Embryology (old) Flashcards
there are two poles that are in the yolk they are names
animal pole ( less yolk) and vegatal pole ( more yolk)
What is a blastomere
a single cell following mitotic division
what is a Morula
multiple blastomeres are connected in most mammals its typically between 16-32 blastomeres. ( blastocoel has not formed yet)
Blastocyte or Blastula is
a morula that has changed to have a blastocoel cavity
What is a Trophoblast
A layer of cells surrounding a blastocoel
what is a blastocoel
Internal cavity
types of cleavage/ yolk concentrations
Holoblastic meroblastic and discoidal
holoblastic celavage completes
cell division (regardless of pole)
holoblastic has ______ eggs ( which includes amphioxus and eutherian mammals
microlecithal
holoblastic has ______ eggs ( which includes lampreys amphibians and some fish)
mesolecithal
meroblastic has
macroleathal eggs
Discoidal have extreme
meroblastic
Discoidal have _______ eggs which include hagfish, Osteichthyes reptiles birds and monotremes
macrolecithal
a group of cells that form germinal layers is called a
blastoderm
the three germinal layers are called
ectoderm, mesoderm, and endoderm
hagfish, chondrichthyes and modern bony fish have a _______ membrane
viteline
What is a periblast
a layer of cells surrounding yolk
Monotremes have a _________ ________ and a ________
Macrolecithal discoidal ; Blastoderm
Marsupials have ___________ and _______
no distinct morula stage and protoderm
Eutherian mammals have a ___ ____ ___ and _____-_____
Inner cell mass ; Trophoblast-nourishment
in human gastrulation the formation of _____ ______ occur
germ layers
in human gastrulation ______ starts first
trophoblast cells differentiate into cytotrophoblast and syncytiotrophoblast
in human gastrulation the _______ _____ appears at start
primitive streak
human gastrulation
cells from the superficial layer migrate to deep layer ______ deep cells
displacing
human gastrulation
superficial cells that migrate become
endoderm
human gastrulation
superficial cells that migrate to the middle layer become
mesoderm
human gastrulation
superficial cells that remain there become
ectoderm
in human gastrulation the coelom forms at the end of
neurulation
__________ and __________ can occur simultaneously
Grastrulation and neurulation
Gastrulation is the
Formation of endodermal tube and Gastrocoel- primitive gut cavity surrounded by endoderm
Neurulation is the
- formation of ectodermal
- neural tube- primitive central nervous system
- neurocoel- cavity surrounded by ectoderm
gastrulation is the
rearrangement of cells, and formation of germ layers
Neurulation is the formation of the ______ tube
neural
Neurulation is the formation of
Notochord ( mesoderm) and neural plate (ectoderm)
Primary neurulation is
Neural plate folds to form circular neural tube and is in most chordates
Secondary neurulation
Neural keel
Cavitation results in neurocoel formation and is in lampreys and modern bony fish
Types of movement in gastrulation
Invagination, epiboly, involution, delamination, and ingression
Invagination
Wall of cells fold inward
invagination occurs in
amphioxus
invagination results in ___ layers of cells
2
ectoderm- outer layer
endomesoderm- inner layer