all the Craniata, and in the lower forms (fishes and See also:Amphibia) it consists chiefly of lymph spaces and sinuses in communication with the coelom. In fishes, for instance, there is a large subvertebral lymph sinus surrounding the aorta and another within the See also:spinal canal. In Amphibia the subvertebral sinus is also found, and in the Anura (frogs and toads) there is a great subcutaneous lymph sinus. Lymph hearts are muscular dilatations of vessels and are found in fishes, amphibians, See also:reptiles and See also:bird embryos, and drive the lymph into the veins; they are not known in adult mammals. In birds the thoracic duct is first recognized; and opens into both right and left precaval veins, as it always does in some mammals. In birds, however, some of the lymphatics open into the sacral veins, and it is doubtful whether true lymphatic glands ever occur. In birds and mammals lymphatic vessels become more definite and numerous and are provided with valves. From A. M. See also:Paterson, See also:Cunningham's Teri--See also:book of Anatomy. C. Common iliac glands. M. Mediastinal glands and C.I. Common intestinal trunk. vessels. [vessels. D.C. Deep cervical glands. P.A. Pre-aortic glands and E.I. External iliac glands. R.C. Receptaculum chylii. 1. Intercostal glands and R.L.D. Right lymphatic duct. vessels. S. Sacral glands. I.I. Internal iliac glands. S.A. Scalenus anticus muscle. L. Lateral aortic glands. T.D. Thoracic duct. Haemolymph glands are See also:present in mammals and birds, but have not been seen lower in the See also:scale, though S. See also:Vincent and S. See also:Harrison point out the resemblance of the structure of the head kidney of certain Teleostean fishes to them (Journ. Anat. and Phys. vol. xxxi. p176). For further details see Comparative Anat. of Vertebrates, by R. Wiedersheim (London, 1907). (F. G. P.) Diseases of the Lymphatic System and Ductless Glands. Lymphadenitis or inflammatory infection of the lymphatic glands, is a See also:condition characterized by hyperaemia of and exudation into the gland, which becomes redder, firmer and larger than usual. Three varieties may be distinguished: simple, suppurative and tuberculous. The cause is always the absorption of some toxic or infective material from the periphery. This may take See also:place in several of the acute infectious diseases, notably in See also:scarlet See also:fever, See also:mumps, See also:diphtheria and See also:German See also:measles, or may be the result of poisoned wounds. The lymphatic glands are also affected in constitutional diseases such as syphilis. Simple lymphadenitis usually subsides of its own See also:accord, but if toxins are produced in the inflamed See also:area the enlargement is obvious and painful, while if pyogenic organisms are absorbed the inflammation progresses to suppuration. Tuberculous lymphadenitis (See also:scrofula) is due to the infection of the lymph glands by See also:Koch's tubercle bacillus. This was formerly known as " See also: This condition, if untreated, may persist for years and may finally give rise to a See also:general See also:tuberculosis. The treatment consists mainly in improving the general See also:health with good See also:diet, fresh air (particularly See also:sea air), See also:cod-liver oil and See also:iron, and the removal of all sources of local irritation such as enlarged tonsils, See also:adenoids, &c. See also:Vaccination with tuberculin (TR) may be useful. Suppuration and ex-tension of the disease require operative See also:measures, and removal of the glands en masse can now be done through so small an opening as to leave only a very slight scar. In Tabes mesenterica (tuberculosis of the mesenteric glands), usually occurring in children, the glands of the mesentery and retroperitonaeum become enlarged, and either caseate or occasionally suppurate. The disease may be primary or may be secondary to tuberculous disease of the intestines or to pulmonary See also:phthisis. The patients are See also:pale, wasted and anaemic, and the abdomen may be enormously enlarged. There is usually moderate fever, and thin watery See also:diarrhoea. The caseating glands may liquefy and give rise to an inflammatory attack which may simulate See also:appendicitis. Limited masses are amenable to surgical treatment and may be removed, while in the earlier stages constitutional treatment gives good results. Tuberculous See also:peritonitis frequently supervenes on this condition. Lymphadenoma (See also:Hodgkin's Disease), a disease which was first fully described by Hodgkin in 1832, is characterized by a progressive enlargement of the lymphatic glands all over the body, and generally starts in the glands of the neck. The See also:majority of cases occur in young adults, and preponderate in the male See also:sex. The first symptom is usually enlargement of a gland in the neck, with generally progressive growth of the glands in the submaxillary region and axilla. The inguinal glands are early involved, and after a See also:time the internal lymph glands follow. The enlargements are at first painless, but in the later stages symptoms are caused by pressure on the surrounding organs, and when the disease starts in the deeper structures the first symptoms may be See also:pain in the See also:chest and cough, pain in the abdomen, pain and oedema in the legs. The glands may increase until they are as large as eggs, and later may become firmly adherent