Amoebozoa & Apicomplexa

Question 1

Entamoeba histolytica trophs

Answer 1

Oval or oblong shape
Fine, uniform ring of peripheral chromatin along the nuclear membrane
Small centric endosome (karyosome) in nucleus
Sometimes contains ingested RBCs
Intestinal parasite of humans
Causes amoebiasis, amoebic dysentery, diarrhea, amoebic hepatitis

Question 2

Entamoeba histolytica cysts

Answer 2

Circular
Thin, even peripheral chromatin
Young cysts have one nuclei, then 2, mature have 4
Same centric karyosome
Chromatoidal bars with rounded ends
Glycogen vacuoles may be present in immature cysts, but usually disappear as cysts mature

Question 3

Entamoeba coli trophs

Answer 3

Usually larger than E. histolytica
Nucleus has irregular clumps of peripheral chromatin
Large eccentric karyosome
Cytoplasm is granular with lots of vacuoles, no RBCs, and little distinction b/w endoplasm and ectoplasm
Bacteria in food vacuoles
Commensal
Infects large intestine of humans

Question 4

Entamoeba coli cysts

Answer 4

1-8 nuclei (mature have 8)
Large eccentric karyosome, clumpy peripheral chromatin
Splintery or irregular chromatoidal bars with sharp, pointed ends

Question 5

Endolimax nana trophs

Answer 5

Little or no peripheral chromatin
Large endosome that may be centric or eccentric in position, often irregular outline
Cytoplasm contains food vacuoles with bacteria
Commensal, infects large intestine of humans

Question 6

Endolimax nana cysts

Answer 6

Ovoid, but can be spherical
Little or no peripheral chromatin
1-4 nuclei
Large irregular endosome

Question 7

Iodamoeba butschlii trophs

Answer 7

Large central endosome surrounded by ring of small chromatin granules
Bacteria may be in cytoplasm
Commensal, infects large intestine of humans

Question 8

Iodamoeba butschlii cysts

Answer 8

Irregular in outline
Ring of chromatin granules
Usually only 1 nuclei with large endosome
Large glycogen vacuole prominent

Question 9

Plasmodium malariae

Answer 9

Blood parasites of humans
Causes: quartan malaria
Troph (ring form): large fleshy rings with a single chromatin dot. Can be distorted and look like bands
Schizont: approx 8 merozoites in a single ring. Pigment present as a central black mass
Gametocytes are round, contain a lot of black, chromatin is compact in females and diffuse in males

Question 10

Plasmodium ovale

Answer 10

Causes: ovale tertian malaria in blood of humans
Troph: rings remain compact as they develop. Late trophs are round and consolidated
Schizonts: smaller than RBC and contains 8 merozoites, RBC is enlarged, stippled, and oval
Gametocytes: round, same effect on RBCs, contains pigment which looks like concentric rods, mostly at the periphery

Question 11

Plasmodium falciparum

Answer 11

Causes: tertian malaria, subtertian malaria in blood of humans
Troph: chromatin found as single bead, double beads and curved rods occur too
Schizont: contains about 16 merozoites
Gametocytes: crescentic shape, RBC distorted

Question 12

3 stages of Plasmodium life cycle

Answer 12

1. Exo-erythrocytic
2. Erythrocytic
3. Sporogonic