One of the major sections of protozoology is devoted to single-celled microorganisms, and considers human parasitic protozoa as one of the forms of existence of organisms.
From the point of view of medical parasitology, which studies the ways and causes of diseases, their symptoms (one of the individual signs, the frequent manifestation of a disease, a pathological condition or the disturbance of any life process)and treatment methods, protozoa occupy a leading position. They are followed by helminthology aimed at getting rid of helminthic invasions, and arachnoentomology - systemic methods in medicine that get rid of arthropod parasites.
The animal world is abundantly represented by single-celled microorganisms that live everywhere - from the seabed to the upper atmosphere. All of them belong to the subkingdom of protozoa, or protozoa, which has more than 15, 000 representatives of single-celled creatures.
Among the free-living unicellular species, there are parasitic forms classified in a separate category that cause a number of serious diseases - protozoonoses, and their corresponding symptoms, says a senior researcher of the medical center.
The simplest have several dozen species of parasites that live at the expense of the human body. Amoebas are localized in the intestinal tract, causing symptoms (one of the individual signs, a frequent manifestation of any disease, pathological condition or disturbance of any vital process) amoebiasis. If it is a dysenteric form of the parasite, then it provokes the development of dysentery, as well as Giardia, which causes giardiasis. The soft tissues of internal organs can be affected by Plasmodium and Toxoplasma, causing unpleasant symptoms of toxoplasmosis, requiring specific treatment.
The structure of unicellular organisms
The body of a microorganism is just a single cell, which includes the nucleus and the cytoplasm. It is lined with a cytoplasmic membrane containing organelles - the endoplasmic reticulum, ribosomes, Golgi apparatus and mitochondria. All provide the processes of nutrition, respiration, movement, metabolic processes and excretion.
The body of a single-celled organism has both a constant and a variable shape (it can mean: the shape of an object - the relative position of the boundaries (contours) of the object, the object, as well as the relative positionpoints of the line). Some representatives of protozoa have symmetrical bodies, and some have an asymmetrical body shape. Representatives of flagellated parasites resemble a spindle in appearance. The rhizomes of the shape (it can mean: the shape of the object - the mutual arrangement of the boundaries (contours) of the object, the object, as well as the relative position of the points of the line) have nobody at all.
Cells divide by simple mitosis, but in some species, in the process of reproduction, fertilization occurs sexually with the formation of a zygote. Almost all the simplest organisms are heterotrophs, but among them there are autotrophic species of single-celled parasites.
Motor function is produced in the amoeba due to pseudopodia, it seems to overflow, throwing pseudopodia. Ciliates move due to the often shortened cilia that cover their body abundantly. The movement of the flagella is due to the movement of the flagella themselves, hence their unpretentious name.
The feeding process of amoebas is also associated with pseudopodia, wrapping food with pseudopodia and absorbing it. Some forms feed using a cell mouth. Digestion is carried out by phagocytosis - an internal process, as well as pinocytosis - the process of external absorption of food by the entire surface of the body.
The main feature of protozoa during the onset of adverse conditions is the formation of cysts. Particularly characteristic is the process of cyst formation for dysenteric amoeba. It allows the parasite (one of the coexisting types of organisms) to maintain its vital capacities for a prolonged period of anabiosis.
The main classes of protozoan parasites (one of the types of coexistence of organisms)
Representatives of single-celled organisms (a living body that has a set of properties that distinguish it from inanimate matter, including metabolism, self-maintenance of its structure and organization, and the ability to reproduce them) are attributed tofour main classes:
Sarcode-class
The class of sarcodes includes one of the most common and dangerous single-celled parasites for humans - the dysenteric amoeba, which exists in 4 different forms:
- The vegetative form is the largest, reaching 20 microns. The discovery of a parasite in freshly passed stool confirms a disappointing diagnosis, the symptoms of which speak for themselves.
- Tissue, or pathogenic form of the parasite, leading a parasitic life in the lumen of the colon. The defeat of the intestinal mucosa amoeba occurs in a specific way.
- Translucent, or the main form of the dysenteric amoeba which lives in the lumen of the large intestine. This form causes characteristic symptoms of this disease. They are observed in the process of remission of the patient or at the stage of carriage. In stools of any kind, the presence of the parasite has not been established.
- The pre-cystic form of the amoeba is fixed in the semi-formed feces of a human carrier of the disease, or in a patient in the healing phase.
The main symptoms of diseases caused by amoebic forms are manifested by permanent sharp pains in the lower abdomen, frequent bowel movements of brown stools due to blood content and streaks of mucus. Body temperature remains within normal limits. A similar picture can periodically accompany the patient for several years and lead to exhaustion, as well as the development of anemia. With complications caused by the tissue form of the amoeba, and without proper treatment, the patient can die.
Class flagellates, or flagellates
A characteristic feature is the equipment of the body with the simplest organs of movement - one or several flagella. Widespread pathogenic microorganisms of this class are:
- trypanosomes, responsible for African sleeping sickness;
- leshmania causing urban or rural leishmaniasis;
- trichomonas - causative agents of trichomoniasis, mainly of the vaginal form;
- Giardia is a protozoan that causes giardiasis.
class of sporozoa
Typical representatives of sporozoa are malarial plasmodium, which causes symptoms of valaria and toxoplasma, causing noxoplasmosis.
ciliated class
For microorganisms of this class, a feature is the presence of cilia throughout the body of the microorganism. They perform a motor function, due to which ciliates have the ability to move quickly. The representative of the class is balantidia - the largest human parasite from the protozoa family. Causes severe and severe balantidiasis on the background of the ulcerative process. The disease progresses in an acute subclinical form and can be fatal.