one to another, forming large lobulated tumours. Increase of growth in this manner in the neck may cause obstructive dyspnoea and even See also:death. In the majority of cases the spleen enlarges, and in rare instances lymphoid tumours may be found on its surface. See also:Anaemia is common and is secondary in See also:character; slight irregular fever is present, and soon a great and progressive emaciation takesplace. The cases are of two types, the acute cases in which the enlargements take place rapidly and death may occur in two to three months, and the chronic cases in which the disease may remain apparently stationary. In acute lymphadenoma the See also:prognosis is very unfavourable. Recovery sometimes takes place in the chronic type of the disease. Early surgical intervention has in some cases been followed by success. The application of X-rays is a valuable method of treatment, superficial glands undergoing a rapid diminution in size. Of drugs See also:arsenic is of the most service, and See also:mercurial inunction has been recommended by Dreschfeld. Organic extracts have of See also:late been used in the treatment of lymphadenoma. Glandular Fever is an acute infectious fever, generally occurring in epidemics, and was first described by E. See also:Pfeiffer in 1889. It usually affects childrenand has a tendency to run through all the children of a See also:family. The See also:incubation period is said to be about 7 days. The onset is sudden, with pain in the neck and limbs, headache, vomiting, difficulty in swallowing and high temperature. On the second See also:day, or sometimes on the first, swelling of the cervical glands is noticed, and later the posterior cervical, axillary and inguinal glands become enlarged and See also:tender. In about See also:half the cases the spleen and liver are enlarged and there is abdominal tenderness. See also:West found the mesenteric nodes enlarged in 37 cases. Nephritis is an occasional complication, and See also:constipation is very usual. The disease tends to subside of itself, and the fever usually disappears after a few days; the glandular swellings may, however, persist from one to three See also:weeks. Considerable anaemia has been noticed to follow the illness. See also:Rest in See also:bed while the glands are enlarged, and cod-liver oil and iron to meet the anaemia, are the usual treatment. Status lymphaticus (lymphatism) is a condition found in children and some adults, characterized by an enlargement of the lymphoid tissues throughout the body and more particularly by enlargement of the thymus gland. There is a special lowering of the patient's See also:powers of resistance, and it has been said to account for a number of cases of sudden death. In all cases of status lymphaticus the thymus has been found enlarged. At See also:birth the gland (according to Bovaird and See also:Nicoll) weighs about 6 grammes, and does not increase after birth. In lymphatism it may weigh from to to 5o grammes. The clinical features are indefinite, and the condition frequently passes unrecognized during See also:life. In most cases there is no hint of danger until the fatal See also:syncope sets in, which may be after any slight exertion or See also:shock, the patient becoming suddenly faint, gasping and cyanosed, and the heart stopping altogether before the respirations have ceased. The most trifling causes have brought on fatal issues, such as a wet See also:pack (Escherich) or a hypodermic injection, or even a sudden plunge into water though the head is not immersed. The greater number of deaths occur during the See also:administration of anaesthetics, which seem peculiarly dangerous to these subjects. When an attack of syncope takes place no treatment is of any avail. See also:Virchow, West and Goodhardt have described a form of See also:asthma in adults which they ascribe to a hypertrophied thymus gland and See also:term " thymic asthma." Diseases of the Spleen.—Physiological See also:variations and abnormalities and See also:absence of the spleen are so rare as to require no comment. The most usual pathological condition which gives rise to symptoms is that of wandering spleen, which may or may not be secondary to a wandering left kidney. It may produce symptoms of dragging and discomfort, See also:dyspepsia, vomiting and abdominal pain, and sometimes See also:jaundice (Treves), or the pedicle may become See also:twisted, producing extremely severe symptoms. The treatment is entirely surgical. Abscess in the spleen occasionally occurs, usually in association with infective endocarditis or with general pyaemia. The spleen may be the seat of primary new growths, but these are rare, and only in a small portion of cases does it See also:share in the metastatic See also:reproduction of carcinoma. Infection of the spleen plays a prominent part in many diseases, such as See also:malaria, typhoid fever, lymphadenoma and leucaemia. Diseases of the thyroid gland (see See also:GOITRE) and See also:Addison's disease (of the suprarenal glands) are treated separately. (H. L. Additional information and CommentsThere are no comments yet for this article.
» Add information or comments to this article.
Please link directly to this article:
Highlight the code below, right click, and select "copy." Then paste it into your website, email, or other HTML. Site content, images, and layout Copyright © 2006 - Net Industries, worldwide. |
|
|
[back] LYMPH |
[next] LYNCH LAW |