Developmental Biology Test 3 Review Vocabulary

A collection of vocabulary flashcards for key terms related to developmental biology, focusing on cellular processes and embryonic development.

Cytokinesis

The constriction of the cell using a contractile ring of actin microfilaments, leading to the division of the cytoplasm.

Karyokinesis

The mitotic division of the nucleus via the mitotic spindle and tubulin microtubules.

Gastrulation

A process of highly coordinated cell and tissue movements that dramatically rearranges cells of the blastula, leading to the creation of the entire GI tract.

Cleavage

A series of unusual mitotic divisions without cell growth, leading to an increased number of cells without expanding cytoplasm.

Cortex

The layer on the outside of the cell that includes microfilaments and the fragile phospholipid bilayer, and contains no myosin.

Holoblastic

Complete cleavage of the entire embryo, common in embryos with sparse yolk (isolecithal).

Meroblastic

Incomplete cleavage that affects only a small amount of cytoplasm without penetrating the yolk, common in embryos with large amounts of yolk.

Trophoblasts

The outer layer of the cell, also known as the chorion.

Placenta

The structure formed where the chorion from the baby fuses with the endometrium from the mother.

Syncytial Cleavage

A type of cleavage where nuclei are all in the same cytoplasm, allowing karyokinesis to occur without cytokinesis.

Epiboly

The expansion of an epithelial sheet to enclose deeper layers during development.

Invaginations

Infoldings of a sheet of cells; the creation of indentations that push the sheet of cells inside the embryo.

Ingression

The migration of individual cells from an epithelium into the interior of the embryo.

Delamination

The splitting of one cellular sheet into two parallel sheets.

Primary Germ Layers

The three layers formed during gastrulation: endoderm, mesoderm, and ectoderm.

Polyspermy

The condition where multiple sperm enter the egg, leading to chromosome abnormalities and embryo death.

Monospermy

The entry of a single sperm into the egg, initiating cellular processes essential for embryo development.

Deuterostome

An organism where the mouth forms second, after the anus.

Protostome

An organism where the mouth forms first.

Archenteron

The invagination that deepens to form the primitive stage of the intestine.

Mesenchyme

A loose network of cells that are not necessarily in contact with each other.

Blastocyst

An early stage of embryonic development that develops from the blastula.

Blastula

A hollow sphere of cells produced during cleavage in early development.

Blastocoel

The fluid-filled cavity inside the blastula.

Blastopore

The initial indentation that forms the opening of the gastrointestinal tract during development.

Radial Holoblastic Cleavage

A type of cleavage found in sea cucumbers, sea urchins, and frogs.

Spiral Holoblastic Cleavage

A type of cleavage typical in mollusks.

Bilateral Holoblastic Cleavage

A type of cleavage seen in chordates.

Rotational Holoblastic Cleavage

A type of cleavage that occurs in mammals.

Discoidal Meroblastic Cleavage

A type of cleavage that occurs in birds and fish involving dense yolk.

Superficial Meroblastic Cleavage

A type of cleavage that occurs in insects, where karyokinesis happens without cytokinesis.

Asynchronous Cleavage

A cleavage where embryos do not divide together, resulting in a number of blastomeres that is not a multiple of $2^n$.

Compaction

The process in which cell boundaries become indistinct to hold the embryo together during the morula stage.

Zygote

The initial single-cell stage of development formed after fertilization.

Cleavage

A series of mitotic divisions that increase the number of cells while maintaining the overall size of the embryo.

Blastula

A hollow sphere of cells formed during cleavage, leading to the blastocyst in mammals.

Gastrulation

The phase that reorganizes the blastula into a more complex structure, leading to the formation of the gastrointestinal tract.

Neurulation

The process in which the ectoderm rolls up to form the neural tube, which develops into the central nervous system.

Morphogenesis

The biological process that causes an organism to develop its shape.

Differentiation

The process in which cells become specialized in structure and function.

Archenteron

The invagination that deepens to form the primitive stage of the intestine.

Blastopore

The initial indentation that forms the opening of the gastrointestinal tract during development.

Epiboly

The expansion of a sheet of tissue, typical during the early stages of an embryo.

Ingression

The movement of individual cells from an epithelial layer into the interior during development.

Invagination

The process in which a sheet of cells folds inward to create a pocket.

Trophoblast

The outer layer of the blastocyst that will form part of the placenta.

Syncytial Cleavage

A type of cleavage in which multiple nuclei share a common cytoplasm without cytokinesis.

Polyspermy

The condition where multiple sperm enter an egg, leading to abnormal embryo development.

Monospermy

The entry of a single sperm into the egg, a normal occurrence essential for proper embryo development.

Holoblastic Cleavage

Complete division of the egg into separate cells; can be radial, spiral, bilateral, or rotational.

Meroblastic Cleavage

Partial division of the egg, generally occurring in species with large yolk reserves.

Discoidal Meroblastic Cleavage

A type of cleavage occurring in species with significant yolk, resulting in a blastoderm.

Superficial Meroblastic Cleavage

A type of cleavage where cell division occurs around a central yolk without dividing the yolk.

Asynchronous Cleavage

Cleavage where not all cells divide synchronously, leading to an uneven distribution of blastomeres.