Difference Between Mesenchyme and Ectomesenchyme

The key difference between mesenchyme and ectomesenchyme depends on the type of cells they contain. Mesenchyme contains loose cells that migrate easily to form the ground tissue of collagen, and bone and cartilage tissue while ectomesenchyme contains neural crest cells and forms the tissues of neck and cranium.

Both mesenchyme and ectomesenchyme are present in the embryonic stage. The development of the mesenchyme and the ectomesenchyme is important to study the development of various tissues that arise from these cells.

CONTENTS

1. Overview and Key Difference
2. What is Mesenchyme 
3. What is Ectomesenchyme
4. Similarities Between Mesenchyme and Ectomesenchyme
5. Side by Side Comparison –  Mesenchyme vs Ectomesenchyme in Tabular Form
6. Summary

What is Mesenchyme?

Mesenchyme originates from the mesoderm during the embryonic development of animals. The mesenchyme consists of loose cells embedded in the extracellular matrix. Upon the development of the fetus, these cells give rise to many important tissues in an animal system. The Mesenchymal cells originate from the mesenchyme; they give rise to the connective tissue which contains collagen, bone tissue, and cartilage tissue. Thus, the ground tissue of animals originates from the mesenchyme.

Mesenchyme is a transitive tissue due to the changes it can undergo during late development stages. The mesenchyme that is present in the early embryonic stage changes in the late gastrulation phase. Mesenchyme forms the mesodermal layer by losing its adhesive properties with the epithelia. This is referred to as the epithelial-mesenchymal transition.

What is Ectomesenchyme?

Ectomesenchyme is a mesenchymal tissue developed from the ectoderm. In other words, ectomesenchyme is an ectoderm that is capable of producing a mesenchyme. The ectomesenchyme composes neural crest cells. The cranial neural crest of the ectoderm leads to the development of two main tissue groups: the ectomesenchymal and the non-ectomesenchymal regions. The ectomesenchyme, therefore, gives rise to the formation of ground tissue in the cranial region or the head region. The ectomesenchyme also gives rise to bones, cartilage, connective tissue and dentine of the cranial region. This includes the head and the neck regions.

In context with the anatomy of the cranial region, the ectomesenchyme crest lies in the ventral position and fills the pharyngeal arches and the facial regions. Furthermore, the presence of ectomesenchyme is characteristic to vertebral evolution.

What are the Similarities Between Mesenchyme and Ectomesenchyme?

• Both mesenchyme and ectomesenchyme are present in animals.
• Mesenchyme and ectomesenchyme give rise to tissues such as bone tissue, cartilage, and connective tissue although their distributions differ.
• Both are present during the early embryonic development stage.

What is the Difference Between Mesenchyme and Ectomesenchyme?

Summary – Mesenchyme vs Ectomesenchyme

Both mesenchyme and ectomesenchyme develop from the mesoderm and the ectoderm, respectively. Mesenchyme contains loose cells which give rise to connective tissue, bone and cartilage tissues. In contrast, ectomesenchyme is restricted to the development of connective, bone and cartilage tissues of the cranial region. This is the difference between mesenchyme and ectomesenchyme.

Reference:

1. Blentic, Aida, et al. “The Emergence of Ectomesenchyme.” Developmental Dynamics : an Official Publication of the American Association of Anatomists, U.S. National Library of Medicine, Mar. 2008, Available here.
2. “The Embryo Project Encyclopedia.” Mesenchyme | The Embryo Project Encyclopedia, Available here.

Image Courtesy:

1. “Mesenchyme” By Jpogi at Wikipedia – Transferred from en.wikipedia to Commons by FastilyClone using MTC!., (Public Domain) via Commons Wikimedia