Unit 3 Flashcards
first known study of comparative anatomy was undertaken by _________
aristotle
some animals are born from eggs
oviparity
some live by birth
viviparity
some by producing an egg that hatches inside the body
ovoviviparity
two major cell division patterns by which embryos are formed
holoblastic and meroblastic pattern of cleavage
he concluded that all animals, even mammals, originate from eggs.
William Harvey
Ex ovo omnia means ___________
all from the egg
he published the first microscopic account of chick development
Marcello Malphigi
the egg or sperm contains an embryo
preformationism
a preformed miniature infant or ___________ that simply becomes larger during development
homunculus
a period of rapid cell division without growth
cleavage
cleavage partitions the cytoplasm of one large cell into many smaller cells called ____________
blastomeres
this is a ball of cells with a fluid-filled cavity
blastula
this is a fluid-filled cavity in blastula
blastocoel
the eggs and zygotes of many animals except _________ have a definite polarity
mammals
it is defined by the distribution of yolk with the vegetal pole having the most yolk and the animal pole having the least
polarity
the distribution of yolk with the most yolk
vegetal pole
the distribution yolk with the least yolk
animal pole
the cleavage furrow extends through entire egg
holoblastic cleavage
eggs undergoing partial cleavage, resulting in unequal blastomeres
Meroblastic cleavage
two types of meroblastic cleavage
Discoidal and superficial
this is limited to a small disc of cytoplasm at the animal pole
discoidal cleavage
this is limited to a thin surface area of cytoplasm that covers the entire egg
superficial cleavage
types of eggs under holoblastic cleavage
isolecithal, mesolecithal, telolecithal, centrolecithal
they have small amount of yolk that is equally distributed in the cytoplasm
isolecithal eggs
they have a moderate amount of yolk, and the yolk is present mainly in the vegetal hemisphere
mesolecithal eggs
they have a large amount of yolk that fills the cytoplasm, except for a small area, the animal pole
telolecithal
they have a lot of yolk that is concentrated within the center of the cell
centrolecithal eggs
the process by which cells occupy their appropriate locations involves; gastrulation and organogenesis
Morphogenesis
the movement of cells from the blastula surface to the interior of the embryo
gastrulation
this is the formation of the organs
organogenesis
having two germ layers
diploblast
having three embryonic germ layers
triploblasts
what are the three embryonic germ layer of triploblast?
Acoelomates, coelomates, pseudocoelomates
- this is the epidermis of ski and its derivatives (including sweat glands, hair follicles)
- pituitary gland, nervous and sensory system, jaws and teeth, germ cells
Ectoderm
- this is the middle layer of the embryo
- skeletal and muscular system, circulatory and lymphatic system, excretory and reproductive system, dermis of skin, adrenal cortex
Mesoderm
- this is the inner layer of embryo
- epithelial lining of digestive tract and associated organs
- epithelial lining of respiratory, excretory, and reproductive organs, thymus, thyroid, and parathyroid glands
Endoderm
types of cell arrangement in the embryo
epithelial cell and mesenchymal cell
these are tightly connected to one another in sheet or tubes
epithelial cells
they are unconnected or loosely connected to one another and can operate as independent units
mesenchymal cells
what are the gastrulation cell movements
invagination
involution
delamination
epiboly
ingression
infolding of epithelium, mesenchymal is present
invagination
inward movement of expounding outer layer/ external cell
involution
splitting of one to more parallel shape
delamination
epithelial sheath movement, to enclose deeper cell
- formation of ectoderm
epiboly
there is a migration from surface to embryo’s interior
- formation in mesoderm
ingression
where does gastrulation begins in sea urchins
vegetal pole of the blastula
this is the newly formed cavity
archenteron
archenteron is the newly formed cavity and will open and will form ________
blastophore
it open from mouth to anus
protosome
it opens from anus to mouth
deuterostome
the part above the crease is called the _______ _____ of the blastophore
dorsal lip
the midline thickens and is called the _____________
primitive streak
it contributes to the sac that surrounds the yolk and a connection between the yolk and the embryo, but do not contribute to the embryo itself
hypoblast cells
humans eggs have _______ yolk
very little
it is the human equivalent of the blastula
blastocyst
this is a cluster of cells at one end of the blastocyst
inner cell mass
it is the outer epithelial layer of the blastocyst and does not contribute to the embryo, but instead initiates implantation
tropoblast
embryos are surrounded by a fluid in sac called _______
amnion
this protects the embryo from dessication and allows reproduction on dry land
amnion
mammals and reptiles including birds are called ________
amniotes
it forms from mesoderm and later on will become neural tube
notochord
it begins as cells from the dorsal mesoderm form the notochord
Neurulations
the neural tube will become _________
CNS
it develops along the neural tube of vertebrates and form various parts of the embryo
neural crest cells
mesoderm lateral to the notochord forms blocks called ________
somites
he recognized that there is a common pattern to all vertebrate development
Karl Ernst von Baer
Von Baer laws
- general features of large group of animals appear earlier in development than specialized features of smaller group
- less general characters develop from the more general until most specialized appear
- embryo of a given species instead of passing through the adult stages of lower animals, departs more and more
- early embryo of higher animal is never like a lower animal, only like its early embryo
it is a major force in changing cell shape during development
reorganization of the cytoskeleton
it promotes elongation of the archenteron in the sea urchin embryo
cytoskeleton
the rearrangement of cells of a tissue that cause it to become narrower and longer
convergent extension
this is the meshwork of secreted glycoproteins and other macromolecules lying outside the plasma membrane of cells
ECM
programmed cell death
apoptosis
it is used to describe the process by which a cell or group of cells becomes committed to a particular fate
determination
resulting specialization in structure and function
differentiation
diagrams showing organs and other structures that arise from each region of an embryo
fate maps
researchers were able to determine the lineage of each of the ___ somatic cells in the worm
959
they are specialized cells that give rise to sperm or eggs
germ cells
it persist throughout development, and can be detected in germ cells of the adult worm
P granules
what are the axis formations?
right-left axes
anterior-posterior axes
dorsal-ventral axes
axis formation that is largely symmetrical
right-left axis
axis formation that is not determined until fertilization
dorsal-ventral axis
it is involved in establishing the anterior-posterior axis
gravity
he performed experiments to determine a cell’s developmental potential
Hans Speman
the first two blastomeres of the frog embryo ate ________
totipotent
They transplanted tissues between early gastrulas and found that the transplanted dorsal lip triggered a second gastrulation in the host
Speman and Mangold
it functions as an organizer of the embryo body plan, including changes in surrounding tissues to form notochord, neural tube, so on
dorsal lip
development of spatial organization
pattern formation
the molecular cues that control pattern formation are called ________
positional information
it is thickened ectoderm at the bud’s tip
apical ectoderm ridge
it is mesodermal tissue under the ectoderm where the posterior side of the bud is attached to the body
zone of polarizing activity (ZPA)
It is an inductive signal for limb development
Sonic hedgehog
it plays a role during limb pattern formation
hox genes
it is essential for proper specification of cell fate in the human embryo
ciliary function
it play roles in left-right specification
motile cilia
play roles in normal kidney development
Monocilia