Transcript Document
• • • Single stomach Eat feed low in fiber Humans are also non-ruminants
• • • • • 1. Mouth 2. Esophagus 3. Stomach 4. Small Intestine 5. Large Intestine
• • • • Breaks down feedstuffs into …..
simple chemical parts…..
so the pig can absorb…..
and utilize them .
• • Breaks down feed stuffs by chewing Adds saliva to help in digestion
• Muscles contract to move the food down to the stomach
• Adds digestive juices to break down food
The small intestine….
• • Mixes secretions Absorbs nutrients
• • • Storage and formation of feces Absorption of water Secretion and reabsorption of electrolytes
Non-ruminant
• • • • Abomasum- true stomach depends on digestive enzymes pepsin, rennin, trypsin, chymotrypsin, HCL Needs – energy (fat and CHO), protein (a.a.), minerals (Ca:P 1.2:1 to 1.5:1), vitamins, water, antibiotics and other additives
Swine Gastrointestinal Physiology
11/04
Digestive secretions: saliva
• • Functions of saliva in non-ruminants: – Lubricates food to facilitate swallowing – Contains antibodies and lysozyme – Some amylase in saliva of swine and rats, but much less than in humans Functions of saliva in ruminants: – Maintains fluid consistency of rumen – Slightly alkaline; helps neutralize acids formed by fermentation – May help prevent frothing in rumen
Gastric pits in gastric mucosa • Gastric pits are openings to ducts into which gastric glands empty their secretions
Exocrine gland
• Any gland that directs its secretions through a duct into a compartment that is contiguous with the exterior of the body
Pyloric Cardiac Glandular regions of simple stomach Fundic
Glandular regions of equine, porcine and ruminant stomachs • • Cardiac, fundic and pyloric gland regions are glandular Esophageal regions (“E”) are non glandular epithelium
Pyloric Cardiac Cardiac gland region (cardiac mucosa) Fundic
Pyloric Cardiac Fundic Fundic gland region • • • Mucous neck cells Parietal cells Chief cells
Fundic gland region • • Mucous neck cells secrete mucus Parietal cells secrete: – HCl – Intrinsic factor (not in cats); necessary for absorption of Vitamin B12
Fundic gland region • Chief cells secrete pepsinogen – HCl converts pepsinogen into pepsin – Pepsin is a proteolytic enzyme (breaks down proteins into peptides)
Cardiac Pyloric Fundic Pyloric gland region • • Mucous secreting cells G cells
Pyloric gland region • • G cells are endocrine gland cells – secrete the endocrine hormone, gastrin Endocrine cells secrete hormones into the bloodstream – travel to a distant part of the body where they produce an effect on another cell type
Gastrin may interact with either receptor Substances that stimulate HCl secretion by parietal cell • • • Gastrin Acetylcholine Histamine – Histamine secreted by ECL cells in gastric mucosa
Rennin
• Enzyme secreted by abomasal mucosa of young ruminant – Acts to coagulate milk protein, which facilitates its digestion
Site of secretion
Hormone secretions of small intestine: cholecystokinin
Stimuli for secretion Actions Primarily duodenal mucosa Chyme with a: •High amino acid concentration •High fatty acid concentration •Low pH •Inhibits gastric emptying •↑ secretion of pancreatic enzymes and HCO 3 •Stimulates gall bladder contractions
Hormone secretions of the small intestine: secretin
Site of secretion Stimuli for Actions secretion Duodenal mucosa Chyme with a: •Low pH •High fatty acid concentration •↓ HCl production in stomach •↑ pancreatic HCO 3 secretion •↑ biliary HCO 3 secretion
Exocrine pancreatic secretions
• • • Liquid rich in HCO 3 Pancreatic digestive enzymes Both are secreted into duodenum
Pancreatic digestive enzymes
• Pancreatic proteolytic enzymes (pancreatic proteases) are secreted as proenzymes (zymogens)
Proelastase Elastase Activation of pancreatic proteases in small intestine • CCK stimulates duodenal mucosal cells to produce enteropeptidase