Embryology Gastrulation 12Th Oct

Front 1

Week 2 overview

Back 1

Implantation (d7/8)

Bilaminar disc (d7)

Amniotic cavity (d8)

Primary yolk sac (d9)

Circulation:

- Trophoblastic Lacunae merge with maternal capillaries (d9-11)

- Formation of chorionic villi (d11-13)

Extra-embryonic mesoderm (d11-12)

Chorionic cavity (d12-13)

Formation of the definitive yolk sac (d13-14)

Formation of secondary villi (d16)

Front 2

Rule of 2s

Back 2

2 weeks

2 embryonic germ layers

- Hypoblast- columnar

- epiblast - Cuboidal

2 embryonic cavities

- Amniotic cavity

- yolk sac

2 parts to trophoblast

- Synctiotrophoblast

- Cytotrophoblast

2 parts to placenta

- Decidua basalis

- Choroid ???

Front 3

Gastrulation

Back 3

Formation of trilaminar germ disc from the epiblast

Axial orientation is established

Front 4

Formation of chorionic villi

Back 4

Primary (Cytotrophoblast invades Synctiotrophoblast

Secondary - Extra-embryonic mesoderm invades primary stem villi

Tertiary - Mesoderm differentiates into CT and B.V.s connecting to embryonic b.v.s

Uteroplacental Circulation @ day 21

Front 5

Primitive streak

3 parts

Back 5

Establishes L/R symmetry

1.Faint groove @ longitudinal midline - first marker of rostrocordal axis

2.Primitive Pit

3. Primitive Node

Front 6

Which 2 areas establish strong bonds w/ epiblast and hypoblast

Back 6

Oropharyngeal membrane

Cloacal membrane

Front 7

Epitheal to mesenchymal Transition (EMT)

Back 7

Start of gastrulation

Epiblasts proliferate -》 Loose their adherence =》 Change Shape

Front 8

Ingression

Back 8

2 waves

1. Displacement of hypoblast

- Formation of the Derivative Embryonic Endoderm

2. Population of space btwn Epiblast and embryonic endoderm

-》 formation of definitive embryonic Mesoderm

Front 9

Gastrulation Start

Back 9

1. Epiblast near primitive streak change shape and proliferate

2. Ingrission - Definjtive endoderm, definitive mesoderm

3. Epiblast -》 Definitive embryonic ectoderm

Front 10

Mesodermal Condensation

Cranial to caudal

Back 10

Cardiogenic mesoderm @ Crainal end

Pre-Chordal plate

- ingression through cranial part of primitive node

- Signalling Centre for the forebrain development

- Head mesenchyme

Notochord

- Ingression through primitive node

- V. Important signalling centre

- no adult derivatives

Paraxial mesoderm

- Surrounnds notochord

- Somites in trunk, head mesenchyme

Intermediate mesoderm

- only in trunk, lateral to para-axial mesoderm

- Urinary and genital systems

Lateral Mesoderm

- only in trunk

- most lateral mesoderm formation

Front 11

2 places with no mesoderm

Back 11

Oropharyngeal membrane (4weeks) -》 mouth

Cloacal membrane( 7 weeks) -》 Anal, uterine and genital, openings

Front 12

Pre chordal plate

Back 12

Pre-Chordal plate - ingression through cranial part of primitive node - Signalling Centre for the forebrain development - Head mesenchyme

Front 13

Notochord

Back 13

Notochord - Ingression through primitive node - V. Important signalling centre - no adult derivatives

Front 14

Paraxial Mesoderm

Back 14

Aka Somite

Paraxial mesoderm - Surrounnds notochord - Somites in trunk, head mesenchyme

Front 15

Intermediate Mesoderm

Back 15

Intermediate mesoderm - only in trunk, lateral to para-axial mesoderm - Urinary and genital systems

Front 16

Lateral mesoderm

Parts

Back 16

Sheet of mesoderm

Starts splitting at day 17

Splanchic mesoderm (Visceral)

- associated w/ endoderm

- mesothelial coverings of viscera and visceral walls

Somatic Mesoderm

- Associated w/ ectoderm

- inner lining of body walls and limbs

Presumptive Intra embryonic coelum

- abdominal/ thoracic cavities

Front 17

Gastrulation gone wrong

Back 17

Caudal Dysplasia

Caudal regression syndrome

VATER

VACTERL

Front 18

VACTE(O)RL

Back 18

Vertebrae defect

Anal Atresia

Cardiovascular anomolies

Tracheal-oesophageal fistula

Renal defects

Radial forearm anomolies

Limb defects

Front 19

VATE(O)R

Back 19

Vertebrae

Anal atresia

Tracheal-oesophageal fistula

Renal defects, radial forearm anomolies

Front 20

Gastrula

Back 20

Embryo during gastrulation

Front 21

Mesenchyme

Back 21

Tissue found in organisms during development

Non specialised

Mobile

Front 22

Caudal Dysplasia/ Caudal regression syndrome

Back 22

Varying degrees of;

Flexion, inversion and lateral rotation of the lower extremities

Anomolies w/ lumbar and sacral vertebrae

Imperforated anus

Agenesis of kidney and uterine tract

Agents is of internal genital organs except for gonads (Intermediate mesoderm)