Acarids

An acarid is that alive being that live and you are nurtured to another alive being's expenses without contributing any benefit to this I finish. This alive other being, receives the hospedador (sometimes, in confused way, guest) name to expenses from which the acarid is nurtured, being able to take place in some cases damage or injuries.

Definition
In a precise definition, we can summarize that you are metabolically a relationship simbiótica anisoespecífica (among different species) in which the acarid is dependent of your hospedador and you are not beneficial for this. Nevertheless, from an ecologic point of view, the definition of the term can be expanded considerably.

Although parasitism usually involves a relationship trófica, the acarid he/she can also obtain other benefits of your hospedador like protection in front of predators or competitors. Also, they can benefit of parental cares. The reproductive acarids, as some African fish winch of the family synodontidae, make that other fish ciclidos that habitually incubate your eggs in the mouth, also protect the petty fish winch next to your own breedings. These fish, although they don't feed the breedings of the sinodontidos, they protect them and they defend in front of other fish.

Also, it can be said that a hospedador doesn't always nurture to the copy that the parásita, it can also nurture your eggs or breedings. This way, the most important relationship cannot be trófica, although these cases are enough isolated.

Lastly, you are important to say that the acarids usually cause always some nuisance value to your hospedador in general ledger or pettier grade, although you are sometimes impossible to discern the parasitism of the comensalismo and they don't lack examples of parásitismos that can produce to have some positive effect on the hospedador in spite of being pathogen clear agents. You are believed that in this relationship it can evolve, throughout many generations of acarids and hospedadores, toward a mutually beneficial (mutualismo) symbiosis.

Classification
Microparasitos and Macroparasitos Exist. The first are petty and extremely numerous. They multiply inside the guest and in general they make it inside the guest's cells, therefore they are related with the metabolism and they cause reactions on the part of the antibodies. Macroparasitos grows, but they don't multiply inside the guest. They produce infectious phases that leave outside of the guest, to affect others. They live inside the body or in the cavities of the affected one for the acarids and in general, it can be considered the I number of existing macroparasitos in the affected organism. The parasitism involves a relationship trofica with your guest (obtaining of nutritious) but it can also involve other relationships as you are it that of protection on the part of this I finish.

Types of acarids
Many types of acarids exist. Among them they are:

* The viruses
* The bacteria
* The mushrooms
* The plants
* The protozoa
* The helminths
* The arthropods
* The algae

Attending the place occupied in the body of the hospedador, the acarids can be classified in:

* ectoacarids: They live in contact with the exterior of your hospedador (for example the flea)
* endoacarids: They live inside the body of your hospedador (for example a taenia or a trichina)
* mesoacarids: They possess a part of your body looking toward the exterior and another anchored deeply in the tissues of your hospedador. In some extreme cases of mesoacarids of fish (copepods pennellidae), they can have the head inserted in the heart of your hospedador and to extend for the arteries until the gills, or to perforate the visceral cavity.

Parasitology
The science that he study the acarids is the parasitología, as well as the biologic interaction between two species, acarid and hospedador, you are named parasitism. Since most of the microorganisms that produce infections are studied by the microbiology, the parasitología takes charge of studying exclusively to the acarids eukaryotes except the mushrooms. That is to say, so much the one-celled eukaryotes of the polifilético group Protozoa, as the pluricelulares (metazoos) that include to platelmintos, nematodes, arthropods, etc.

In occasions, you are díficil to differentiate the phenomenon of the parasitism of the comensalismo, the symbiosis, the foresis, or the pillaging, since the distinctions among these they vary from an author to another.

One of the features common of the parasitism is that you bear an exchange of substances that they cause in the hospedador an immunologic answer.

An inmunoevasión petition for the acarid is the one of forming antigens that resemble those of the guest (mimicry). Other, you are the one of sticking antigens from the hospedador to the extraneous surface of the body of the acarid (camouflage antigénico); Other, you are the petition of going constantly varying and quickly your surface (antigens) proteins so that the antibodies taken place by the guest cannot recognize it; the result is that the invaded hospedador doesn't recognize to the acarid like invasive or the answer that this takes place you are not completely actual.

