 Pancreas  Exocrine function: secretes pancreatic juice into small intestines  Pancreatic juice includes buffers to increase pH of chyme  Pancreatic enzymes  Lipase  Amylase  Proteases  Liver  Reddish-brown, ~3.3lb  4 lobes: left, right, caudate, quadrate  Hepatocytes: liver cells that secrete bile into the common bile duct (duodenum) or the cystic duct (gallbladder)  Gallbladder  pear-shaped organ; functions in storage of concentrated bile ACCESSORY ORGANS (PANCREAS, LIVER, & GALLBLADDER)

 Metabolic regulation: monitor levels of nutrients in blood from digestive tract  Hematological regulation: removes aged and damaged RBCs, debris and pathogens from circulation  Bile production: bile salts emulsify lipids into small droplets for absorption FUNCTION OF THE LIVER

 Cirrhosis: fibrous (scar) tissue replaces healthy tissue  Alcoholism  Hepatitis A & C : viral infections  Symptoms: jaundice, liver failure, etc… CLINICAL NOTE: LIVER DISEASE

 Horse-shoe shaped, from end of ileum to anus (~5ft)  Functions:  Water absorption  Vitamin absorption  Compaction and storage of feces  3 sections  Cecum: compaction; attached to appendix  Colon: 4 segments (ascending, transverse, descending, sigmoid)  Rectum: temporary storage of feces  Internal anal sphincter (involuntary)  External anal sphincter (voluntary) THE LARGE INTESTINE

 Polyps form in colon and become malignant  Second most common form of cancer  Prevention and early detection can save your life!! CLINICAL NOTE: COLON CANCER

 Carbohydrates: salivary amylase begins breakdown; continued by pancreatic amylase in small intestine; form simple sugars which are transported into the bloodstream via the liver.  Lipids: triglyceride emulsified into small droplets; bile salts from micelles which are then transported into the bloodstream  Protein: HCl and digestive enzymes (proteases) break proteins into single amino acids which are absorbed into the bloodstream DIGESTION AND ABSORPTION

 Inability to breakdown lactose (lipid in milk)  At adolescence, lactase production can decrease/stop  Causes digestive problems  Possible treatments: probiotics CLINICAL NOTE: LACTOSE INTOLERANCE

 Water & Electrolytes: water flows from high to low [C] of water; easily moves into surrounding tissues to maintain osmotic equilibrium  Vitamins: fat-soluble (A,D, E and K) absorbed in micelles; water-soluble (B vitamins and vitamin C) are easily absorbed by epithelium (vitamin B12 needs intrinsic factor) DIGESTION AND ABSORPTION

 Epithelium becomes thinner as division rate of stem cells decreases  Smooth muscle tone decreases making contractions weaker  Cumulative damage from exposure to toxins, etc… (i.e. liver disease, tooth decay)  Increase in cancer rate  Domino effect from other systems (i.e. dental health or dietary change) AGING & THE DIGESTIVE SYSTEM

 Chapter Objectives 1-5 (p. 515)  Vocabulary: mucosa; submucosa; muscularis externa; serosa; peristalsis  Due: Wednesday, 4/10  Chapter Objectives 6-11  Due: Monday, 4/15  Chapter 16 Test: Monday, 4/15 HOMEWORK