The Digestive System




The region of the tooth which is exposed above the gingiva is the crown. this region of the tooth has a covering of enamel and a thick layer of dentin beneath. The enamel extends just sligtly beneath the soft gingival tissues, but the dentin extends on into the tooth socket. The neck of the tooth is the region beneath the gingiva, between the crown and the root. The root of the tooth extends into the tooth socket. between the dentin of the tooth and the bone that surrounds the tooth socket, there are two layers of modified tissues. The outer periodontal ligament is a modified collagen, a dense connective tissue that holds the tooth to the jaw. The inner cementum has a matrix which is similar to dentin in the composition of its matrix, and similar to bone, in that it has cells in lacunae. However, unlike bone, cementum is avascular.

The pulp cavity of a tooth is occupied by a connective tissue, blood vessels, and nerve fibers. Some of these nerve fibers extend into the dentin of the tooth, allowing for sensitivity in the dentin.





Introduction to Human Digestive System

Human Oral Cavity

Structure of a Tooth

Tooth Development

Human Salivary Glands

Divisions of the Pharynx

Human Esophagus

Human Stomach

Human Small Intestine

Human Large Intestine

Human Biliary System and Pancreas

Mouth Development

Formation of Pharyngeal Derivatives

Development of Liver, Gall Bladder, and Pancreas

Development of Intestines

Urorectal Fold and Separation of Cloaca

A Comparative Look at Vertebrate Teeth

A Comparative Look at the Vertebrate Tongue

A Comparative Look at Digestive Tubes