mod- Bios 256 Final Exam Review Packet

A&P IV Final Exam Review Packet Ch. 24 DIGESTIVE PROCESSES 1. Ingestion 2. Digestion (mechanical and chemical) 3. Motility (mixing and propulsion) 4. Secretion 5. Absorption 6. Defecation GI TRACT AND ACCESSORY DIGESTIVE STRUCTURES GI TRACT INNERVATION • Autonomic NS o Parasympathetic NV (enhances digestion) o Sympathetic NV (inhibits or slows down digestion) • Enteric Nervous System o Submucosal plexus o Myenteric plexus ENZYMES originating in the oral cavity Salivary glands Parotid glands (under the cheek bones) Submandibular glands (under the mandible) Sublingual glands (under the tongue) • All secrete SALIVA, which contains: o Mostly water o Ions o Buffers o Lysosyme o Salivary amylase Salivary Amylase (made by the salivary glands) - Break down carbohydrates - Converts Polysaccharides to monosaccharides, maltose, maltotriose and alpha-dextrins - Deactivated by stomach acid Lingual Lipase (made by the lingual glands of the tongue) - From lingual glands of the tongue - Break down lipids - Activated by HCl of stomach - Converts triglycerides to fatty acids and monoglycerides THE SIGNIFICANT CELLS OF THE STOMACH AND THEIR SECRETIONS (GASTRIC JUICE) Parietal Cells - Secrete HCl - makes the chyme acidic - kills bacteria - denaturing (unfolding) proteins - activates pepsin along with lingual lipase. - Secrete intrinsic factor, which allows for absorption of vitamin B12 Chief Cells - The major stomach cells - Secrete pepsinogen, which is activated (by stomach acid) and becomes pepsin, a peptidase - Pepsin breaks down proteins - Secrete gastric lipase - breaks down triglycerides into monoglycerides and fatty acids G Cells ............................................continued............................................................