Also called GI (gastrointestinal) tract because of the importance of the stomach and intestines
Digestive tract is __ feet long(in adult male)
(every part lined with mucus membrane)
Organs of the digestive tract
3.Esophagus (diaphragm closes around)
Accessory Organs of the Digestive System
3.Gall Bladder (tucked up underneath the liver)
4.Pancreas (epigastric area of abdomen)
Walls of the Digestive Tract
1.Mucous membrane lining
2.Connective Tissue Layer
3.Smooth muscle layer with two types of muscle action
a.local muscle contractions for mixing
b.peristalsis: wave-like muscle contractions that move "food" along the tract
4.outer layer of connective tissue
5.below diaphragm, the outer layer is instead the peritoneum, a 2 layered serous membrane covering over the organs of the abdominal and some of the organs of the pelvic cavity and lining the abdominal/pelvic cavities themselves.
Sections of the peritoneum anchor various organs in place
A double layered portion of the peritoneum shaped like a fan.
Attached to the posterior abdominal wall, and the expanded long edge is attached to the small intestine
The section of the peritoneum that extends from the colon to the posterior abdominal wall.
A large double layer of the peritoneum containing much fat hangs like an apron over the front of the intestines.Extends from the lower border of the stomach into the pelvic cavity and then loops back up to the transverse colon.
Smaller than the greater omentum, extends between the stomach and the liver
Functions of the Digestive Tract
1.Ingestion: process where "food" is taken into the mouth, chewed (mastication), and swallowed (deglutition)
2.Digestion: process where "food" is mechanically broken down and chemically split into different smaller substances
Proteins become amino acids
CHO become simple sugars
Fats become fatty acids and glycerol
3.Absorption: process where nutrients pass into the bloodstream (much of the fat in the form of fatty acids and glycerol goes into the lymph then into the bloodstream)
4.Elimination: process where undigested and unabsorbed "food" leaves the digestive tract by the process of defecation
Parts of the Mouth
b.taste buds: sweet, salty/both in front of tongue, sour/sides, bitter/back, umami(pungent or savory)
4.Gingival tissue (gums)
Anatomy of the tooth
There are _____temporary teeth and ___permanent teeth.
20 & 32
1.central incisors:2 on top and 2 on bottom
2. lateral incisors:2 on top and 2 on bottom
3. canines: 2 on top , 2 on bottom
4.premolars:4 on top and 4 on bottom
5.molars: 6 on top, 6 on bottom (last set of molars called wisdom teeth)
produce saliva with enzymes to digest starch, food is moistened into a bolus for swallowing.
Parotid glands/below & in front of ears
Submandibular glands/underneath the mandible
Sublingual glands/under tongue
in the oropharynx swallowing happens; this means a bolus of food is moved into the esophagus
Piece of tissue hanging down (punching bag) assists with swallowing. Keeps things from going up into the nose when swallowing. A piece of tissue with some cartilage. No ducts or secretions.
Esophagus is_______to the trachea
A defect in the wall of the diaphragm where the esophagus goes through. Too much space around esophagus
LES (lower esophageal sphincter)
Want it to stay closed normally until food gets to it.
hydrochloric acid goes up into esophagus causing burning sensation near the heart
J shaped/hot dog shaped. Very muscular storage pouch, want food to stay in it for 2-4 hours
Water, some meds & alcohol absorbed into the stomach
Hydrochloric Acid (HCI)
very strong, kills microorganisms, breaks down connective tissue in meats
impacts on B12/ many people make less with age so can end up with B12 deficiency
help make food more slippery, to break down foods into fatty acids, amino acids & glucose
folds from empty stomach shrinking.Nerve receptors under rugae only feel then when stomach is full and rugae are stretched
keeps food in stomach, opens a little and lets in about one tsp full of food into the small intestines
"Dumping syndrome" stomach emptying too much food into small intestines
The most absorption happens here as well as majority of digestion/cells have secretions that contain enzymes