Question

Can anyone please teach me Development Of A Chick comprehensively :(

Answer 1

The Formation of an Egg:

The Yolk: The chicken egg starts as an egg yolk inside a hen. A yolk (called an oocyte at this point) is produced by the hen's ovary in a process called ovulation.
Fertilization: The yolk is released into the oviduct (a long, spiraling tube in the hen's reproductive system), where it can be fertilized internally (inside the hen) by a sperm.

The Egg White (albumin): The yolk continues down the oviduct (whether or not it is fertilized) and is covered with a membrane (called the vitelline membrane), structural fibers, and layers of albumin (the egg white). This part of the oviduct is called the magnus.

The Chalazae: As the egg goes down through the oviduct, it is continually rotating within the spiraling tube. This movement twists the structural fibers (called the chalazae), which form rope-like strands that anchor the yolk in the thick egg white. There are two chalazae anchoring each yolk, on opposite ends of the egg.

The Eggshell: The eggshell is deposited around the egg in the lower part of the oviduct of the hen, just before it is laid. The shell is made of calcite, a crystalline form of calcium carbonate.

This entire trip through the oviduct takes about one day.

Growth of the Embryo: The fertilized blastodisc (now called the blastoderm) grows and becomes the embryo. As the embryo grows, its primary food source is the yolk. Waste products (like urea) collect in a sack called the allantois. The exchange of oxygen and carbon dioxide gas occurs through the eggshell; the chorion lines the inside surface of the egg and is connected to the blood vessels of the embryo.

The Incubation Period: The embryo develops inside the egg for 21 days (the incubation period), until a chick pecks its way out of its eggshell and is hatched.

Answer 2

And what about the blastula, morrula, gastrula, neurula stages?

Answer 3

wow

Answer 4

These are stages in early development of chick embryo. First of all make sure that you understand what nature is trying to do when it makes the embryo pass through these stages, i will first try to explain some general terms which will help you to understand the actual development process of the chick embryo better. I hope you know about the three germ layers, ectoderm, mesoderm and endoderm. Life begins with a single cell, every cell present in a fully grown body is a progeny of that first cell called zygote. Now as this cell multiplies, it gives rise to a mass of cells, u can imagine it as a solid ball made up of cells. This is Morula. Now morula contains precursors of all the three germ layers, and these cells need to be arranged according to their respective positions in future embryo viz endoderm inside, ectoderm outside and mesoderm inbetween, for this purpose the cells need to be moved and this cannot happen in a solid ball like morula, so a cavity develops inside this cell mass, this cavity is filled with fluid which facilitates the movement of the cells. This cavity is called as blastocyst and the stage of embryo is called blastula stage. Next comes the stage where actual sorting of the cells will take place. In this stage, the endoderm cells will move inside the embryo usually through a pore that develops, (blastopore). Followed by mesodermal cells which will be placed in between. Now the remaining ectodermal cells will proliferate and eventually cover up the whole embryo from the outside, the phenomenon known as epiboly of the ectoderm. This whole process is called gastrulation and the new three layered embryo will be called a gastrula.

Answer 5

Now first the egg of the chicken is telolecithal. That means a small disc of cytoplasm sits on the top of large dollop of yolk (yolk is that material which nourishes the developing embryo). As fertilization takes place, this cytoplasm begins to divide into cells. The mass of cells is called blastoderm. Once sufficient number of cells are formed, a few cells will move BENEATH the blastoderm to form a few islands of cells between the blastoderm and the yolk. Now from the posterior end of the blastoderm, a sheet of cells advances beneath the blastoderm, towards the anterior end, which now connects these islands of cells into a continuous layer called hypoderm. Hypoderm separates blastoderm from underlying yolk, it also encloses a cavity between itself and blastoderm, this cavity is blastocoel in the chick embryo and the embryo now becomes a blastula. Now the next task is to bring the cells of respective germ layers into their correct order of arrangement. First the endodermal and mesodermal cells begin to move towards the center of the blastoderm, there they form a thickening which forms a sort of a ridge on the blastodisc from posterior to the anterior end. u cal imagine this ridge as a line that divides an ovoid blastodisc into right and left halves. This ridge is called primitive streak. Now there appears a depression on the primitive streak which will elongate along the length of the ridge, this depression takes a form of a furrow through which the endodermal and mesodermal cells will pass inside the embryo to be arranged in their respective order. The ectodermal cells will now proliferate to cover up the entire embryo (epiboly) remember that ectodermal cells also cover the large dollop of yolk, so this is the longest task that is performed in this process. It usually takes 3 -4 days. Now we have a three layered embryo which will now develop further to form various organs like notocord, brain, heart etc.

Answer 6

The neurula stage is the stage in which the nervous system is formed. After the development of notocord, the area above notocord thickens and forms a plate, which is called neural plate. Neural plate folds upon itself to form neural tube which lateron gives rise to brain and spinal cord.