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A trophozoite (G. trope, nourishment + zoon, animal) is the activated, feeding stage in the life cycle of certain protozoa such as malaria-causing Plasmodium falciparum and those of the Giardia group. [1] The complementary form of the trophozoite state is the thick-walled cyst form. They are often different from the cyst stage, which is a ...
A Giardia trophozoite, drawn by Vilém Lambl and published in 1859 Drawings of a Giardia trophozoite and cyst by Charles E. Simon in 1921. The first likely description of Giardia was in 1681 by Antonie van Leeuwenhoek, who in a letter to Robert Hooke, described "animalcules" resembling Giardia trophozoites in his stool.
About 40 species have been described, but most of them are probably synonyms. [11] Currently, five to six morphologically distinct species are recognised. [12] Giardia duodenalis (=G. intestinalis, =G. lamblia) infect humans and other mammals, G. microti infects voles, G. muris is found in other mammals, G. ardeae and G. psittaci in birds, and G. agilis in amphibians. [4]
It penetrates epithelial cells lining the midgut of mosquitoes to form a thick-walled structure known as an oocyst under the mosquito's outer gut lining. [11] Ookinetes are motile and they move by gliding. A trophozoite (G. trophē, nourishment + zōon, animal) is the activated, intracellular feeding stage in the apicomplexan life cycle. After ...
The small intestine begins at the duodenum and is a tubular structure, usually between 6 and 7 m long. [18] Its mucosal area in an adult human is about 30 m 2 (320 sq ft). [ 19 ] The combination of the circular folds , the villi, and the microvilli increases the absorptive area of the mucosa about 600-fold, making a total area of about 250 m 2 ...
A duodenal biopsy may incidentally detect Giardia organisms, as in this H&E stained sample. [ 33 ] According to the CDC, the detection of antigens on the surface of organisms in stool specimens is the current test of choice for diagnosis of giardiasis and provides increased sensitivity over more common microscopy techniques.
The largest structure of the digestive system is the gastrointestinal tract (GI tract). This starts at the mouth and ends at the anus, covering a distance of about nine metres (30 ft). [1] A major digestive organ is the stomach. Within its mucosa are millions of embedded gastric glands. Their secretions are vital to the functioning of the organ.
They have a simple life cycle. The trophozoite (feeding-dividing form) is approximately 10-20 μm in diameter and feeds primarily on bacteria. It divides by simple binary fission to form two smaller daughter cells. Almost all species form cysts, the stage involved in transmission (the exception is Entamoeba gingivalis). Depending on the species ...