ExerciseⅠ Observation of Medical Protozoa
Experimental objective:
1.Master the use and maintenance of microscope.（Low magnification to find the Microscopic view，low power—High magnification 10×lens 40×lens）
You must be patient to find，see and observe.
2.Master the morphological features of different genius of medical Protozoa include trophozoite and cyst of E.histolytica，the LD.Body（Amastigote form）and Promastigote form of Leishmania，trophozoite of Trichomonas vaginalis，and each development period of the plasmodium.
Experimental Principles:
To observe the morphological features of different genius of medical Protozoa by the optical microscope.
Laboratory equipment:
1.Optical microscope.
2.Human parasitology teaching specimen.
Experiment methods and contents
Methods find the parasites at high magnification，and then observe them with oil microscope（if necessary）.
1.Trophozoite It is irregular in shape，and varies in size from 10-60μm in diameter，average being 20μm.Cytoplasm：Outer ectoplasm is clear，transparent，and refractile.Inner endoplasm is finely granular.The finely granular endoplasm contains nucleus，food vacuoles，erythrocytes，bacteria，and often ingested red blood cells when it isolated from dysenteric individuals.Nucleus is spherical 4-7μm in size and contains central karyosome.
2.Cyst：The cyst is spherical in shape about 10-20μm in size.In Precystic Stage，It contains a large glycogen vacuole and two chromatoid bars，also called（chromatoid bodies），with only a single nucleus.In mature cyst，Glycogen mass and chromatoid bodies disappear，Nuclueus undergoes 2 successive mitotic divisions to form 2 and then 4 nuclei（Figure 1，2）.
Figure 1 histolytica
（Contents NO.16，NO.17，NO.18）
Figure 2 E·histolytica
The parasites exists in 2 forms.Amastigote form-in humans and other mammals Promastigote form-in the sandfly and in artificial culture.（Figure 3）
1.Amastigote（LD.body）：it is ovoid or rounded shape，and size is about 2 to 4μm.The large oval nucleus is stained red.Besides the nucleus is the red or purple-stained kinetoplast.Amastigote inhabit in mononuclear phagocytes of humans and other mammals.Macrophage ruptures releasing amastigotes.
Figure 3 Leishmania donovani
（Corresponding book color chart NO.19，20，21）
2.Promastigote The promastigotes are spindle-shaped，10-20μm in length and 1.5-4μm in breadth.A single nuceus is situated at the center：the kinetoplast lies near the anterior end.The flagellum is single，delicate.Giemsa or Leishman-stained films show pale blue cytoplasm with a pink nucleus and bright red kinetoplast.（Figure 4）
(https://www.daowen.com)
Figure 4 Trichomonas vaginalis
（Corresponding book color chart NO.22，23）
The parasite only exists in 1 form：
Trophozoite：it is pear-shaped or ovoid and measures 10-30μm in length and 5-10μm in breadth with a short undulating membrane reaching up to the middle of the body.It has 4 anterior flagella.
A prominent axostyle runs throughout the length of the body and projects posteriorly like a tail.The cytoplasm shows prominent granules，which are most numerous alongside the axostyle and costa.（Figure 5）
The parasites exists in 3 forms：
1.Trophozoite this is the stage of growth and development of Plasmodium in red blood cells.
Figure 5 Plasmodium vivax
（Corresponding book color chart NO.26.27.28.29）
2.Early trophozoite-ring form：In early trophozoites，the nuclei are small，cytoplasm less，vacuoles in the middle，the parasites are annular，called the ring form Corresponding book color chart NO.25.
3.Advanced trophozoite：The parasites grew up，the nuclei enlarged，cytoplasm increased，the malaria pigment began to appear and dispersive.Erythrocytes can become large，deformed，pale，often with obvious Sch-uffner's dots.
1）Schizont the nucleus division；merozoite.Corresponding book color chart NO.24.
Immature schizont
The cell bodies are large，transform irregularly shape to round like shape；the nucleus begins to divide，about 2-4，and the pigment begins to concentrate.
Mature schizont
Nuclear divide 12-24；the division cytoplasm is around each nucleus，forming 12-24 merozoites（merozoites），pigment is thick，concentrated in blocks.
2）Gametocyte
Spherical，abundant and dispersed pigment granules.
3）Male Gametocyte：Spherical，larger than Normal red blood cell，cytoplasm is stained blue，with a large and intermediate nuclei，light red and.the malaria pigment is dispersive.
4）Female Gametocyte：Spherical，red blood cell is swelling，cytoplasm is stained blue，nuclei is smaller and deep red the malaria pigment is dispersive.
Laboratory report
To draw the morphology of parasites（indicating its morphological structure）.（Figure 6）
Figure 6 Plasmodium