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The Digestive System. Introduction to Veterinary Science Chapter 7. Structures of a Tooth. Enamel. Crown. Dentin. Pulp. Neck. Root. Cementum. Vein, Artery, and Nerve. Canine Dentition. Molars (2). Premolars (4). Canine (1). Incisors (3). Incisors (3). Canine (1). Molars (3).
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The Digestive System Introduction to Veterinary Science Chapter 7
Structures of a Tooth Enamel Crown Dentin Pulp Neck Root Cementum Vein, Artery, and Nerve
Canine Dentition Molars (2) Premolars (4) Canine (1) Incisors (3) Incisors (3) Canine (1) Molars (3) Premolars (4)
___Used for tearing food ___Absent in upper jaw of cattle (2) ___”Cheek teeth” (2) ___Root is twice as long as exposed crown ___Used for crushing and grinding food (2) ___Most caudally located ___Used to bite into food ___Tusks in pigs ___Flatter and tightly packed in herbivores (2) ___Used for age estimation Incisors Canines Premolars Molars Match the description with the tooth type 2 1,2 3,4 2 3,4 4 1 2 3,4 1
Intestinal Tract of a Dog Esophagus Duodenum Rectum Anus Cecum Ileum Colon Stomach Jejunum
Intestinal Tract of a Horse Dorsal Colon Colon Left Ventral Colon Rectum Anus Duodenum Esophagus Stomach Right Ventral Colon Ileum Cecum Jejunum
Intestinal Tract of a Ruminant Duodenum Rumen Colon Esophagus Rectum Anus Reticulum Ileum Omasum Cecum Abomasum Jejunum Spiral Loops
Functions of the Liver and Pancreas • Liver: • Produces bile for storage in gallbladder. Bile salts emulsify fat for faster digestion. • Stores vitamins and iron in reserve. • Controls blood sugar levels and removes excess amino acids from blood. • Pancreas: • Produces sodium bicarbonate to neutralize stomach acid. • Secretes digestive enzymes and hormones (glucagon and insulin). • Secretions from the liver and pancreas empty into the duodenum through ducts.
Intestinal LiningLarge circular folds, villi, and microvilli increase surface area for absorption.
__Absorbs nutrients __An exocrine gland __Divided into duodenum, jejunum, and ileum __Has folds called rugae __Where bolus of food is formed __Contains ascending, transverse, and descending sections __Where digestion begins __Associated with the mesentery __Absorbs water __Divided into cardia, body, and pylorus __Where paristalsis first occurs __Drains through the hepatic duct __Secretes hydrochloric acid __Stores bile Mouth Esophagus Stomach Small intestines Colon Liver Gallbladder Pancreas Match the description with the digestive structure 4 8 4 3 1 5 1 4 5 3 2 6 3 7
The Ruminant Stomach Bacteria in the reticulorumen digest plant fiber and release nutrients for the host animal to absorb and use. This is a symbiotic relationship in which both the animal and the bacteria benefit. Fermentation vat, plant fiber digested by bacteria Traps heavy objects, secondary site of fermentation Grinds food and extracts fluid Secretes digestive enzymes, acts as “true stomach”
Rumination Rumination: The process of bringing up food material from the stomach to the mouth for further chewing • Phase 1 – Regurgitation: • Animal inhales, difference in pressure causes rumen contents to enter esophagus, reverse paristalsis moves food bolus into mouth • Phases 2 and 3 – Remastication and Resalivation: • Food bolus (cud) is chewed repeatedly, liquid is squeezed out and swallowed • Phase 4 – Redeglutition: • Cud is reswallowed, next rumination cycle begins
