Ung di ko makuha sa Gastrulation

Ingression

movement of cells

Invagination

Infolding

Involution

unequal folding

Intercalation

inserting cells alternately

Evagination

Outfolding

Epiboly

Migration

Delamination

Splitting of layers of cell

Convergent Extension

Decrease in # of cells

Ectoderm

gives rise to organs for protection and reaction

Endoderm

Organs for digestion and respiration

Mesoderm

Organs for support, movement, circulation, excretion and reproduction

E-cadherin

Early cells adhere using

Fibroblast Growth Factors

signals the loosening of connections between blastomeres

Primodia or rudiments

specific region that has a precursor cells to form a particular region

ECTODERM

Epidermal Layer IN AMPHIBIANS

MESODERM

Muscle, Bone, Kidneys, Bloods, Gonads and Connective Tissues IN AMPHIBIANS

Neural Ectoderm

Nervous system IN AMPHIBIANS

Endoderm

Gut lining, liver and lungs IN AMPHIBIANS

3 Regions of Amphibian Fate Maps

ANIMAL, MARGINAL AND VEGETAL

Animal Region

• give rise to neural tube (inside)

• forms epidermis with subarea that forms nose, ears and ectodermal part of the mouth

Subarea

• forms eyes (in animal region)

Marginal Region

• notochord and prechordal plate

• forms gills, pharynx and endodermal lining

• somites or segmented muscles are also formed

• the lateral and ventral parts of this marginal zone forms lateral plate mesoderm that lines body cavities

Vegetal Region

midgut and hindgut

Larval

in Marginal region, what stage does gills form?

Body Cavities

in marginal region, the lateral and ventral parts of this marginal zome forms lateral plate mesoderms that lines ____?

Filopodia

cells near the center plate begin to pulsate on their inner surface and form long thin processes called

Primary Mesenchyme Cells

Ingressing cells / cells that loses their cilia and its adhesiveness with neighboring vegetal cells that starts to ingress in blastocoel

micromeres

Primary mesenchyme Cells are derived from

Archenteron

primitive gut cells positioned on the ventrolateral wall of the blastocoel

syncial cables and calcium carbonate spicules

The primary mesenchyme cells begin to fuse to form

Chondroitin Sulfate Proteoglycan

vegetal plate began to secrete ____ in inner lamina of hyaline membrane

Archenteron (in context sa invagination of Archenteron)

• invaginated region

• elongates ad flatten which makes blastopore more constricted

Blastopore (in terms of invagination of archenteron)

• opening

Secondary mesenchyme cells

Cells at the archenteron tip becomes motile which forms _____

stomodeum

ectodermal depression

coelom

body cavity

yolk

Gastrulation in Amphibians is more complex than sea urchin due to the presence of _____ in the vegetal region as it prevents simple invagination

Grey crescent

embryo establishes an entry site for endodermal cells to involute into blastocoel called

Apical Cap

• 3-layer deep region from pigmented animal hemisphere

• contains materials for ectoderm and undergoes epiboly

Non-Involuting Marginal Zone

• 5-layer deep below AC that contriubtes to ectoderm

• epiboly and some expand while others shrink

Involuting Marginal Zone

• Adjacent to NIMZ on ventral side that involutes into blastocoel

• Superficial and Deep Layer

Superficial Layer

contains materials for archenteric root, become endoderm

Deep Layer

Contains materials for mesoderm

Limit of Involution

• boundary between NIMZ and IMZ

• area where involution stops

Deep Zone

• between IMZ and vegetal cells

• contains materias for head mesoderm + heart

• Migration which lead to IMZ + yolky vegetal cell

Bottle Cells

• ring of cels below IMZ

• Undergoes apical contractions changing cell shape

Vegetal Base

• formed by large yolky cell containing endodermal material

• becomes displaced deeper into blastocoel

Grey Crescent Region

Gastrulation begins with shape change of cells below the equator along the marginal zone called

Slender Cytoplasmic Strand

The main body of each cell is displaced to the inside of embryo while it maintains contact with outside surface via

blastopore (FORMATION OF BOTTLE CELLS)

Formation of bottle cells causes formation of a small curve depression called

fibronectin network

DZ cells move from the original position (equator) to the roof of blastocoel moving along blastocoelar wall via

Marginal Zone Constriction Ring

The marginal region acting as a tightening band that helps narrow the blastopore during gastrulation.

Blastopore

The opening formed during gastrulation that becomes constricted by epiboly and convergent extension and later develops into the anus

Expansion

achieved by a change in cell shape and intercalation.

