Intestinal and Luminal Protozoa

Vocabulary flashcards covering the classification, morphology, habitats, and clinical conditions associated with intestinal and luminal protozoa.

Protozoa

A microscopic unicellular organism which is morphologically and functionally complete, meaning a single cell can perform all functions like reproduction, respiration, digestion, and excretion.

Ectoplasm

The outer division of the cytoplasm that serves protective, locomotive (via pseudopodia, cilia, and flagella), and sensory functions.

Endoplasm

The inner division of the cytoplasm that serves nutritive and reproductive functions.

Sarcodina

A sub-phylum of protozoa that move by pseudopodia; an example is the genus Entamoeba.

Mastigophora

A sub-phylum of protozoa that move by flagella; examples include Giardia and Trichomonas.

Apicomplexa

A sub-phylum of protozoa with an apical complex, no locomotor apparatus, and sexual reproduction; examples include Plasmodium and Toxoplasma.

Ciliophora

A sub-phylum of protozoa that move by cilia; an example is Balantidium coli.

Entamoeba histolytica Trophozoite

The ameboid-shaped, motile form of E. histolytica, measuring $15-30\,\mu$ in diameter, found in the large intestine mucosa.

Entamoeba histolytica Cyst

The spherical, non-motile infective form of E. histolytica, measuring $12-15\,\mu$ in diameter, containing $1$ to $4$ nuclei and chromatoid bodies.

Excystation

The process where cysts transform into trophozoites, occurring only upon the entry of the cyst into the human alimentary canal.

Encystation

The process where trophozoites transform into cysts in the lumen of the large intestine.

Quadrinucleate cyst

The mature, infective form of E. histolytica and the only stage capable of surviving outside the body to transmit infection.

Amoeboma

A granulomatous, tumor-like growth produced as a clinical condition of amoebiasis.

Anchovy sauce pus

A thick, chocolate brown mixture of sloughed liver tissue and blood found in an amoebic liver abscess.

Steatorrhoea

The excretion of abnormal quantities of fat with the feces due to reduced fat absorption by the intestine, often associated with Giardiasis.

Giardia lamblia Trophozoite

A tennis racket-shaped organism with a convex dorsal surface and a concave ventral surface with a sucking disc; exhibits "falling leaf motility."

Balantidium coli

The largest protozoal parasite of humans; it lives in the large intestine and moves by cilia.

Trichomonas vaginalis

A sexually transmitted protozoan that exists only in the trophozoite form and has no cyst form.

Naegleria fowleri

A free-living amoeba found in lakes that causes Primary Amoebic Meningoencephalitis (PAM) by entering through the nasal passage.

Acanthamoeba

A free-living amoeba that causes Granulomatous Amoebic Meningoencephalitis (GAE) and Keratitis, particularly in contact lens wearers.