59 terms

BIOL 102 Development Lab

Rob Swatski, Associate Professor of Biology at HACC York Campus (HACC, Central Pennsylvania's Community College) http://robswatski.virb.com/
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Terms in this set (...)

gametogenesis
the formation of the haploid male and female gametes (sperm and eggs)
fertilization
activation of the egg and fusion of the sperm and egg nuclei to form the diploid zygote; initiates embryonic development
cleavage
the subdivision of the zygote into many cells by mitosis; leads to the morula and blastula stages
gastrulation
the formation of germ layers
organogenesis
the initiation and differentiation of specific organs
zygote
the fertilized egg
growth
the increase in mass of the organism through the addition of new cells and/or and increase in size of existing cells
determination
the process by which stem cells become committed to develop into only one type of cell
differentiation
the progressive increase in the complexity of organization and specialization of individual cells and tissues
morphogenesis
the development of body form and organization
gametes
the mature germ cells: eggs and spermatozoa
What are the three main parts of a sperm cell?
head, midpiece, tail
yolk
the fat-rich food supply in an egg
isolecithal eggs
have relatively little yolk; the yolk is uniformly distributed throughout the egg; found in sea stars and humans
mesolecithal eggs
have a moderate amount of yolk; the yolk is concentrated in the vegetal (lower) hemisphere; found in frogs, toads, and salamanders
telolecithal eggs
have a large amount of yolk; the cleaving portion of the embryo is restricted to a small disc at one end of the egg; found in birds and reptiles
centrolecithal eggs
have much yolk; the actively developing portion of the embryo forms a thin layer of cells around the outside of the large central yolk mass; found in insects
Sea star eggs are classified as ___.
isolecithal
Frog eggs are classified as ___.
mesolecithal
Chick eggs are classified as ___.
telolecithal
holoblastic cleavage
cleavage in which all parts of the zygote divide
incomplete cleavage
the dividing cells form an embryo on top of the yolk mass; found in insects, birds, and many mammals
spiral cleavage
the planes of cell division are diagonal to the vertical axis of the embryo; found in protostomes such as flatworms, nematodes, most molluscs, and many annelids
animal pole
the upper portion of the egg where the least yolk is concentrated; opposite of vegetal pole
vegetal pole
the lower portion of the egg where the most yolk is concentrated; opposite of animal pole
radial cleavage
the cleavage planes are either parallel or perpendicular to the vertical axis of the embryo; found in deuterostomes such as sea stars, sea urchins, and frogs
blastomeres
embryonic cells
morula
a stage of embryonic development in which the embryo consists of a solid mass of cells formed after many cleavages; no central cavity
blastula
a stage of embryonic development in which the embryo consists of a hollow ball of cells
blastocoel
the fluid-filled cavity inside a blastula
gastrula
the embryo in the stage of development after the blastula; contains the embryonic germ layers
invagination
the infolding of the embryo that produces the gastrula
primary germ layers
ectoderm, mesoderm, and endoderm
ectoderm
the outermost germ layer; produces sense organs, nerves, and outer layer of skin
endoderm
the inner germ layer that develops into the lining of the digestive and respiratory systems
archenteron
the primitive digestive tract of the gastrula; lined by endoderm tissue
blastopore
the external opening of the archenteron; often becomes the mouth or anus of the adult, depending on the type of animal
coelom
the fluid-filled body cavity lined with mesoderm
mesoderm
the middle germ layer of cells that gives rise to muscles, bone, connective tissues, and circulatory system
bipinnaria
the bilaterally symmetrical, free-swimming larva of a sea star
brachiolaria
the sea star larval stage with several long armlike structures
young sea star
displays radial symmetry
vitelline membrane
the transparent membrane that surrounds the unfertilized egg
gray crescent
an area located close to the equator of frog egg on the side opposite the point of sperm entry
neural plate
a layer formed by differentiating neural cells within the ectoderm of the embryo
neural folds
the raised ridges in the neural plate that surround the deepening neural groove
neural tube
a hollow structure from which the brain and spinal cord develop
amniotic egg
an egg with a shell and internal membranes that keep the embryo moist and protected
extraembryonic membranes
the membranes located outside the embryo of a chick and most other terrestrial vertebrates; include the amnion, chorion, yolk sac, and allantois
yolk sac
the membranous structure enclosing the yolk of eggs in birds and reptiles
chorion
the outermost layer of the two membranes surrounding and protecting the chick embryo
amnion
the innermost membranous sac surrounding the developing embryo in a protective fluid
allantois
a membrane sac that stores metabolic wastes and is the site for gas exchange for the developing embryo
primitive streak
the site of invagination of the surface ectoderm and the formation of the mesoderm layer in the chick embryo
notochord
a cartilaginous skeletal rod supporting the body in all embryonic and some adult chordate animals; may be replaced by a vertebral column in later stages of development
somites
blocks of developing muscle tissue just lateral to the notochord of a vertebrate embryo
otic vesicles
embryonic structures that develop into the ears
flexion
an embryonic movement involving bending of the body along its longitudinal axis into the shape of a "C"; starts at the anterior end with a bending forward of the head
torsion
a twisting of the embryo's body along its longitudinal axis, starting with the twisting of the head toward its right side