DIGESTIVE SYSTEM

Objectives

• Describe digestion• Identify and explain the function of each organ of the system

• Explain preventative measures for digestive disorders

• Describe problems associated with the system

Functions of Digestive System• Digestion-mechanical and chemical breakdown of foods by the body’s cells

• Absorption-passage of digested food from digestive tract to the circulatory system

• Elimination-expulsion of undigested food or body waste

Structure of SystemMESSLA

• Mouth• Esophagus• Stomach• Small Intestine• Large Intestine• Anus• Organs that help-liver , gall bladder, pancreas

Mouth

• Ingestion: Taking of

food into the body•Structures are:

•Teeth: Break down food•Mastication: Process of chewing

•Salivary Glands: Saliva breaks down food, makes it easier to swallow

•Tongue: Prepares food to swallow

Esophagus

•Muscular tube extending from mouth to the stomach

•Peristalsis: Series of involuntary muscular contractions

Stomach

• Hollow, saclike organ enclosed in a muscular wall (3 layers of muscles)

• Function of the stomach is: • Continue to breakdown food

• Store food until it’s ready to enter small intestine

Stomach

• Control rate at which food enters small intestine

• Mix food and gastric juices (contain pepsin and hydrochloric acid) • Chyme: creamy fluid mix of food and gastric juices

Small Intestine

• Major part of digestion and absorption occur here

• 20-23 feet in length, 1 inch in diameter• Chyme enters small intestine and peristalsis moves it at a slow rate (3-5 hours)

• Villi: Fingerlike projections (Increase surface area) • Absorb digested food particles • Undigested food leaves as liquid and fiber

Large Intestine (Colon)

•Absorbs water and

eliminates undigested

food•5-6 feet in length,

2 ½ inches in diameter•Bacteria changes undigested food into feces

• Pancreas – produces the hormone insulin that regulates blood sugar levels

• -- also help neutralize stomach acid

• Liver – produces bile, which breaks down fats in foods

• Gallbladder – pouch-like

organ that stores bile for

future use

Digestive System Crash Course

https://www.youtube.com/watch?v=s06XzaKqELk

Care and Problems with the System• http://videos.howstuffworks.com/discovery-health/14062-b

ody-invaders-digestive-problems-video.htm

Problems with SystemFunctional Problems

• Indigestion• Heartburn• Gas• Nausea• Diarrhea• Constipation

Problems with SystemStructural Digestive problems• Gallstones-crystals that form in gall bladder.• Appendicitis-inflammation of appendix• Gastritis-inflammation of mucous membranes that line stomach

• Lactose Intolerance-inability to digest lactose• Peptic Ulcer-sore in lining of tract• Colitis-inflammation of colon• Hemorrhoids-swollen veins in lower rectum/anus• Tooth Decay

Care of the System

• Eat a variety of foods.• Avoid too many fatty foods• Choose foods low in fat and high in fiber• Do not hurry through meals• Do not wash food down with liquid• Drink plenty of water

1) Digestive System Worksheet

2) Choose one of the following and find a current event article:

• Celiac Disease• Diabetes• Crohn’s Disease• Peptic Ulcer• Diverticulitis

Fiber• Do you get yours?

http://kidshealth.org/teen/food_fitness/nutrition/fiber.html