The Digestive SystemWalter J. Taylor

ResourcesDr. Kehoe, UWRF nutrition course

Images from: An Illustrated Guide to veterinary Medical Terminology 3rd Edition. Janet Amundson

Romich

The Mouth

• Secretes Salivary Amylase (ptyalin)– to breakdown starch, carbohydrates, and urea• into produce maltose and dextrins

• Secretes mucin– to lubricate food

Crop (birds)

• Secretes Mucus– To lubricate food

Rumen

• A chamber compartment of ruminant stomachs that host a viable environment to support microorganism growth– whose enzymes break down• Cellulose into VFAs (volatile fatty acids)• Polysaccharides and starches into microbial protein• Sugars, fats and proteins (urea) into B vitamins and

vitamin K

Stomach (abomasum in mammals and proventriculus in birds)

• Secretes Gastric juices and acids– Enzyme: Pepsin to breakdown proteins • Into proteoses and peptones

– Enzyme: Lipase to break down fats• Into fatty acids and glycerol

• Secretes Mucus– To lubricate food and coat the stomach wall

lining from Chief cells that secrete HCl

Gizzard (birds)

• Grinds foods into smaller pieces.• Birds consume small rocks that when in the

gizzard assist in breaking apart food as the gizzard’s muscles contract

Nursing Animals

• Secrete gastric juices– Enzyme: rennin to breakdown milk protein

(casein)• Into paracasein

Duodenum• Secretes pancreatic juices (from the Pancreas)– Trypsin and Chymotrypsin to breakdown proteins,

protesoses, peptones, and peptides• Into peptones, peptides, and amino acids

– Amylase to breakdown starch and dextrins• Into dextrins and maltose

– Lipase to breakdown fats• Into higher fatty acids and glycerol

– Carboxypeptidase to breakdown peptides• Into amino acids and peptides

• Secretes Bile (from the liver)– To break down fats into an Emulsion of fats

Small Intestine• Secretes intestinal juices– Enzyme: Peptidase (erepsin) to breakdown peptides;

into amino acids and dipeptides– Enzyme: Sucrase (invertase) to breakdown sucrose;

into glucose and fructose– Enzyme: Maltase to breakdown maltose; into glucose– Enzyme: Lactase to breakdown lactose; into glucose

and galactose– Enzyme: polynucleotidase to breakdown nucleic acid;

into mononucleotides

Large Intestine (cecum and colon)

• Enzyme: cellulase from microorganisms to breakdown cellulose; into VFA

Cat

Swine