Digestive System

Digestion:

• Chemical and mechanical breakdown of food so that it can be absorbed

Order of Digestion:Mouth

•Where digestion starts•Mechanical digestion: physical breakdown of food• Chemical digestion: chemical breakdown of food

•Contains salivary glands• Secrete saliva (spit)• Contains amylase• Enzyme that breaks down carbohydrates in mouth

• Dissolves food• Cleans mouth and teeth

Order of Digestion:Pharynx (Throat)

•Connects mouth to esophagus•Contains epiglottis• Flap of tissue covers windpipe when you swallow

Order of Digestion:Esophagus

•Straight tube from pharynx to stomach•Peristalsis: Wave-like muscle contraction that sends food through the digestive system

Order of Digestion:Stomach

•Peristalsis in the stomach breaks down food into chyme• Chyme: Mix of food and digestive juices• Digestive juices contain enzymes• Enzymes: chemicals that break down food more quickly

Order of Digestion:Stomach

•Absorbs a small amount of nutrients•Liquids pass quickly•Solids pass more slowly (a few hours)• Carbohydrates pass the quickest (1 hour)• Proteins pass at a medium rate• Fats pass the slowest (3-6 hours)

Order of Digestion:Movement in Small Intestine

•Mixing and peristalsis constantly occurring•Chyme takes 3-10 hours to pass through

Order of Digestion:Small Intestine

•Absorbs most of the nutrients from food•Intestinal villi: hair-like structures that increase the surface area •More surface area = more absorption•Area of your SI…. The size of a tennis court!

Order of Digestion:Large Intestine

•Diameter is larger than small intestine•Absorbs water and salt from chyme•Forms and stores feces•No digestive function•Secretes mucus (helps things sliiiiiiide)

Order of Digestion:Feces

•Undigested material• 75% = water, mucus, bacteria

•Color comes from bile•Odor comes from bacteria

Accessory Organs:Liver

•Just below the diaphragm•Maintains blood and sugar (carbohydrates) levels•Removes damaged red blood cells•Removes toxins• Drugs and alcohol

Accessory Organs:Liver

•Makes bile: yellowish liquid• Breaks down fats

Accessory Organs:Gall Bladder

•Stores bile between meals

Accessory Organs:Pancreas

•Makes pancreatic juice• Insulin: helps absorb carbohydrates• Pepsin: enzyme that breaks down proteins

Digestive Disorders

Ulcer

•80% cases caused by bacteria•Causes severe stomach pain•If a hole forms, person needs surgery

Cirrhosis

•Liver is damaged and no longer functions well•Liver damage caused by cirrhosis CANNOT be reversed•Caused by drugs, alcohol, and certain diseases (hepatitis)

Anorexia Nervosa

•Person starves them self because the person thinks they are overweight•Affects girls much more than boys•Can cause death

Bulimia

•Person eats A LOT, then throws it up•Can cause death

Obesity

•Caused by eating more than you need, lack of exercise, genetics, hormones•Cause MANY health problems•1 in 6 kids are obese