Structure and Function of the Tongue, Teeth and Mouth in Dogs
3 Aug, 2015 Dr. Bari Spielman
Below is information about the structure and function of the canine tongue, teeth and mouth. We will tell you about the general structure, how they work in dogs, common diseases that affect these areas and common diagnostic tests performed in dogs to evaluate the tongue, teeth and mouth.
What Are the Tongue, Teeth and Mouth?
A dog’s tongue is an elongated, mobile, muscular organ. It is the chief organ responsible for taste and obtaining food. It also aids in the chewing and swallowing of food. The teeth are highly specialized structures that tear, cut and grind food into pieces small enough to swallow. Teeth also serve as weapons of offense and defense for dogs. The mouth is the entrance to the gastrointestinal tract. The mouth, teeth and tongue are collectively termed the oral cavity.
Where Are the Tongue, Teeth, and Mouth Located?
The tongue is located on the floor of the mouth. It extends from its posterior attachment on a small bone called the basihyoid bone to its free tip at the front of the jaw.
The teeth are located on both sides of the mouth. Two rows of upper teeth are anchored in the maxilla bone of the face. Two rows of lower teeth are anchored in the jaw bones (mandibular bone). Each tooth has a crown, which is the part that can be seen in the mouth, and one or more roots, which are located under the gum line The roots of the teeth are anchored within bone. Dogs generally have 28 baby teeth, also referred to as deciduous teeth, and 42 adult or permanent teeth. The permanent teeth include six pairs of sharp incisor teeth, which are in the front of the mouth, surrounded by two pairs of large canine teeth. The premolar teeth are located just behind the canine teeth. The molars sit behind the premolars and are located towards the back of the mouth.
The mouth is located in the lower, front part of the face and is considered the entire area between the upper and lower jaws. The mouth includes the space just outside the teeth and gums, and just inside the lips and cheeks. The main part of the mouth, or oral cavity proper, is bound on the top by the hard palate and the soft palate. On the sides and front of the mouth, the teeth and lips form the major boundary. On the bottom, the tongue and adjacent tissues form the floor of the mouth.
What Is the General Structure of the Tongue, Teeth and Mouth for Dogs?
The tongue is an elongated muscular organ with the top surface covered with specialized little mushroom-shaped structures called papillae. These papillae contain tiny holes or pores that lead to taste buds. The bulk of the tongue consists of muscle bundles mixed with connective (strong/tough) and adipose (fat) tissue. It has many blood vessels and bleeds profusely when lacerated. The tongue is surrounded by the openings of the ducts of the salivary glands, which pour their secretions (saliva) into the oral cavity.
Each tooth consists of four types of tissue: pulp, dentin, enamel and cementum. Connective tissue surrounds the root of the tooth. This tissue, called the periodontal ligament, holds the root in the bony socket in the jaw.
Pulp is the innermost tissue of the tooth. It is the only soft tissue of the tooth and resides in the center of tooth, especially towards the root end. It consists of connective tissue, blood vessels and nerves. The blood vessels nourish the tooth, and the nerves transmit sensations of pain, coldness, or heat to the brain.
Dentin is a hard, yellow substance that surrounds the pulp. It makes up most of a tooth and gives the tooth an inner ivory or creamy color. Dentin is harder than bone and consists mainly of mineral salts and water. It is formed by cells called odontoblasts.
Enamel overlies the dentin on the crown of the tooth. It forms the outermost covering of the crown. It is the hardest tissue in the body. It enables a tooth to withstand the pressure placed on it during chewing. Enamel consists of mineral salts and a small amount of water. It is usually a pearly-white color.
Cementum covers the dentin along the root of the tooth. In most cases, the cementum and enamel meet where the root ends and the crown begins. Cementum is as hard as bone, and it consists mainly of mineral salts and water.
The root is the portion of the tooth that lies below the gum and is embedded in the alveolus or socket. Some premolar and molar teeth have more than one root. Once teeth are fully erupted in the animal, they cease growing.
Dogs have two sets of teeth that develop during their most active growing period. The first set of teeth, called deciduous teeth, are temporary. Deciduous teeth are fully erupted and functional early in the second month after birth. Upon approaching maturity, when the jaws have become longer and larger, the small deciduous teeth are no longer adequate. They are shed and replaced by the permanent teeth, which last through adult life. The adult teeth are larger than the deciduous teeth. As the jaws continue to grow more permanent teeth are added in back of the mouth. These posterior teeth are molars.
The mouth is lined with mucus membranes. The roof of the mouth is called the palate. The front portion consists of a bone covered by a membrane and is called the hard palate. The hard palate separates the mouth from the nasal passages. The soft rear part of the roof of the mouth is called the soft palate. It forms a flexible curtain between the back of the mouth (oropharynx) and the back of the nasal cavity.
Other structures of the mouth include both upper and lower lips and the cheeks. Numerous small glands are present in the mouth, including the sublingual salivary gland, which sits under the tongue. The ducts of the other salivary glands also open into the mouth.