ENTAMOEBA HISTOLYTICA

The are different phases in the life cycle of   Entamoeba Histolytica . The morphology of three phases should be - 

1.        Trophozoite  or Vegetative or Growing or Feeding stage .

2.       Pre-cystic stage .

3.       Cystic stage .

Morphology of Trophozite form –

(a)    Shape – For slow glinding movement , shape is not fixed .

(b)   Size – About 18 to 40 µ .

(c)    Cytoplasm –

i)                    Ectoplasm – It is clear and translucent . The ectoplasm throws pseudopodia for locomotion and ingestion of food .

ii)                   Endoplasm – It is granular , R.B.C , W.B.C and tissue debris may be found inside the endoplasm . This portion digests food and got the power of secretion and excretion .

(d)   Nucleus –

i)                    Spherical in shape

ii)                   Size 4 to 6 µ

iii)                 Presence of karyosome in central position and it is surrounded by clear halo .

iv)                 Presence of nuclear membrane which is delicate and lined by a single layer of chromatin granules .

v)                  Presence of linin network in between nuclear membrane and Karyosome .

Morphology of Pre-cystic form –

i)                    It is smaller than trophozite form .

ii)                   Size is 10 to 20 µ .

iii)                 It is rounded or slightly ovoid in shape with a blunt pseudopodium  .

iv)                 The endoplasm does not contain R.B.C or other ingested food particle .

v)                  Nucles

(a)    Spherical in shape

(b)   Size 4 to 6 µ

(c)    Presence of karyosome in central position and it is surrounded by clear halo .

(d)   Presence of nuclear membrane which is delicate and lined by a single layer of chromatin granules .

(e)   Presence of linin network in between nuclear membrane and Karyosome .

Morphology of Cystic form –

(a)    Shape is rounded

(b)   Size is 6 to 15 µ

(c)    It is covered with highly refractile membrane called the cyst wall .

(d)   Nucleus –

i)                    Spherical in shape

ii)                   Size is 4 to 6 µ

iii)                 After maturation of cyst , the single nucleus divided by binary fission and develops into quadrinucleate bodies . The size of the nucleus becomes 2 µ in diameter

(e)   The cytoplasm is clear and hyaline . But in the early stage of development , there are presence of –

i)                    Chromatid or chromidial Bars which can be seen in normal saline preparation as refractile bars and in iron-haematoxylin preparation as black bars . It ius not stained with iodine .

ii)                   Glycogen mass – This stains brown after iodine preparation .