EMBRYOLOGY-4

The process where a two-layered embryo (epiblast and hypoblast) develops into a three-layered embryo (endoderm, mesoderm, and ectoderm).

The innermost germ layer that gives rise to linings of digestive and respiratory systems, as well as glands.

The middle germ layer that forms muscles, bones, blood, and connective tissues.

The outermost germ layer that develops into the epidermis, nervous system, and sensory organs.

A groove that forms on the dorsal surface of the epiblast during gastrulation, marking the future site of the neural tube.

A thickened area at the cranial end of the primitive streak, containing the primitive pit, a small depression.

The movement of cells during gastrulation from the epiblast to the primitive streak, leading to the formation of the three germ layers.

A signaling molecule that plays a role in the formation of the primitive streak during gastrulation.

A process where epithelial cells lose their specialized characteristics, making them more mobile and adaptable.

A type of protein that acts as a 'switch' to help cells differentiate and become specialized.

A protein involved in EMT that represses epithelial cell features by binding to DNA and turning off genes.

A type of cell that can differentiate into various cell types found in connective tissues.

A gel-like substance that provides a fluid environment for cells to migrate, often found in ECM.

A vital component of the ground substance that helps create a slippery environment for cell movement.

The outer layer of the yolk sac, formed by the primitive endoderm. It gives rise to key structures within the body.

A group of cells found in the developing embryo associated with a region called the anterior visceral endoderm. It plays a key role in the formation of the head and front of the body.

The compartment of the mesoderm that develops into the dermis (skin), ribs, and some muscles. It lies along the axis of the body.

The compartment of the mesoderm that forms the heart and blood vessels. It lies on the sides of the embryo.

The compartment of the mesoderm that forms the kidneys, gonads, and urinary tract. It lies between the paraxial and lateral mesoderm.

A thin, non-mesodermal region at the rostral (head) end of the embryo. It forms the future opening of the mouth and marks the beginning of the digestive tract.

A thin, non-mesodermal region at the caudal (tail) end of the embryo. It forms the future opening of the anus and urinary tract.

A temporary structure that forms in early development, allowing communication between the vitelline sack and the amniotic sack.

A specialized cell layer that develops from the epiblast during gastrulation, giving rise to the nervous system.

A type of cancer that arises from leftover cells of the notochord.

The mesoderm that develops into the head and trunk region of the embryo.

The process by which the paraxial mesoderm forms segmented blocks called somites in the trunk region.

The mesoderm that forms in the trunk region and gives rise to the kidneys, gonads, and urinary system.

The mesoderm that splits into two layers: a ventral layer (splanchnic mesoderm) and a dorsal layer (somatic mesoderm).

The region in the early embryo where heart cells begin to form.

A specialized group of cells derived from the ectoderm, capable of migrating throughout the body and giving rise to a variety of tissues, including parts of the peripheral nervous system, melanocytes, cornea, teeth, and heart.

The process of the neural plate folding and fusing to form the neural tube, a key step in developing the central nervous system.

Signaling molecules that trigger the differentiation of ectodermal cells into neural plate cells, initiating the process of neurulation.

A groove that forms on the neural plate during neurulation, eventually closing to form the neural tube.

The thickening of ectodermal cells in the midline of the embryo, leading to the formation of the neural plate.

The point where the neural tube detaches from the ectoderm, allowing for the migration of neural crest cells.

Cells of the neural crest that migrate away from the neural tube to form various specialized tissues.

The process of neural crest cells migrating from the neural tube to their final destinations, where they differentiate into specific cell types.

The process of forming the caudal (tail end) part of the neural tube and the associated caudal somites from cells of the primitive streak. It involves cavitation and fusion with the existing neural tube.

A type of tumor arising from remnant cells of the primitive streak, most commonly occurring in the sacrococcygeal region. It can be malignant in infancy and needs surgical removal.

The gradual decline in the ability of embryonic cells to differentiate into different cell types as development proceeds. This occurs as cells commit to specific developmental pathways.

The formation of the primitive streak, with higher concentration of Nodal protein in the caudal (tail) end, sets the stage for the development of the head and tail regions of the embryo. This is influenced by Hox genes, which control the expression of other genes like Nodal, Lefty, and Cerberus.

The differential distribution of morphogens, signaling molecules, in the mesoderm during development, determines the dorsal (back) and ventral (belly) sides of the embryo. The mesoderm that was initially medial (middle) becomes dorsal, while the lateral (sides) mesoderm becomes ventral.

The process by which a symmetrical embryo develops asymmetry, with organs positioned more on one side than the other. The mechanisms are complex and involve various signaling pathways, gene expression, and physical forces.

A key signaling molecule that regulates the expression of genes involved in developmental processes, including the formation of the primitive streak. It acts as a switch, turning genes on or off to control cell behavior.