Charadrius is a genus of birds which includes the lapwing, pratincole and oyster-catcher.
The genus is characterised by a long, slender, straight, or slightly recurvate bill, which is higher than broad at the base, and extremely compressed toward the end; an upper mandible with the dorsal line straight and slightly sloping at the base, somewhat convex beyond the nostrils, then straight and sloping to the point, the ridge broad and flattened as far as the prominence, afterwards extremely narrow, the sides sloping at the base, perpendicular towards the end, the edges rather sharp, the tip abrupt and wedge-shaped; the nasal groove is long and bare; a lower mandible with the angle of moderate length, the dorsal line ascending and slightly convex, the sides erect, the edges thin, the tip abrupt and wedged.
The nostrils are sub-basal, linear and near the margin. The head is of a moderate size, ovate with a rounded forehead; the neck is of moderate length; the body compact. The feet are of moderate length, rather stout; the tibia are bare for about a quarter of their length; the tarsus is slightly compressed and covered all round with hexagonal scales; the toes are of moderate length, stout, marginate, flat beneath, webbed at the base, the outer considerably longer than the inner, the first wanting. The claws rather small, arched, moderately compressed and obtuse. The plumage is generally blended and compact on the back. The wings are long and pointed, the first quill being the longest. The tail is short, nearly even, and comprised of twelve feathers. The tongue is short, triangular and fleshy; The Oesophagus is dilated into a fairly large crop; the stomach rectangular, muscular, with the epithelium dense and longitudinally rugous; the intestine is long and rather slender; the coeca is long and nearly cylindrical; the cloaca globular. Research Charadrius
The Dipnoi are an order of fishes, including only the singular mud-fishes (Lepidosiren), important as exhibiting the transition, between fishes and the amphibia. Formerly Lepidosiren was reckoned the lowest of the amphibia, now it constitutes the highest order of fishes. The body is fish-like in shape, covered with small horny scales of a cycloid character; the pectoral and ventral fins are represented by two pairs of long filiform organs; the heart has two auricles and one ventricle, and the respiratory organs are twofold, consisting of ordinary gills opening externally, and of true lungs - formed by the modified swimming-bladder - communicating with the oesophagus by means of an air-duct or trachea, whence the name. They are also called Protopteri. The combination of respiratory organs is similar to that which is presented by the tailed amphibians with persistent gills (perennibranchiate), as the axolotl. This interesting group is allied to the ganoids through the Ceratodus of Queensland. The Lepidosiren paradoxa is found in the Amazon; Lepidosiren annectens in the Gambia. Research Dipnoi
Entomology is the branch of zoology dealing with insects. It was started as a science in 1705 by the publication of Ray's 'Methodus Insectorum'.
The name entomology comes from the Greek entoma, animals 'cut in', the transverse division or segmentation of the body being their most conspicuous feature.
The true insects are those animals of the division Arthropoda or Articulata distinguished from the other classes of the division by the fact that the three divisions
of the body - the head, thorax, and abdomen - are always distinct from one another. There are never more than three pairs of legs in the perfect insect, and these are all borne upon the thorax. Each leg consists of from six to nine joints. The first of these is called the 'coxa,' and is succeeded by a short joint called the 'trochanter.' This is followed by a joint, often of large size, called the 'femur,' succeeded by the 'tibia,' and this has articulated to it the 'tarsus', which may be composed of from one to five joints.
Normally two pairs of wings are present, but one or other may be wanting. The wings are expansions of the sides of the second and third sections of the thorax, and are attached by slender tubes called 'nervures'.
In the beetles the anterior pair of wings becomes hardened so as to form protective cases for the posterior membranous wings, and are called in this condition ' elytra ' or ' wing-cases.' Respiration is effected by means of air-tubes or tracheas, which commence at the surface of the body by lateral apertures called 'stigmata' or 'spiracles,' and ramify through every part of the body.
