Digestion Get that out of your mouth; you don’t know where that has been.
How this works. • What is happening inside as we eat this cookie? • Look for words in bold because there definitions are in the test. • Words in italic will be in the multiple choice. • Underlined words will be in a labeling diagram. We will mark on the overhead. • If a word is in bold, italicized, and underlined will be a health concern.
A tube within a tube. • Gastrointestinal Tract = Alimentary Canal. • Purpose – • Digestion. • Cookie will make 9 stops on its way towards Defecation. • Whole point of this process is for Intake: constant supply of energy and building blocks provided by food. • Can you identify the organs at the left?
Mouth = Oral Cavity • This is where the tube starts. • Teeth are used as tiny hammers to break down food. • Can you identify the teeth on the overhead? • Mastication? • Tongue is important for tasting, chewing, and swallowing. • Where are you tasting this cookie? • Salivary Glands send saliva to moisten food and help break it down further. • Enzymes in saliva help breakdown food. • Now swallow (Deglutition) the cookie. • As it is swallowed, it is only suppose to down 1 passage way: esophagus. 2 “appendages” help keep the cookie on its way: Uvula, which is that ‘hangy down thingy” at the back of your throat and the Epiglottis. • Halitosisis bad breath.
Esophagus • Esophagus is the slide that the bolus takes from the mouth to the stomach. • Before the bolus enters the stomach it must open a “door”: Cardiac Sphincter. • This is all that the esophagus does; nothing is released into the cookie and nothing is taken out. • Just a passage way.
Stomach • Bolus enters the Stomach, where it completely changes. • Gastric juices and liquid from the meal mix in with the solid mass of the cookie to make Chyme. • What are the folds in the stomach that increase surface area inside the stomach? • Stomach is where the main breakdown occurs and mixes everything that is inside together. • When the chyme is mixed, it must open another “door”: Pyloric Sphincter, which prevents food from entering the small intestine too soon. • Hiatal Hernia - Protrusion of the stomach through opening in the diaphragm • Gastrointestinal Ulcer - sores on the mucous membrane of any part of the GI tract
Small Intestine • Made up of 3 sections: Duodenum, Jejunum, and Ileum. • Duodenum is first part of the SI. It receives the bile from the liver (slide coming). Is about 10 in. long. • Jejunum is second part of SI. It is 8 ft. long. • Ileum is the last part of SI. Connects to the large intestine (next slide). • Enzymes also enter SI to continue the breakdown of protein, sugars, and fats. • This is where Absorption (passage of material through walls to blood) takes place. • Peristalsis is used to help move the food along the SI.
Large Intestine • Has 4 parts: Cecum, Colon, sigmoid colon, and Rectum. • Cecum is the first part of LI. It turns waste in feces. • Colon is the second part of LI. Horseshoe shaped and makes up the majority of the LI. • Sigmoid colon is the third part and is basically an extension to the last part of the LI. • Rectum is the last part of the LI. Attaches to the Anus, which is a fancy word for butt. • Waste hangs out here for 12 to 24 hrs. • It is about 5 ft. long, which is as long as me. • The cookie will then exit the system and will not even have any resemblance to that cookie. Here is where the tube ends. • Ulcerative Colitis - recurring ulcers and inflammation of the large intestine, Stress • Appendicitis - Inflammation of the appendix
Liver (accessory organ) • Food never passes through the liver, but it plays a role in digestion. • It is the largest gland and weighs about 3 lbs. • Gives Bile into the gallbladder (next slide). • Jaundice is a sign of liver trouble. • Cirrhosis is from chronic liver trouble.
Gallbladder (Accessory organ) • Has been storing bile from the liver; waiting to be used. • When needed, the gallbladder releases the bile into the duodenum. • Cholecystitis - Inflammation of the gallbladder • Gallstones: • Hard, pebble-like deposits that form inside the gallbladder • May be as small as a grain of sand or as large as a golf ball. • Can be made from cholesterol or too much bile. • Are more common in women, Native Americans and other ethnic groups, and people over 40. • They run in families.
Pancreas (Accessory Organ) • Helps secret enzymes into the SI. • Has exocrine and endocrine functions. • Exocrine glands differ from endocrine glands, because they have ducts that deliver the products in the superficial part of the body, such as the skin, or in the inner part where they are necessary, such as the pancreatic juice that is carried into the intestine to aid digestion.