Embryonic Origin of Tissue- Ectoderm, Mesoderm, Endoderm

Germ Layer - Embryonic Origin of Tissue

 

A germ layer is a group of cells present in an embryo that interact with each other and as the embryo develops and contribute to the formation of all organs and tissues.

 

What are Germ Layers?

 

Germ layer formed in the earliest stages of embryonic development.

Consisting of-

 

1. Ectoderm (ecto- “outer”) 

2. Mesoderm (meso-“middle”)

3. Endoderm (endo- “inner”)

 

The zygote (fertilized egg), is a single cell formed by the fusion of an egg and sperm.

After fertilization the zygote gives rise to many rapid mitotic cycles, generating many cells to form the embryo.

 

Totipotent

The first embryonic cells generated have the ability to differentiate into any type of cell in the body means each has the capacity to divide, differentiate, and develop into a new organism, called totipotent.

 

Three Primary Germ Layers in Embryo

 

As cell proliferation progresses, eight-day after sperm fertilizes an egg, three major cell linings are embedded within the embryo inlining of the uterus and begin to form three primary germ layers.

Each of these three embryonic cells forms the distinct germ layers from which all the tissues and organs of the human body, These germ layers are-

 

1. Ectoderm germ layer

2. Endoderm germ layer

3. Mesoderm germ layer

 

Embryonic Origin of Tissues

1.  Epithelial tissue

Epithelial tissue originates in all three layers; from Ectoderm, Endoderm, and Mesoderm.

 

Check here the types of epithelial tissue and their function.

2. Connective tissue

Connective tissue develops from Mesoderm.

Know here what are connective tissue is and the types and functions of connective tissue.

 

3. Muscle tissue

Muscle tissue develops from Mesoderm.

Check out what is muscle tissue in the human body?

 

4. Nervous tissue 

Nervous tissue develops from Ectoderm.

 

Get details on nervous tissue; types of nervous tissue and their

functions.

 

Embryonic Origin of Tissues and Major Organs

 

Germ Layer	Gives Rises To
Ectoderm	Epidermis, glands on skin, some cranial bone, pituitary and adrenal medulla, nervous system, mouth between cheek and gums, the anus. For example - skin cells, neurons, pigment cells.
Mesoderm	Connective tissue proper, bone, cartilage, blood, endothelium of blood vessels, muscle, synovial membranes, serous membranes lining body cavities, kidneys, lining of glands. For example - Cardiac muscle, skeletal muscle, tubule cells of kidney, red blood cells, smooth muscle.
Endoderm	Lining of airways and digestive system except mouth, and  Distal part of digestive system (rectum and anal canal); glands (digestive gland), endocrine glands, adrenal cortex. For example - Lung cell, thyroid cell, pancreatic cell, liver cell.