Digestive Tract Notes — Comprehensive Study (English)

Alimentary tract / GI tract / Guts

Terminology referring to the digestive system.

Herbivores

Animals that eat plant material.

Carnivores

Animals that primarily eat meat byproducts (e.g., cats, ferrets).

Omnivores

Animals that can utilize both animal and plant material (e.g., pigs, bears).

Monogastric

Animals with a simple stomach (one stomach).

Ruminants

Foregut fermenters with a four-chamber stomach (rumen, reticulum, omasum, abomasum), common examples being cattle, sheep, and goats.

Foregut fermenters

Herbivores where fermentation primarily occurs in the foregut (e.g., ruminants).

Hindgut fermenters

Herbivores where fermentation primarily occurs in the hindgut (e.g., large intestine, cecum, colon in horses, rabbits, guinea pigs).

Microbial digestion

The process by which microbes break down plant cellulose/hemicellulose, which mammals cannot digest effectively on their own.

Prehension

The process of taking food into the oral cavity, involving lips, teeth, and tongue.

Mastication

The mechanical breakdown of food by chewing.

Bolus formation

The process of saliva and chewing forming a smaller, easily swallowed mass of food.

Autonomic nervous system (GI function)

Controls most GI tract smooth muscle; Parasympathetic (rest and digest) increases motility and saliva, Sympathetic (fight-or-flight) decreases motility and saliva.

Vomeronasal (Jacobson extquotesingle s) organ

A sensory organ that detects pheromones or scents via oral exposure, enabling the flehmen response in some species.

Papillae

Raised structures on the tongue, some specialized for mechanical functions (filiform, conical) and others for taste (fungiform, vallate, foliate).

Taste buds

Sensory receptors on the tongue for taste (salty, sweet, bitter, sour, umami).

Incisors

Teeth at the front of the mouth, used for biting and cutting.

Canines

Pointed teeth, typically used for tearing food.

Premolars

Teeth located between canines and molars, used for grinding and crushing.

Molars

Large, flat teeth at the back of the mouth, primarily used for grinding.

Occlusal surface

The contact surface where upper and lower teeth meet during chewing.

Diastema

A space between teeth.

Lingual surface

The surface of a tooth toward the tongue.

Palatal surface

The surface of a tooth toward the hard palate.

Buccal surface

The surface of a tooth toward the cheek.

Labial surface

The surface of a tooth toward the lips.

Enamel

The outermost, hardest tissue covering the crown of a tooth.

Dentin

The primary structure of a tooth, produced by odontoblasts and forming most of the tooth.

Cementum

A bone-like tissue covering the root of a tooth, providing attachment for the periodontal ligament.

Pulp

The inner chamber of a tooth containing blood vessels and nerves.

Periodontal ligament

A ligament that holds the tooth in its socket, forming a gomphosis joint.

Gingiva / Gum tissue

The tissue surrounding the teeth.

Gingival sulcus

The space between the tooth and the surrounding gingiva; its depth indicates periodontal health.

Triadan system

A quadrant-based tooth numbering system: 100-series (right upper), 200-series (left upper), 300-series (left lower), 400-series (right lower).

Carnassial teeth

The largest shearing teeth in small animals: the upper fourth premolar and the lower first molar.

Wolf extquotesingle s tooth

A small first premolar in some horses that may interfere with bits and require extraction.

Dental pad

A keratinized pad in bovines that replaces upper incisors and is used with lower incisors for grinding.

Wave mouth

An abnormal occlusal pattern in horses causing malocclusion and potentially weight loss.

Hypsodont teeth

High-crowned, continuously erupting teeth found in horses and some ruminants.

Brachydont teeth

Short-crowned teeth with defined crowns and limited eruption, such as in dogs and cats.

Vesicular stomatitis

A reportable disease causing vesicles around the lips and tongue in horses and small ruminants.

Foot-and-mouth disease (FMD)

A highly contagious, reportable disease causing vesicular lesions around the lips, tongue, and coronary band in ruminants.