Blastodisc

disc-shaped region of cytoplasm where cleavage occurs, located above the yolk.

Subgerminal Cavity

A cavity formed beneath the blastodisc during cleavage, separating blastomeres from the yolk.

Area Pellucida

The lighter-colored central region of the blastodisc where cells are separated from the yolk.

Area Opaca

The darker peripheral region of the blastodisc that remains in contact with the yolk.

Hypoblast

A layer formed by cells migrating from the area opaca into the subgerminal cavity.

Epiblast

The layer of cells above the hypoblast that gives rise to the embryo proper.

Blastocoel

A slit-like cavity formed between the epiblast and hypoblast.

Fate Map (Reptiles and Birds)

The developmental map of the embryo that is restricted to the epiblast.

Primitive Streak

– A longitudinal thickening formed by the ingression of presumptive mesoderm from the posterior region and medial migration of lateral epiblast cells, which elongates anteriorly during gastrulation.

Posterior Region of the Embryo

– The site where presumptive mesodermal cells first ingress into the blastocoel to initiate primitive streak formation.

Epiblast Cell Migration

– The movement of lateral epiblast cells toward the midline, contributing to thickening and elongation of the primitive streak.

Primitive Groove

– A midline depression formed by converging cells within the primitive streak that serves as an entry site for ingressing cells.

Primitive Knot (Hensen’s Node)

A notch-like thickening at the anterior end of the primitive streak that functions as a major organizer region.

Primitive Pit

A funnel-shaped depression at the center of Hensen’s node that serves as an entry site for ingressing cells into the blastocoel.

Presumptive Foregut Cells

The first cells to ingress into the primitive streak; migrate anteriorly and displace the hypoblast to form the germinal crescent.

Germinal Crescent

An anterior region of the area pellucida that does not contribute to the embryo proper but contains primordial germ cells that later migrate to the gonads.

Head Process

A raised anterior midline structure of the epiblast formed by the anterior migration of notochordal and head mesoderm cells.

Presumptive Hindgut and Midgut Cells

Cells that ingress through the lateral portions of the primitive streak, move deep into the blastocoel, and displace hypoblast cells laterally.

Extraembryonic Endoderm

Endodermal cells that join the hypoblast and contribute to extraembryonic structures rather than the embryo proper.

Presumptive Mesoderm Cells

Cells that ingress simultaneously with midgut and hindgut cells and spread through the blastocoel as a loose sheet between endoderm and epiderm.

Mesodermal Derivatives

Structures formed from presumptive mesoderm, including the epimere, mesomere, hypomere, and extraembryonic mesoderm.

Primitive Streak Regression

The posterior movement of the primitive streak as mesodermal cells continue to ingress, pulling Hensen’s node backward and leaving behind the head process.

anteroposterior elongation.

Hensen’s Node (Regression Phase) – Moves posteriorly during streak regression, dragging previously laid-down tissues and contributing to

Head Process

A structure left behind as the node regresses, formed from earlier-ingressed material that elongates posteriorly.

Anal Region

final posterior location reached by Hensen’s node during primitive streak regression.

Presumptive Ectoderm

Cells that proliferate to replace cells that ingressed, maintaining surface coverage of the embryo.

Epiboly of Area Opaca Cells

The spreading of cells at the margin of the area opaca to cover the entire yolk, compensating for cell loss during ingression.

Neural Tube (Elongation)

Tissue pulled posteriorly as the node regresses, causing the neural tube to elongate from anterior to posterior.

Neural Plate Deepening

Slight inward movement of the neural plate during elongation, making the neural folds more prominent.

Mammalian Blastocyst

An early embryonic structure composed of an outer trophoblast and an inner cell mass, analogous to the reptilian blastodisc.

Cleavage in Mammals

Holoblastic cleavage, but with a gastrulation pattern similar to reptiles and birds.

Blastocyst Cavity

A cavity homologous to the yolk of reptiles, despite the absence of yolk in mammals.

Hypoblast

The lower layer that migrates downward to line the blastocyst cavity and forms the yolk sac.

Epiblast

The upper layer that further delaminates into amniotic epiblast and embryonic epiblast.

Amniotic Epiblast

The upper epiblast layer that lines the amniotic cavity.

Embryonic Epiblast

The lower epiblast layer that gives rise to the embryo proper.

Amniotic Cavity

A fluid-filled space between epiblast layers that provides protection to the developing embryo.

Trilaminar Germ Disc

A three-layered structure composed of ectoderm, mesoderm, and endoderm, formed at the end of gastrulation.