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 tissueAlcoholismHepatitis 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 rateDomino effect from other systems (i.e.
dental health or dietary change)
AGING & THE DIGESTIVE SYSTEM