- intake of food via the mouth
- mechanically or chemically breaking down food into their subunits
- movement of nutrients across the GI tract wall to be delivered to cell via the blood
- Process of expelling substances from the body
- Discharge of feces from the rectum through the anus
- Specialized proteins
- mass of chewed food
- rhythmic wavelike contractions that propel substances along a tubular structure
epiglottis (S and F)
- - S: elastic cartilage
- F:covers the voice box to make sure food is routed into the esophagus.
Give the overall structure involved in the digestive system and its main functions.
- mouth- teeth chew food;
- tongue tastes and pushes food for chewing and swaloowing
- pharynx- passageway where food is swallowed
- esophagus- passageway where peristalsis pushes food to stomach
- stomach- secretes acid and digestive enzymes for protein, churns mixing food w/secretions
- small intestine- mixes chyme w/ digestive enzymes for final breakdown; absorbs nutrients molecules into body; secretes digestive hormones into blood
- large intestine- absorb water and salt to form fecescolon-eliminates toxins in the intestines, blood and lymph systems.
- rectum- stores and regulates elimination of feces
- anus- expells feces
List and describe the two types of digestion and the organs/substances involved in each.
- 1- mechanical - physical methods
- 2- chemical - requires enzymes
List and describe the 4 layers found in the organs and parts of the GI tract.
- 1- mucosa - innermost layer that produces mucus that protects the lining and also produces digestive enzymes
- 2- submucosa- 2nd layer of loose connective tissue that contains blood vessels, lymphatic vessels, and nerves
- 3- muscularis - 3rd layer made of 2 layers of smooth muscle that move food along the GI tract
- 4- serosa - outer lining that is part of the peritoneum (epithelial)
Which parts of the GI tract are mainly involved in digestion, absorption, and elimination?
- Digestion - mouth, pharynx, esophagus, stomach
- Absorption - small intestine
- Elimination - large intestine, colon/rectum, anus
Describe the things within the mouth and their role in digestion.
- 1- 3 pairs of salvary glands - begin carb digestion
- 2- tonsils -fight disease
- 3- teeth - mecanical breakdown of food
- 4- tongue - taste buds, assists in the mechanical breakdown and movement of food
List and describe the 2 phases of swallowing.
- 1- voluntary phase - from the mouth into the pharynx
- 2- involuntary phase - becomes a reflex
Pharynx ; S&F
- S: is a cavity between the mouth and esophagus
- F: that serves as a passageway for food (and air)
Esophogus ; S&F
- S: is a long, muscular tube
- F: carries food to the stomach
Stomach ; S&F
- S: J-shaped organ, thick muscular wall, wall and deep folds and gastric pits
- F: stores food (2-6 hours) ,Churns food – mechanical digestion,Secretes gastric juice (pepsin, HCl, mucus) – chemical digestion
Small Intestine ; S&F
- S:Long tube from stomach to large intestine,Averages 6m (18 ft) in length, Has ducts coming from pancreas, gallbladder, Hasvilli (finger like porjections of the intestine);
- F:Digestion (ezymes frompancreas and Bile from gall baldder) Absorbtion (villi)
Large Intestine ; S&F
- S: Includes the cecum (beginning), colon (allthe middle), rectum (ending) and anal canal, Larger in diameter but shorterthan the small intestine;
- F:Absorb water to prevent dehydration,Absorbsvitamins (B complex and K) produced by intestinal flora (good bacteria), Formsand rids the body of feces through the anus
Pancreas ; S&F
- S: Fished-shaped spongy exocrine gland behindthe stomach;
- F: digestion, buffers, sugar control
Gallbladder ; S&F
- S: small organ under the right lobe of the liver;
- F: store and release bile
Liver ; S&F
- S: Large organ that lies under the diaphragm andis made of 100,000 lobules;
- F: Filters blood, removes iron, vitamins, storesglucose as glycogen, makes plasma proteins, makes bile, breaks down hemoglobin
Explain how the S/V ratio is so large in the small intestine. Why is that important?
Absorption is slow, so the increased S/V ratio allows absorption of nutrients.
Be able to list the major facts associated with each of the following Disorders: (the information underlined in the power point)
- a. Gas swallowing air or during the breakdown process of certain foods by the bacteria that is present in the colon.
- b. lactose intolerance lack an enzyme that is called lactasec.
- c. ulcers Ulcers are holes in the GI tract; The mucous lining that normally protects the stomach from digestion must be compromised for an ulcer to developd.
- d. diarrhea watery stool, Caused by:Irritation of the intestine; Usually related to a bacterial or viral infectione.
- e. constipation Infrequent bowel movements due to hard, dry stool; Caused by:Lack of fiber.
- f. colorectal cancer Cancer of the colon or rectum; Colorectal cancer is the second leading cause of death by cancer in the U.S.A.; Caused by polyps – polyp growth directly related to diet and/or constipationg. g. stomach cancer Helicobacter pylori infection and a poor diet
- h. liver disorders i. jaundice When bile pigments leak to blood
- ii. hepatitis Infection of the liver, usually viral
- iii. cirrhosis Chronic disease of the liver