Cestodes Ovum Flashcards
broadly ovoidal, operculate, moderately thick shelled
light golden yellow in color
measure 45 - 70 um
has a small knob at one end
immature when laid with abundant yolk granules
D latum
glistening, opaque white, which has an antero-posterior polarity
an invaginated anterior end but has no scolex and is unsegmented
measures 6 mm in length
Sparganum
spherical, thin shelled, hyaline except for a brick-red tinge
measures 23-40 micra in diameter covering of the mature egg consists of an outermost yolk shell, an innermost embryophoric membrane and an intermediate albuminous layer
contains a hexacanth embryo
D caninum
oval or globular in shape, measuring 30 - 45 in diameter
has 2 distinct membranes:
- outer membrane is thin and colorless
- inner embryophore encloses an
oncosphere with 3 pairs of lancet-shaped hooklets
space between the two membranes is filled with yolk granules and polar filaments originating from polar knobs at either end of the embryopore
polar filaments are 4-8 in number
H nana
sub spherical in shape with yellowish transparent outer membrane
measures 60-79 micra by 72-86 micra
has an inner membrane around the oncosphere which has 2 polar knobs but no polar filament
three pairs of lanceolate hooklets are arranged in a fan shaped pattern
H diminuta
spherical, brown in color with a thick shell
measures 31-43 micra in diameter
contains an oncosphere with 3 pairs of hooklets
T solium
opalescent ellipsoidal body
measures 8 - 10 mm in length and 5 mm in breadth
long axis of the cyst lies parallel with the muscle fiber
consists of a wall with the larval scolex developing from the wall
scolex bears suckers and hooklets
a dense milky white spot is seen on the side where the scolex remains invaginated
contains fluid rich in salt and albuminous material
Cysticercus cellulosae
spherical and brown in color
thin, outer transparent shell, when present, represents the remains of the yolk mass, it causes the eggs to clump together
inner embryophore is brown, thick walled and radially striated
contains an oncosphere with 3 pairs of hooklets
resembles T. solium egg
T saginata
the larval form of the parasite
represents the structure of the scolex of the future adult worm, and remains invaginated within the vesicular body
spherical in shape and has:
external laminated cuticle (ectocyst)
inner germinal layer (endocyst)
Fluid that causes distention of the limiting membrane
brood capsules containing scolices
daughter cysts
walled off from the surrounding tissues by fibrous adventitia
Hydatid cyst
