Digestive System Overview

Digestive System

GI tract. Extracts usable nutrients from food. Excretes waste products. Food provides energy for the body

GI Tract

The series of organs that food and liquids pass through as they are digested, absorbed, and leave the body as feces

Deciduous Teeth

The first set of teeth that mammals develop

Retained Deciduous Teeth

Teeth that remain in the mouth after the permanent tooth has erupted

Mastication

The process of chewing food

Hypersalivation

Condition where the body produces too much saliva or has difficulty swallowing it

Cheek Teeth

The premolar and molar teeth in mammals

Milk Teeth

Any of a set of early, temporary teeth in young mammals that fall out as the permanent teeth erupt

Gingiva

The tissue of the upper and lower jaws that surrounds the base of the teeth

Gingiv/o

Gingiva

Dentition

Refers to teeth as a whole. Primary is temporary. Secondary dentition is permanent. Eruption times vary with species

Dent/o, Dent/i, Odont/o

Dentition

Decidu/o

Shedding

2(I3/3, C1/1, P4/4, M2/3)=42 teeth

Canine adult dental formula

Prognathia

A condition where the lower jaw protrudes forward beyond the face, resulting in an abnormally prominent chin

Brachygnathia

A condition where the lower jaw is shorter than the upper jaw, causing an abnormal alignment of the jaw

Bolus

A small round lump of digested food

Gustation

The act or sensation of tasting

Deglutition

The act or process of swallowing

Peristalsis

A series of automatic, wave-like muscle contractions that move food, urine, and bile through the body

Oral Cavity

Where ingestion begins. Lips form the opening. Cheeks form walls. Palate forms roof of mouth. Lined with mucous membranes

Or/o, Stomat/o

Ingestion

Labi/o

Lips

Bucc/o

Cheek

Palat/o

Palate

Mandibular

Relating to, located near, or of the nature of the lower jaw

Pharynx

Throat. Shared with respiratory system. Lined with mucous membranes. Connects with the esophagus, the larynx, and the trachea

Pharyng/o

Pharynx

Esophagus

Carries food from pharynx to stomach. Dorsal to the trachea. Has striated and smooth muscle

Esophag/o

Esophagus

Monogastric Stomach

Simple, 1 chamber. Produces secretions. Has 4 parts: cardiac sphincter, fundus, body and pylorus

Gastr/o

Stomach

Ruminant Stomach

Compound stomach, multi-chambered. Found in ruminants. Four Chambers (one true stomach and three forestomachs. Adapted for fermentation of ingested food

Rumen

Largest chamber of the ruminant stomach. First stage of digestion. Fermentation vat

Reticulum

Second chamber of the ruminant stomach.Most cranial portion. Food mixes with saliva. Regurgitated to remasticate food

Omasum

Third chamber of the ruminant stomach. Squeezes fluid out of food bolus. Where water and minerals are absorbed into the bloodstream

Abomasum

Fourth chamber of the ruminant stomach and “True stomach.” Where food digestion is completed

Small Intestine

Extends from pylorus to large intestine. Three segments: duodenum, jejunum and ileum. Major site of enzymatic digestion and absorption. Food mixes with digestive juices. Inner surface covered with villi

Enter/o

Intestine

Duoden/i, Duoden/o

Duodenum

Jejun/o

Jejunum

Ile/o

Ileum

Duodenum

The first part of the small intestine immediately beyond the stomach, leading to the jejunum

Jejunum

The second part of the small intestine

Ileum

The third portion of the small intestine, between the jejunum and the cecum

Large Intestine

Extends from ileum to anus. No villi or digestive glands. Divided into 4 parts: cecum, colon, rectum, anal sphincter

Cec/o

Cecum

Col/o

Colon

Rect/o

Rectum

An/o, Proct/o

Anus

Cecum

Joins ileum to ascending colon

Colon

Absorbs water, vitamins and electrolytes

Rectum

Holds feces

Anal Sphincter

Controls passage of feces out of the body

Chol/e, Syst/o

Gallbladder

Pancreat/o

Pancreas

Liver

Largest gland in body. Lies in cranial abdomen. Divided into lobes. Detoxifies the body systems, breaks down fat and produces bile as a byproduct.

Gallbladder

Lies under lobes of liver. Reservoir. Contains salts for fat digestion. Stained yellow-green. Secretes bile into duodenum. Aids in fat digestion

Pancreas

Lobular gland. Lies in curve of duodenum. Exocrine gland. Endocrine and exocrine functions

Exocrine

Secretes digestive enzymes and bicarbonate into duodenum

Unable to Vomit

Rabbits, rodents, equine. Do not have a gallbladder. No bile is produced to stimulate intestines

Distension

The act of swelling or becoming larger due to pressure from within, or the result of this

Torsion

A twisting or rotation of an organ or body part

Ascites

The build-up of fluid in the space between the lining of the abdomen and abdominal organs

Cirrhosis

A progressive liver condition that occurs when the liver is permanently scarred due to long-term damage

Colic

Abdominal pain

Regurgitation

Passive ejection of esophageal contents. No effort or abdominal contractions. Caused by an overflow of esophageal contents. Normal in ruminants and birds. Not normal in other species

Vomiting

Involuntary, reflexive ejection of stomach contents. Caused by message sent from stomach to brain. Usually preceded by salivation and nausea. Active abdominal contraction. Can be projectile

Flatulence

Passing gas. Caused by excess gas formation in the GI tract. Can be a sign of poor absorption

Hemorrhagic Gastroenteritis (HGE)

Acute vomiting and/or bloody diarrhea. Can be caused by intestinal parasites

Septicemia

Blood infection. Caused by bacteria backing into bloodstream through intestinal wall. Can be acute or gradual onset. Common symptoms include lethargy, chills, fever, tachycardia

Gastric Dilation and Volvulus (GDV)

Stomach distended with gas and fluid or food. “Bloat.” Prevents gas or contents from escaping. Torsion. Requires immediate treatment, usually surgery. Common in large or deep-chested dog breeds. Colic in horses

Exocrine Pancreatic Insufficiency (EPI

Pancreas fails to produce sufficient enzymes. Trypsin. Chronic diarrhea. Gradual weight loss

Diarrhea

Frequent evacuation of watery feces. May be acute or chronic. Indicates some form of intestinal disturbance