#ectoderm

Embryonic Choreography

The transformation of an embryo into a baby involves the staggeringly complex choreography of billions of cells. In the opening scenes of this show, three layers of cells must form in an embryo: the endoderm, mesoderm and ectoderm. Researchers now probe how the endoderm, which goes on to form your stomach, intestines, lungs, liver and pancreas, comes to be. Using two-photon, time-lapse microscopy of spheres of mouse embryonic stem cells called gastruloids (pictured), they tracked all cells by labelling them with a dye (left). By fluorescently tagging different proteins, they found some cells lost a protein called E-cadherin while others retained it. Next, islands of cells with E-cadherin were surrounded by cells containing a mesoderm marker, T-Brachyury (middle), and flowed towards one end of the elongating sphere before finally maturing into endoderm cells. This sheds light on some of the earliest moves in the complicated dance of development.

Written by Lux Fatimathas

Video from work by Ali Hashmi and colleagues

Aix-Marseille University, CNRS, IBDM, Turing Center for Living Systems, Marseille, France

Video originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in eLife, April 2022

Bioscientists learn how ectoderm cells begin to differentiate — ScienceDaily

During embryonic development, the entire nervous system, the skin and the sensory organs emerge from a single sheet of cells known as the ectoderm. While there have been extensive studies of how this sheet forms all these derivatives, it hasn’t been possible to study the process in humans — until now.

Rice bioscientist Aryeh Warmflash, graduate student George Britton and their colleagues have…

The fertilized egg, travels through the oviduct and before even the implantation onto the urine tract, it has turned from one enormous cell to blastocyst - as the rapid mitotic divisions take place. When the rate of these divisions slows down, our ball of cells will become a gastrula (from a blastula) as the cells rearrange themselves and start organization into the three germ layers: ectoderm, mesoderm and endoderm. Let's start with the first one. What is this ectoderm layer? Is it the layer form which epidermis cells will arise (skin cells) and your nervous system. The neural tissue is induced after the organizer, autonomous cells which determine neurulation and other events, this is a very important structure as the experiments have shown that if we transplant the organizer from the blastopore of a frog into another embryo, an additional embryo will form. So it has the capability to induce formation of a second individual! (Which will be connected to the first). It's job is tremendous as it will induce the formation of the nervous system and from gastrula, we will move on to the stage called neurula. Here, neurulation will take place which is the folding process of the neural plate into neural tube. It is called neural plate because at first it is just part of the embryo, flat-like top (anterior) structure. But when a node of mesodermal cells (middle layer) tell the ectodermal cells above them that they are not going to become epidermis but instead form the nervous system, it all changes.

SO when this rod of mesodermal cells, or notochord, induces the formation of neural tube, first the cells above it will elongate and then begin to fold, forming a tube-like structure. This happens because of the cytoskeleton of the cells which can allow them to constrict their "necks" and thus acquire the mechanical force to pull themselves together and then elongate. Neural crest cells play a part here because they are part of the neural plate and when the folding begins, they will elevate themselves to form a "circle" (the to be neural tube) below them and thus close it.

Three primary germ layers are formed during gastrulation: ectoderm, mesoderm, and endoderm.

Ectoderm: (ectodermal cells develop into the outer coverings of the body, e.g. outer layers of skin, nails, and tooth enamel, and into the cells of the nervous system and sense organs) Epidermis of skin, nervous system, sense organs

Mesoderm: (structures lying between the inner and outer coverings of the body) Skeleton, muscles, blood vessels, heart, blood, gonads, kidneys, dermis of skin

In the next couple of weeks I will be writing about germ layers so I feel the need to explain exactly what a germ layer is, as simply as I can, and although it can certainly go much deeper than my explanation, how Dr. Hamer uses these tissues in explaining his work. 

Basically, when an egg is fertilized it then divides (remember your biology class?) and forms three cellular layers called ectoderm (outer layer), mesoderm (middle layer) and endoderm (inner layer). These layers will give rise to all of the body’s tissues and organs.

For example, from the Ectoderm (in red below) develops the outer skin and nervous tissue. From the Mesoderm (in orange below) develops muscle, bone, cartilage, blood vessels and connective tissue. And the Endoderm layer (in yellow below) develops into the lining of the digestive and respiratory systems.

Although these cellular layers are also called germ layers, according to traditional medicine, they have nothing to do with germs. Dr. Hamer however, in his research, has determined that the organs derived from this ectoderm tissue uses viruses and certain bacteria when healing from a conflict. Organs derived from the mesoderm tissue use bacteria and sometimes fungi for healing, and the organs that originate from the endoderm tissue use TB bacteria and fungi for healing.

Dr. Hamer has also determined that these germs multiply at the time of a DHS and they do not cross the tissue layers. For example, in a lung cancer (death fright) you will never find a virus but instead TB bacteria. (The following is a diagram taken from Dr. Hamer’s book.)

Merhaba arkadaşlar Sinir sistemiyle dönüyorum

Sinir sistemi “ektodermden” köken alır. Embriyonun sırtındaki ektodermin kalınlaşmasıyla nöral plak gelişir. 3.haftadan itibaren lamina nöralis, crista nöralis, sulcus nöralis ve nöral tüp gelişir. Nöral tüpün “pars cranialis” dediğimiz ön bölümünden primer beyin kesecikleri gelişir. Bunlar : PROSENCEPHALON MESENCEPHALON RHOMBENCEPHALON dur.

Flexible Neural Tube #neuroanatomy #neuroembryogenesis #neuroscience #gummischlauchtheorie #vonBaer

Several days ago I mentioned the work of Wilhelm His, who modeled the neural tube after a flexible rubber tube. He noted that a rubber tube could be manipulated into forms that resembled the neural tube of the chick embryo, at various stages by pulling strings attached to certain places on the rubber tube. The strings represented forces that were applied to the actual neural tube by unknown…

Surface Ectoderm:   NILE & AHE MAP

N ails

I nner & Outter Ear

L ens of eye

E pidermis

A nterior Pituitary (Rathke pouch)

H air

E enamel of teeth

M ammary glands

A anal canal BELOW pectinate line

P arotid gland

Neuroectoderm = Neural Tube:   CAN  PRO

C NS: Somatic Motor Neurons and Preganglionic Neurons (ANS)

A strocytes ☆

N eurohypophysis (Posterior Pituitary)

P ineal gland

R etina & O ptic Nerve

O ligodendrocytes (myelinate all the cell)

Neural Crest:  MA & POPE  GASP

M eninges: Pia & Arachnoid

A drenal medulla

P igment cells (chromaffin cells)

O dontoblasts

P haringeal arch CARTILAGE

E ndocardial cushions  ♥

G anglia: Sensory Pseudounipolar neurons & Postganglionic Neurons (ANS)

A orticopulmonary Septum

S chwann cells (PNS, myelinate one segment)

P arafollicular (C) cells