Mosquito is a term applied to any fly of the family Culicidae. The female mosquito has needle-like mouth-parts and sucks blood before laying eggs. Males feed on plant juices. Some mosquitoes carry diseases such as malaria. Human odour in general is attractive to mosquitoes, also lactic acid in sweat and heat at close range. Peoples' varying reactions to mosquito bites depend on the general allergic reaction and not on the degree of the bite; the allergic reaction is caused by the saliva injected from the mosquito's salivary glands to prevent coagulation of the host's blood. Natural mosquito repellents include lavender oil, citronella (from lemongrass), thyme, and eucalyptus oils.
Mosquitoes are remarkable for their quick genetic development, new species develop in around 100 years, as was discovered when mosquitoes became trapped in the London Underground system when it was built, and in 1998 were discovered to have become distinct species developing to feed first on rats and then on humans rather than their usual sheep hosts. Research Mosquito
The water shrew (Neomys fodiens) has a fringe of bristly silvery-white hairs on the hind feet, a double row of hairs act as a keel on the tail for swimming. It is very dark in colour above, but the underside varies from white to grey. Sometimes it occurs as a very dark morph. The ear openings can be closed, and there are four uni-cuspid teeth. The water shrew moults in spring and autumn. Water shrews live generally close to water, that is mostly on the banks of swiftly flowing streams and weirs, and are especially abundant in watercress beds, and are also occasionally found near ditches, ponds and the seashore. They may be found as a temporary visitor in woodlands and grasslands. The nest is a ball of vegetation in an extensive burrow system, excavated by the shrew, using its front feet and nose. The entrance may be above or below water level, and the shrew may re-use mole tunnels. Water shrews eat mostly aquatic crustaceans and insect larvae, and terrestrial beetles, molluscs, worms, occasionally small fish, amphibia and mammals, which are caught both under water and on land. The water shrew produces a venom in its saliva which is effective against small mammals, and is a fast, adept swimmer, a good diver and floats like a cork due to the air caught in its very water-repellent coat. The breeding season is from April to September, with two litters a year possible, each of about six young, but maybe as few as three or as many as fifteen. The animals becoming sexually mature in their second year. Research Water Shrew
Atrophy is a wasting of the flesh due to some interference with the nutritive processes. It may arise from a variety of causes, such as permanent, oppressive, and exhausting passions, organic disease, a want of proper food or of pure air, suppurations in important organs, copious evacuations of blood, saliva, semen, etc, and it is also sometimes produced by poisons, for example arsenic, mercury, lead, in miners, painters, gilders, etc. In old age the whole frame except the heart undergoes atrophic change, and it is of frequent occurrence in infancy as a consequence of improper, unwholesome food, exposure to cold, damp, or impure air, etc. Single organs or parts of the body may be affected irrespective of the general state of nutrition; thus local atrophy may be superinduced by palsies, the pressure of tumours upon the nerves of the limbs, or by artificial pressure, as in the feet of Chinese ladies. Research Atrophy
The autonomic nervous system is responsible for the self-controlling aspects of the body's nervous network, and is under the control of the cerebral cortex, the hypothalmus, and the medulla oblongata. Working in tandem with the central nervous system, the autonomic nervous system features two subsystems which regulate body functions such as involuntary smooth muscle movement and heart rate. These two subsystems are called the sympathetic and parasympathetic nervous system, and their functions operate in opposition to one another, delicately balancing the bodily functions which they control. The sympathetic nervous causes fight or flight responses in moments of stress or stimulus, such as increased heart rate, saliva flow, and perspiration. The parasympathetic system counterbalances these effects by slowing the heart rate, dilating blood vessels, and relaxing involuntary smooth muscle fibres. Viewed individually, the sympathetic nervous system, also referred to as the thoracolumbar system, features a series of nerves which branch out of the spinal cord between the first thoracic vertebra and the second lumbar vertebra. These nerve fibres join into a long trunk of fibres, called the sympathetic trunk, on each side of the spinal cord. Along the sympathetic trunk are enlarged clusters of nerve fibres, called ganglia.
