Mechanical and Chemical breakdown of foods into forms that cell membranes can absorb
Functions of the Digestive System
Taking food into the mouth
Breakdown of big pieces of food into smaller pieces of the same food. It increases the surface area that amylase can work on.
enzyme initiates chemical digestion
Breakdown of the chemical components of food into smaller components that are absorbed and distributed throughout the body.
Muscular contractions move food down the AC
Removal of waste products
Chains of amino acids, around 20 total and we can synthesize around 11
3 fatty acids and 1 glycerol
Made up of monosacchrides (simple sugars)
Made up of neucleotides that link together in long chains to form DNA and RNA
Secrete saliva which contains amylase
Stores bile, introduces it into the small intestine
Produces and secretes pancreatic juice into the small intestine
Contains digestive juices and bicarbonate ions
At the back of the upper mouth, blocks off the flow of air throughout the nasal passages
Both Mechanical and Chemical digestion start here
Blocks off the openings into the respiratory system
Connects the mouth to the esophagus, keeps food from entering into the nasal passages
Hardest structures, 20 deciduous (baby) teeth, 32 permanent teeth, mastication
4 blade-shaped incisors, 4 pointed cuspids (canines), 4 bicuspids (premolars), 4 molars both top and bottom
breakdown of food using teeth
Taste buds are found here, aids in the rolling and mixing of food with saliva
Secretes saliva which begins digestion of carbs using amylase
Located under the back of the tongue, secretes primarily serous fluid and mucus
Located under each jaw/ear; secretes clear, watery, serous fluid; rich in amylase. Usually becomes infects with Mumps
Located below the tongue, secretes mucus
Thin-walled, collapsed tube that opens to let food pass to the stomach. Doesn't contribute to the Digestive system other than serving as a passageway. Food passes by gravity and peristalsis
J-shaped pouch that expands with the amount of food. It is located below the diaphragm. The stomach has sphincters that allow food to pass into/out of the stomach. Has circular, longitudinal, and oblique muscles that allow it to squeeze everyway. Very acidic. Doesn't absorb.
A thin, sheet-like, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity.
Cells that coat the stomach
M(en)-Mucous cells. M(en)-Mucous
C(an)-Chief cells. P(ass)-Pepsinogen
P(ass)-Parital cells. H(ot)-HCl
G(as)-G cells. G(as)-Gastrin
Cells coat the stomach and keeps it from being burned/eaten by acid
Pepsinogen is an inactive form of pepsin. It converts to pepsin when exposed to HCl
Secrete intrinsic factor
Secreted by the parietal cells, helps with Vitamin B12 absorption
Gastric Juice Release
Site of food.
Stretching of the stomach when food enters it.
Food in the small intestine triggers both the intestinal cells and the stomach wall to release GJ
Liquid food that has the consistency of pancake batter. Starts out acidic due to stomach acid
A tubular organ that extends from the pyloric sphincter to the LI. A few tbsp of chyme are released into the duodenum and a inches below that bile and pancreatic juice are released into it as well. All CD is finished here. It absorbs products of digestion and transports the remaining waste to the LI.
Short beginning of the SI
Yellow, greenish liquid that is constantly secreted by hepatic cells. It contains bile salts that emulsify fats and absorbs fatty acids, cholesterol, and fat soluble vitamins. Also contains bile pigments, cholesterol, and electrolytes. It is NOT an enzyme but it is an emulsifier of lipids
Makes amylase that breaks down carbs. Lipase that breaks down lipids. Trypsinogen, chymotrypsinogen, and carbozypeptidse that digests proteins. Nucleases that digest nucleic acids. PJ is very alkaline, makes the chyme basic. Must have the pancreas, due to digestive purposes.
Largest internal organ. It is located in the upper-right abdominal quadrant just beneath the diaphragm, off to the side of the stomach.
Makes bile, breaks down old RBC's and takes the hemoglobin and makes it into bile
What keeps the small intestine in place
Cecum-beginning of the LI, blind pouch.
Rectum-where waste is stored until the sphincters relax and all the waste to drop to the anal canal
NO absorption of digested end products, but it does absorb water which allows the waste to compact
Located where the small intestine and the large intestine meet
Functions of the LI
No digestive absorption, absorbs water and electrolytes, secretes mucus, forms feces, carries out defecation, houses intestinal flora-reduces B/K vitamins, antibiotics kill the B/K and it reduces the good colon bacteria. Supposed to eat yogurt and take pills to replenish the vitamins.
Waste materials that were not digested or absorbed. Contains water, electrolytes, mucus, bacteria, and bile pigments provide color. The odor is produced by bacteria including phenol, hydrogen sulfide, indole, skatole, ammonia
Movements of the LI
Similar to the movements of the SI, slower and less frequent, includes mixing movements and peristalsis. Mass movements usually follow meals.
Movements of the SI
It's long length, the plicae, the surface villi of the plicae, and the epilthelium of the villi all increase surface area.Iimportant due to secretion and absorption.