EMBRYOL LONG EXAM 2 ROSE TEST

Delamination

The process by which two distinct layers, the hypoblast and epiblast, form from the Inner Cell Mass of the blastocyst.

Blastocyst Structure

The organization of the blastocyst into two cell populations: the Inner Cell Mass (ICM) and the Trophoblast.

ICM Differentiation

The process by which the Inner Cell Mass further divides into the epiblast and hypoblast layers.

Epiblast Derivatives

The structures that arise from the embryonic epiblast, including the amniotic ectoderm.

Hypoblast Derivatives

The extraembryonic endoderm that forms the yolk sac.

Primitive Streak Formation

The process involving the migration of cells towards the midline of the embryonic epiblast.

Invagination

The inward movement of epiblast cells through the primitive streak to form the endoderm.

Ingression

The process by which individual cells move from the epiblast into the blastocoel cavity.

Germ Layers

The three primary layers formed during embryonic development: endoderm, mesoderm, and ectoderm.

Notochordal Process

The formation of a rod

Bilaminar Disc

The early stage of embryonic development consisting of two layers: the epiblast and hypoblast.

Trilaminar Disc

The later stage of embryonic development where three germ layers are established.

Notochord Formation

The process involving the migration of prenotochordal cells through the primitive streak.

Notochordal Plate

The structure formed by migrating cells intercalating with the endoderm.

Definitive Notochord

The structure formed when the notochordal plate detaches from the endoderm.

Cranial to Caudal Progression

The sequence in which the notochord forms from the head region towards the tail.

Paraxial Mesoderm

The mesoderm located on either side of the axial mesoderm, contributing to somite formation.

Intermediate Mesoderm

The mesoderm situated between the paraxial and lateral plate mesoderm, involved in forming urogenital structures.

Lateral Plate Mesoderm

The mesoderm that splits into parietal and visceral layers, contributing to the embryonic coelom.

Somites

Segmented structures derived from paraxial mesoderm that give rise to skeletal muscle, vertebrae, and dermis.

Epithelialization

The process by which mesenchymal cells become epithelial cells during somite formation.

Sclerotome

The part of the somite that gives rise to the vertebrae and ribs.

Myotome

The part of the somite that develops into skeletal muscle.

Dermatome

The part of the somite that contributes to the dermis of the skin.

Shh (Sonic Hedgehog)

A signaling molecule that induces sclerotome formation during somite differentiation.

PAX1

A gene that regulates chondrogenesis and the formation of vertebrae.

WNT proteins

Signaling molecules that demarcate the dermamyotome and influence muscle development.

MYF5

A muscle

Cephalocaudal Folding

The process that affects the positioning of various embryonic structures during development.

Gut Tube Formation

The process by which the embryonic gut narrows into the vitelline duct.

Mesonephros

An embryonic structure that develops from the intermediate mesoderm and contributes to the urinary system.

Visceral Mesoderm

The layer of mesoderm that surrounds the visceral organs.

Endodermal Outpocketings

Structures that develop from the endoderm, including the pharyngeal gut and lung bud.

Ectoderm

The germ layer that gives rise to the nervous system and skin.

Mesoderm

The germ layer responsible for forming the skeletal, muscular, and circulatory systems.

Endoderm

The germ layer that develops into the digestive and respiratory systems.

Neural Crest Cells (NCCs)

Cells that originate from the neural ectoderm and have the potential to differentiate into various cell types.

Pluripotency

The ability of a cell to differentiate into multiple cell types.

Epithelial

Mesenchymal Transition (EMT)

Microenvironment

The local environment surrounding cells that influences their behavior, fate, and differentiation.

Lateral Migration Pathway

A route that leads to the development of pigment cells known as melanocytes.

Medial Migration Pathway

A route that leads to the formation of various ganglia including dorsal root and sympathetic ganglia.

Ventral Pathway

A migratory route through the anterior sclerotome that contributes to the formation of the vertebral column's cartilages and bones.

Dorsolateral Pathway

A migration route between the epidermis and dermamyotome that results in the formation of pigment cells.

Cranial Neural Crest Cells (NCCs)

Cells that contribute to the formation of structures in the face, neck, and several sensory organs.

Cardiac Neural Crest Cells (NCCs)

Cells that play a role in forming the septum between the pulmonary and aortic arches.

Vagal Neural Crest Cells (NCCs)

Cells that contribute to the development of neurons, melanocytes, and various ganglia.

BMP Concentration

The varying levels of Bone Morphogenetic Proteins that influence the fate of ectodermal cells.

Signaling Factors

Proteins such as FGF and WNT that interact with BMPs to regulate gene expression in neural crest cells.

Initiation of Migration

The process triggered by high levels of BMPs that leads to changes in the cytoskeleton and cell adhesion.

Guidance of Migration

The role of extracellular matrix proteins in promoting or restricting the movement of migrating cells.

