Characteristics of protozoa
- lack a cell wall
- typically possess a means of locomotion during at least one stage of life cycle
- heterotrophic
- primarily reproduce asexually
- unicellular
- eukaryotic
Sarcomastigophora
- sarcodina (pseudopodia)
- mastigophora (flagella)
Sarcodina
PSEUDOPODIA
- Free-living: Amoeba
- Parasite: Entamoeba histolytica
Mastigophora
FLAGELLA
- Free-living: Euglena
- Parasite: Giardia lambia, Trypanosoma
Ciliophora
CILIA
- Parasite: Balantidium coli
Apicomplexa
NO LOCOMOTION
- parasite: Plasmodium, Toxoplasma
Morphological forms
protozoa enters the body via ingestion
- cyst
- trophozoite
Cyst
- infective form that survives acidic stomach conditions
- EXCYSTATION upon entering intestines, developing into trophozoites
Trophozoite
- Feeding and reproducing stage that lives within the host
- Trophozoites undergo ENCYSTMENT before leaving the host in feces
Amoebae (Sarcodina) characteristics
- protozoa with no truly defined shape
- move and acquire food through use of pseudopodia
- found in water sources throughout the world
- few cause disease
Entamoeba histolytica
SARCODINA (pseudopodia)
2. fecal-oral contamination by cysts
3. Cyst - ring and dot nuclei and chromatid body
Trophozoite - ingested RBCs
- cyst can handle the acidic env. of the stomach, upon entering the (less acidic) env. In the intestines, cysts under
Amoebiasis (amoebic dysentery)
cause mucous / bloody diarrhea
Flagellate (Mastigophora) characteristics
- endemic in Central and South America
-