Invagination

Invagination refers to the folding in of a cell layer or the turning inward of a part of an organism or structure. It is a biological process where one part of a structure telescopes or tucks inside another, creating a pocket or indentation. This can occur at the cellular level, during embryonic development, or in the anatomy of certain organisms. The process is crucial for the formation of complex structures and the development of specialized tissues.

Invagination meaning with examples

• During gastrulation in embryology, the blastula undergoes invagination to form the gastrula, establishing the primary germ layers. Cells on one side of the blastula fold inward, leading to the formation of the archenteron, the primitive gut, and defining the body plan.
• In the development of a sea urchin embryo, the vegetal plate cells undergo invagination to form the archenteron. This inward folding involves cell shape changes and coordinated movements that eventually establishes the digestive tract.
• The early embryonic stage of the frog embryo is crucial to forming the blastopore, through the process of invagination where cells on the dorsal side of the blastula involute inwards and establish the body axis.
• The formation of intestinal villi, tiny finger-like projections that increase the surface area of the small intestine, involves invagination of the gut lining during fetal development, leading to increased nutrient absorption.