Chemotactic Factors

Soluble factors secreted by target tissues that influence the migration and differentiation of cells.

Final Differentiation

The process by which cells become specialized, influenced by various signaling factors from their environment.

Hox Genes

Genes that provide positional information along the anterior

Evolutionary Conservation of Hox Genes

The preservation of Hox gene function across different species, from yeast to vertebrates.

Paralogy

The relationship between genes that arise from duplication events within a genome.

Rhombomere Migration

The process by which neural crest cells migrate from specific rhombomeres to form distinct structures.

Extraembryonic Membranes

Membranes that support the embryo without becoming part of it, aiding in nourishment and protection.

Yolk Sac

An extraembryonic membrane that plays a role in nutrient conversion and hematopoiesis.

Amnion

An extraembryonic membrane that surrounds the embryo in a fluid

Chorion

An extraembryonic membrane involved in gas exchange and hormone production, forming part of the placenta.

Allantois

An extraembryonic structure that serves as a reservoir for waste and contributes to the formation of the umbilical cord.

Somatopleuric Origin

Originating from ectoderm and somatic mesoderm, referring to membranes like the amnion and chorion.

Splanchnopleuric Origin

Originating from endoderm and splanchnic mesoderm, referring to membranes like the allantois and yolk sac.

Umbilical Cord Formation

The process of forming the umbilical cord, which includes components like the connecting stalk and blood vessels.

Placenta

An interface for physiological exchange between mother and embryo, facilitating the transfer of nutrients, gases, and waste.

Deciduous

A type of placenta where uterine tissues are damaged and shed during parturition, indicating intimate contact with the maternal tissue.

Diffuse Placenta

A type of placenta characterized by villi spread out over a large surface area, as seen in pigs.

Cotyledonary Placenta

A placenta type with localized patches of villi, typical in ruminants.

Zonary Placenta

A placenta that forms a girdle

Discoidal Placenta

A placenta that is restricted to a disc shape, seen in humans and rodents.

Epitheliochorial

A classification of placenta with six tissue layers separating maternal and fetal blood.

Implantation

The process where the blastocyst attaches to the uterine wall, typically occurring 7 to 10 days after fertilization.

Trophoblast

The outer layer of the blastocyst that differentiates into cytotrophoblast and syncytiotrophoblast during implantation.

Decidual Reaction

The transformation of endometrial stromal cells into decidual cells in response to implantation.

Lacunae

Spaces formed in the syncytiotrophoblast that become filled with maternal blood during the lacunar stage of placentation.

Monozygotic Twins

Identical twins that share a placenta and outer membrane if the inner cell mass splits early.

Dizygotic Twins

Fraternal twins that develop from two separate oocytes, each with its own placenta and membranes.

GnRH

Gonadotropin

FSH

Follicle

LH

Luteinizing hormone released by the anterior pituitary, triggering ovulation and corpus luteum formation.

Estrous Cycle

A reproductive cycle in lower vertebrates characterized by pronounced behavioral changes during heat.

Menstrual Cycle

The cycle in anthropoid primates involving uterine changes due to ovarian events, typically lasting 28 days.

Corpus Luteum

The structure formed from the remnants of the follicle after ovulation, secreting progesterone and estrogen.

Progesterone

A hormone produced by the corpus luteum that maintains the uterine lining for potential implantation.

Menstrual Phase

The phase of the uterine cycle characterized by the shedding of the endometrial lining due to a decline in hormone levels.

Proliferative Phase

The phase of the uterine cycle marked by the growth and regeneration of the endometrial lining in response to rising estrogen levels.

Secretory Phase

The phase of the uterine cycle where the endometrium thickens and develops glands, maintained by progesterone and estrogen.

Follicle Stimulating Hormone (FSH)

A hormone that promotes the growth of ovarian follicles and stimulates the secretion of estrogen.

Luteinizing Hormone (LH)

A hormone that triggers ovulation and the development of the corpus luteum, leading to progesterone production.

Estrogen

A hormone that plays a key role in the repair of the uterine lining and stimulates growth and blood flow during pregnancy.

Human Chorionic Gonadotropin (hCG)

A hormone that maintains progesterone production by the corpus luteum until the placenta takes over.

Human Placental Lactogen (hPL)

A hormone that influences growth, lactation, and metabolism during pregnancy.

Gastrulation

A process during embryonic development where cells move to form the three germ layers: ectoderm, mesoderm, and endoderm.

Notochord

A rod

Mesenchymal Transition

The process where epithelial cells lose their tight arrangement and become loosely organized mesenchymal cells capable of migration.

Bone Morphogenetic Proteins (BMPs)

Signaling molecules that influence the fate of embryonic ectoderm at the neural plate border.

Deciduous Placenta

A type of placenta that is shed during parturition, as seen in humans.

Non

Deciduous Placenta

Ovulation Trigger

The hormonal events leading to ovulation, primarily involving a surge in estrogen and the release of LH.