Digestive System Notes Quiz Friday!

4 main functions: 1. Ingestion—food material taken into mouth 2. Digestion—food is broken down, mechanically and chemically, as it travels through the gastrointestinal tract. Digestive enzymes aid the breakdown of complex nutrients. Proteins → amino acids Sugars → glucose Fats → fatty acids or triglycerides

3. Absorption 4. Elimination *The body eliminates solid waste materials that cannot be absorbed into bloodstream. *The large intestine concentrates feces. *The wastes pass out of the body through the anus. Digested food passes into the bloodstream through lining cells of the small intestine. Nutrients travel to all cells of the body. Cells burn nutrients to release the energy stored in food.

Small Intestine Villi in the lining of the small intestine help absorb nutrients into the bloodstream. What is the function of the villi? Microscopic projections in the wall of the small intestine that absorb nutrients into the bloodstream

Epiglottis- Flap leading to two tubes. The esophagus & Trachea The pharynx is the common passageway for both air and food. What potential problems do you see with this arrangement? How does the body address this problem?

The Digestive Tract Diagram on Quiz- With Word Bank Have the students check their answers. What is the name of the pigment produced from the breakdown of hemoglobin during red blood cell destruction? The Digestive Tract

Parts of the Stomach Food travels through the digestive tract by peristalsis (wave like movements) The esophagus is a 9- or 10-inch muscular tube that extends from the pharynx to the stomach. How does the esophagus move the bolus toward the stomach? peristalsis Rugae=Ridges on the hard palate and the wall of the stomach pyloric sphincter=Ring of muscle at the end of the stomach, near the duodenum; opens when a wave of peristalsis passes over it Sphincter=Circular ring of muscle that constricts a passage or closes a natural opening

Stomach Continued What is the function of a sphincter? Opens to allow for food to travel through when peristalsis passes by.

Parts of the small intestine: Extends from Ilium to anus Function: Major digestive organ. Usable food is prepared for journey into cells of the body. Length? 6-13 feet long 3 parts: D-J-I Duodenum (10 inches) Jejunum (8 feet) Ileum (12 feet)- joins the large intestines

Large Intestines (AKA colon) Function: Receives fluid waste from digestion and stores until it can be released form the body. Size? Larger in width then small intestines, but shorter in length (5 feet) Made up of? Ascending, Transverse & Descending, Sigmoid colon and Anus. Subdivisions of L.I.? Cecum, appendix, colon, rectum and anal canal.

Large Intestines Continued Function of appendix? No real function, not needed!

Function Pancreas? Converts food into fuel & helps assist in regulating blood sugar. Function of Gall Bladder? Store & concentrates bile (help in breakdown of fats & food) What is emulsification? Physical process of breaking up large fat globules into smaller globules

Functions of the Liver… Besides producing bile, the liver also… Helps maintain normal blood glucose levels Manufactures blood proteins necessary for clotting Releases bilirubin, a pigment in bile Removes toxins and poisons from the blood How does the liver maintain blood glucose levels?

Food Pathway through the GI Tract Food enters through the oral cavity and exits through the anus

Abnormal Conditions Hernia – protrusion of an organ or part through the muscle normally containing it

Abnormal Conditions Continued Anal fistula – abnormal tube-like passageway near the anus Colonic polyposis – polyps (out pouching) protrude from the mucous membrane of the colon Diverticulosis – abnormal side pockets (outpouchings) in the intestinal wall

Abnormal Conditions Continued Dysentery – painful, inflamed intestines Hemorrhoids – swollen, twisted, varicose veins in the rectal region Cirrhosis – chronic degenerative disease of the liver Viral hepatitis – inflammation of the liver caused by a virus Cholelithiasis – gallstones in the gallbladder