Digestion and Absorption

Continued…

Mouth to Stomach

• food pushes into the esophagus (muscular tube connecting the mouth to the stomach)

• food carried via peristalsis• lower esophageal sphincter controls the

passage of food and liquid between the esophagus and stomach

• as food approaches the closed sphincter, the muscle relaxes and lets food pass through to the stomach

Stomach

• stores swallowed food and liquid

• mixes food and liquid with digestive enzymes and acid it produces (chyme)

• Acidic due to HCl (pH 1-3)– Why doesn’t the stomach

get damaged with such a low pH?

Gastric Enzymes

• Pepsin: breaks protein into amino acids

• Gastric Lipase: breaks apart lipids

Small Intestine

• muscles mix food with digestive enzymes from the pancreas, liver, and intestine and push the mixture forward (via persistalsis) to the large intestine

• walls absorb the digested nutrients (via vili) into the bloodstream

• pH 8

Major Pancreatic Enzymes

• Trypsinogen: protease

• Lipase: breaks apart lipids into glycerol and fatty acids

• Amylase: breaks starch down into glucose

Liver and Gallblader

• gallbladder is located under the liver and on the right side of the abdomen– primary function is to store

and concentrate bile (yellow-brown liquid produced by the liver)

• bile aids in the digestion of fats and neutralizing the chyme leaving the stomach

Large Intestine

• waste products of the digestive process include undigested parts of food and older cells from the GI tract lining

• absorbs water and any remaining nutrients and changes the waste from liquid into stool

• rectum stores stool

Gastric Parasites

• Coccidiosis: acute invasion and destruction of intestinal mucosa by protozoa

• Clinical signs: diarrhea, fever, decreased appetite, weight loss, & emaciation

• Potential to be fatal

Coccidiosis

• Pathogenesis: ingestion of oocysts via feces

• Diagnostic: clinical signs and fecal sample

• Treatment: Sulfadimethoxine

• Canine or feline coccidia are not considered zoonotic agents

Gastric Parasites

• Giardia: intestinal infection caused by a protozoan parasite (“beaver fever”)

• Clinical signs: acute foul-smelling diarrhea, greenish tinge or bloody diarrhea, excess mucus in the feces, and vomiting gradual weight loss may become apparent

• Potential to be fatal

Giardia

• Pathogenesis: transmitted by eating or sniffing the cysts from contaminated ground, or by drinking contaminated water

• Diagnostics: clinical signs and fecal test

• Treatment: Metronidazole

• Zoonotic