Patterns of Cleavage Flashcards
it is a pattern of cleavage where blastomeres lie directly on top of each other
Radial
in this type of pattern of cleavage blastomeres lie on the junction between lower blastomers due to coiling of internal organs and determine the placement of opercular opening
Spiral
it is a type of spiral pattern cleavage where it turns in clockwise direction, normal and has right sided opening
dextral
what are the two types of spiral pattern of cleavage
dextral (clockwise), and sinistral
spiral pattern of cleavage, for left and right axis
tunicate
kind of spiral pattern of cleavage which is evident in mammals
rotational
type of sinistral under spiral patterns of cleavage
tunicate and rotational
if the spindle fiber is oriented in this way there will be spiral cleavage
sinistral; rotational
it is a pattern of cleavage where the whole part of the embryo divides
Holoblastic
what are the factors that determines whether an organism divides holoblastic or meroblastic
- Yolk (if there is little or none, it is holoblastic)
- Fish (meroblastic)
- Frog (holoblastic; there are always that are bigger)
- sea urchin (holoblastic, radial)
pattern of cleavage in fish
meroblastic
pattern of cleavage in frog
holoblastic
patterns of cleavage in sea urchin
holoblastic, radial
pattern of cleavage where only those carrying nucleus and cytoplasm will divide
Meroblastic
it is a type of meroblastic cleavage pattern where it distinguishes left and right
bilateral
type of meroblastic cleavage in fish and birds
discoidal
type of yolk distribution where there is superficial cell division which migrates towards the periphery which is most common in insect
centrolecithal
type of meroblastic cleavage pattern in birds
blastodisc, equivalent of blastula
these are the two cavities from the division of the blastoderm into epiblast and hypoblast
subgerminal space and blastocoel
peculiarity under subgerminal space
layers of cells on top of yoke will give rise to future vascular system
why are layers of cells on top of yoke where it will give rise to future vascular system
for nutritive purposes, to reach the yolk
only one part is dividing
it is a type of cleavage evident insects where it migrates towards the periphery and it acts as extension, which then gives rise to cell membranes
Superficial cleavage
it is a type of cleavage where it is defined by the time wherein the blastomeres are already determined as the what types of cells they will be
during the eight cell stage cells are already determined (determined fate)
Mosaic/Determinate Cleavage
type of cleavage where even after a series of divisions when you took the cell and put it in a certain environment it will still regulate
fates are not yet determined and evident in more complex organisms
Indeterminate/Regulative Cleavage
