Stomach, Intestines and Accessory
Organs
Do Now
List the path of this morning’s breakfast through the Digestive Tract, from start to finish
Do Now
Mouth Pharynx Esophagus Stomach Small Intestines Large Intestines Rectum
What to Eat
Talk with your partner about the reading What did you like about the reading? Anything you did not like?
Style of writing? Confusing?
Prepare to respond
Review
STOMACH The diameter and volume of the stomach varies depending
on the amount of food it contains Can hold up to 1 gallon of food
When it is empty, it collapses inward and folds into “rugae” Main functions
“Storage tank” Food break down Minimal absorption
Stomach
Site of breakdown of proteins Contains deep gastric pits which house protein-
digesting enzymes What is an enzyme?
Cells produce Hydrochloric Acid creating a highly acidic nature in the stomach
Stomach maintains a pH of approx. 2.0 Very Acidic? Mildly Acidic? Mildly Basic? Very Basic?
pH Scale
Stomach
If the stomach is so acidic, why does it not eat away at itself? The Answer: Mucous
Ulcers are the result of gastric juice penetrating the lining of the stomach Caused by bacteria becoming present on the
stomach lining and prevents the secretion of mucous
Ulcers
Duodenum
First part of the small intestines Chyme enters duodenum by spurts from the
stomach Chyme?
Proteins and carbohydrates are now partially digested
Fats not yet started to become digested
Pancreas
Releases pancreatic juice into the small intestines
Neutralizes the acidic material from the stomach
Gallbladder
Located right below liver Stores bile Helps break down large fat molecules into
smaller particles Fat gets absorbed, the then the bile is also
reabsorbed back into the liver
Small Intestines
Digestion using enzymes Main site of absorption of nutrients Includes
Duodenum Jejunum Ileum
Don’t get punched in the jejunum… https://www.youtube.com/watch?v=oHulRDk__ko
Small Intestines
Approximately 3 meters long Numerous projections called villi that function
to increase surface area Total surface area of 500-600 square meters Why is increased surface area important?
Large Intestines
Also called the colon Colon cancer?
Receives approximately 10 liters of water per day 1.5 L from food 8.5 L is from secretions
Last major part of the digestive system Function is to remove water from indigestible food, and
then pass waste material from the body Takes approx. 16 hours to finish digestion
Large Intestines
Also absorbs sodium and other ions If water is not absorbed, diarrhea can result
Causes dehydration and ion loss
Polyps
Small growths in the lining of the colon (large intestines)
Cancerous (malignant) or benign Benign?
Low-fat, high-fiber diets are recommened to protect against colon cancer
Liver
Important in metabolism, glycogen storage and detoxification
Many vital functions Secretes bile Cannot live without a liver
Homework
Read 3/31 p. 470-474 Split page notes – ATLEAST 1 page
Top Related