The head is composed of several segments amalgamated together, and carries a pair of feelers or 'antennae', a pair of eyes, usually compound, and the appendages of the mouth. The thorax is composed of three segments, also amalgamated, but generally pretty easily recognized. The abdominal segments are usually more or less freely movable upon one another, and never carry locomotive limbs; but the extremity is frequently furnished with appendages connected with generation, and which in some cases serve as offensive and defensive weapons (stings).
The organs of the mouth take collectively two typical forms, the masticatory and the suctorial, the former exemplified by the beetles, the latter by the butterflies, in which the mouth is purely for suction. The alimentarycanal consists of the oesophagus or gullet, a crop, a gizzard, a stomach, and an intestine, terminating in a cloaca. There is no regular system of blood vessels ; the most important organ of the circulation is a contractile vessel situated dorsally and called the 'dorsal vessel.' The nervous system is mainly composed of a series of ganglia placed along the ventral aspect of the body and connected by a set of double nerve-cords.
The sexes are in different individuals, and most insects are oviparous. Reproduction is generally sexual, but non-sexual reproduction also occurs. Generally the young are very different from the full-grown insect, and pass through a 'metamorphosis' before attaining the mature stage. When this metamorphosis is complete it exhibits three stages - that of the larva, caterpillar, or grub, that of the pupa or chrysalis, and that of the imago or perfect winged insect.
Insects have been divided into three sections - Ametabola,Hfemimetabola, and Holometabola, according as they undergo no metamorphosis, an incomplete one, or a complete one. The young of the Ametabola differ from the adult only in size. They are all destitute of wings; the eyes are simple and sometimes wanting. The Hemimetabola undergo an incomplete metamorphosis, the larva differing from the imago chiefly in the absence of wings and in size. The pupa is usually active, or if quiescent capable of movement. In the Holometabola the metamorphosis is complete, the larva, pupa, and imago differing greatly from one another in external appearance and habits. The larva is wormlike and the pupa quiescent. The section Ametabola (which in the opinion of many naturalists are scarcely within the pale of the true Insecta) is divided into three orders - Anoplura (lice), Mallophaga (bird-lice), and Thysanura (springtails). The section Hemimetabola comprises the orders Hemiptera (cicadas, bugs, plant-lice, etc), Orthoptera (cockroaches, crickets, grasshoppers, locusts, earwigs, etc), and Neuroptera (dragon-flies, may-flies, white-ants, etc). The Holometabola comprises the orders Aphaniptera (fleas), Diptera (gnats, bot-flies, gad-flies, mosquitos, house-flies, etc), Lepidoptera (butterflies and moths), Hymenoptera (bees, wasps, and ants), Strepsiptera (stylops, minute and parasites), and Coleoptera (ladybirds, glow-worms, cockchafers, weevils, and all of the beetle tribe).
A division is sometimes made into Mandibulate and Haustellate groups, the oral apparatus of the former being adapted for mastication, the latter for imbibition of liquid food. Both types are, however, sometimes modified, and occasionally combined. Research Entomology
Achalasia is a rare disorder of the oesophagus in which the muscle at the end of the oesophagus does not relax enough for the passage to open properly. Research Achalasia
Endoscopy is the examination of internal parts of the body using special instruments known as endoscopes. The simplest method of instrumental examination is that employed for the analcanal and rectum. A 'speculum' (proctoscope) which is in fact a simple tube with a handle, is introduced through the analcanal and the surgeon examines the rectal wall through the tube. To facilitate the introduction of the instrument, there is a shaped conical stopper which is known as the 'obturator.' This same principle of a shaped introducer is used on many instruments which have an open tubular end. Sigmoidoscopy is the examination of the upper regions of the rectum and the sigmoid or pelvic colon with a longer tubular speculum. Because the folds of mucousmembrane fall against the end of the instrument and obstruct the view, air inflation is used for the introduction of the sigmoidoscope so that the lumen of the bowel is distended. The surgeon inserts the instrument under direct vision, inspecting the wall of the bowel as far as 25 cm. from the anus.
