Stages of Embryo Development

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What is the first stage of embryo development called?

The first stage of embryo development is called fertilization, where the sperm and egg combine to form a zygote.

What happens during cleavage in embryo development?

During cleavage, the zygote undergoes rapid cell division without increasing in size, forming a cluster of cells.

What is a blastocyst?

A blastocyst is a structure formed in the early development that contains a fluid-filled cavity, the trophoblast, and the embryoblast.

At what stage does implantation occur?

Implantation occurs when the blastocyst attaches to the uterine wall, around 6-7 days after fertilization.

What is gastrulation in embryo development?

Gastrulation is the process where the blastula reorganizes into a trilaminar structure with three germ layers: ectoderm, mesoderm, and endoderm.

Which structures arise from the ectoderm layer?

The ectoderm layer gives rise to the nervous system, skin, and hair.

What does the mesoderm layer develop into?

The mesoderm layer develops into the circulatory system, bones, muscles, and reproductive organs.

Which organs are derived from the endoderm layer?

The endoderm layer forms the digestive tract, liver, pancreas, and respiratory system.

What is neurulation and when does it occur?

Neurulation is the process of forming the neural tube, occurring after gastrulation during embryonic development.

At what stage do somites form, and what is their significance?

Somites form during the third week of development and are crucial for the segmentation of body structures.

What is the role of the placenta in embryo development?

The placenta facilitates the exchange of nutrients and waste between mother and embryo and produces hormones essential for maintaining pregnancy.

How does the embryonic heart develop initially?

The embryonic heart begins as a simple tube that twists and folds, eventually forming a four-chambered heart.

What is the significance of limb bud formation?

Limb buds are early stages of limb development where the future arms and legs of the embryo begin to emerge.

What role does apoptosis play in embryo development?

Apoptosis, or programmed cell death, is crucial for shaping embryonic structures, such as separating digits in limbs.

When does the fetal stage begin, and what characterizes it?

The fetal stage begins at the end of the 8th week, characterized by the continued growth and maturation of organs and systems.

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