Digestive System Jr/Sr Veterinary Science Mrs. Chotkowski #1
Functions Intake & digestion of food Absorption of nutrients Elimination of solid waste products
Structures Oral cavity & pharynx Esophagus Stomach Small Intestines Large Intestines, rectum, anus
Oral Cavity (Mouth) Lips: responsible for ingestion Prehension: Grasping of food Tongue: organ which tastes food; contain papillae (bumps & ‘taste buds’) Mastication: Breaks food into pieces with saliva Teeth: grind food –Deciduous dentition: temporary ‘baby’ teeth –Permanent dentition: adult teeth
Esophagus Collapsible, muscular tube; brings food to the stomach Peristalsis: waves of muscle contraction that move food through the digestive tract
The Stomach Stores food, begins digestion Monogastric (Simple Stomach): –Humans, pigs, dogs, cats Monogastric w/ a functional cecum: –Horses, rabbits Ruminant (four compartments): –Cattle, sheep, goats (chew cud)
Monogastric (Dog)
What are the parts A – G ?
Monogastric w/ Functional Cecum
Ruminant
Digestive Juices Saliva (mouth); lubricates feed, contains amylase, which breaks down starch Bile (liver); helps break down fat Intestinal juices: contain enzyme peptidase, to break down proteins, & maltase, sucrase, & lactase to break down sugars
Gastric Juices HCl: stops action of amylase Pepsin: enzyme, digests proteins Rennin: enzyme, digests milk protein Lipase: enzyme, digests fats Mucus: protects stomach lining Gastrin: stimulates stomach to produce more juices
Pancreatic juices Lipase: breaks down fats Trypsin: Breaks down proteins Chymotrypsin: acts on proteins Amylase: works on starch
Ruminant Digestion Rumen: largest compartment, serves as a fermentation vat Reticulum: honeycomb, helps filter feed Omasum: contains papillae that help grind food Abomasum: true stomach, secretes gastric juices, starts protein digestion
Small Intestine Duodenum: first portion, continues digestion Jejunum & Ileum: rest, performs absorption of nutrients into the bloodstream
Large Intestine Cecum: enlarged first portion, contains micro-organisms, fermentation vat Colon: absorbs water and forms feces Rectum: carries feces to the anus Anus: passes solid wastes out of body
The End