From these ganglia, a number of nerve fibres extend throughout the body's tissues. Many of these nerves create additional ganglia, such as the celiac ganglia and the mesenteric ganglia. The sympathetic nerves are responsible for contracting involuntary smooth muscle fibres, viscera, and blood vessels, speeding up the heart rate, and dilating the bronchial tubes in moments of stress. The parasympathetic nervous system, also referred to as the craniosacral system, features ganglia in the midbrain, in the medulla oblongata, and in the sacral region. The first two, the cranial ganglia of the parasympathetic system, give pass impulses to the facial, oculomotor, glossopharyngeal, and vagus nerves. The sacral group of parasympathetic nerves originate at the second, third, and fourth vertebrae and extend nerves to the bladder, the distalcolon, the rectum, and the genitals. The nerves of the parasympathetic nervous system are responsible for conserving and restoring energy in the body following a sympathetic response to stress. Research Autonomic Nervous System
Bell's paralysis or Bell's Palsy (paralysis of the seventh cranial nerve or 'facial nerve') occurs in both sexes equally and at all ages, though it is commonest in early adult life. It comes on rapidly, generally after exposure to wet or cold, or to draughts on the side of the face. An exactly similar type of facial paralysis may occur in cases of acuteinflammation of the middle ear, or after operations on the mastoid. The onset is usually sudden, and the paralysis is generally complete from the first. If it is incomplete, the lower part of the face is more affected than the upper. The first symptom is that the patient feels one side of the face to be stiff when he attempts to move it. The paralysed side of the face shows a striking contrast with the normal side. It is smooth and free from wrinkles, and devoid of any form of expression, so that the patient cannot laugh or weep or frown or express any feeling or emotion, while the features of the normal side are in fullplay. The eye cannot be closed because of the drooping of the lower eyelid, and the mouth cannot be moved on the affected side so as to expose the teeth. Speaking becomes difficult, and fluids may escape from the mouth on drinking, and saliva dribbles away. The duration of the paralysis varies within wide limits. Quite slight cases may recover in ten to fourteen days. Others remain unaltered for many weeks or months, but recovery always occurs finally, and as a rule within two years. The recovery always appears first in the upper part of the face. In cases associated with some underlying disease of the brain or bones of the ear, recovery may be uncertain. Research Bell's Paralysis
The corniculate cartilages rest on the tops of each of the arytenoid cartilages. During swallowing, the epiglottis bends down to meet the corniculate cartilages, sealing off the airway to prevent food or saliva from entering the airway. Research Corniculate Cartilages
Cystic fibrosis is a hereditary disorder of the exocrine glands. The disorder affects the mucus-producing glands in the pancreas, lungs, and intestines and is marked by production of very thick mucus, excess sweating (with accompanied loss of electrolytes), more concentrated saliva, and overactivity of the part of the nervous system that controls automatic actions. It is the most common life-threatening genetic disease among anglos, affecting roughly one in 2000 births.
Cystic fibrosis is caused by a defective recessive gene. A person must inherit the defective gene from each parent before any abnormality is apparent. If a person inherits the gene from only one parent, they are a carrier and have no symptoms. Research Cystic Fibrosis
The digestive system is responsible for processing food, breaking it down into usable proteins, carbohydrates, minerals, fats, and other substances, and introducing these into the bloodstream so that they can be used by the body. The digestive, or alimentary, tract begins at the mouth, where the teeth and tongue begin the breakdown of food, aided by saliva secreted by the salivary glands. The chewed food, combined with saliva, is swallowed, carrying it in peristaltic waves down the esophagus to the stomach. In the stomach, the food combines with hydrochloric acid which further assists in breaking it down. When the food is thoroughly digested, the fluid remaining, called chyme, is passed through the pylorus sphincter to the small intestine and large intestines. Within the long, convoluted intestinal canals, the nutrients are absorbed from the chyme into the bloodstream, leaving the unusable residue. This residue passes through the colon (where most of the water is absorbed into the bloodstream) and into the rectum where it is stored
prior to excretion. This solid waste, called faeces, is compacted together and, upon excretion, passes through the analcanal and the anus. Along the way through the digestive tract, the pancreas, spleen, liver, and gall bladder secrete enzymes which aid in the digestive process. Research Digestive System
Mononucleosis is an acute viral infectious disease characterised by fatigue, fever, pharyngitis, and lymphadenopathy. Mononucleosis is caused by the Epstein-Barr virus (EBV) and transmitted by way of prolonged contact with infected saliva or through a blood transfusion. Research Mononucleosis
The mouth is a versatile area of the human anatomy, responsible for articulation in speech, and tasting, chewing, and swallowing food. The mouth cavity is located just below the nasal cavity and is formed by the palatine bones and the palatine processes of the maxilla on top and by the mandible on bottom. At the opening of the mouth cavity are the lips - muscular structures which are covered with thin, membranous skin. The lips occlude the mouth opening during chewing to keep food and liquid within, help manipulate food during chewing, facilitate articulation in speech, and even give a friendly kiss. Within the mouth cavity, the teeth extend down from their maxillary sockets and up from their mandibular sockets to form the dental arcade. The muscles and skin of the cheeks cover the outer sides of the mouth cavity, while the muscular structures of the tongue and sublingual mucosal lining and muscles. When food is brought into the mouth the salivary glands produce saliva. The saliva lubricates the mouth and moistens the food. The inner
surface of the lips, the tongue, and the cheeks manipulate the food so that it is brought between the teeth as the teethclamp down on the food. In a combined action of these motions, with a semi-circular, grinding motion of the teeth, the food is chewed into a paste with the saliva. Enzymes within the saliva begin to break down the food and the tongue moves a portion of this food paste to the back of the
mouth cavity by pressing it up and back along the hard palate. The soft palate, meanwhile, raises to seal off the nasal cavity. The ball of food paste, called a bolus, is passed into the pharynx. The epiglottis lowers to cover the airway so that the food does not enter the larynx. From the pharynx, wave- like contractions, called peristaltic waves, push the bolus down into and through the esophagus and into the stomach, where it is further digested. Research Mouth
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Mosquito