The oesophagoscope is a similar instrument passed down the oesophagus through the mouth, thus enabling the surgeon to inspect the whole length of the gullet. The inside of the stomach is examined by the gastroscope, using air inflation. Through a very small incision in the abdominal wall the surgeon may introduce another viewing instrument, the peritoneoscope, and with this he may inspect the inside of the peritoneal cavity and obtain infonnation to enable him to reach a decision without open operation. In order to separate the coils of intestine from one another and allow the satisfactory inspection of the viscera, the peritoneal cavity is inflated with air through a separate cannula. Endoscopic instruments, except for the simpler forms of proctoscope, carry their own miniature lamps which draw electric current either from a battery or the mains through a transformer to reduce the voltage. The bladder and urethra are inspected with the cytoscope and urethroscope. The urinary tract is distended with water instead of air for the inspection, but air inflation is sometimes used for the lower part of the urethra. Various forms of speculum are used for the vagina and these are usually illuminated by direct light, although some forms carry a lamp of their own. Operations for the removal of tissue for microscopic examination (biopsy) are performed through some of the tubular instruments, and for this purpose there are special long forceps and diathermy electrodes. Examinations carried out with endoscopic instruments may be made with local or general anaesthesia and in the case of the rectum and colon, without anaesthesia. Research Endoscopy
Nifedipine is a calcium-channel blocker, anti-arrhythmic and anti-anginal drug used to prevent angina attacks, treat Reynaud's disease, treat high blood pressure and treat spasm of the oesophagus. Research Nifedipine
The oesophagus is the region of the alimentary canal following the pharynx. The walls of the
oesophagus are muscular and force food along by contractions. The oesophagus is composed of a thick muscle wall which is voluntary (striped) muscle in the upper part, and involuntary (smooth) muscle in the lower part. The oesophagus ends byjoining the cardiac orifice of the stomach a little less than four cm below the diaphragm. It therefore has three parts. The cervical portion in the lower part of the neck lies immediately behind the trachea with lobes of the thyroid on either side. The thoracic portion lies, in the upper part, close to the back of the trachea in front of the vertebral column. In the lower part the oesophagus passes a little to the left and is crossed by the left bronchus, later .lying immediately behind the pericardium until it pierces the diaphragm.
Except during the passage of food, the oesophagus is flattened like a muscle strap but can distend to 25 mm in diameter. With the exception of the pylorus it is the narrowest portion of the alimentarytract and the oesophagus itself has three constrictions where it becomes narrower than in the rest of its course. The first is at the upper end behind the cricoid cartilage; the second is at the level of the bifurcation of the trachea into right and left bronchus; while the third narrow point is where the oesophagus passes through the diaphragm. Unlike the abdominal parts of the alimentarytract, there is no peritoneal coat on the thoracic and cervical
oesophagus. Research Oesophagus
In the human body, the throat is the part of the body extending from the base of the tongue to the trachea (windpipe). The throat contains the organs for the production of sound and affords passage to the stomach and to the lungs.
The beginning of the throat is presented on looking into the mouth. In the middle line above, is the uvula hanging from the soft palate. On either side the soft palate becomes continuous with the two pillars of the fauces, and below, these again are continuous with the root or base of the tongue. Between the pillars of the fauces on either side are the tonsils, which if enlarged can narrow the enterance to the throat to a dangerous extent. Above and behind the soft palate is the nasopharynx into which the posterior ends of the nostrils open.
Projecting upwards in the middle line at the base of the tongue is the epiglottis. From each side of this two folds project backwards and touch one another behind, leaving a triangular interval, which is the enterance to the larynx. Behind the place where these bands join is a narrow gap forming the enterance to the oesophagus.
The vestibule of the larynx contains two fleshy-looking bands, called the false cords, which are highly developed in the lower animals. Deeper in the larynx are two thinner, pearly-white bands which are the true vocal cords, the essential organs of sound. Theye are enclosed in a more or less rigid box of cartilage, the front of which can be seen in the middle line of the neck in a man and is popularly known as the 'Adam's Apple'. Research Throat
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Charadrius