Another feature of the parasitism is that although the acarid should adapt to the answer inmunitaria and, in general, to the parasitic life, the hospedador also debit side to make it. This is because the population parásita exercises a selective pressure in this, so guest and hospedador coevolucionan parallelly as a consequence of the parasitism. This explains, for example that the gene of the falciform anaemia is very frequent in endemic fields of malaria.

Almost all the important groups of animals possess some species parásitas. Some quite unexpected ones. For example besides the good known groups of acarids (monogéneos, digéneos, cestodes, nematodes, hirudíneos, copepods) among the acarids some species of barnacles can be included, clams, turbelarios, hidrozoos, birds like the cuckoo... and even some sharks.

Retinal Detachment

The retina is the nervous membrane of the eye and the most important. Their intimate structure is not exactly same in its fullest extent. A petty part exists, in what we could name axis central, called stain or yellow blemish that it allows the perfect vision of the objects for its fine composition. Their alteration well for accident or for illness, it determines the visual central forfeiture.

Their lawsuits are numerous, but maybe the most frequent have a vascular origin, be general or local, that is to say reside in the same vessels of the retina or not. It can exist the occlusion of the central artery or a thrombosis of the vein, general ledger haemorrhages or pettier importance, phlebitis, alterations originated by the diabetes, the hypertension, the arteriosclerosis, etc. many times the sick person experiences a visual forfeiture, in a sudden or gradual way, according to the affection that it is. It owes recomendársele that still not being pains, be made recognize urgently for the expert.

The retina can also suffer degenerative, parasitic illnesses, tumors, etc.; that they usually carry always importance.

As it is that the retinal detachment is the most frequent affection and it is usually in the mind of many people, it is considered opportune to extend in the relationship of its lawsuits, symptoms and treatment. A good number of cases can cures with surgical medical treatment and what is more important, to be prevented by means of periodic visits to the expert. The treatments are usually effective and with a good prevention many times the feared abruption doesn't arrive.

Condition such as inflammatory alterations of the ciliary body, processes senile involutivos or degenerative, some vitreous mood disturbances, cranial traumatisms or violent efforts, certain coroides tumors, some possible acarid like the cisticerco and, certainly, the hereditary predisposition, they are lawsuits common of the retinal detachment, as he/she comes off of the test of all the oculists. The most frequent lawsuit that originates the retinal detachment resides in the myopia, visual quite communio bug. Of there the importance that all myopic fellow goes to the specialist physician regularly, not only as soon as it concerns to his optical correction that should be always for that, but also to prevent the possible retinal detachment appearance. The myopia like refractive bug is strange, the so much biggest percent constitutes it the nearsighted illness or myopia axil. All myopic person, although it already takes the appropriate eyeglasses and believe to be well, he/she should go to the oculist at least once a year. Many abruptions and other visual serious dysfunctions would be avoided if you follows this standard and not the pernicious and frequent custom of going to the optics store without the previous visit to the specialist physician.

The sick person at the beginning of the retinal detachment, notes that he lacks a part of its visual field, or you see the deformed objects and it appraises in general kind of a velum or of curtain for before the space that is about looking with one of its eyes. This sensation, days before he/she can go preceded of fotopsias, that is to say, as of some luminous gleams more or less volatile. With the night rest the symptom sometimes disappears, but he/she repeats and it is accentuated as they lapse the hours of the day. The fellow doesn't sometimes perceive these symptoms, mainly if the eye with abruption already had worse vision or knowingly he/she went defectively corrected.
Although in general a retinal detachment doesn't require an operation of urgency, it is convenient that the patient is visited soon. The oculist should make a careful exploration of the bottom of the eye, and overdraft the abruption, although it is of little extension, it will overwork the exploration in the search of some possible retina fissure. It is not always in the first exploration, for what is advisable some days of absolute rest in bed with binocular bandage to discover the fissures before making the intervention, only mean of obtaining the cure of the illness.

The more old it is the abruption minors possibilities he/she offers of a total cure: because although in the surgical aspect the reaplicación of the retina can be procured in its place, the grade of visual recovered capacity is affected by the lapsed time. It is explained to it because, to the being the retina such a delicate membrane, and when being deviant of their free position, it is affected in their nutrition, with the degenerative consequential alterations, accented point as much as general ledger has been the time in that the retina has suffered this deviation.