ADSC 2010: Monogastric Digestive System

Monogastrics

simple stomached animals usually with an acid environment

• pigs, humans, dog, cat

Mouth

• Chewing- physical breakdown

• Salivation- adds moisture to food (H2O), lubricates (mucin), source of enzymes (amylase), bicarbonate salts (raises pH)

Esophagus

passageway for food from mouth to stomach

• squeezes food down (peristalsis)

Stomach

storage and digestion of food/muscle contractions cause physical breakdown

• HCl: lowers pH of stomach kills most of bacteria and activates enzymes

• pepsin: protein degradation

• rennin: coagulates milk protein

Chyme moves to small intestine

Small intestine

main point of digestion and absorption

• duodenum: first part

• jejunum: middle

• ileum: end section

Digests polypeptisde → amino acids, starch → monosaccharides, lipids → fatty acids

Gall bladder

secretes bile produced in the liver

Bile

encapsulates and degrades fats

Pancreas

secretes enzymes into the duodenum to breakdown macromolecules, also secretes insulin and glucagon

Large intestine

• cecum: blind end of the anterior large intestine

  • important in horses as a site of microbial digestion

  • microbes digest cellulose and produce volatile fatty acids (acetate, proprionate, butyrate)

• colon: major site of water absorption

• rectum: expels material out of the body

Functional cecum

enlarged cecum and large intestine ferments dietary fibers via microbes

• horses, rabbits (warzen sorts out indigestible fiber then sends it out the colon, eats cecotropes to absorb nutrients that they passed)

Produces VFAs, synthesis of B-vitamins