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, Lingual, and Labial sides of Teeth.
buccal side– near the cheek
lingual side – near the tongue
labial side – near lips
Types of Teeth
Incisor – cutting teeth
Cuspids – canines – conical
Bicuspids – premolars
Molars- grinding teeth
Where is the swallowing Center
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.
(gastro-esophageal reflux disease)
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.
Special cells of the Stomach (4)
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.
What is absorbed in the stomach?
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.
Microvilli contain these enzymes to aid in digestion
Brush Border Enzymes
First short section after the stomach, only 1 ft long
Pancreatic enzymes and gall bladder bile enter the duodenum.
Duodenum also releases several hormones to coordinate digestion.
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
The Large Intestine does what?
1. Reabsorbs water from chyme
2. Absorb vitamins from resident bacteria, vitamin K,
3. Store waste temporarily, external sphincter, voluntary control
Neural Mechanisms controlling digestion-
1. Cephalic phase- think, smell, taste food, the phase before it reaches the stomach
2. Gastric phase- Gastric release by stimulation
3. Intestinal phase-
Hormonal Control – hormones that are released in the presence of chyme or food
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.
Liver’s Functions (7)
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
The liver makes important plasma proteins – such as:
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