A&P233 Exam 3 Digestion

Inner lining with mucus glands, constantly turning over, new lining every 7 days.

• Pharynx & Rectum= stratified squamous epithelium no absorption here
• Stomach, Small In & Large In = simple columnar epithelium with goblet cells (mucus)absorption of nutrients, vitamins, and water here.

Dense irregular connective tissue with blood & lymph vessels, nerves, glands.

• 2 layers of smooth muscles causes mixing and peristalsis
• circular layer – inner
• longitudinal layer – outer

visceral peritoneum – tough outer covering, continuous with the mesentery.

the opposing or chewing surface of a tooth.

• buccal side– near the cheek
• lingual side – near the tongue
• labial side – near lips

• Incisor – cutting teeth
• Cuspids – canines – conical
• Bicuspids – premolars
• Molars- grinding teeth

The Medulla

is a hollow muscular tube with mucus glands, to the left and posterior of the trachea. Stratified squamous epithelium.

• Takes food from esophagus and liquefies it into chyme.
• Creates a pH of 2.0 to activatethe enzyme pepsin, which digests protein. Simple Columnar epithelium.

Lower esophageal sphincter doesn’t closecompletely and allows the return or reflux of stomach contents into the esophagus.

Opening in the diaphragm is too large and allows protrusion of the stomachthrough the diaphragm.

• 1. Parietal cells = HCl
• 2. Chief cells = pepsinogen
• 3. Goblet cells = are all over stomach surface, create a bicarbonate mucous to protect surface.
• 4. G cells – produce Gastin – hormone – (hormone goes by blood back to the stomach.) Gastin stimulates parietal cells to release more HCl, and stimulates gastric motility.

Enteroendocrine cells, ECL, are like Mast cells since they release histamine which also activatesthe parietal cells and cause the release of HCl.

Water and Alcohol ONLY!

Majority of digestion and absorption of all nutrients occurs here.Simple columnar epithelium absorbs all the products of digestion in the small intestine.

circular folds of mucosa or plicae that increase the absorptive surface area.

Brush Border Enzymes

• First short section after the stomach, only 1 ft long
• Pancreatic enzymes and gall bladder bile enter the duodenum.

• 1. Secretin – from duodenum, increases gall bladder’s release of bile
• increases pancreas’s release of bicarbonate
• decreases stomach’s motility
• 2. Cholecystokinin –CCK -from duodenum, increases gallbladder’s release bile
• increases pancreas’ release enzymes

• inferior and posterior to the stomach.
• 1. Bicarbonate ion, HCO-3 to neutralize stomach acid and activate pancreatic enzymes
• 2. Exocrine function- enzymes- Amylase, Trypsin, Chymotrypsin, LipasePancreas is responsible for digestion of all food items and has enzymes to breakdown each type offood, carbohydrates, proteins and fats.
• 3. Endocrine function- hormones –Isles of Langerhans - insulin and glucogon

• Cecum, appendix
• Ascending Colon
• Transverse Colon
• Descending Colon
• Sigmoid Colon
• Rectum
• Anus

• 1. Reabsorbs water from chyme
• 2. Absorb vitamins from resident bacteria, vitamin K,
• 3. Store waste temporarily, external sphincter, voluntary control

• 1. Cephalic phase- think, smell, taste food, the phase before it reaches the stomach
• 2. Gastric phase- Gastric release by stimulation
• 3. Intestinal phase-

• Gastrin – from stomach G cells, increases enzymes release and motility of stomach
• Secretin – from duodenum, increases gall bladder’s release of bileincreases pancreas’s release of sodium bicarbonatedecreases stomach’s motility
• Cholecystokinin – from duodenum, increases pancreas’ release enzymes and increases gallbladder’s release biledecreases stomach’s motility

inferior to the diaphragm, produces bile that is stored in the gall bladder.

stores bile made by liver. The cystic duct drains the gall bladder into the Common bile duct.

• 1. Detoxifies blood
• 2. Removes large proteins from the blood, plasma proteins, Red Blood Cells, big things.
• 3. Carbohydrate metabolism – stores excess glucose as glycogen
• 4. Lipid metabolism- makes materials cells need, phospholipids for cell membranes and makesthe HDL and LDL fats that circulate to the cells and eventually become fat storage.
• 5. Protein metabolism
• 6. Synthesis of Bile
• 7. Storage of Nutrients

• Albumin – acts as a protein buffer and maintains osmotic pressure in plasma
• Clotting factors –are required to stop bleeding and form a fibrin mesh or clot.
• Complement – work with macrophages (Non Specific) and antibodies (Specific) Defense Systems