Download File

CHAPTER 47: ANIMAL DEVELOPMENY
–TERMINOLOGYcytoplasmic determinants are maternal substances present in an egg
cell differentiation is caused by selective gene expression which leads to
the specialization of cells in structure and function
morphogenesis is the process by which an animal takes shape
acrosomal reaction is when a sperm come in contacts with the jelly
coating of an egg, and then the acrosome of the sperm releases
hydrolytic enzymes through exocytosis
acrosome is a specialized vesicle at the tip of the sperm
fast block to polyspermy prevents polyspermy, the fertilization of the
egg by multiple sperm.
cortical granules fuse with the plasma membrane and release their
contents into the perivitelline space, the space between the plasma
membrane and the vitelline layer
fertilization envelope is the vitelline layer which hardens in which it
resists the entry of additional sperm.
slow block to polyspermy prevents polyspermy in which the
fertilization envelope and other changes in the egg’s surface function
together as a long-term prevention of multi-sperm fertilization
zona pellucid is the extracellular matrix of the egg
cleavage is rapid cell division
morula is the first five to seven divisions that form a cluster of cells
blastocoel is a fluid-filled cavity that forms within the morula
blastula is a hollow ball of cells
blastomeres are formed when the zygote is partitioned into smaller cells
yolk is a substance found in a egg, of certain species, that contains
nutrients
vegetal pole is the portion of the egg where most yolk is concentrated;
opposite of animal pole
animal pole Is the portion of the egg where the least yolk is
concentrated: opposite of vegetal pole
gray crescent is a light-gray region of cytoplasm located near the
equator of the egg on the side opposite the sperm entry
meroblastic cleavage is the incomplete division of a yolk-rich egg
holoblastic cleavage is the complete cleavage of eggs with little or
moderate yolk
blastoderm is in early cleavage in a bird embryo produces a cap of cells,
which rests on undivided egg yolk
grastulation is the rearrangement of the embryo into a triploblastic
gastrula.
gastrula early multicellular embryo, composed of two or more germinal
layers of cells from which the various organs later derive
germ layers are the three main layers that form the various tissues and
organs of an animal body
ectoderm is the outermost of the three primary germ layers in animal
embryos; gives rise to the outer covering and, in some phyla, the nervous
system, inner ear, and lens of the eye
mesoderm is the middle primary germ layer of an early embryo that
develops into the notochord, the lining of the coelom, muscles, skeleton,
gonads, kidneys, and most of the circulatory system
endoderm is the innermost of the three primary germ layers in animal
embryos; lines the archenteron and gives rise to the liver, pancreas,
lungs, and the lining of the digestive tract
invagination is the infolding of cells
archentern is the endoderm-lined cavity, formed during the gastrulation
process, that develops into the digestive tract of an animal
blastopore is the opening of the archenteron in the gastrula that
develops into the mouth in protostomes and the anus in deuterostomes
dorsal lip is the dorsal side of the blastopore
involution are the cells rolling over the edge of the lip of the blastopore
into the interior of the embryo during gastrulation
neural tube is a tube of cells running along the dorsal axis of the body,
just dorsal to the notochord. It will give rise to the central nervous
system
neural crest is a band of cells along the border where the neural tube
pinches off from the ectoderm. The cells migrate to various parts of the
embryo and form the pigment cells in the skin, bones of the skull, the
teeth, the adrenal glands, and parts of the peripheral nervous system
primitive streak is a groove on the surface of an early avian embryo
along the future long axis of the body
somites are paired blocks of mesoderm just lateral to the notochord of a
vertebrate embryo
amniote is a member of a clade of tetrapods that have an amniotic egg
containing specialized membranes that protect the embryo, including
mammals and birds and other reptiles
extraembryonic membranes are four membranes (yolk sac, amnion,
chorion, allantois) that support the developing embryo in mammals and
birds and other reptiles
yolk sac is one of four extraembryonic membranes that support
embryonic development; the first site of blood cells and circulatory
system function
chorion is the outermost of four extraembryonic membranes;
contributes to the formation of the mammalian placenta
allantois is one of four extraembryonic membranes; serves as a
repository for the embryo’s nitrogenous waste
blastocyst is an embryonic stage in mammals; a hollow ball of cells
produced one week after fertilization in humans
inner cell mass is a cluster of cells in a mammalian blastocyst that
protrudes into one end of the cavity and subsequently develops into the
embryo proper and some of the extraembryonic membranes
trophoblast is the outer epithelium of the blastocyst, which forms the
fetal part of the placenta
convergent extension is a mechanism of cell crawling in which the cells
of a tissue layer rearrange themselves in such a way that the sheet of
cells becomes narrower while it becomes longer
cell adhesion molecules (CAMs) are glycoproteins that contribute to cell
migration and stable tissue structure
cadherins is an important class of cell-to-cell adhesion molecules.
induction is The ability of one group of embryonic cells to influence the
development of another
totipotent is describing a cell that can give rise to all parts of an
organism
pattern formation is the ordering of cells into specific threedimensional structures, an essential part of shaping an organism and its
individual parts during development
positional information are signals to which genes regulating
development respond, indicating a cell’s location relative to other cells in
an embryonic structure
apical ectodermal ridge (AER) is a limb-bud organizer region consisting
of a thickened area of ectoderm at the tip of a limb bud
zone of polarizing activity (ZPA) is a limb-bud organizer region
consisting of a block of mesoderm located where the posterior side of the
bud is attached to the body